Palouse Cooperative River Basin Study - Steep III (Solutions To ...

Chapter Contents PageVTable of ContentsRESPONSES TO CONSERVATION PRACTICES (Cont’d.)Major Applicable Rotations ..................................................................................................... 85Less Than 12” Precipitation Zone ........................................................................................ 85Wheat-Fallow12”-15” Precipitation Zone .................................................................................................... 89Annual GrainWheat-Barley-FallowWheat-Fallow15”-18” Precipitation Zone .................................................................................................... 97Annual GrainWheat-Barley-PeasWheat-Barley-FallowWheat-PeasWheat-FallowMore Than 18” Precipitation Zone ..................................................................................... 109Wheat-Peas-AlfalfaAnnual GrainWheat-Barley-PeasWheat-PeasPractice Description ..................................................................................................................119Minimum Tillage .................................................................................................................. 120Stubble Mulch ....................................................................................................................... 121Field Strips ............................................................................................................................. 122Divided Slope Farming ....................................................................................................... 123Terraces ... 124Retirement from Cultivation .............................................................................................. 125No-Till Farming .................................................................................................................... 126Grass Waterways .................................................................................................................. 127VI RESOURCE EVALUATION ...................................................................................................... 131Effects of Conservation Treatment ......................................................................................... 13212”-15” Precipitation Zone ................................................................................................. 132Alternatives Analysis and Comparisons .......................................................................... 134Present or Future Without Alternative ............................................................................. 134The Second Alternative ........................................................................................................ 134The Third Alternative ........................................................................................................... 134Alternative Four .................................................................................................................... 134Effects of Conservation Treatment .......................................................................................... 13815”-18” Precipitation Zone .................................................................................................. 138Alternatives Analysis and Comparisons ........................................................................... 140Alternative I ........................................................................................................................... 140Alternative II .......................................................................................................................... 140Alternative III ........................................................................................................................ 140Alternative IV ........................................................................................................................ 140Effects of Conservation Treatment .......................................................................................... 144Over 18” Precipitation Zone ................................................................................................ 144Alternative Analysis and Comparisons ............................................................................. 147Alternative I ........................................................................................................................... 147Alternative II .......................................................................................................................... 147Alternative III ........................................................................................................................ 147Alternative IV ........................................................................................................................ 147No-Till Analysis ......................................................................................................................... 151Conclusions 151Implementation ......................................................................................................................... 151iii

Table of ContentsChapter Contents PageVII THE IDAHO PALOUSE .............................................................................................................. 155Cropland ......... 157Forest Lands ... 157Management .............................................................................................................................. 159Vegetative Cover ....................................................................................................................... 159Stream Channel Stability .......................................................................................................... 160Climate ........ 163Water Yield . 164Flooding ...... 166Erosion ........ 167Sediment ..... 168Bedload Component of Gross Sediment ................................................................................ 169Water Quality ............................................................................................................................ 173VIII AGENCY ACTIVITIES ............................................................................................................... 185Soil Conservation Service ....................................................................................................... 185Small Watershed Projects ..................................................................................................... 185RC&D Potential for the Basin .............................................................................................. 185Conservation Districts ............................................................................................................. 185Department of Ecology—State of Washington ................................................................... 186Washington State Conservation Commission .................................................................... 186Forest Service ............................................................................................................................ 187Department of Lands—State of Idaho ................................................................................. 187Economics, Statistics, and Cooperatives Service ............................................................... 187The Cooperative Extension Service ...................................................................................... 187Agricultural Stabilization & Conservation Service ........................................................... 188Agricultural Research Service ............................................................................................... 188Farmers Home Administration .............................................................................................. 188University of Idaho .................................................................................................................. 189Washington State University ................................................................................................. 189IX BIBLIOGRAPHY .......................................................................................................................... 193X GLOSSARY .... 203XI APPENDIX ..... 213Study Methodology ................................................................................................................. 213Literature Search ................................................................................................................... 213Evaluation Area Selection—Cropland ............................................................................... 213U.S.L.E. Computer Analysis—Cropland ........................................................................... 214Economic Computer Analysis ............................................................................................ 217Linear Program—U.S.L.E. and Economics ....................................................................... 217Evaluation Areas—Rangeland ........................................................................................... 218Evaluation Areas—Forest Land .......................................................................................... 218Evaluation—Wildlife Habitat .............................................................................................. 219Habitat Values ....................................................................................................................... 226Alternative I ....................................................................................................................... 226Alternative II ..................................................................................................................... 226Alternative III .................................................................................................................... 227Evaluation—Sediment Delivery Rates .............................................................................. 228Data Expansion Procedures ................................................................................................. 228iv

Table of ContentsTable No. Tables PageCHAPTER III1 Water Yield by Subwatershed .................................................................................................... 122 Total Agricultural Produce Sales ............................................................................................... 273 Cropland Use—1974 ................................................................................................................... 284 Annual Farm Sales Comparison ............................................................................................... 295 Wildlife Habitat Condition by Present Land Use ................................................................... 346 Game Harvest by Species, Whitman County, Washington ................................................... 36CHAPTER IV7 Cropland and Erosion Distribution .......................................................................................... 498 Projected Average Annual Soil Loss Rates by Soil Association ............................................ 599 Soil Losses Due to Stream Channel Erosion ............................................................................ 5710 Estimated Average Annual Sediment Yield ............................................................................ 6211Average Annual Sediment Yields, Deposits, and Sediment Leaving Basin ........................ 63CHAPTER V12 Predicted Average Annual Soil Losses by Crop Rotation by Precipitation Zone .............. 8213 Effectiveness of Conservation Practices by Precipitation Zone ........................................... 83CHAPTER VI14 Effect of Conservation Treatment—Low Precipitation Zone ............................................. 13315 Palouse Display of Effects of Alternatives and Comparisons to Future Without ........... 13616 Effect of Conservation Treatment—Intermediate Precipitation Zone .............................. 13917 Palouse Display of Effects of Alternatives and Comparisons to Future Without ........... 14218 Effect of Conservation Treatment—High Precipitation Zone ............................................ 14519 Palouse Display of Effects of Alternatives and Comparisons to Future Without ........... 14820 Effect of Various Levels of Erosion Reduction—Cropland ................................................ 150CHAPTER VII21 Total Annual Soil Erosion, Palouse River Basin—Idaho ..................................................... 15522 Total Sediment Delivery, Palouse River Basin—Idaho ....................................................... 15523 Average Annual Soil Erosion from Cropland by Soil Association .................................... 15724 Gross Erosion and Sediment by Forest Land Use ................................................................ 15825 Landownership—Idaho Palouse Forest Land ...................................................................... 15926 Channel Erosion and Sediment Rates by Stability Class .................................................... 16027 Average Air Temperatures ....................................................................................................... 16328 Annual Palouse River Basin Precipitation—Idaho Forests ................................................ 16329 Mean Annual Erosion--Forest Lands, Idaho ......................................................................... 16730 Gross Sediment Delivery—Idaho Forest Area ..................................................................... 16831 Mean Annual Data—Idaho Forest ......................................................................................... 16832 General Description—Past Land Use and Cover Within Erosion Map Units ................. 16933 Water Quality Data ................................................................................................................... 17334 Comparative Water Quality Analysis .................................................................................... 174CHAPTER XI35 Crop Rotations and Conservation Practices ......................................................................... 21536 Soil Loss Summary Table Per Evaluation Area .................................................................... 21637 Vegetation Abundance and Habitat Value for the Palouse River Basin ........................... 22038 Habitat Management Values ................................................................................................... 22139 Water Availability Values ........................................................................................................ 22440 Habitat Values ........................................................................................................................... 225v

Table of ContentsFigureNo.Page1 Average Monthly Streamflow ........................................................................................................ 152 Land Use—Palouse River Basin .................................................................................................... 233 Downward Trend in Pheasant and Hungarian Partridge Populationin the Cotton Plot ....................................................................................................................... 334 Annual Sheet and Rill Erosion ....................................................................................................... 445 Profile of Typical Palouse Hill ....................................................................................................... 496 Average Annual Soil Loss—Cropland .......................................................................................... 527 Predicted Sediment Yield by Watershed fromExisting Land Management Systems ....................................................................................... 648 Water Sample Recordings in JTU’s ............................................................................................... 659 Nitrate and Nitrite Recording ........................................................................................................ 7010 Winter Wheat Production Loss From Erosion ............................................................................. 7211 Palouse Implementation Proposal—Annual Costs .................................................................. 15212 Forest Land, North Fork of Palouse River—Runoff Relation to Elevation ........................... 16413 Estimated Water Yield Increase ................................................................................................... 16414 Average Discharge—Palouse River, Potlatch, Idaho ................................................................ 16515 Total Monthly Discharge—Palouse River, Potlatch, Idaho ..................................................... 166A-1 Major Soils in the Palouse—Athena Association ...................................................................... 214Table of ContentsMapsPageGeneralized Geology ......................................................................................................................... 9Watersheds ........ 13Soil Association 19Precipitation ..... 21Land Use .......... 25Historic Erosion Damage, 1939-1972 ............................................................................................ 45Erosion Damage on Cropland ....................................................................................................... 47Sediment Yield . 67Forest Land, Stream Stability, Erosion and Sedimentation ..................................................... 161Forest Land, Erosion and Sediment Yields ................................................................................ 171vi

PREFACE

PrefaceThis report assesses impacts of soil erosionon land and water quality. Physical, economic,and social impacts of sediment reduction areevaluated.The major study thrust is to provide basicdata needed to develop sediment reductionplans and to implement Section 208 of PublicLaw 92-500. The study is oriented to the agriculturalelements of non-point sources of sedimentsand other pollutants. Range and forest areas areevaluated and discussed in less detail becausesoil losses on these lands are much less significant.Basin forests are located primarily in theState of Idaho. Therefore, forestry data on theIdaho-Palouse is shown in a separate chapter tobetter meet Idaho’s water quality data needs.The United States Department of Agricultureagreed to participate with the State of Washingtonin this special study in 1975. The study isunder authority and provisions of Section 6 ofthe Watershed Protection and Flood PreventionAct (Public Law 566, 83rd Congress 68 Stat. 666,as amended). Cooperating in the study were theU.S. Soil Conservation Service (SCS), U.S. ForestService (FS), the Economics, Statistics andCooperatives Service (ESCS), and the Departmentof Ecology (DOE) representing the State ofWashington.The following summary provides a briefoverview of report findings.ix

SummaryThe Palouse River Basin Study has shown thatsoil erosion is a continuous and serious problemon non-irrigated cropland areas in eastern Washington.The study has shown that the problemcan be solved. It has also shown what kinds ofconservation practices can be most effective insolving the problems and what economic andother impacts will result from their application.Study results show that:• over 90 percent of the basin’s erosion resultsfrom sheet and rill erosion on crop land• 360 tons of soil has been lost from everycropland acre in the basin since 1939• it is projected that the basin will continue tolose 17 million tons of soil, an average of 14tons per acre per year, from all cropland areas• average annual soil erosion rates from thecentral portion of the basin are 20 tons peracre• annual erosion rates in the western (12-15”precipitation zone) and eastern (over 18”precipitation zone) average over 12 tonsper acre• present average wheat yields of 50 bushelsper acre could be an estimated 20 percenthigher if erosion in past years had beencontrolled• all of the original topsoil has been lost from10 percent of the land• 3 million tons of sediment is carried out ofthe basin in and with runoff water each year• over 50 percent of the erosion in the basincomes from the steeper land which accountsfor only 25 percent of the cropland summerfallow is a major cause of soil erosion• minimum tillage can reduce erosion ratesby 35 percent• field strip-cropping can reduce erosion by15 to 28 percent• terraces can reduce erosion rates by 8 to3 percent• erosion rates can be reduced by 40 to 60percent without adversely affecting farmincome, additional reduction becomes increasinglycostly• erosion can be reduced by as much as 80percent but at a cost of $29 million• retirement of steep, highly erosive croplandareas to grass can significantly improvewildlife habitat and increase wildlifepopulations.Since the basin was first farmed in the late1800’s, soil erosion resulting from runoff waterhas been a continuous and increasing problem,Most of the precipitation, both rain and snow,occurs during winter months. Most erosionoccurs in the winter and spring. Amounts oferosion are influenced by the steep topographyof much of the cropland area; highly erodibleloess soils; kinds of farming systems used; temperature;and rainfall intensity patterns.Study results also show that erosion rates onrangeland areas are projected to average lessthan one ton per acre per year. Forested areas inthe mountainous eastern Idaho-Palouse and inthe northern Washington basin average less theone-half ton per acre per year.Gully erosion, though serious when it occurs,accounts for only a minor part of soil erodedfrom the basin annually. Stream channel erosionis most serious in mountain forest areas.It accounts for 50 percent of the erosion fromthese areas. It amounts to less than 1 percent oftotal basin erosion, however.Studies conducted since 1939 show erosioncaused by runoff water on cropland is a seriousenvironmental problem. During the past 39 yearsnearly 360 tons of soil has been lost from everyacre—an average of over 9 tons per acre per year.These high soil erosion rates are expected toincrease. Erosion rates were projected using theUniversal Soil Loss Equation (USLE), newlydeveloped for eastern Washington, Annual erosionrates are projected to be 17 million tons peryear—an overall average of 14 tons per acre—unless farming systems change.Erosion rates on portions of fields are muchhigher than overall averages. Rates of 20 to 30tons are common and 100 to 200 tons per acrelosses occur frequently on some steep slopes.Erosion rates on cropland are usually less inthe lower precipitation zones of the westernbasin (13 tons per acre per year) and in the highprecipitation zones of the eastern basin (12 tonsper acre per year). Highest rates have consis-xi

tently been measured in the intermediate 15 to18 inch precipitation zone (20 tons per acre peryear). They are highest in that zone becauseof extremely steep topography; complexity ofslopes; farming systems used and climatic conditions.High erosion rates cause severe losses. All ofthe original topsoil has been lost from 10 percentof the cropland in the basin. One-fourth tothree-fourths of the top soil has been lost fromanother sixty percent of the cultivated area. Thisloss has left the land less productive. Erodedsoil causes other problems, too. Silt smotherscrops in bottomland areas. Nearly a million dollarsis spent each year cleaning silt from highwayditches. Stream channels, water-ways anddrainage ditches fill with silt, increasing floodproblems. At Palouse Falls, near the mouth ofthe Palouse River, half a million acre feet ofwater flows from the basin each year. It is abeautiful waterfall but the water in late winterand spring rarely flows pure and clear. Instead,it runs thick and brown with approximately3 million tons of precious topsoil from someof the most valuable farmland in the nation.From there sediment goes on to fill downstreamhydroelectric reservoirs, destroy fish habitat,ruin recreation areas, and pollute the waters,making them unfit for other uses.The study shows that the problems of soilerosion and water pollution from sediments canbe solved. The farmer can do little to change theweather, kind of soil, or steepness of the landhe farms, but he can change the way he farmsthe land. If farmers are going to reduce erosionthey need to do such things as reduce acreagesof summer fallow, till the soil less, retire thesteepest, most erosive areas from cultivation,change cropping systems, divide long slopeswith two or more crops and install terraces onlong, gentle slopes.The use of summerfallow, especially in thehigher rainfall portions of the central and easternbasin, is a major contributor to soil erosion.When fields are summerfallowed, uncroppedland is clean tilled during the summer to controlweeds and store moisture for growth of thenext year’s crop. Erosion rates on summerfallowfields average 25 to 30 percent higher thannon-fallow fields.Fields that are excessively cultivated alsoerode more. Use of minimum tillage methodsfor seedbed preparation on annually croppedland or stubble mulch on summerfallow fieldscan reduce erosion rates by 35 percent.More than 50 percent of the erosion comesfrom 25 percent of the steeper cropland. Retirementfrom cultivation of part or all of this landcould reduce erosion and sediment significantly.Divided slope farming and installation offield strip-cropping systems can reduce erosionrates by 15 to 28 percent. Terraces can reduceerosion rates another 8 to 13 percent.In the study, effects of applying combinationsof these conservation practices with differentcropping systems were evaluated. A series ofbranching charts are displayed to show thesecombined effects. The charts show that erosionrates on Class II and III lands can be reduced toless than 5 tons per acre if the right combinationsare used. Erosion rates on Class IV and VIlands can also be reduced significantly. However,erosion rates on Class VI lands will remainhigh and can best be controlled by retirementfrom cultivation.As various levels of conservation treatmentare applied to the land, the economy of the basinwill be affected. Erosion rates can be reduced by40 percent in the low and high precipitation zoneand 60 percent in the intermediate precipitationzone without adversely affecting farm income.Erosion rates can be reduced by 80 percentthrough application of maximum levels of conservationpractices and retirement of 35,000 acresof Class IV and VI land. The benefits of achievingthis erosion reduction level could be attained,but at a cost in excess of $29 million in reducedproductivity and increased operating costs.As erosion rates are reduced through conservationpractice application, sediments deliveredto stream systems will decrease accordingly.Wildlife habitat values increase only slightlyas more conservation is applied to the land.However, when Class IV and VI land is retiredfrom cultivation, habitat values increase by 4 to18 percent. Fuel and fertilizer use will increaseif less land is summerfallowed and insteadplanted to crops each year. As maximum erosionreduction levels are achieved throughretirement of the steeper farmland, fuel andfertilizer use will decline significantly.A specific combination of alternatives has notbeen selected in this study. This decision hasbeen left for user groups. Results of the studyhave been provided to user groups as it wasdeveloped. Its primary benefit was to peoplein eastern Washington as they have developedCounty water quality plans and selected bestmanagement practices for these plans. Theinformation will continue to be useful as thesexii

plans are implemented in carrying out themandates of PL 92-500 (Section 208)—the CleanWater Act of 1972. It will be useful as a guide tofarmers in selecting conservation practices. It isalso a useful tool to those who provide technicalassistance to farmers and those who mustmake policy decisions dealing with soil erosionand sediment problems.Much more conservation should be appliedin the basin as County water quality plans areimplemented. The series of Erosion ReductionPlans presented are practical alternatives that arebeing used by some farmers at this time. They arealternatives that user groups, including ConservationDistrict Supervisors, County Water QualityCommittees, and conservation and researchtechnicians, asked the study team to evaluate.Since significant erosion reduction can beachieved without adverse economic impacts,implementation should be easier. Farmers willhave to change farming systems and learn howto farm differently. This is not easy and willtake time. If very high levels of erosion reductionare to be achieved, large capital outlaysand reduced incomes will result. Someone willhave to pay this cost, either the farmer or thetaxpayer or both.Legislative changes may be needed beforeadequate conservation can be achieved. Proceduresfor implementation of the Water QualityAct have not as yet been fully resolved. Aspectsof current farm programs encourage use ofsummerfallow while little encouragement isprovided for retirement of the most erosiveacres from production. Cost-share programsfor conservation practices need to be evaluated.Improved methods to motivate people to makeneeded changes in farming practices need to bedevised.Since 1934 nearly three-fourths of a ton of soilhas been lost for every bushel of wheat producedin the basin. There is a plentiful supplyof soil in the basin but it is not inexhaustible.Some have come to regard it as only an immediatesource of wealth. There are many others,however, who realize that it is truly a pricelessheritage belonging as much to our children’schildren as to us. It is a heritage that can andmust be saved for those future generations.xiii

BASIN DESCRIPTION

Description Of The BasinHistoryThe Palouse Basin has been inhabited byhuman beings perhaps as long as 10,000 years,according to discoveries at the Marmes RockShelter near the mouth of the Palouse River,(a) The river was named for the tribe of Indianswho lived along its lower reaches whenthe white people arrived on the scene. Severaltribes used portions of the basin, but only thePalouse lived there the year round. The latterlived along the lower reaches of the PalouseRiver between the Palouse Falls and the SnakeRiver.Indians, never numerous (b), made their livingfrom the land and the streams. Food limitedexpansion of their tribes. Fish was a main staple,but some deer, elk, rabbits, and bears werekilled for meat and hides. There were no buffaloin the basin and the Indians trekked eastwardover the Bitterroot Mountains in search of themto augment winter food reserves.The Lewis and Clark Expedition is the firstknown overland exploration by whites this farwest—as early as 1805. David Thompson, ageographer and trader for the English-ownedNorthwest Company, was the first white manreported to have crossed the basin, in August1811. A year later, a Pacific Fur Company partytraced a similar route, and the ever-increasingstream of “whites” began.Fur traders passed through the basin. Theyheadquartered at Spokane House to the north;Lewiston, in the southeast; and Walla Walla, tothe southwest. Little trapping was done, however,except in the Moscow Mountains of theupper basin.Missionaries came in the 1830’s and ‘40’s;military units in the 1850’s and early 1860’s—first as explorers, and later to keep the peace. By1860, gold was discovered in the rich placers ofthe Clearwater River, the Coeur d’Alenes andnear present-day Colville. A flood of prospectorsand miners poured through the Palouse,many of them lawless elements of society whodid not care about Indian culture or even Indianlife. Conflicts increased, first by words and thenby weapons.As whites continued to pour westward, bettertransportation routes were developed; treatieswere made and later broken, and Indiansbegan losing their rights to desirable areas.In 1853, Washington was made a Territory.Territorial Governor Isaac Stevens and the U.S.Government pressured Indians to relinquishtitle to their lands. Many battles broke out. (c)Indians were finally given reservation lands inexchange for rich, productive lands they hadonce claimed.Horses and determined pioneers broke trail forpresent day agriculture in the Palouse.3

In 1863, George Pangburn settled on lowerUnion Flat Creek, planted a few fruit trees, andbegan raising livestock. By 1869, several smallsettlements sprang up. The first trickle of settlersbecame a tide during the next two decades.Colfax and Palouse City were the earliest communitiesto reach significant size.The government surveyed most of the landin the Palouse River Basin during the period1872-77. (d) Some land was settled before this,but the surveys provided means for legal acquisition.Virtually all arable land in the basin wassettled from 1870-1885. (e)Early settlers raised livestock and cultivatedonly enough bottom land to produce gardensand grain for family needs. Markets for largecrops of grain was the limiting factor. ThePalouse grassland-livestock era ended withrailroad construction in the early 1880’s. Almostovernight “horsepower” cultivation of thePalouse hills changed lush grassland to blackcropland. Major crops in those first years ofdryland farming were grains, sugar beets andthousands of acres of orchards.Until railroads brought new and betterequipment west from factories in the east, graincropping was quite primitive. In those times,soil on the Palouse hills were exceptionallyfertile, with many fields yielding upward of70 bushels of wheat per acre. Forty years later,the average yield in Whitman County was only26.4 bushels per acre.There were many problems over the years—some disastrous. Pests, mainly grasshoppersand ground squirrels, were the first, (f) In 1893,many farmers were unable to harvest a spear ofgrain because of unusually wet fall weather, (g)a national money panic followed. Floods tooka severe toll in 1910; grain diseases reducedyields just prior to World War I, and by theearly 1940’s weeds began invading fields. (h)The most widespread and critical problemof all was scarcely noticed; erosion of soil fromPalouse hills. Until people cultivated andpulverized the soil with farm equipment, therewas little erosion. Summerfallow became a wellestablished practice on most Palouse farms bythe early 1890’s. Washington and Idaho StateExperiment Stations began to recognize erosionas a problem. (i)A chain reaction of changes and events—some good and some bad for the land—hastaken place in the last five or six decades. Introductionof field peas for areas of high precipitationmade annual cropping possible, therebyreducing the erosion hazard. (j) Then, thenewer, horse-drawn combine harvesters createdthe problem of excess straw after harvest. Theonly recourse for the farmer was to set fire tothe stubble after harvest. Eighty to 95 percent ofthee residue went up in smoke an nothing wasreturned to the soil as humus, (k)Stubble burning leaves abare unprotected soilsurface.When crawler tractors replaced the horse,steeper lands previously used for hay andpasture were converted to grain. Greater powermoved equipment faster, pulverized soil evenmore, and caused more down-slope movement.Now farmers were able to go up and down hillsinstead of working on the contours, as in thedays of horse-drawn equipment.Since pastures were no longer needed forhorses, fences and fence rows were removed,along with many early timber plantings. Habitatfor wildlife was gradually disappearing.Concerned about the erosion problem, Congressin 1929 authorized ten regional experimentstations throughout the nation to studythe causes and cures of soil erosion, of them oneat Pullman, on Washington State College land.4

Erosion problemswere studiedand cures werereccomended.By 1933, the new Soil Erosion Service andCivilian Conservation Corps were workingclosely on natural resource problems. The SoilConservation Service was established April 7,1935 as a permanent agency in the U.S. Departmentof Agriculture. The new agency had broadauthority to carry out erosion and flood controlwork on public and private lands.A model conservation district law was presentedto governors of the 48 states to furthersoil and water conservation efforts by localpeople. Washington and Idaho acted quicklyand passed the enabling legislation by 1939.The Latah district in Idaho and North Palouseof Washington were the first to organize in theNorthwest. Erosion control programs were wellon their way when World War II began. Duringthe war, many grasslands were plowed out andplanted to grain or peas as part of the “Food ForFreedom” program. This was a severe setbackfor erosion control progress.In the post-war period, commercial fertilizersreplaced the practice of growing and turningunder legumes for fertilizer. Chemical sprays,improved crop varieties, huge grain surplusesand a return to summerfallow under the wheatallotment program also set back erosion controlprograms.The Soil Erosion Service made a reconnaissancesurvey to determine the extent of soilerosion in the area. Demonstration projects wereestablished to demonstrate erosion control. Menfrom the CCC camps carried out cooperativeprojects between farmers and the government.Among the accomplishments were numerousgrass and tree plantings, construction of grassedwaterways and gully control structures andimproved farm management systems. The SoilConservation Service has continued to carry outactivities started by these early efforts. MajorSCS activities have included technical assistanceto basin farmers and ranchers in planning andapplying conservation practices on the land.5

GeologicalDevelopment 1Geological processes formed the PalouseRiver Basin millions of years ago and basicallydetermined what the area is like today. Forcesdeep within buckled the earth’s crust. Upwardshifting of giant slabs of granite were forcedeven higher. Thus began the geological uplift,volcanic activity, erosion and flooding thatcreated the Palouse. Remnants of this massiveuplift are still visible in the mountains andbuttes of the eastern portion of the basin.Following the mountain uplift, volcanoeserupted about 10-30 million years ago, spewingforth a series of lava flows-sometimes atshort intervals; but during other periods, tensof thousands of years intervened. Early flowsfilled the valleys. Subsequently, the flowscovered most of the high hills and eventuallyformed a solid sea of basalt-more than 10,000feet thick in places. Many individual flows,more than 75 feet thick, extended more thana 100 miles. A few hills protruded—islandlike—throughthe basalt around the edges ofthe lava field. The most prominent of these hillsis Steptoe Butte near Colfax, Washington, Thisterm now is used by geologists worldwide toidentify any island of older rock, surrounded bylava: a “steptoe”.Then the dust storms started. Widespreadwind erosion occurred in eastern Washingtonand Oregon. The magnitude can hardly beimagined. Windblown soils drifted over and filtereddown to cover the lava field with depositsas thick as 200 feet.Prevailing southwest winds left loessaldeposits in dune-like shapes. These hills havegentle south and west facing slopes. Manynorth and east slopes were left with steep andshort slopes. All but the highest buttes andmountains of the eastern basin were buried bythese deposits. 9This, then, was the Palouse of about 100,000years ago—a thick, tilted saucer of basalt,warped in places into ridges, and completelyoverlain by a frosting of loess. According togeologists, the view from the top of the SteptoeButte would have revealed peaceful, rollinggrasslands. To the east, the Bitterroot Mountainsand to the west, the Cascade Mountainswere distant hazy blue backdrops of peace andquiet. This tranquil scene, however, was the settingfor a catastrophe.Movement and melting of glaciers and greatice fields in southern British Columbia createdmammoth ice dams in the valleys, forminglakes. When the ice dams burst, they releasedSteptoe Butte - a remnant of the past.7

water swept away the loess material like a giantbroom. Three giant rivers raced across easternWashington. Soil was scoured down to the lavafield, leaving behind a significantly differentlandscape that has become known as the channeledscablands—which exist nowhere else inthe world. Here and there a loess island stillstands above the surrounding terrain as a relicof the past. The easternmost river carved thewidest channel: The Cheney-Palouse Tractwhich is the channeled scabland area of thewestern portion of Palouse Basin. Elsewhere,however, the deep loess has remained to becomethe fertile soil of the Palouse. Thus, was thisvast, beautiful and highly productive land calledthe Palouse formed in geologic history.8

47º30SilverLake47º30117º30SPOKANE CO.LINCOLN CO.Palouse RiverBasinADAMS CO.FRANKLIN CO.WHITMAN CO.BENEWAH CO.LATAH CO.NEZ PERCE CO.118º00DamageTURNBULLR. R.CreekNATIONALWILDLIFEREFUGEPhilleaLakeRock Cr.LOCATION MAPR. R.90FishtrapLakeR. R.DamageBadgerLakeAmberLakeWilliamsLakeChapmanLakeSandersCr.PlazaB. N.LINCOLNSpragueLakeSpragueCOUNTYDownsLakeNegroCreekBonnie LakeSPOKANE COUNTYWHITMAN COUNTYR. R.RosaliaCreek47º00FinnelLakeCowCreekCowLakeUP. & C.M. ST. P. & P.BengeB. N.CPalou seCreekADAMS COUNTYWHITMAN COUNTYRockRiverImblerBC. M. ST.P & P.CreekLa CrossePackerCottonwoodRebelCreekEwanRockLake23Dawning Cr.EndicottCreekPleasantR. R.FlatSt. JohnU. P.FlatValleyPineCreekPalouseCreekThornBB. N.R. R.195CreekB. N.SteptoeColfaxSouthR. R.ClearFork PalouseOakesdaleCreekFourRoseRiverMileCreekGarfield27Palouse27R. R.R. R.CreekWASHINGTONIDAHO117º00ASAINTDeepCr.Creek95FlanniganGoldJOEPotlatchCreekHatter Cr.NATIONALPrincetonBENEWAH COUNTYLATAH COUNTYCr.MeadowFOREST116º30116º3047º00Hooper26117º30CreekRiverMissouriFlat Cr.FRANKLIN CO.WHITMAN CO.118º00195PullmanParadise Cr.WHITMAN COUNTYLATAH COUNTYMoscow95NEZGenessePERCE CO.GENERALIZED GEOLOGYLoess of late Pliocene, Pleistocene, and Holocene ageMostly sild and clayBasalt of Columbia River Group of Miocene andPliocene ageExposed primarily in channels eroded by glacial floodsduring Pleistocene timeMetamorphic and intrusive igneous rock or pre-Tertiary ageGENERALIZED GEOLOGYPALOUSE RIVER BASINIDAHO AND WASHINGTON5 0JANUARY 19775SCALE 1: 1,100,00010 MILESBoundary between subareasSubareasA, eastern steptoes and foothills of Clearwater Mountains, ofhigh local relief, with timber in higher areas.B, central area, chiefly loessal hills of moderate local relief, with sometimber in northern part.C, channeled scablands, with some loess-mantled islands, little localrelief, with timbered areas in northern part.Source:Base map prepared by SCS, WTSC Carto. Unit from State Staff compilation.Thematic detail prepared from USGS Generalized Geology Map.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977M7-OL-23731-39

Resources of the BasinWaterRivers and StreamsThrough this unique landscape flows thePalouse River which originates in the MoscowMountains of west-central Idaho’s “Panhandle.”The Palouse flows southwesterly toward adeep canyon of basalt and plunges over PalouseFalls near the confluence of the Palouse andSnake Rivers. Major tributaries are the Northand South Fork of the Palouse River, RebelFlat Creek, Rock Creek, Pine Creek, Union FlatCreek and Cow Creek.The Palouse North Fork watershed drains 15percent of the river basin and yields 41 percentof the runoff. Cow Creek watershed, whichdrains 20 percent of the area, yields 7 percent ofthe runoff water in the basin.Palouse River Canyon11

Table 1. Average Annual Water Yield From Sub Watersheds—Palouse River BasinSub-WatershedAcresMain StemLength(Miles)Avg. AnnualWater Yield(Ac. Ft./Yr.)S. Fork Palouse 187,220 34 77,000N. Fork Palouse 316,910 54 188,000Rebel Flat Creek 50,940 20 6,000Cottonwood Creek 96,390 20 12,000Pine Creek 197,400 48 44,000Thorn Creek 42,970 14 8,000Rock Creek 283,530 28 30,000Cow Creek 427,820 38 33,000Union Flat Creek 201,720 72 31,000Palouse River Main Stem 309,070 70 26,000Total Palouse River 2,113,970 398 455,000These streams drain a basin that begins at anelevation of 5,300 feet. Where the Palouse emptiesinto the Snake River, the elevation is about500 feet. Flows begin to decrease in May whenmountain snows have melted and then steadilyincrease in late October when precipitationbegins to build up again.Extremes in mean annual discharge in cubicfeet per second, measured at Hooper, Washington,vary from a low of 256 cfs in 1937 to anall-time high of 1410 cfs in 1974.Agricultural use of water from the PalouseRiver and its tributaries is limited to a few sprinklersystems on land adjoining these streams,principally for supplemental irrigation of hay,pasture, and some small grains. Extreme fluctuationsin flow rates, low summer flows, lackof adequate storage sites and extremely heavysiltation severely limit domestic use of PalouseRiver water. In the canyon rangeland areas,especially in the low-rainfall areas of the westernbasin, these streams are a valuable source ofwater for livestock. Except for three small pondsin Idaho, the river is free flowing.Palouse River at Hooper, Washington12

WATERSHEDS47º00FRANKLIN CO.FinnelLakeWHITMAN CO.CowCreekCowLakeUP. & C.M. ST. P. & P.14z-8-1Hooper14z-10Benge26B. N.118º00118º00LINCOLNSpragueLakeB. N.Palou seCreekADAMS COUNTYSpragueWHITMAN COUNTYRockRiverR. R.COUNTYImbler90C. M. ST.P & P.La Crosse14z-814z-7CreekFishtrapLakePackerDamageR. R.DownsLakeCottonwoodRebel47º30DamageCreekEwanR. R.CreekSilverLakeBadgerLakeAmberLakeWilliamsLakeNegroCreekRockLake23Dawning Cr.14z-3Endicott14z-947º30ChapmanLakeSanders14z-4117º30117º30Bonnie LakeSPOKANE COUNTYWHITMAN COUNTYCreekPleasantR. R.FlatTURNBULLNATIONALWILDLIFEREFUGESt. JohnU. P.FlatValleyPineCreekPalouseCreekThornPhilleaLakeR. R.Rock Cr.Cr.14z-10B. N.R. R.195PlazaRosalia14z-6CreekCreekB. N.SteptoeColfaxSouthCreek14z-5R. R.ClearFork PalouseOakesdaleCreekRiverFourRose195RiverMileCreekMissouriPullmanGarfield27Palouse27R. R.Flat Cr.R. R.Paradise Cr.CreekWASHINGTONIDAHOWHITMAN COUNTYLATAH COUNTY117º0014z-2SAINTDeepCr.CreekFlannigan14z-1Moscow14z-114z-214z-314z-414z-514z-614z-714z-814z-8-114z-914z-1095GoldJOEPotlatchCreekHatter Cr.NATIONALPrincetonSouth Fork Palouse RiverNorth Fork Palouse RiverRebel Flat CreekCottonwood CreekPine CreekThorn CreekRock CreekUpper Cow CreekLower Cow CreekUnion Flat CreekPalouse RiverWatershed BoundryBENEWAH COUNTYLATAH COUNTYCr.MeadowFOREST116º30116º3095NEZGenessePERCE CO.SPOKANE CO.LINCOLN CO.Palouse RiverBasinADAMS CO.FRANKLIN CO.WHITMAN CO.LOCATION MAPBENEWAH CO.LATAH CO.NEZ PERCE CO.WATERSHEDSPALOUSE RIVER BASINIDAHO AND WASHINGTONJANUARY 19775 0510 MILESSCALE 1: 1,100,000Source:Base map prepared by SCS, WTSC Carto. Unit from State Staff compilation.Thematic detail compiled by State Staff.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977M7-SL-23731-213

Figure 1Average Monthly Streamflow—Palouse River GaugingStation 1929-1976, Hooper, WashingtonCubic Ft.Per Sec.15

LakesThe basin has 42 lakes that contain waterthroughout the year. In addition, there arenumerous seasonal lakes and potholes that dryup during summer months. Most lakes are inthe Cow Creek and Rock Creek watersheds.They were formed by flooding, carving, andgouging of the landscape during early ice ageand glaciation periods.Many of these lakes have no outlets and areessentially large water filled depressions withbasalt or lava rock bottoms.Surface areas of the lakes range from under20 acres to the 2,147 acres of Rock Lake. Totalwater surface of lakes in the basin is more than8,500 acres—13 square miles.Rock Lake in thechannel scablandsof western basin.Ground WaterBasalt, the primary aquifer unit, occurs atvarying depths throughout most of the basin.Water is stored in and moves through this basalt.Wells in the central and western basin yieldfrom 500 to 2,000 gallons of water per minute.Fine-grained sedimentary strata has reducedpermeability of the basalt in most of the easternbasin where wells generally yield 500 gallonsa minute or less. Even where ground water isavailable, the aquifer is often very deep andhigh lift pumps are required.Since groundwater yields are so variable,determination of yield potential from individualwells can be obtained only through specialinvestigation and testing. Costs of drilling andtesting can be very high.Most of the wells in the basin are now used fordomestic and livestock water. Only a few wellsproduce sufficient water for irrigation purposes.Heavy municipal use of water at Moscow andPullman has lowered water tables in that area.16

Soils, Climate and TopographyThere are many different soils in the basin.Topography and climate also differ within thearea. Major differences in soils, climate andtopography can be found as one travels throughthe basin from east to west.Temperature is influenced by both continentaland marine weather patterns. Maximum temperaturesof 110 degrees F. have been recorded.Summers are hot, dry, and sunny. Conversely,winters are cold, with frequent periods ofcloudy or foggy weather. A minimum temperatureof 37 degrees below zero has been recorded.Lengthy cold periods are unusual. Frequentsubfreezing temperatures often cause the topseveral inches of soil to freeze. Warm, moist airmasses—called “chinooks”—move through thebasin, resulting in rain on frozen soils. Whenthis occurs, soil erosion is extensive and severe.The frost-free period in these cultivatedareas averages 150 days, compared to less than100 days in the Moscow Mountains. The shortgrowing season limits the types of crops thatcan be grown.Prevailing winds from the southwest aregenerally moderate. High wind velocities of1-2 days duration occur several times annually,primarily in April and October.Soils have been grouped into 20 associations(see map, following page 14). Each ofthese associations designate a landscape with adistinctive proportional pattern of soils, usuallyone or more major soils, and at least one minorsoil. Soil associations have been further incorporatedinto six major groups. These groupsinclude associations with similar depth, parentmaterial, and positions.In the extreme eastern basin, mountain peaksusually are clad with deep snow in winter andreceive up to 46 inches of precipitation annually(proceeding page 15). These mountainsare generally covered with dense forests. Here,at elevations of 2,800 to 5,000 feet, moderatelydeep soils have formed in weathered rocks onmountain uplands. Topography of the area issteep, often rocky and extremely erosive whennot protected by vegetative cover. These soilscover about 8 percent of the basin.Deep soils formed in loess on uplands arelocated in foothills to these mountains. Averageannual precipitation ranges from 22 to 35 inches.Although forested, many parts of the area havebeen cleared for intensive nonirrigated crop production;some at higher elevations are still usedfor forest production. These soils cover approximately4 percent of the basin.Near the Washington-Idaho border are verydeep to moderately deep soils formed in loessand rock fragments on buttes that are a permanentfeature of the landscape. This groupoccupies scattered buttes with elevations rangingfrom 2,500 to 4,000 feet. The buttes rise 1,000feet or more above the surrounding landscape.Sideslopes of the buttes are steep. Most soils inthe group are well-drained silt loams. Landswith milder slopes are used for dryland farmingwhile steeper areas are used for range, forest,and wildlife. Average annual precipitationranges from 21-23 inches. This group coversabout 2 percent of the basin.Surrounding these buttes and extendingwestward to the channeled scabland areas arevery deep soils formed in loess on uplands.This group occupies upland hills and ridgesranging from 1,200 to 3,000 feet. These soilscover 44 percent of the basin and are the basefor most of the cropland.Soils in this group have many similaritiesand some differences. Most differences relateto the low (12 inches) average annual precipitationin the western basin and high (23 inches)in the eastern basin. Precipitation differencesinfluence types of vegetation and conditionsunder which the soils were developed. Soils inthe higher annual rainfall areas were developedwith more lush vegetation and are for the mostpart darker because of high humus content.Loess hills in the eastern basin generally havemore gentle slopes than in the central basin,but are still steep. In the central basin, hills aremuch more irregularly shaped and steeper. Thenorth side of the hills often have amphitheaterlikeenclosures. Many hills in the central basinhave narrow tops and are more irregular thanin other areas of the basin. Primary topographyis a series of roughly parallel hills.Most drainage patterns in this group arenearly parallel, with U-shaped draws. Somesoils in the eastern portion of the area are notwell-drained and have slow permeability.Hills in the western basin are not as steep.Stream channels are more pronounced andoften are gouged through loess to bedrock.There are some trees, primarily along streams.17

Transecting these deep loess soils are areasdominated by very deep soils formed in loessin valleys. This group occupies major drainagewaysin the basin, including the valley sideslopes.Soils are similar to those of the area thestreams transect. In this group are bottom landsoils and gentle sloping to very steep side slopesleading down to the flat bottom land. Soils inthese areas encompass approximately 11 percentof the basin and are used for dryland farming,pasture, rangeland, forests, and wildlife.Bordering the western edge of the basin arevery shallow to moderately deep soils formedin loess and glacial outwash in channeledscablands. Precipitation here varies from 12inches annually in the southwest to 18 inchesin the north. Soils are well-drained cobblyloams and silt loams underlain by basalt bedrock.Basalt bedrock and steep basalt cliffs areexposed randomly. Occasional loess islands, notremoved by glacial outwash, also are found inthis area.There are many undrained basins and lakesof varying sizes in the northern portion of thearea. Because of shallow soils and rocks, mostof the area is used for rangeland, forest production,and wildlife. Vegetation consists of grasses,sagebrush and various forbs. Scattered standsof ponderosa pine, aspen, and Douglas fir occurin the northern portion of this association whereprecipitation is sufficient. This soil group encompassesapproximately 31 percent of the basin.Stream channels are deeply etched into thebasalt, with canyon walls reflecting these deep,sharp cuts. Winding southward, through thecanyons, the Palouse River makes a final majesticplunge of 185 feet over Palouse Falls, near itsconfluence with the Snake River.18

92019171013111111111118111111881111111181181911223121211231013321010231222221233103212343323410210210104554454555101012104441061461461445661014106146771014106767710710714141414671020151516151617616191810Hatter Cr.71021415101720SOIL ASSOCIATIONSAREAS DOMINATED BY VERY DEEP SOILSFORMED IN LOESS, ON UPLANDSWalla Walla AssociationAthena AssociationSilverLakeAthena-Palouse Association117º30Palouse-AssociationPalouse-Staley AssociationPalouse-Thatuna AssociationPalouse-Thatuna-Naff Association47º3047º30118º00Bagdad AssociationRitzville-Willis AssociationPhilleaLakeTURNBULLNATIONALWILDLIFEREFUGER ock CrCreekR. R..AREAS DOMINATED BY VERY DEEP SOILSFORMED IN LOESS, IN VALLEYSDamDamaaggeeChapmanLakeBadgerLakeCr.S a ndersAmberLakeFishtrapLake90Palouse-Athena AssociationR. R.R. R.AREAS DOMINATED BY VERY SHALLOW TOMODERATELY DEEP SOILS FORMED IN LOESSAND GLACIAL OUTWASH; IN CHANNELEDSCABLANDSPlazaWilliamsLakeNegroSpragueB. N.Bonnie LakeCOUNTYCOUNTYDownsLakeSPOKANEWHITMANCOUNTYLINCOLNAnders-Benge-Kuhl AssociationCreekSpragueLakeCreekRosaliaR. R.Bakeoven-Tucannon-Cheney AssociationPineStratford-Roloff-Starbuck Association117º00R. R.CreekB. N.Creek1113 9AREAS DOMINATED BY VERY DEEP TO MODER-ATELY DEEP SOILS FORMED IN LOESS AND INCOLLUCIUM AND RESICUUM FROM METASEDI-MENT, ON BUTTES195ThornRockLakeCreekOakesdalePackerCowLakeCreek23ImblerPalouse-Thatuna-Tekoa AssociationEwanCreekSt. JohnPleasantCottonwoodC. M. ST.P & P.UP. & C.M. ST. P. & P.FinnelLakeAREAS DOMINATED BY DEEP SOILS FORMEDIN LOESS, ON UPLANDSValleyR. R.116º30COUNTYCOUNTYSAINTJOEWASHINGTONIDAHOCreekCreekLarkin-Southwick AssociationFreeman-Joel-Taney AssociationBENEWAHLATAHCreekB. N.Cr.Dawning Cr.Creek1 1GarfieldHelmer AssociationSteptoeNATIONALFORESTWHITMAN COUNTYADAMS COUNTY47º00MeadowSanta-Carlinton-Helmer AssociationDeepGoldR. R.R. R.River2 3R. R.PalouseAREAS DOMINATED BY MODERATELY DEEPSOILS FORMED IN WEATHERED ROCKS, ONMOUNTAIN UPLANDS9527B. N.RebelU. P.EndicottRockPotlatchCreekFlatRiverCowCr.PalouseClearBenge19116º30PrincetonVasssar-Moscow-Grano AssociationHuckleberry-Minaloosa-Xerolls AssociationFlanniganCreekSouthColfaxFlatFourCreekMileEach area outlined on this map consists of morethan one kind of soil. The map is thus meant forgeneral planning rather than a basis for decisionson the use of specific tracts.Fork PalouseLa Crosseu seRosePalo27Creek26CreekFlat Cr.MissouriRiver117º30HooperMoscowPullmanParadise Cr.10118º00WHITMAN CO.106 6WHITMAN COUNTYLATAH COUNTY195FRANKLIN CO.95GenessePERCE CO.NEZSPOKANE CO.LINCOLN CO.Soil Association MapPalouse RiverBasin BENEWAH CO.LATAH CO.ADAMS CO.PALOUSE RIVER BASINIDAHO AND WASHINGTONNEZ PERCE CO.WHITMAN CO.FRANKLIN CO.LOCATION MAPJANUARY 197710 MILES55 0SCALE 1: 500,000Source:Base map prepared by State Staff.Thematic detail compiled by State Staff.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 M7-EN-23732-1

18PRECIPITATIONLess than 15 inches15-18 inchesSilverLake47º3047º30117º30More than 18 inches118º001516R. R.CreekTURNBULLNATIONALWILDLIFEREFUGEPhilleaLakeRock Cr.R. R.Damage18Average Annual Precipitationin inches2090FishtrapLakeR. R.DamageBadgerLakeAmberLakeWilliamsLakeChapmanLakeSandersCr.Plaza14B. N.SpragueLakeLINCOLNSpragueCOUNTYDownsLakeNegroCreekSPOKANEWHITMANBonnie LakeCOUNTYCOUNTYR. R.RosaliaCreek47º00FinnelLakeCowCreekCowLakeBengeUP. & C.M. ST. P. & P.B. N.Palou seCreekADAMS COUNTYWHITMAN COUNTYRockRiverImblerC. M. ST.P & P.CreekLa CrossePackerCottonwoodRebelCreekEwanRockLake23Dawning Cr.Endicott16CreekPleasantR. R.FlatSt. JohnU. P.FlatValleyPineCreekPalouseCreekThornB. N.R. R.195OakesdaleCreekB. N.GarfieldSteptoePalouseColfaxSouthR. R.ClearFork PalouseCreekFourRoseRiverMileCreek27R. R.27R. R.Creek22WASHINGTONIDAHO117º0026SAINTDeepCreekGoldJOE95PotlatchCr.FlanniganCreekHatter Cr.NATIONALPrincetonBENEWAHLATAH26Cr.COUNTYCOUNTYMeadow2626FOREST2636116º30116º303647º00Hooper261415117º3018CreekRiverMissouriFlat Cr.FRANKLIN CO.WHITMAN CO.118º00195PullmanParadise Cr.WHITMAN COUNTYLATAH COUNTYMoscow222695NEZGenessePERCE CO.20SPOKANE CO.LINCOLN CO.Palouse RiverBasinADAMS CO.FRANKLIN CO.WHITMAN CO.LOCATION MAPBENEWAH CO.LATAH CO.NEZ PERCE CO.PRECIPITATIONPALOUSE RIVER BASINIDAHO AND WASHINGTONJANUARY 19775 0510 MILESSCALE 1: 1,100,000Source:Base map prepared by SCS, WTSC Carto. Unit from State Staff compilation.Thematic detail compiled by State Staff.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977M7-SL-23731-121

Land UseFive major land uses have been summarizedby acreage in Figure 2. These broad categorieshave been determined both on the basisof cover and use. Cropland is categorized as ause. Forested grassland occurs in the channeledscabland areas of Washington. Mountain forestsare found in the eastern basin in Idaho. Forestland has more than 10 percent forest cover.Rangeland areas have broad range cover characteristics.Other land includes land specificallybased on use, such as urban. Since this informationhas been generalized, isolated areas ofdifferent categories may occur within the broadpattern.Figure 2 Land Use—Palouse River Basin 1Cropland—1,231,000 Acres58%Rangeland—597,000 Acres28%Forested Grassland—62,000 Acres3%Mountain Forest—163,000 Acres8%Other Lands—61,000 Acres3%Soil, water, topography, and climate largelydetermine land use in the Palouse and are thefactors that have influenced the “how, when,and where” of people as they moved in andbegan cultivating the crops.The Palouse River Basin is more denselypopulated in the east than in the west. Thispopulation density is closely related to farmsize. Farms in the western basin average about1,150 acres, compared with about 500 acres inthe east. Approximately 19 percent of the populationlives on these family farms. Most farmsare operated by second and third generationfarmers.The average age of farmers in the PalouseRiver Basin is 50 years. Only about 13 percent ofthe farmers are under 35 years of age.Approximately 63 percent of the farms areoperated by part-owners, 19 percent by tenants,and only 18 percent by owner-operators. 1 Muchof the land is owned by non-residents.Farm population in the basin has been slowlydeclining. Students account for a significant shareof the basin population of 70,000. Enrollment inthe fall of 1975 was 16,184 at Washington StateUniversity and 7,627 at the University of Idaho.1 U.S. Department of Commerce, Bureau of the Census; 1974 Censusof Agriculture, Whitman County, Wash., Latah County, Idaho.23

Hatter Cr.SPOKANE CO.LINCOLN CO.Palouse RiverBasin BENEWAH CO.LATAH CO.ADAMS CO.WHITMAN CO.FRANKLIN CO.SilverLakeNEZ PERCE CO.117º3047º3047º30LOCATION MAP118º00PhilleaLakeTURNBULLNATIONALWILDLIFEREFUGECreekR. R.Rock Cr.DamageChapmanLakeBadgerLakeDamageCr.AmberLakeFishtrapLake90SandersR. R.R. R.PlazaWilliamsLakeNegroSpragueB. N.LAND USEBonnie LakeCOUNTYCOUNTYDownsLakeSPOKANEWHITMANCOUNTYLINCOLNCreekSpragueLakeCreekRosaliaR. R.CroplandPine117º00R. R.CreekRangelandB. N.195CreekThornRockLakeCreekForested GrasslandOakesdalePackerCowLakeCreek23ImblerEwanMountian ForestCreekSt. JohnPleasantCottonwoodC. M. ST.P & P.UP. & C.M. ST. P. & P.FinnelLakeValleyR. R.Urban116º30COUNTYCOUNTYSAINTJOEWASHINGTONIDAHOCreekCreekBENEWAHLATAHCreekB. N.Cr.Dawning Cr.CreekGarfieldSteptoeNATIONALWHITMAN COUNTYADAMS COUNTY47º00MeadowDeepGoldR. R.R. R.RiverR. R.Palouse9527B. N.Rebel25U. P.FORESTEndicottRockPotlatchCreekFlatRiverCowCr.PalouseClearBenge116º30PrincetonFlanniganCreekSouthColfaxFlatFourCreekMileFork PalouseLa Crosseu seRosePalo27Creek26CreekFlat Cr.MissouriRiver117º30HooperMoscowParadise Cr.Pullman118º00WHITMAN CO.WHITMAN COUNTYLATAH COUNTY195FRANKLIN CO.95LAND USEGenessePERCE CO.NEZPALOUSE RIVER BASINIDAHO AND WASHINGTONJANUARY 197710 MILES55 0Source:Base map prepared by State Staff.Thematic detail compiled by State Staff.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 M7-EN-23732-2SCALE 1: 500,000

Table 2. Total Agricultural Produce Sales—Palouse River BasinProductsTotal Sales1969Million Dollars1974Crops 49 162Forest Products 1 1.5Livestock, Poultry and theirProducts 10 10Source: 1974 Census of Agriculture, Whitman County, Wash., Latah County, Idaho.Fifty percent of the people live in Pullmanand Colfax, Washington and Moscow, Idahowhere trade and service industries are principalsources of employment. Most other opportunitiesfor employment are in agriculture.Most areas have adequate facilities for transportingmanufactured goods, crops, forestproducts, livestock, and livestock products tomarkets within and outside the area. Approximately2,500 miles of county roads and 400miles of north-south and east-west state andU.S. highways provide good access to majormarketing centers in Spokane, Lewiston, thePacific Coast, and water transportation facilitieson the Snake River.Freight service is supplied by the BurlingtonNorthern, Union Pacific and Milwaukee Railroadsystems. Several air transportation facilitiesserve the area, including the Pullman-Moscowregional airport, and numerous other smallcommunity facilities.Barge navigation along the Snake River, justsouth of the drainage basin area, provides yearroundwater transportation from Lewiston tothe Pacific Ocean.Barges being loaded to transportgrain to ports on the Columbiafrom points along the Snake River.27

CroplandTable 3. Cropland Use, Palouse River Basin 1974PERCENT OFCROP ACRES TOTAL CROPLANDWheat 598,000 49Barley 159,000 13Peas and Lentils 159,000 13Summerfallow 305,000 25Total 1,221,000 100Source: 1974 Census of Agriculture, Whitman County, Wash., Latah County, Idaho.Soft white winter wheat grown in the basin isexcellent for pastry flour and bread flour blends.Some spring wheat is spot seeded on fieldswhere fall wheat has been winter killed and onannually cropped fields in higher rainfall areas.In the low precipitation western basin, half thecropland is left fallow every year to build up soilmoisture for cropping the following year.Crop rotations in the 15-18 inch precipitationzone of the central basin include about a fourthfallow land, a third in wheat, and the remainderin barley, peas, or lentils. With more than 18inches of average precipitation the eastern basinis cropped annually to about half wheat andhalf peas or lentils.Grain harvest in theeastern basin.28

Table 4. Annual Farm Sales ComparisonPalouse River Basin: Washington StateAnnual Sales($1,000)Palouse BasinPercent of FarmsWashington StatePercent of Farms100 34 1940-100 31 2120-40 16 1610-20 7 140-10 12 30Source: 1974 Census of Agriculture, Whitman County, Wash., and Latah County, IdahoAnnual sales of products from the 2100 farmsin the basin are much higher than state averages.Total farm cropland returns for the basin in1975 were approximately $147 million. Totalcropland production expenses in the basin were$60 million in 1975. (m)Cropland values have increased significantlyin recent years, responding to higher cropprices and changes in farm commodityprograms. Recent land sales in the basin haveranged from $300-400 per acre in the low-rainfallareas of the western basin to more than$1,200 per acre in the higher rainfall portions ofthe eastern basin.Farmland and farm buildings in the PalouseRiver Basin are valued at more than $700 million.29

RangelandTwenty-eight percent of the basin—597,000acres—is rangeland. Palouse rangeland has bothnatural grasslands and shrub communities whichoccur in certain soils, wetlands and alkali areas.This land provides good forage for livestock andis important to various wildlife species. Rangelandareas generally are unsuited to cultivationbecause of steepness, frequent rock outcroppings,general stoniness, shallow soils, wetness, alkalinity,or elevation above irrigation systems. Mostof the range is in the channeled scabland regionof the western basin, where annual precipitationvaries from 12-15 inches. Small areas are foundalso on the isolated buttes or along major drainagesin the central and eastern basin.Rangeland, which is of primary value forlivestock production, is also important forwatershed, aesthetics, and open space.How people have changed vegetation throughmisuse of range can be seen by looking at presentratings of range conditions; about 8 percent arepoor; 49 percent, fair; 33 percent, good; and only10 percent, excellent (near-climax) condition.Various range conservation practices couldbe implemented to improve range in poor tofair ecological condition.Current livestock operations are primarily thecow-calf type. Ranches vary from a few hundredto several thousand acres. Most of the rangeis grazed during the spring, summer, and fallmonths. However, the trend has been to irrigatepastures and provide green forage during thehot, dry summer and fall months. Hay usually isfed for 90 days during the winter. This may varyfrom 30 days up to 5 months or more, dependingon the location, and the severity of winter.Livestock production is the major source ofincome on only 15-20 ranches. The remainder ofthe 590,000 acres of rangeland and 150,000 acresof grazed forest is owned by farmers who operategrain enterprises, with livestock as a secondarybut important consideration. Beef cattle predominate.Small quantities of hogs, sheep, dairycows, horses, and poultry are raised in the basin.Annual livestock sales average $10 million.Range grass is an important resource in thewestern basin.30

Forest LandThe Palouse Basin has more than 225,000acres of forest land, nearly 72 percent of whichis in Idaho. These 163,000 acres have a continuity,annual yield, and proximity to industry andmarket which makes management practical.Despite varied ownerships, these forests providea variety of products and recreation opportunities.Forested Grasslands in the Washington portionof the basin are closely related to soils inwhich they grow. Most of the Washington forestis in the northern channel scabland area. Inthis area, open stands of ponderosa pine coverapproximately 62,000 acres.Average annual precipitation ranges from 16-20 inches. Elevations range from 1,600-2,000 feet.Areas of lower elevation and precipitation aremostly grasses. Ponderosa pine occurs withbluebunch wheatgrass and Idaho fescue whereprecipitation reaches about 18 inches. Ponderosapine occupies flat areas on well-drained, moderatelypermeable soils and is found on moderateto steep slopes which rise, even slightly, abovethe general elevation of the basalt plain. Slopesalong streams support ponderosa pine, leadingdown to poorly drained soils supporting cottonwoodand aspen. Natural reproduction occursevery 20-30 years, when good pine seed yieldsand favorable growing conditions coincide. Artificialreforestation is very difficult.Shallow soils producepine and native grassin the scablands.The Turnbull Wildlife Refuge in the northernbasin—managed by the U.S. Fish and WildlifeService—covers approximately 13,000 acres ofthe forest in Washington. The timber is managedfor wildlife and has not been harvested since1973.Elsewhere in the Washington Palouse, woodlandsgrow in strips along streams where soilmoisture and precipitation provide enoughwater for tree growth. These strips are commonlyin ponderosa pine, which grows well inloess soils. Cottonwood, aspen, and willow arefound on poorly-drained soils.Douglas-fir grows on upland areas nearthe Washington-Idaho border where averageannual precipitation is about 22 inches. Thesetrees usually are found on north slopes wheresoil moisture is sufficient and soil temperatureis lower. Generally, woodlands are found onlyon steeper slopes difficult to clear and farm.Woodlands in these areas generally are wellstocked. All but those on shallow soils arecapable of fairly high production. Because ofgood growing conditions and dense understoryvegetation, stagnated thickets are uncommon.Mountain Forest of the Idaho Palouse canbe classified in associations with five majorspecies: ponderosa pine, western white pine,western hemlock, grand fir, and Douglas-fir.The most noticeable characteristic common tothe forest is that it is highly mixed.The complexity of the cropland and timberpatterns, as well as species composition of theforest, on state and private lands at lower elevations,is the result of land clearing and cuttingpractices.31

The forest resource is a valuable and significantpart of the economy in the Idaho Palouse.Thirty-nine percent of Latah County’s forestresource is within the basin. Many people livingnear the forested areas in Idaho find employmentin one of the two sawmills, others in logharvest, road construction, and forest management.Most people living in Potlatch, Princeton,and Harvard are dependent upon the forestindustry for their livelihood. Average annualstumpage value is estimated at $1.5 million.(Based on the average stumpage price of timbersold on publicly-managed lands during 1975).(n) Most of the forest is managed for a sustainedyield of forest products, and these will continueto be an important part of the basin’s economy.Approximately 27 million board feet (international1/4” log rule) of sawlogs are producedannually in the Idaho Palouse. (n) This volumeis produced from a standing inventory ofapproximately 1,264 million board feet.Logs produced in the area are marketed atvarious mills in and adjacent to the basin. ThePotlatch Company Mill at Potlatch is now usedexclusively for production of 2-inch dimensionstock. Better-grade logs are trucked to a standardsawmill at Plummer, Idaho. There is alsoa sawmill at Princeton, but logs are commonlytrucked to mills outside the basin, such as thoseat St. Maries and Julietta.Logging in the upper watershed.32

Fish and WildlifeResident fish and wildlife populations inmost of the Palouse River Basin are generallylow because of limited habitat. A small numberof deer are in rangeland areas of the westernbasin, along streams and wooded areas of thecentral basin and in the mountain foothills ofIdaho. Ring-necked pheasants occur in all butheavily forested areas of the eastern basin.Larger populations of pheasant occur in thecentral and eastern cropland portions of thebasin, where there are more brush and grassyareas, (o) Large numbers of migrating waterfowlstop in the northwestern basin in springand fall. Up to 50,000 birds have been observedat the Turnbull National Wildlife Refuge in thenorthern basin during fall migration. At least15 species of ducks use the areas along streamsand around lakes in the northwestern basin.Once abundant populations of native andintroduced upland game birds have beendeclining steadily since the early 1900’s. Theplight of wildlife in the Palouse is illustrated bythe results of an upland game bird study on a2,560-acre study area (the Colton Plot, Figure 3)between Pullman and Colton. This plot, whichis typical of agricultural land in southeastWashington, has been studied intensively byvarious investigators for the past 30 years. (p)Figure 3Downward Trend Pheasant and Hungarian Partridge in the Colton Plot.Source: Poelker, R.J. and Buas, J.O.—Habitat Improvement The Way to Higher Wildlife Populations in the Southwest WashingtonNorthwest Science, Vol. 46, No. 1, 1972.33

Pheasant and hungarian partridge populationtrends in this area have been graduallydownward since the study was first started in1940. This decline in population has coincideddirectly with the removal of vegetative cover asfarming in the areas has become more intensive.To evaluate how current farming methodsaffect wildlife, habitat, and population werestudied in conjunction with erosion studies ofthe basin. This study shows wildlife numbers areclosely related to quality of habitat, which in turnis closely related to land use and management.The best habitat is where there is the leastdisturbance from intensive farming and a goodmix of cropland, grassland, woody vegetation,and water. Wildlife habitat quality varies significantlythroughout the basin. As the supplyand distribution of water and the variety ofvegetation decreases, so do wildlife populations.Practices that contribute to erosion andsediment are also detrimental to wildlife andtheir habitats. Conversely, practices that reduceerosion and sediment are generally beneficial towildlife. The best habitat and greatest wildlifeTable 5. Wildlife Habitat Condition by Present Land UsePrecipitationZoneEvaluationAreaNumberSoilAssociationLandUseHabitatCondition% of Optimum 115” 7 Anders-Benge-Kuhl13 Anders-Benge-KuhlRangeland,Cropland23Rangeland 299 Walla Walla Cropland 115-18” 1 Athena-Calouse Cropland 215 Athena Cropland 212 Bakeoven-Tucanon-Cheney18”+ 5 Palouse-ThatunaCropland,Rangeland,ForestCropland 12 Palouse-Staley Cropland 211 Palouse-Thatuna-Naff4 Palouse-Thatuna-Tekoa8 Palouse-Athena(Upland)Cropland 1Cropland,ForestCropland 210 Palouse Cropland 215”+ 6 Palouse-Athena(Valley)CroplandPasture,Forest1 Optimum level (100%) possible only if entire land and water resource is managed specifically for wildlife.Source: Aakerman, Grover, Wildlife Evaluation in the Palouse River Basin, 1976.44183234

populations were found in the cropland-rangeareas of the western basin and along the PalouseRiver near Colfax where cropland is interspersedwith native cover.In the study, thirteen 1,200-acre evaluationareas—representing major soil associations inthe basin—were studied. Existing wildlife habitatvalues were compared with values of habitatunder optimum conditions.Low rainfall cropland areas of the basinhave the least wildlife because many are nearlydevoid of grassy areas, fence rows, grassedwaterways, or windbreaks. Sources of waterare usually scarce. Habitat generally improvesin higher rainfall cropland areas of the easternbasin where vegetative cover is heavier, watermore plentiful, and nesting and hiding placeseasier to find. Along the Palouse River habitat isgenerally quite good as are rangeland areas inthe western basin. In the Rock Lake area, grassycover is abundant, small areas of cropland arepresent, and sources of water are available towildlife.Habitat for fish in the lower Palouse River,Cow Creek, and Rock Creek is limited becauseof poor water quality, low flows, and high summerwater temperatures. The upper PalouseRiver in Idaho, popular with trout fishermen,provides good rainbow and native cutthroattrout fishing. Many smaller streams dry upduring summer. Water temperatures in moststreams exceed desirable levels during low flowperiods in summer.Lakes with prime fishing include Williams,Badger, Amber, Fishtrap, and Hog Canyon.These lakes are stocked almost exclusively withrainbow trout and managed intensively by theWashington State Game Department.Sprague and Rock Lakes, larger than anyother lakes in the basin, have severe sedimentproblems and are not fished intensively. However,they do provide good fall and winterfishing. Rock Lake is managed for trout fishing,with 10,000 to 15,000 trout planted in the lakeannually. Both lakes provide fishing for bullhead,crappie, and bass.Hunter and Labrador retriever team upfor a successful hunt.35

Recreation and TourismRecreation opportunities in the basin are limited.Proximity to the Snake River, Blue Mountains,and many lakes in and near the basin,however, provides ample recreation opportunityfor area residents. Recreation opportunitiescan be found at university athletic events andrecreational programs. The main tourist sitesare the universities, Palouse Falls, Steptoe Butte,McCroskey State Park (highland drive) and theMoscow Mountains.Wildlife provides a significant amount ofsport hunting. There was much opportunity forupland game bird hunting in the early 1900’s,but this activity has declined steadily since the1930’s. Wildlife populations have been steadilydeclining in Washington State so, WhitmanCounty still contributes a significant portion ofthe statewide harvest of pheasant, quail, chukar,and Hungarian partridge.Table 6. Game Harvest by Species;Withman County, Washington-1975SpeciesNo. HarvestedPercent ofTotal StateHarvestDeer 290 aRing-Necked Pheasant 35,670 8Ruffed Grouse 390 aDucks 9,250 1Geese 830 1Dove 5,100 2Snipe 240 aRabits 660 aJackrabbits 180 aRockchucks 7,830 11Quail 21,000 8Chukar 17,830 10Gray (Hungarian Partridge) 22,000 36Raccoon 20 aCoyote 21,120 4a=less than 1%Source: Washington State Game Department36

Literature Cited(a)Fryxall, Roald“Thru a Mirror; Darkly,” 1963(b) Parker, Rev. Samuel“Exploring Tour Beyond the RockyMountains”Ithaca, N.Y. 1844. Chapter XXII.(c)Kip, Col. Lawrence“The Indian Council at Walla Walla—1855”Eugene, Oregon 1897(d) See microfilmed copies of original landsurveys of Whitman and Spokane Countieson file in the Spokane Office of Bureauof Land Management, U.S. Departmentof the Interior.(e) Platt, John A.“Whispers from Old Genesee”Moscow, Idaho. 1959, p.1(f)(g)Smith, Joe“Bunchgrass Pioneer”nd. np. p.11Johnson, Randall“Cashup Davis”Pacific Northwesterner, Volume 12,No. 4, Spokane 1968, p.51(h) Tierey, Wm. M.“In the Heart of the Uniontown ThornCreek Country”Masters Thesis University of Idaho,Moscow, 1932, p.37(i)Mathews, Serena F. (Almquist, Ed)“Determined Bridegroom Hikes SixteenMiles through Flood”Bunchgrass Historian, Volume 1, No.4,Colfax, 1973(j) Heald, Frederick D., and Wollman, H. M.“Bunt or Stinking Smut of Wheat”State College of Washington, Agric.Exp, Station, Bulletin No. 126—Pullman, Washington 1915(k) Fairfield History Committee“Early History of Fairfield”Fairfield, Washington 1960, p.22(l) Annual Agronomy Reports-South ForkPalouse Demonstration ProjectUnpublished material prepared by SoilConservation Service, USDA, Moscow,Idaho. 1938-1942(m) U.S. Department of Interior, GeologicalSurvey, 1974“The Channeled Scablands of EasternWashington”(n) Economic Research Service, 1977“Linear Programs Progress Analysis,Palouse River Basin”(o) 1971 Statistical Yearbook, WPA, March1971, Forest Survey ReleaseNovember 3, 1962, and Research NoteINT—132.(p) Oakerman, Grover, 1976“Wildlife Evaluation in the PalouseRiver Basin”—Mimeographed report—Washington State Game Department.(q) Poelker, R. J. and Buas, J. 0.“Habitat Improvement, the Way toHigher Wildlife Populations inSouthwest Washington”Northwest Science, Vol. 46, No. 1,1972.37

PROBLEMS39

ProblemsSoil erosion is a major environmental problemin the Palouse River Basin. Erosion by runoffwater, the most prevalent, removes the mostsoil. Soil blowing and tillage erosion also resultin high soil losses.Soil erosion by runoff is widespread duringthe period of November through March. Localized,high intensity rainstorms can cause heavyrun off and serious soil erosion any month ofthe year.Several kinds of soil erosion occur. Sheetand rill erosion affects the largest area andremoves the most soil. All slopes of more than3 to 5 percent are susceptible to sheet and rillerosion under certain weather conditions andland treatments. Soil slips occur on manysteeper slopes. Silty clay soils on ridgetops areespecially vulnerable to sheet erosion when rainstrikes bare ground.Other basin problems are related to erosionand sedimentation. Gully and stream channelerosion removes soil and deposits sediments onthe fields as well as polluting streams. Productivityis being rapidly depleted as soils erode,increasing the need for mineral fertilizers.Runoff and soil movement carry nutrientsand pesticides that accumulate in the depositionareas or pollute the streams. Wildlife and fishpopulations are adversely affected, and environmentalquality of the area is greatly reduced.Water runoff, the major cause of soil erosionand sedimentation in the Palouse, results primarilyfrom snowmelt during spring. Amountsand intensities of precipitation vary during thegrowing season. Most runoff occurs when thesurface is frozen and snowmelt cannot penetratethe soil. The flow of water literally scalps thehills down to the frozen layer, carrying a largevolume of sediment. Considerable lowlandflooding and varying amounts of streambankerosion also are common over the entire 170miles of the Palouse River’s length. The PalouseRiver drainage basin discharges approximately3 inches of runoff per acre per year into theSnake River. Carried in and with these runoffwaters are almost 3 million tons of sediment.41

Sheet And Rill ErosionCroplandSheet and rill erosion have been observedsince the early 1890’s in the basin. As the originalgrass cover yielded to the plow, the soilbegan to erode.Horses were replaced by tractors and thegrass pastures were replaced by cultivated land.Increased size and speed of machines acceleratedsurface soil pulverization and subsurfacesoil compaction, which reduced its naturalability to absorb moisture. Soil was tilled andaerated more frequently. Organic matter decomposedmore rapidly than it could be replaced bynatural processes. Erosion also took its toll oforganic matter. As soil lost this natural spongelikecharacter the ability to absorb moisturewas lessened and runoff increased. This in turnincreased erosion.Sheet and rill erosion in the Palouse is influencedby many factors. The most important ofthese are: kind of soil; length and steepness ofslope; exposure; kind, amount, intensity, andfrequency of precipitation; temperature of thesoil before and during precipitation or snowmelt; kind and degree of previous erosion onthe field, and land management.People have little or no control over any ofthe factors except land management. Chief landmanagement factors are: crop sequence, tillage,crop residue management, special erosioncontrol measures, and plant cover.Cropland ErosionHistoric ObservationsAn extended study of Palouse soil erosionoffers clues to what happens, why, and how.Beginning with the 1939-40 runoff season, anannual Purvey has been made for the 1,040,000acres of cropland in Whitman County, whichcontains the bulk of basin cropland. A visualappraisal is made of soil loss by rill, gully andsoil-slip types of water-caused erosion on differentland capability classes for up to 1,500 fieldseach year. At first, only fields planted to fallgrains were studied. In later years, fields withother types of treatment were included. Fieldswere selected at random, but over the years anannual record has been kept on 10-20 “key”fields in the county.The Alutin Method of rill erosion measurementwas modified for basin conditions. Checksagainst research data several times during the38-year period indicated survey data have anerror not greater than plus or minus 25 percent.43

Erosion rates on the fields are plotted on amap each year. Different degrees of erosionseverity are delineated. The map followingpage 34 shows the accumulated effects of theseannual losses through the 1972 season. Whiledata was collected through 1977, it was notincluded in preparing the map. The map wouldremain relatively unchanged if the data for1972-1977 were included, however.Soil loss rates have not been uniform. On anannual basis, they have had wide variations. Agood example of this is the data for the 1975-76runoff season, (map, preceding page 35) whenan average of 15.1 million tons were washedfrom the fields. The following season only604,000 tons, the lowest of record, were lost.During the entire survey period to date, anaverage of 358 tons of soil has eroded fromevery acre of cropland in Whitman County. 1That is equivalent to 9.2 tons of soil movingfrom each acre of basin cropland annually! Sucha rate of erosion could remove approximately 2inches of top soil from all basin land in less than40 years. This is equivalent to the amount ofmaterial that would be required to cover eightcity blocks eight-stories high.Figure 4Annual Sheet and Rill ErosionWhitman County, Washington 1939-1977Soil ErodedMillions of Tons44

Hatter Cr.1SOIL LOSS BY WATER EROSION 1939-1972SilverLakeTotal Soil Loss28 Yrs. Tons/Ac.Avg. Soil LossPer Yr. Tons/Ac.Degree of Erosion117º3047º3047º30None to Slight 0-2 0-60Slight 2-7 60-200118º00Moderate 7-10 200-275PhilleaLakeTURNBULLNATIONALWILDLIFEREFUGECreekR. R..R ock CrSevere 10-13 275-350DamDamaaggeeChapmanLakeBadgerLakeCr.AmberLakeFishtrapLake90Very Severe 13-15 350-425S a ndersR. R.R. R.PlazaWilliamsLakeExtremely Severe 15-18 425-500NegroSpragueB. N.Bonnie LakeCOUNTYCOUNTYDownsLakeSPOKANEWHITMANCOUNTYLINCOLNData from field survey by SCSRecords for 4 years are missing.1CreekSpragueLakeCreekRosaliaR. R.Pine117º00R. R.CreekB. N.195CreekThornRockLakeCreekOakesdalePackerCowLakeCreek23ImblerEwanCreekSt. JohnPleasantCottonwoodC. M. ST.P & P.UP. & C.M. ST. P. & P.FinnelLakeValley1R. R.116º30COUNTYCOUNTYSAINTJOEWASHINGTONIDAHOCreekCreekBENEWAHLATAHCreekB. N.Cr.Dawning Cr.47º00CreekGarfieldSteptoeNATIONALWHITMAN COUNTYADAMS COUNTY47º00MeadowDeepGoldR. R.R. R.RiverR. R.Palouse9527B. N.RebelU. P.45FORESTEndicottRockPotlatchCreekFlatRiverCowCr.PalouseClearBenge116º30PrincetonFlanniganCreekSouthColfaxFlatFourCreekMileFork PalouseLa Crosseu seRosePalo27Creek26CreekFlat Cr.MissouriRiver117º30HooperMoscowParadise Cr.Pullman118º00WHITMAN CO.WHITMAN COUNTYLATAH COUNTY195FRANKLIN CO.SPOKANE CO.LINCOLN CO.HISTORIC EROSION DAMAGETO CROPLAND 1939-1972Palouse RiverBasin BENEWAH CO.95LATAH CO.ADAMS CO.GenessePERCE CO.NEZNEZ PERCE CO.WHITMAN CO.FRANKLIN CO.PALOUSE RIVER BASINIDAHO AND WASHINGTONLOCATION MAPJANUARY 197710 MILES55 0SCALE 1: 500,000Source:Base map prepared by State Staff.Thematic detail compiled by State Staff.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 M7-EN-23732-7

Hatter Cr.EROSION DAMAGE OF CROPLANDTons/AcreSilverLakeTotal TonsLossFall SeededFieldsAllCroplandDegree ofErosion117º30Acres47º3047º3076,740 Slight 0-3 3-5 153,500118º00239,205 Moderate 3-8 5-10 1,280,500PhilleaLakeTURNBULLNATIONALWILDLIFEREFUGECreekR. R.8-15 10-25 8,585,250700,021 ModeratelySevere.R ock CrDamDamaaggeeChapmanLake205,193 Severe 15-30 25-50 5,130,000BadgerLakeCr.AmberLakeFishtrapLake90S a ndersR. R.R. R.Uncultivated LandsPlazaWilliamsLakeNegroSpragueB. N.Total 1,221,159 15,138,750Bonnie LakeCOUNTYCOUNTYDownsLakeSPOKANEWHITMANCOUNTYLINCOLNCreekSpragueLakeCreekRosaliaR. R.Pine117º00R. R.CreekB. N.195CreekThornRockLakeCreekOakesdalePackerCowLakeCreek23ImblerEwanCreekSt. JohnPleasantCottonwoodC. M. ST.P & P.UP. & C.M. ST. P. & P.FinnelLakeValleyR. R.116º30COUNTYCOUNTYSAINTJOEWASHINGTONIDAHOCreekCreekBENEWAHLATAHCreekB. N.Cr.Dawning Cr.47º00CreekGarfieldSteptoeNATIONALFORESTWHITMAN COUNTYADAMS COUNTY47º00MeadowDeepGoldR. R.R. R.RiverR. R.Palouse9527B. N.RebelU. P.EndicottRockPotlatchCreekFlatRiverCowCr.PalouseClearBenge116º30PrincetonColfax47FlanniganCreekSouthFlatFourCreekMileFork PalouseLa Crosseu seRosePalo27Creek26CreekFlat Cr.MissouriRiver117º30HooperMoscowParadise Cr.Pullman118º00WHITMAN CO.WHITMAN COUNTYLATAH COUNTY195FRANKLIN CO.95SPOKANE CO.LINCOLN CO.GenessePERCE CO.NEZPalouse RiverBasin BENEWAH CO.LATAH CO.ADAMS CO.EROSION DAMAGE ON CROPLAND1975-76 RUNOFF SEASONNEZ PERCE CO.WHITMAN CO.FRANKLIN CO.PALOUSE RIVER BASINIDAHO AND WASHINGTONLOCATION MAPJANUARY 197710 MILES55 0SCALE 1: 500,000Source:Base map prepared by State Staff.Thematic detail compiled by State Staff.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 M7-EN-23732-3

Topographic ConsiderationsMost nearly-level bottom land in the PalouseRiver Basin has been classified 2 as capabilityClass II; gently-sloping land, Class III; andsteeply-sloping land, Class IV or Class VI.Comparison of land capability class acreagesand the percentages of erosion they produceprovides additional insight into where the mostsignificant problems arise. Fifty-two percent ofthe erosion comes from 22 percent of the land(Class IV and VI as shown in Table 7).Table 7. Cropland and ErosionDistribution, by Land CapabilityClass Palouse River BasinLand Capability ClassesII III IV VPercent ofCropland 7% 71% 15% 7%Percent ofErosion 2% 46% 25% 27%Soil surveys indicate that, in the relativelyshort period of time the Palouse Basin has beenfarmed (less than a century), all original topsoilhas been lost from about 10 percent of theland. One-fourth to three-fourths of the originaltop-soil has been removed from an additional60 percent of the cultivated area. Many fertilebottomland areas are covered by up to 6 feet ofsediment deposits.Data from approximately 800 soil samples ctaken from typical hill sites indicate topsoildepth and organic matter content graduallydecrease from the base to the top of a hill,especially on the south and west slopes. (Figure5.) On lower slopes, average depth of topsoil is21-24 inches, while most hilltops average lessthan 6 inches. Few narrow-topped hills haveany topsoil left. The deeper the topsoil, thehigher the organic matter content of the topsoil.This, in turn, aids in retaining scarce moisturefor crop production. Runoff and erosion are lessfrom fields with deeper topsoil.Soil movement from the hilltops and steepslopes expose larger and larger areas of lessfertilesoil. Erosion also leaves the land moreirregular and difficult to farm.2 See page 65 for detailed description of land capability classes.Figure 5Profile of typical Palouse hill, showing differences in percent slope, depth of topsoil, and soilorganic matter by land classes. Land classes are based on Soil Conservation Classification.Source: Idaho, Oregon, and Washington Agricultural Experiment Stations and Agricultural Research Service,USDA—Economics of Cropping Systems and Soil Conservation in the Palouse. Bulletin No. 2—August 196149

Potential Soil Erosion 1A major effort of this study has been todevelop a means of predicting rates of erosionin different precipitation and topographic zonesand under a variety of cropping and managementsystems. Some method of estimating presentconditions and predicting effects of changingmanagement systems was needed.The Universal Soil Loss Equation (USLE) 2has been developed for this purpose. Soils,cropping patterns, and management systemscan be evaluated for potential soil erosion rates.The equation has been adapted to the Palouseby the Agricultural Research Service and theSoil Conservation Service.Experiences and observations of the 38-yearWhitman County erosion study were keys toestablishing many of the values. Significantassistance came from field experiences of SoilConservation Service and Cooperative ExtensionService personnel.Field data for USLE computation were collectedon farms in 13 of the 20 soil associationsin the basin. Most of the cropland in the basinis within these 13 associations. One 1,400-acrearea was selected for intensive USLE analysis ineach association. 3 Results of this analysis havebeen used to predict erosion rates under existingand alternative land management systems.Data presented is not specific as to sites. It isbased on averages from the analysis. Actualerosion rates will vary because of site, climate,management, culture, and similar influences.1 For sloping land only—does not include non-eroding bottomlands.2 See glossary for definition.3 See Appendix for detailed study methodology.Palouse River BasinUnder current land management systems,projected soil erosion rates for the entirePalouse River Basin exceed 17 million tons peryear—an overall average of 14 tons of soil forevery acre of cropland in the basin.Sheet and rill erosion have been seriouswith consistent problems, but intensity hasbeen much lower in certain parts of the basin.Annual soil loss rates are usually lower in lowerprecipitation zones of the western basin and inhigh precipitation zones of the eastern basin.Highest average annual soil erosion rates havebeen consistently recorded in the intermediate15 to 18 inch precipitation zone. Soil erosionrates are highest in this intermediate precipitationarea because of the extremely steep topography,complexity of slopes, types of farmingsystems used, and climatic conditions.50

Table 8. Projected Average Annual Soil Loss Rates by Soil Associationof Cropland with ExistingLand Management System, Palouse River BasinPrecipitationZone(In/Yr.)Soil AssociationCroplandSubject toErosion(1,000 ac.)Avg. AnnualErosionRate 1(tons/acre)PotentialSoil lossRate(1,000 Tons)Less than Walla Walla 44 15 66015 Anders-Benge-Kuhl 21 15 315Bagdad 17 15 255Stratford-Roloff-Starbuck 15 5 75Rittzville-Willis 11 5 55Others 12 15 180Subtotal 120 1,54015-18 Walla Walla 108 21 2,268Athena 90 19 1,710Athena-Palouse 90 22 1,980Bakeoven-tucannon-Cheney 25 10 250Others 49 18 882Subtotal 362 7,09018+ Palouse-Thatuna 215 11 2,365Palouse-Staley 106 14 1,484Palouse-Thatuna-Naff 111 12 1,332Palouse-Thatuna-Tekoa 31 12 372Larkin-Southwick 33 7 231Freeman-Joel-Taney 11 12 132Helmer 3 6 18Santa-Carlington-Helmer 4 6 24Palouse 51 19 969Others 174 11 1,914Subtotal 739 8,841TOTAL 1,221 17,471Basin Average Soil Loss (cropland) = 14 Tons/Ac.1 Average annual Erosion Rate: potential movement of the soil from slopes.Does not imply movement from the field or into stream system.51

Figure 6Average Annual Soil Loss—CroplandPalouse River BasinPRECIPITATIONLess than 15 inchesSilverLake15-18 inches118º00Damage117º3047º30R. R.Creek47º30TURNBULLNATIONALWILDLIFEREFUGEPhilleaLakeRock Cr.18More than 18 inchesAverage Annual Precipitationin inchesR. R.90FishtrapLakeR. R.DamageBadgerLakeAmberLakeWilliamsLakeChapmanLakeSandersCr.PlazaB. N.SpragueLakeLINCOLNSpragueCOUNTYDownsLakeNegroCreekSPOKANEWHITMANBonnie LakeCOUNTYCOUNTYR. R.RosaliaCreek47º00FinnelLakeCowCreekCowLakeBengePalou seCreekADAMS COUNTYWHITMAN COUNTYRockRiverImblerC. M. ST.P & P.CreekLa CrossePackerCottonwoodRebelCreekEwanRockLakeDawning Cr.EndicottCreekFlatSt. JohnFlatValleyPineCreekPalouseCreekCreekSteptoeColfaxSouthClearFork PalouseOakesdale12”-15” 18”+UP. & C.M. ST. P. & P.B. N.23PleasantR. R.U. P.ThornB. N.R. R.195B. N.R. R.CreekFourRoseRiverMileCreekGarfield27Palouse27R. R.R. R.CreekWASHINGTONIDAHO117º00SAINTDeepCreekGoldJOE95PotlatchCr.FlanniganCreekHatter Cr.NATIONALPrincetonBENEWAHLATAH26Cr.COUNTYCOUNTYMeadowFOREST26116º30116º3047º00Hooper26117º30CreekRiverMissouriFlat Cr.FRANKLIN CO.WHITMAN CO.118º0015”-18”195PullmanParadise Cr.WHITMAN COUNTYLATAH COUNTYMoscow95NEZGenessePERCE CO.SPOKANE CO.LINCOLN CO.Palouse RiverBasinADAMS CO.BENEWAH CO.LATAH CO.Tons25Average Annual Soil LossTons Per AcreFRANKLIN CO.WHITMAN CO.NEZ PERCE CO.20LOCATION MAP1510Source: Base map prepared by SCS, Portland Carto. Unitfrom State Staff compilation, Thematic detailcompiled by State Staff.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE012”-15” 15”-18” Over 18”52

Precipitation affects kinds of crops grown,intensity of farming systems used, types of tillagesystems and equipment used, erosion rates,and sediment delivery rates. Land managementsystems, combinations of crop rotations, tillagemethods and structural treatments vary consistentlyby precipitation zones.Low Precipitation Zone (less than 15-inchaverage annual precipitation)The major cropping system used here iswinter wheat and summerfallow. The summerfallowyear is used to preserve precipitationfrom the noncrop year for the following winterwheat crop. Land is cultivated repeatedly duringthe fallow year for weed control.Release of nitrogen, ordinarily needed forbreakdown of crop residue and residual soilorganic matter breakdown during this fallowperiod, reduces the amount of commercialnitrogen needed for the wheat crop.Soil erosion ranges from 8 tons per acre annuallyunder good stubble mulch in the wheatfallowrotation to more than 23 tons per acrewhere the stubble or crop residue is depleted byrepeated cultivation. More than 90 percent of theerosion occurs during winter on land planted towheat following a season in summerfallow.The overall average soil erosion rate for thearea is projected at 13 tons per acre annually.(See page 38) Ninety percent of the more than120,000 acres of cropland in this rainfall zonehave an erosion problem. Annual soil erosionrates are predicted at 1.5 million tons per year.Intermediate Precipitation Zone (15-18-inchaverage annual precipitation)Farmers in this zone use two major croppingsystems: Winter wheat and fallow or winterwheat, spring barley and fallow. (Some farmersuse 2 years of spring barley after the winterwheat crop.) Summerfallow is practiced toinsure good moisture for winter wheat, to controlweeds and to enhance the natural release ofnutrients from the soil. Summerfallow problemsare compounded by two factors: higherrainfall and steeper slopes.Predicted soil erosion rates, under the existingwheat-fallow system on individual farms,range from approximately 11 tons per acre tomore than 30 tons per acre per year. With poormanagement, average erosion rates of morethan 40 tons per acre per year are predictedunder the wheat and fallow cropping system.Farms where wheat, barley, and fallow rotationis practiced also have high erosion rates.Some farms have an average annual erosionrate of more than 20 tons per acre. Soil erosionrates did not go below 8 tons per acre with thismanagement system. Potential erosion on individualslopes averages almost 50 tons per acreon farms with the most severe topography.Average soil erosion rates of 20 tons per acreper year are predicted for cropland in the entirearea. With more than 360,000 acres of croplandsubject to erosion, annual soil erosion of over7 million tons per year can be expected in thisarea, under existing land management systems.(See page 13)High Precipitation Zone (More than 18inches annual precipitation)The predominant cropping system in thisarea is winter wheat and peas or winter wheatand lentils in rotation. Some farmers, however,annually plant small grain or use various combinationsof winter wheat, barley, and peas. Adecreasing number of farmers also plant alfalfa,clover, and grasses in rotation with smallgrains, peas, and lentils. Only small areas aresummerfallowed. Major erosion problems areassociated with low crop residues following peaor lentil crops.The study indicated that—with limited tillageand fewer acres in peas or lentils—mostfarmers could hold soil erosion rates to an averageof near 5 tons per acre annually.Predicted sheet and rill erosion on croplandin the entire precipitation zone averages 12 tonsper acre annually. (With most of the 740,000acres of cropland in this area.) Total potentialannual sheet and rill soil erosion can beexpected to total almost 9 million tons if currentland management systems are continued.53

RangelandErosion rates from rangeland vary, dependingon range condition, soil, exposure, precipitation,and slope.In the Western United States, range soils canbe expected to lose an average of 0-2 tons peracre annually under “natural” conditions (withouthuman influence). These rates depend onsoils, exposure, slope, precipitation, and vegetativecover. When the range resource is misused,the soil erosion rate predicted for the same siteswill exceed 2 tons per acre per year (acceleratederosion).Based on present sampling techniques, thepredicted soil erosion from rangeland in thePalouse River Basin at present is about 597,000tons annually. This represents approximately1 ton per acre average for the 597,000 acres ofrangeland. Compared to erosion from cropland,these rates appear to be of lesser significance.Erosion rates on rangeland can be reducedthrough various conservation practices: stockwaterdevelopment to improve distributionof the livestock; fencing to regulate the timeof year for grazing; brush management andnoxious weed control; planned grazing systemsto maintain enough cover to protect rangelandresources, and proper grazing of vegetation tosustain or improve ecological conditions.These practices will protect the resource andcould increase “red meat” production fromrangeland.Mountain Forests And ForestedGrasslandsErosion from mountain forests and forestedgrasslands average .39 tons per acre per year.These lands are in steep areas with high precipitationand shallow, marginal soils which canleast afford erosion.Forest land differs from cropland in that notall soils are disturbed each year by cropping. Atypical harvest rotation cycle on forest lands is100 years. Harvesting operations occupy anygiven area only two or three times during thisperiod. After the initial road system is constructedand stabilized, erosion rates declinerapidly.Sheet and rill erosion are the most commonon the 225,000 acres of forest land in the basin.This amounts to an average of 72,890 tons peryear, of which about 84 percent originates inIdaho. Sheet and rill erosion rates range from.06 to .57 tons per acre per year on undisturbedforest lands. Forested land disturbed by humanactivities—such as mining, road construction,logging, and skiing—have much higher rates:from .77 to 3.95 tons per acre per year.54

Tillage ErosionTillage erosion is downhill soil movementon steep slopes caused by equipment such asthe moldboard plow and one-way disk, which“turns” the soil. Heavy soil loss results whenthe furrow is thrown downhill especially whenequipment is pulled at high speeds.Most farmers in the high precipitation zoneof the basin have used moldboard plows as theinitial or primary tillage implement ever sincethe sod was first broken. Farmers, traditionally,plow the fields by turning the furrow downhillon the upper two-thirds of the hill. From 2 to4 feet of soil has been plowed off the tops ofsharp-topped ridges, exposing unproductivesubsoil on these sites. The same thing is happeningon upper slopes of the hills, but at aslower rate. Development of banks or “berms”along field edges is another problem commonlyassociated with tillage erosion.Banks or “berms” of soil 4 to 10 feet high arecommon at the foot of slopes where the furrowhas been turned up against a fence.“Drop-offs” or cuts 16 inches to 3 feet high havebeen formed at the lower edges of areas plantedto grass for 10 to 30 years. These high berms onsteeply sloping land often result in another kindof erosion, “deep soil slips”. (page 43)Considerably less research has been done onthe causes of tillage erosion than for water erosion.Field observations over a long period bySoil Conservation Service technicians indicatedthree factors are most important in determiningthe amount of soil lost by tillage in the Palouse.They are: (1) kinds of equipment used, (2) speedof operation, and (3) steepness of slopes. Withpresent equipment, it is possible and practicalto turn the furrow slice uphill on slopes up toabout 25 percent gradient when using a moldboardplow. This is one of the basic reasons whythe break between Class III and IV land was setat that figure for soils developed under grasscover in the Palouse region.55

Deep Soil SlipsDeep soil slips occur on the steepest slopesand are closely related to snowdrifts and tillageerosion. Deep slips can occur on any soil whenthe soil profile becomes super-saturated withwater. In the Palouse they occur most often onthe Thatuna soils with slopes steeper than 40percent, especially if the lower edge of the slopehas been undercut by tillage erosion.Deep soil slips often occur in the basin as lateas May, a full month after the last significantspring rain. This usually happens after a deep,late melting snowdrift has covered the site.They often occur after a spring thaw when thelower soil profile is still frozen. A deep slip mayremove as much as 300 to 600 tons of soil froma limited spot, leaving a deep scar which isimpossible to farm over.Excess moisture on frozen soilcaused this soil slip.56

Gully ErosionIn terms of soil erosion, gully formation, oneof the most spectacular forms of erosion in thebasin, is a minor problem compared with sheetand rill erosion in terms of tons of soil erosion.It is caused by concentrated flow of runoffwater. When it does occur, sediment delivery ishigh. This kind of erosion is not common in allfields, nor does it occur every year. It usuallyoccurs when winter rain falls on frozen soil. Fallplant growth simply does not protect exposedsoil sufficiently under these conditions. Whenrain falls or snow melts, part of the moisture isabsorbed by the soil; part evaporates, and theremainder runs down the hills. As runoff wateraccumulates, it forms tiny rills. Further on, rillssometimes come together. If the slope is longenough or steep enough, the rill will become sodeep it cannot be obliterated by normal tillage.Thus, a gully is formed.Gullies were major problems in the 1920’sand 1930’s. In the mid-1930’s, numerous erosioncontrol structures and grassed waterwaysinstalled in the eastern basin did a good job ofsolving the gully erosion problem. Increaseduse of large machinery, removal of acreage controls,and lack of maintenance removed mostof these gully control structures or made themineffective. Grassed waterways have not beenused extensively in the central or western basinbecause of difficulty in establishing effectivegrasses in lower rainfall areas.Gully erosion is not a problem in the denseforested region of Idaho. However, in heavilygrazed understory areas, gullies have been aminor source of erosion.57

Stream Channel ErosionApproximately 390 miles of stream channelin the Palouse River Basin have erosion problems.These eroded channels lose an averageof 54.6 tons per mile per year. Effects of basinstream channel erosion vary widely. On steepupland forested areas, channel erosion averages65.5 tons per mile per year—13 percent of allerosion from forest lands.Mountain streams flow at high velocities andare frequently agitated by debris which deflectsflow toward the banks. Brush, tree roots, androcks are the main source of bank stabilitythroughout the forested basin. Many streams inthe lower elevations/areas have low gradientsand flow at low velocities. They have a naturaltendency to meander, which increases bankerosion. Grass sod is the primary stabilizerin cropland areas. If this cover is removed bywater or mechanical means, erosion and sedimentdelivery are accelerated.Erosion resulting from bedload movementis the primary cause of stream channel scour infast flowing mountain streams. It is often acceleratedby organic debris which constricts flowand increases natural streamflow velocity.Bedload becomes a major problem when itsettles out and plugs the low gradient streams.This accelerates flood frequency and bank erosion.Channel erosion accounts for only a smallpart of the total basin erosion, but has the highestsediment delivery rate. During high runoffperiods, damages to isolated areas on individualfarms can be very high. Undercuttingof highways, railroads, and buildings by channelerosion has caused high monetary losses.Channel meander isolates fields and adds to theoperating costs of farming.Table 9. Soil losses Due To Stream Channel Erosion By DrainageSystem, Palouse River Basin, 1978Moderate toSevereSlightDrainage SystemTotalStreamlength(miles)StreamLength(miles) 1Avg. AnnualSoil loss(tons)StreamLength(miles) 1Avg. AnnualSoil Loss(tons)Union Flat Creek 72 3 360 15 375Rebel Flat Creek 20 6 720 10 250Palouse River toColfax 70 5 600 42 1,050Downing Creek 10 5 600 3 75North Fork Palouse 54 15 1,800 20 500Deep Creek 12 6 720 3 75South Fork Palouse 35 5 600 30 750Cottonwood Creek 30 6 720 15 375Pleasant Valley 16 _ _ 8 200Thorn Creek 16 10 1,200 6 150Pine Creek 48 5 600 30 750Idaho Forest Lands 150 35 332 104 8,322Total 533 101 8,252 286 12,8721 Remainder of stream length has insignificant erosion59

Wind ErosionWind erosion is often a problem in the western,and occasionally the central part of thebasin during extremely dry years. Isolated areasof ashy soils, which contain little organic matter,will blow if strong winds come during dryconditions. Fields are most subject to damagewhen excessively tilled, thereby destroyingsoil structure, before adequate crop growth hasoccurred on the fallow land.Dry cold winds often desiccate grain plants.Enough damage occurs to some fields to necessitatespring re-seeding. In many instances,these areas are not capable of producing aspring crop because of low precipitation. Consequently,overall production is reduced. Duringthe average year, soil loss from wind erosion—even in the extremely low rainfall zones of thebasin—is less than 1 ton per acre.60

Water QualitySedimentationDetrimental effects of erosion do not endwith erosion of valuable topsoil. After soil hasbeen washed from place of origin, some of it isdeposited after traveling only a short distance;other, a considerable distance. Sediment canfill creek beds and lessen capacity to carry highflood flows.Sediment can result in flooding and otherdamages to flood plains. New flood plainsmay be created. Once sediment is depositedon bottom lands near and far from the source,croplands are damaged. Recreation lakes of thebasin and the Lower Monumental hydroelectricstorage reservoir on the Snake and lowerPalouse Rivers are filling with sediment. This hasdepleted storage capacity, degraded fisheryhabitat, increased dredging costs, and causedloss of recreation facilities—all of which adds upto millions of dollars in damages. Sediment issignificant, not only in terms of voluminous soilloss, but because plant nutrients and other pollutantsare transported with the soil particles.In the Palouse River Basin, only part of theeroded soil is delivered to the stream system.Delivery rates vary from 25-45 percent fromcropland, depending on the physical watershedcharacteristics. Delivery rates from forest landsrange from 8 to 88 percent. Using these deliveryrates the average annual sediment yield tostreams from all of the subwatersheds is estimatedat more than 5 million tons.Bottom landcovered withwater duringspring runoff.61

Table 10. Estimated Average Annual Sediment YieldIn Source To Stream system—Palouse River BasinSourceSediment ProducedBy Erosion - TonsDelivery RatioPercentSedimentYield - TonsCropland 17,471,000 30 5,167,000Noncropland* 1,646,000 11 184,000Stream Channels 21,000 90 19,000Total 19,138,000 5,370,000* Includes forest, rangeland, roads, and other areas.Not all of the 5.4 million tons of sedimentleaves the basin. Much is deposited in basinlakes, stream channels, or as flood plaindeposition.62

Table 11. Average Annual Sediment Yield, Sediment Deposit,And Sediment Leaving Palouse River BasinSubwatershed1,000AcresTotalSediment DepositedSedimentWithin The BasinYieldTons/Yr. Tons/Yr. LocationSedimentLeavingBasinTonsS. Fork Palouse 187 590,000 59,000 Channels &bottom landN. Fork Palouse 317 390,000 39,000 Channels &bottomlandRebel Flat Creek 31 232,000 23,000 Channels &bottom landCottonwoodCreek96 591,000 59,000 Channels &bottom land531,000351,000209,000532,000Pine Creek 197 786,000 770,000 Rock Lake 16,000Thorn Creek 43 231,000 226,000 Rock Lake 5,000Rock Creek 283 661,000 648,000 Rock Lake 13,000Cow Creek 428 508,000 498,000 Sprague,Finnel Lakes& othersUnion Flat Creek 202 762,000 76,000 Channels &bottom landLower Palouse—Mainstem309 619,000 62,000 Channels &bottom land10,000686,000557,000TOTAL 5,370,000 2,460,000 2,910,00063

Figure 7Predicted sediment yield by watershed from existing land management systemsSediment yields from watersheds within thebasin vary significantly. Pine Creek watershedyields almost 786,000 tons—4 tons per acre—annually. In this watershed of 308 square miles,that is 2,474 tons per square mile. CottonwoodCreek watershed, with 151 square miles, hasa predicted sediment yield of almost 591,000tons—-4,000 tons per square mile or 6 tons peracre.Sediment rates vary not only among subwatersheds,but from year to year and even fromday to day. Close correlation between turbidityand sediment is not possible. Turbidity indicateswater cloudiness caused by suspendedsolids. High sediment levels are the major causeof high turbidity levels in the Palouse River.Turbidity data have been collected twicemonthly at several locations in the basin. Sampleswere collected twice monthly at Hooper,near the mouth of the Palouse River: August1970 through September 1971, and October 1973through August 1976. They show frequent highturbidity. (Figure 8) Washington State waterquality standards permit a maximum of 10 Jacksonturbidity units beyond naturally-occurringconcentrations for the lower Palouse River. Turbiditydata indicates that the river seldom meetsand often exceeds those standards significantly.64

Figure 8Water Sample Recordings in Jackson Turbidity Units, Palouse River Basin,Hooper, Washington65

Hatter Cr.SEDIMENT DELIVERY(to streams)SHEET AND RILL EROSIONTons/Sq. MileSilverLake0-1,000117º3047º3047º301,000-2,000118º002,000-3,000PhilleaLakeTURNBULLNATIONALWILDLIFEREFUGE14z-8CreekR. R.3,000-4,000.R ock CrDamDamaaggeeChapmanLakeBadgerLakeCr.AmberLakeFishtrapLake90STREAMBANK EROSIONTons/MileS a ndersR. R.R. R.PlazaWilliamsLakeNegroSpragueB. N.25-100Bonnie LakeCOUNTYCOUNTYDownsLakeSPOKANEWHITMANCOUNTYLINCOLNCreekSpragueLakeCreekRosaliaR. R.Over 100117º0014z-5PineR. R.CreekB. N.195CreekThornRockLakeCreek14z-1 South Fork Palouse River14z-2 North Fork Palouse River14z-3 Rebel Flat Creek14z-4 Cottonwood Creek14z-5 Pine Creek14z-6 Thorn Creek14z-7 Rock Creek14z-8 Upper Cow Creek14z-8-1 Lower Cow Creek14z-9 Union Flat Creek14z-10 Palouse River14z-7Oakesdale14z-6PackerCowLakeCreek23ImblerEwanCreekSt. JohnPleasantCottonwoodC. M. ST.P & P.UP. & C.M. ST. P. & P.FinnelLakeValley116º3014z-4R. R.COUNTYCOUNTYSAINTJOEWASHINGTONIDAHOCreekCreekBENEWAHLATAHCreekB. N.Cr.Dawning Cr.47º00CreekGarfieldSteptoeNATIONALFORESTWHITMAN COUNTYADAMS COUNTY47º00MeadowDeepR. R.14z-8-1GoldR. R.RiverR. R.Palouse9527Rebel14z-2B. N.U. P.EndicottRockPotlatchCreekFlatRiverCowCr.14z-3PalouseClearBenge67116º30Princeton14z-10FlanniganCreekSouthColfax14z-9FlatFourCreekMileFork PalouseLa Crosseu seRosePalo27Creek26CreekFlat Cr.MissouriRiver117º30Hooper14z-1MoscowPullmanParadise Cr.118º00WHITMAN CO.WHITMAN COUNTYLATAH COUNTY195FRANKLIN CO.95GenessePERCE CO.NEZSPOKANE CO.LINCOLN CO.SEDIMENT YIELDPalouse RiverBasin BENEWAH CO.LATAH CO.ADAMS CO.PALOUSE RIVER BASINIDAHO AND WASHINGTONNEZ PERCE CO.WHITMAN CO.FRANKLIN CO.LOCATION MAPJANUARY 197710 MILES55 0SCALE 1: 500,000Source:Base map prepared by State Staff.Thematic detail compiled by State Staff.U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 M7-EN-23732-6

NitrogenMuch of the nitrate in Palouse River watercomes from subsurface drainage. When soil erosionrates are high, high nitrate levels also arecarried into streams along with eroding soils.Nitrate and ammonia concentrations are oftenhigh during winter and spring runoff. Nitratelevels during these periods are usually highenough to cause algae bloom in downstreamlakes and reservoirs during the summer months.Urban discharge of nitrogen occurs throughoutthe year. d During winter peak flow periods,urban discharges are overwhelmed by theheavy flows from rural reaches of the basin.Peak nitrogen levels of the Palouse River atHooper, Washington often exceed 5 mg/l (Figure9). Concentrations in smaller tributarieshave been measured as high as 22-24 mg/l.Most of the nitrate in runoff water from thebasin, originates from agricultural lands, muchresults from subsurface drainage of these lands.Rainwater and snow in this area contain verylittle nitrogen. The soil surface which is most subjectto soil erosion is low in nitrate concentrationswhen nitrate ions are leached down into the soilprofile by percolating autumn rainwater. If higherosion rates occur before the nitrate are leachedinto the lower soil profile the runoff waters andthe soil it carries will contain heavy concentrationsof nitrate. Nitrogen fertilizers typicallyused in the region are applied in the fall and areinjected about 8 inches beneath the soil surface.At this depth they are not normally picked up bysheet erosion but by severe rill erosion.Ground water percolation of nitrate can addto water pollution problems. Studies indicatesevere nitrate losses from fallow fields duringthe rainy winter months. A study conducted in1971-72 e near Pullman, Washington recordedlow concentrations of nitrate from surface runoffand high levels from subsurface drainage.PhosphorusPhosphorus is strongly bonded to soil particles.Therefore, soil phosphorus does not leachappreciably but is transported easily with soilfrom eroding fields. Total phosphate levelsin the Palouse River at Hooper, Washingtonexceeded 1 mg/l in seven of 45 samples takenbetween October 9, 1974, and September 28,1976. To date, state water quality standardshave not been established for total phosphates.However, .01 mg/l is considered an indicationof potential algae bloom problems.ChemicalsHerbicides for weed control are the mostcommon chemical applied in the Palouse RiverBasin. They usually are applied in the spring,after the high rainfall season. Nearly all studiesindicate that, except when heavy rainfall occursshortly after treatment, concentrations in runoffwaters are very low. The total volume of herbicidesrunning off the land during a crop year ismuch less than 5 percent of what was applied. fToxicity of these chemicals is extremely variable;some can persist in the aquatic environmentfor a long time. Even very low levels of thesechemicals in the runoff may be enough for environmentalconcern. Use of agricultural chemicalshas increased with changing technology.Increased applications could cause higher levelsof these materials in runoff waters unless erosionis reduced.69

Figure 9Nitrate and Nitrite Recordings, Palouse River Basin,Hooper, Washington70

EffectsCrop Yields 1Despite tremendous soil losses, crop yieldshave been increasing in much of the Palouseregion. This deters efforts to get soil and waterconservation on the land by reducing farmer andpublic concern about loss of the resource base.A close analysis of grain yields, however,reveals that alarm about heavy soil loss is justified.Erosion ultimately will seriously damagethe productive capacity of the land if allowed tocontinue.Since 1934, the average yield of wheat inWhitman County has increased from about 26bushels per acre to more than 50 bushels peracre. (See Figure 10). From 1934 to 1977, soil waseroding at an average rate of 9.5 tons of soil peracre each year. Soil erosion rates have averagedmore than 13 tons per acre since 1970. Rates over14 tons per acre are expected to continue if managementdoes not change (see projections, page37). Nearly three-fourths of a ton of soil was lostby erosion for every bushel of wheat produced. 2A common belief—that high crop yields canbe maintained without erosion control—ignoresthe long term effects and is only part of the story.During these four decades, erosion took about5,000 acres of land out of production—includingsteep slopes where deep soil slips left sites impossibleto farm. Soil was lost also from areas borderingmain drainage-ways—so much soil that thereisn’t enough left above bedrock to farm.Had it not been for declining soil resources,improved technology would have boosted averageyields considerably above the present 50bushels per acre figure. The combination of1 SCS, “Crop Yield, Soil Loss & Management Table for Soils ofWhitman County, Wash.” June 1976.2 Kaiser, Verle G., Unpublished date—”Erosion Surveys of WhitmanCounty, Wash.” 1939-1977higher-yielding grain varieties—improvedtillage—considerably more application of commercialfertilizer—and better chemical weedsprays since 1945 should have produced anaverage yield of 65-70 bushels per acre insteadof the present 50 bushels per acre (Figure 10).Most of the present yield increase is comingfrom good soil areas in each field—from areaswhere the original fertile topsoil has had onlyslight erosion damage. For example, hilltopswith eroded topsoil produced an average of15 bushels per acre in the 1930’s. With today’simproved technology, they produce an averageof 35 bushels per acre, for an increase ofabout 20 bushels per acre. In both situationsthe increased grain yield barely pays the cost ofproduction. Areas on lower slopes with about2 feet of topsoil produced 50 bushels per acrein the 1930’s and now produce 80-90 bushelsper acre—an increase of 30-40 bushels per acrewhich is attributable to improved technology(See Figure 5). Eroded hilltops now encompassabout 22 percent of the cropland (ClassesIV and VI); non-eroded bottom lands, about7 percent (Class II). As erosion continues, theaverage of land without topsoil continues toincrease.Thus, because improved technology hasproduced much greater benefits on non-erodedland than on eroded land, erosion is adverselyaffecting crop yields in the Palouse.Each additional inch of topsoil (to a total of24 inches) can increase yields by as much as2.5 bushels of wheat per acre. Soil loss studiesindicate that .05 inch of topsoil is lost from eachacre of cropland in the basin each year—or aninch of soil every 20 years. g At this rate, the riverbasin loses an approximate 150,000 bushels ofwheat production capacity each year. Using arate of 50 bushels per acre, these 150,000 bushelsare equivalent to losing 3,000 acres from production.Since 1935, the basin has lost productivecapacity equivalent to 126,000 acres of cropland.71

Figure 10Winter Wheat Production Loss From Soil Erosion—Palouse River Basin72

Soil MoistureOne reason for decreased productive capacityin the basin is loss of soil moisture holding ability.For holding moisture and air, soil with deeptopsoil can be likened to a good natural sponge.When this sponge is lost, productive capacityof the soil decreases. Each additional inch ofavailable moisture held in this sponge—beyondthe 4 inches needed to produce the plant—canproduce approximately 7 bushels of wheat. Ifmoisture is not held in the soil, it runs off andcauses erosion. Fields without severe erosionproblems are approximately 3 times as productiveas otherwise comparable fields that havelost all of the topsoil. hEven the best farm managers have some erosionproblems in the Palouse River Basin. Someerosion will occur on virtually all slopes underany conservation treatment.During years of greater-than-normal snowfall,deep drifts accumulate on steep, northand east facing slopes. When the drifts melt,serious erosion often develops on slopes belowthem. Severe rill and gully erosion slows downfarming operations. Delays can increase fueluse, disrupt schedules for farming operations,and critically affect planting and weed controloperations. Some rills become so deep farmershave to cultivate over them and replant winterwheat to spring crops, thereby reducing income.Harvest may be slowed because of rough, rilledfields. Equipment breakage problems increaseand access to portions of some fields with trucksand other equipment often is limited.Sediment on flat bottom land areas cansmother crops. Weed control problems in bottomland areas increase. Increased costs fromcrop loss, reseeding, reduced use, and cleanupof the areas can be extensive. Cleaning ditchesand waterways requires special equipmentwhich adds to farm operating costs and inconvenience.Because sediment deposition makes itdifficult to maintain grassed waterways, somefarmers have abandoned them during the last15 years. Field drains again are being damagedby gullies. As water travels overland followinga flood, extensive scour often accompaniesother flood damage.Most major drainage systems in the basinhave recurring problems with plugging bysilt. As silt fills these areas, channel capacity tocarry runoff water decreases. Crop losses andproperty damage resulting from the associatedflooding can be very costly.Excessive runoff causes severe damage.73

Removal of silt from road and highwayditches is costly, too. Repairing 2,500 miles ofcounty roads and 400 miles of state and federalhighways damaged by sedimentation anderosion in 1968 was estimated at $500,000. i Thisannual cost is now estimated at $1 million.Erosion has significant direct impacts onwildlife. As soil is depleted, capacity of land toproduce wildlife and wildlife habitat is diminished.Relationships may be subtle. In intensivelyfarmed areas such as the Palouse, reductionof wildlife populations by erosion may bereversed at first as eroded areas are abandonedto native vegetation. But as the soil resourceis lost, so too will wildlife population decline.Wildlife numbers have declined sharply ascover has been removed for high intensity farming.Removal of siltfrom road systemsis costly.Severe sedimentation, intermittent streamflows,and high water temperatures limit fishpopulations in the basin streams. Most Washingtonreaches of the streams are unsuitable forfish, particularly valued game fish such as trout.Usefulness of Rock Lake and Sprague Lakefor fisheries has been severely impaired. Fishpopulations are affected because of the sediment-coveredspawning beds in streams of thebasin. Penetration of light into the lakes is drasticallyreduced by high sediment levels. Lack ofadequate light has reduced growth of algae, thebase of the food chain for fish in these lakes.Wildlife habitatgives way to modernfarming operations.74

Recreation And Hydroelectric PowerImpacts on downstream reservoir sites alsoare significant. For example, the U.S. ArmyCorps of Engineers originally considered waterbasedrecreation sites at 27 places in connectionwith multipurpose dams along the Snake River.Plans for developing 24 of these wereabandoned because of high levels of erosionand sediment in the basin. 1 Reservoir capacityof Snake River dams is double that required forproject life power generation. The reason is tohandle silt deposits during the next 50 years.Lower Monumental Dam on the Snake River1 U.S. Army Corps of Engineers, Walla Walla District, March 1973.Social And EconomicErosion and sediment from the PalouseRiver Basin have resulted in persistent andvaried social and economic problems, some ofwhich have had significant effects on erosioncontrol decisions and measures. National farmprograms, land ownership, market limitations,time, risk, and farm income levels all affect decisionson whether to implement the measuresthat would reduce erosion.Some U.S. farm programs were instituted tohelp farmers stay economically sound. Theyhave dealt, for example, with problems of erraticcrop production, changes in labor requirementsand scientific and technical improvements. Theoriginal Agricultural Adjustment Act reducedproduction and provided crop support paymentsas key elements. Farm surpluses had amajor impact in the Palouse between 1954 and1972 by spawning programs to limit productionthrough acreage controls. Price support paymentswere based on average individual farmyields. To meet acreage restrictions, farmersreduced wheat plantings. Since alternate cropsgenerally could not be substituted because theywere either under acreage controls or unsuitedfor climatic conditions, most farmers achieved75

acreage reduction by increasing summerfallow.This not only helped reduce the wheat acreagebut also improved average yields through collectionof additional moisture in the soil and releasingsoil nitrogen. As yields increased in responseto the summerfallow, support payments basedon average yields also increased.Average annual soil erosion rates increased to11.7 tons per acre during this period, comparedwith about 8.3 tons per acre per year in previousyears. Basin cropland, soil loss during the 13years the summerfallow provision was in effect(1960-1972), is estimated at almost 54 milliontons.Additional research on new and better waysto stop erosion and workable incentives toaccomplish application of conservation practicesis needed. Past research has been very effectivein developing new crop varieties, chemicals forweed control, and improvements in crop yields.These developments have been very effectivein increasing production and maintaining farmincome levels. Continual high production has,in fact, helped mask the adverse effects of soilerosion. Research has shown how to control erosion.It is estimated farmers could reduce erosionby at least 75 percent through practices alreadyknown.Technical assistance programs have beeneffective in reducing erosion problems on manyfarms. Much more is needed, however. Muchtime and money has been directed successfullyto land users willing to cooperate in solvingerosion problems. Many who have equallysevere problems have not sought help in solvingthem. In some instances, technical assistanceefforts have not been effective in getting farmersto apply practices with maximum conservationbenefits. Efforts to encourage use ofpractices such as minimum tillage and surfaceresidues often have not been successful. Farmershave often been more interested in installingimproved drainage systems, sediment collectionponds or small gully control structures whichhave minimal conservation benefit.Conservation cost-share programs often havebeen used for more profit oriented practices tocontrol erosion. For example: in 1975, the AgriculturalConservation Program spent $122,713.00in Whitman County. Almost $98,000 of this wasused for underground tile drainage, which hasminimal erosion control benefits. Funds wereavailable for more effective conservation practicesbut few farmers applied these practices. Thefederal government pays up to 75 percent of thecost, but this has not caused enough farmers toapply these conservation practices to the land.Many concerned conservationists believeowner-operators are better soil stewards. However,only 18 percent of the land is farmed byfull-time, operator owners and the remainder bypart-time owners or tenants. Owner-operatorsare usually more willing to apply conservationpractices. The owner-operator usually knowsif his land has problems needing conservationtreatment. The owner-operator does not have alandlord to disagree with on who should pay forapplication of conservation practices.Increased mechanization on grain farmsaffects soil resources of the area, both helpingand hindering soil and water conservation.Modern tractors and tillage equipment makeit possible to farm larger acreages. The trendtoward wider equipment prevents farmers fromtreating smaller units of land according to theirsoil and site limitations. Modern farm machineryalso promotes soil and water conservation: newtools have higher clearance and sturdier frames,making it possible to operate in heavier stubble.Hydraulic controls facilitate strip-cropping andfarming adjacent to waterways and terraces.Long-term records throughout the basin substantiatethat soil conservation pays. Croppingsystems that require less tillage usually are lesscostly and better for the land. Farms with highsurface residue and low erosion rates usuallyhave more moisture available to produce a crop.Farmers who learn how to control erosion usuallyrealize greater economic benefits.Operating costs and prices received for productsinfluence erosion problems. As crop pricesdecrease, a farmer often places minimal valueon his own labor. This may lead to tillage operationsdamaging to the soil. For example, chemicalweed control usually requires less labor andhigh material costs. Tillage labor requirementsare high and material costs, low. If the farmer hasplaced a low value on his labor, usually he willchoose the tillage program.Supply and demand can impact farmingdramatically. Without price support programs,prices received for the basic soft white winterwheat crop can fluctuate greatly. Based onrecorded data, assurance of higher per-acreyields on summerfallow ground has been preferredto the combined risk of low yields andlow income in low rainfall years under recropfarming systems.76

Time affects erosion problems in the basin,too. When conservation practices are incorporatedinto a management program, timing ofsuch farm operations as seeding, weed control,and harvest often becomes more critical especiallyunder annual cropping.Overall farm income in the Palouse RiverBasin is usually good even from operationswith the highest soil loss rates. Good cropsmake some farmers reluctant to change to lesserosivepractices even though most conservationpractices bring better economic returnsover long periods. The short-term risk ofreduced income during low rainfall years oftenis greater to farmers practicing conservation.The costs of applying conservation practices—whichcan vary extremely—also influencewhether farmers will use them. Variouspractices and costs are discussed in ChaptersV, and VI, Responses to Conservation Practicesand Resource Evaluation.Literature Cited:a Kaiser, V.G., Report of Annual Erosion Damage—Whitman County, 1939-1976.b Soil Conservation Service Plant Science Hand book,Washington State Agronomy: Erosion on Croplandc Pawson, Brough, Swanson, Horner: Economicsof Cropping Systems and Soil Conservation in thePalouse, August 1961d Johnson, L.C., B.L. Caudill, D.L. Johnstone, H.H.Cheny, Surface Water Quality in the Palouse Dryland Grain Region, Washington AgriculturalExperiment Station, Bulletin 779, August 1973e Johnson-Molnau, Water Discharge—Palouse Watersheds,1971-1972.f ARS-EPA, Control of Water Pollution from Cropland,November 1975.g Kaiser, V.G. Report of Annual Erosion Drainage,Whitman County, Washington, 1939-1976.h USDA, SCS—Crop Yield Soil Loss and ManagementTables for Soils of Whitman County, Washington, June1976.i Columbia Palouse Resource Council, Analysis ofProblems and Proposals for Solution—ColumbiaPlateau in Eastern Washington, May 1968.77

RESPONSES TOCONSERVATIONPRACTICES79

Responses toConservation PracticesAs a result of sheet and rill erosion duringthe past 40 years, Palouse cropland soils haveeroded at an average rate of 9.5 tons per acre peryear. Unless management of the land is changedin the next 40 years, this rate is predicted to be14 tons, using the USLE. What can be done? Arethere solutions that will reduce erosion effectively?Can a farmer have flexibility in crops hegrows and the conservation practices he uses? Inthis section are some answers to these questions.Unless a farmer willing to move to anotherarea, he must farm the soil he has. Length andsteepness of slope and north-south or east-westfield exposures have been formed by nature.Climate—more specifically; precipitation—haspatterns over which the farmer has little control.Each of these natural factors affects how, when,and to what extent erosion occurs.The farmer usually has control over how heuses and manages the land resource: kinds ofcrops sequence for growing them; tillage practices;planting times; residue use; and erosioncontrol.Each decision has a specific impact—good orbad—on erosion rates. Each decision also affectsother decisions in a complementary or negativeway even cancelling out other decisions. Managementis a series of interacting decisions toinfluence achievement of the farmer’s goal.If conservation is an important goal, a farmermust make management decisions to reduce erosionto desired levels. The management systemmust be tailored to the individual farm: to cropsgrown, soils, topography, and climate.ResultsThis study has determined what rates of erosioncan be expected from various crop rotationsand conservation practices anywhere in thebasin. Erosion rates differ for each of the threemajor precipitation zones and for the four landcapability classes within each precipitation zone.Erosion rates shown are not specific to sites.They are based on averages from field data collectedin the study. Actual erosion rates will varydue to site, climate, management, cultural, andsimilar influences.“Land Capability Class” is a practical groupingof soils by factors that influence production:erodibility, slope, depth, surface texture, subsoilpermeability, water holding capacity, and annualprecipitation. These add to the complexity offarming. Cropland soils in the basin have beengrouped into four land capability classes.Class II soils have few limitations orhazards. Erosion rates are low, and onlysimple conservation practices are neededto control erosion. Slopes of most Class IIland in the basin are less than 7 percent.Approximately 7 percent of the croplandin the basin is Class II.Class III soils have more limitations orhazards than Class II soils. They can havesevere erosion problems. Slopes generallyrange from 7 to 25 percent. Theyneed more complex conservation practices.Approximately 71 percent of thecropland in the basin is Class III.Class IV soils have greater limitationsor hazards than Class III soils, Erosion isvery difficult to control and erosion ratesusually are high. They need very complexconservation practices if erosion is tobe controlled. Slopes range from 25 percentto 40 percent on most soils. Approximately15 percent of the cropland in thebasin is Class IV.Class VI soils have severe limitations orhazards. They are considered unsuitedfor cultivation because of erosion problems,shallowness, and/or steep slopes.Approximately 7 percent of the croplandin the basin is Class VI.Soil erosion rates are different for each landcapability class (lowest in Class II and highest inClass VI) and each precipitation zone. They alsodiffer in relation to the cropping system used.In the Palouse, annual precipitation is themajor single determinant of what can be grown.Major crop rotations that can be used in the variousprecipitation zones are shown in Table 12.The average soil erosion rates for each of thesecrop rotations with “no conservation management”is shown also.81

Selection Of Crop RotationsThe farmer must decide how he is going tofarm his land. The first decision is what cropsto grow and in what sequence. The annualprecipitation of the area in which his farm islocated has major significance on the practicalchoices available to him. The crop rotation thatis selected has major impact on the potentialerosion rates.Table 12. Predicted Average annual soil losses by CropRotation by Precipitation Zoneswith No Conservation Management 1Precipitation ZoneCrop RotationErosionRateLess than 12” WHEAT FALLOW 8 T/Ac.ANNUAL GRAIN15 T/Ac.12”- 15” WHEAT-BARLEY-FALLOW 17 T/Ac.WHEAT-FALLOW23 T/Ac.ANNUAL GRAIN20 T/Ac.WHEAT-BARLEY-PEAS22 T/Ac.15”-18” WHEAT-BARLEY-FALLOW 23 T/Ac.WHEAT-PEAS25 T/Ac.WHEAT-FALLOW30 T/Ac.WHEAT-PEAS-4 YRS.ALFALFA-4 YRS.4 T/Ac.18” + ANNUAL GRAIN 10 T/Ac.WHEAT-BARLEY-PEAS11 T/Ac.WHEAT-PEAS20 T/Ac.1 No consercation Management, as used in this section, refects a field condition with low surface residue, latefall germination, excessive soil pulverization, and farming without regard to the slope or the land.As shown in Table 12, predicted soil erosionrates vary significantly between different croprotations within each precipitation zone andbetween the same cropping system in differentprecipitation zones. There are several reasonsfor these differences.Management of crop residues is the mostimportant factor in erosion control. Crop rotations,such as annual grain which produce cropresidues each year, provide more protectivecover than wheat-fallow rotations. Increasedamounts of protective cover help reduce erosion.Another factor is tillage. Annual graincrops usuallyreceive much less tillage than rotations withfallow. More tillage usually results in a finersoil surface and a greater possibility of erosion.Annual grain crops use most of the yearlyprecipitation and provide a soil profile that canhold winter moisture. A cropping system suchas grain-fallow provides a soil profile that ispartially filled with moisture that it receivesduring spring and summer. Fallow ground,which has not had a crop on it the previousyear, is often unable to hold all the precipitationit receives during winter. Consequently, runnoffand erosion are more likely to occur.82

Two major factors can be attributed for differencesin erosion rates on similar crop rotationsin different precipitation zones; precipitationand topography.Erosion rates are higher in the 15-18” precipitationzone than the 12-15” precipitationzone. Erosion rates for annual grain are lowerin the over 18 inch precipitation zone becausemore crop residues can be produced than in the15-18” precipitation zone. Less crop residue isproduced in the 12-15” precipitation zone buterosion rates are lower because of more moderatetopography and less annual precipitation.Extremely steep topography in much of the 15”to 18” precipitation zone also contributes to thehigh erosion rates in this area.These erosion rates by land capability classare predicted for crop rotations with “no conservationmanagement.” Different conservationpractices have different levels of effectiveness inreducing erosion. Conservation practices evaluatedand displayed in the following branchingcharts are: Minimum tillage (for annual grainrotations), stubble mulching (for summerfallow),field stripcropping, divided slope farming,and terraces.Each of these different conservation practicescan reduce erosion rates at different levels. Theaverage rate of erosion reduction resulting fromeach of these practices is shown on Table 13.Table 13. Average Effectiveness of Conservation Practices-Erosion Reduction, Palouse River Basin by Precipitation ZonePrecipitation ZoneConservation Practice 12-15”% Reduction15-18”% Reduction18” +% ReductionMinimun Tillageor Stubble Mulch 35 35 35Field Stripcropping 28 15 24Divided Slope Farming 28 15 24Terraces 8 13 10Minimum tillage and/or stubble mulchgenerally have the same effectiveness in allprecipitation zones. The other practices differ ineffectiveness because of topography. The studyshows that field strips and divided slope farmingare most effective in the high and low precipitationzones. Terraces would be much moreeffective if they could be applied to all the land.Much of the land is not suitable for terraceinstallation, however. The following branchingcharts show terraces can reduce overall croplanderosion rates by only 8-13 percent. Studyresults show that where slopes can be entirelyprotected with terraces, erosion rates can bereduced by 50 percent.83

Management EffectsA series of branching line charts have beendeveloped to show effects of various conservationpractices. These charts provide flexibilityin practice selection and in the order of application.If some conservation practices have beenapplied to the land already, the effectiveness ofthese and of applying additional practices canbe determined. The charts also show relationshipsof conservation practices to soil erosionrates for each land capability class.To use the branching charts, follow thesesteps:1. Select the precipitation zone where thefarm is located.2. Select the desired crop rotation.3. Note the average annual erosion ratefor the crop rotation selected for thegiven precipitation zone.4. Note the average annual erosion ratesby and capability class for the croprotation selected.(Step 1)Precipitation Zone = 18+ inchesAverage Annual Soil Erosion Rate inTons/AcreLand Capability ClassCrop Rotation All Land II III IV VIWheat-Peas 20 Tons 6 16 31 45(Step 2) (Step 3) (Step 4)Each Land capability class is color coded on the charts for ease in identification of effects of applying additional conservation practices tothese areas.5. Compare effects of various conservationpractices on reducing erosionrates of the basic crop rotation.Choices of conservationmeasures to useAverage erosion rates remainingafter each practice has beeninstalledWHEAT-PEAS-20T6 16 32 45MinimumTillageField Strips orDivided SlopesTerraces6T15T18T2 5 9 135 12 24 345 14 29 41Low Surface ResidueLate Fall GerminationExcess Foil PulverizationFarming Without Regard To Slope6. Once the impact of the first selectedpractice is found, follow that branch ofthe chart to see how additional practiceapplication will further reduce erosion.7. For Conservation Practice descriptionssee pages 119 to 12884

MAJOR APPLICABLE ROTATIONSLess than 12” Annual PrecipitationAverage Annual SoilErosion Rates—Tons/AcreLess Than 12” WHEAT-FALLOW 8 TONSPrecipitationThe above erosion rates reflect the influence of the rotation with a management system generally as follows: Conservationpractices have not been applied. Fall seed germination is generally late; crop residues have been incorporated into the soiland not left on the surface. Tillage has reduced most clods to a very small size.85

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill ErosionLess than 12” Annual PrecipitationField Strips orDivided Slopes 6T 1 4 8 23WHEAT-FALLOW - 8T 2 5 11 32Stubble Mulch andMinimum Tillage 3T 1 2 4 11Terraces 7T 2 5 10 29Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocationsmay, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Stubble Mulch 2T 1 1 3 8Terraces 5T 1 4 7 20Field Strips orDivided Slopes 2T 1 1 3 8Terraces 2T 1 2 3 10Stubble Mulch 2T 1 2 3 10Field Strips orDivided Slopes 5T 1 4 7 20Terraces 2T 1 1 2 7Stubble Mulch 2T 1 1 2 7Terraces 2T 1 1 2 7Field Strips orDivided Slopes 2T 1 1 2 7Field Strips orDivided Slopes 2T 1 1 2 7Stubble Mulch 2T 1 1 2 787

MAJOR APPLICABLE ROTATIONS12”–15” Annual PrecipitationAverage Annual SoilErosion Rates—Tons/Acre12”-15” ANNUAL GRAIN 15 TONSPrecipitation WHEAT-BARLEY-FALLOW 17 TONSWHEAT-FALLOW23 TONSThe above erosion rates reflect the influence of the rotation with a management system generally as follows: Conservationpractices have not been applied. Fall seed germination is generally late; crop residues have been incorporated into the soiland not left on the surface. Tillage has reduced most clods to a very small size.89

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill Erosion12”–15” Annual PrecipitationField Strips orDivided Slopes 12T 3 7 18 54WHEAT-BARLEY-17TFALLOW4 10 25 75Stubble Mulch andMinimum Tillage 6T 1 3 9 26Terraces 16T 4 9 23 69Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Stubble Mulch andMinimum Tillage 4T 1 2 6 17Terraces 11T 3 6 17 50Field Strips orDivided Slopes 4T 1 2 6 18Terraces 5T 1 3 8 23Stubble Mulch andMedium Tillage 5T 1 3 8 23Field Strips orDivided Slopes 11T 3 6 17 50Terraces 4T 1 2 6 17Stubble Mulch andMinimum Tillage 4T 1 2 6 17Terraces 4T 1 2 6 17Field Strips orDivided Slopes 4T 1 2 6 17Field Strips orDivided Slopes 4T1 2 6 17Stubble Mulch andMinimum Tillage 4T 1 2 6 1791

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill Erosion12”–15” Annual PrecipitationField Strips orDivided Slopes 17T 5 10 24 68Stubble Mulch 8T 2 5 12 32WHEAT FALLOW-23T 7 14 34 95Terraces 21T 6 13 31 87Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Stubble Mulch 6T 2 3 8 23Terraces 15T 4 9 22 63Field Strips orDivided Slopes 6T 2 3 8 23Terraces 7T 2 5 11 29Stubble Mulch 7T 2 4 11 29Field Strips orDivided Slopes 15T 4 9 22 63Terraces 5T 2 3 7 21Stubble Mulch 5T 2 3 7 21Terraces 5T 2 3 7 21Field Strips orDivided Slopes 5T 2 3 7 21Field Strips orDivided Slopes 5T 2 3 7 21Stubble Mulch 5T 2 3 7 2193

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill Erosion12”–15” Annual PrecipitationMinimumTillage 5TANNUAL GRAIN - 15T4 9 22 65Terraces 14TLow Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 1 3 7 224 8 20 60Terraces 5T 1 3 6 20MinimumTillage 5T 1 3 6 2095

MAJOR APPLICABLE ROTATIONS15”–18” Annual PrecipitationAverage Annual SoilErosion Rates—Tons/Acre15”-18” ANNUAL GRAIN 20 TONSPrecipitation WHEAT-BARLEY-PEAS 22 TONSWHEAT-BARLEY-FALLOW23 TONSWHEAT-PEAS25 TONSWHEAT-FALLOW30 TONSThe above erosion rates reflect the influence of the rotation with a management system generally as follows: Conservationpractices have not been applied. Fall seed germination is generally late; crop residues have been incorporated into the soiland not left on the surface. Tillage has reduced most clods to a very small size.97

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill Erosion15”–18” Annual PrecipitationMinimumTillage 7T 1 5 12 13ANNUAL GRAIN-20T3 15 36 37Field Strips orDivided Slopes 17T 3 13 31 32Terraces 17T 3 13 31 32Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Field Strips orDivided Slopes 6T 1 4 10 11Terraces 6T 1 4 10 11MinimumTillage 6T 1 4 10 11Terraces 15T 3 11 27 28MinimumTillage 6T 1 4 10 11Field Strips orDivided Slopes 15T 3 11 27 28Terraces 5T 1 3 9 10Field Strips orDivided Slopes 5T 1 3 9 10Terraces 5T 1 3 9 10MinimumTillage 5T 1 3 9 10Field Strips orDivided Slopes 5T 1 3 9 10MinimumTillage 5T 1 3 9 1099

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill Erosion15”–18” Annual PrecipitationMinimumTillage 7T 1 5 12 16WHEAT-BARLEY-22TPEAS3 16 35 48Field Strips orDivided Slopes 19T 3 14 30 41Terraces 19T 3 14 30 42Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Field Strips orDivided Slopes 6T 1 4 10 14Terraces 6T 1 4 10 14MinimumTillage 6T 1 4 10 14Terraces 16T 3 12 26 36MinimumTillage 6T 1 4 10 14Field Strips orDivided Slopes 16T 3 12 26 36Terraces 5T 1 4 9 12Field Strips orDivided Slopes 5T 1 4 9 12Terraces 5T 1 4 9 12MinimumTillage 5T 1 4 9 12Field Strips orDivided Slopes 5T 1 4 9 12MinimumTillage 5T 1 4 9 12101

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill Erosion15”–18” Annual PrecipitationField Strips orDivided Slopes 20T 3 14 37 43WHEAT-BARLEY-23TFALLOW3 16 44 50Stubble Mulch andMinimum Tillage 8T 1 5 15 17Terraces 20T 3 14 38 44Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Stubble Mulch andMinimum Tillage 7T 1 5 13 15Terraces 17T 3 12 32 37Field Strips orDivided Slopes 7T 1 5 13 15Terraces 7T 1 4 13 15Stubble Mulch andMinimum Tillage 7T 1 4 13 15Field Strips orDivided Slopes 17T 3 12 32 37Terraces 6T 1 4 11 13Stubble Mulch andMinimum Tillage 6T 1 4 11 13Terraces 6T 1 4 11 13Field Strips orDivided Slopes 6T 1 4 11 13Field Strips orDivided Slopes 6T 1 4 11 13Stubble Mulch andMinimum Tillage 6T 1 4 11 13103

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill Erosion15”–18” Annual PrecipitationMinimumTillage 9T 1 6 15 19WHEAT-PEAS-25T4 19 45 55Field Strips orDivided Slopes 21T 3 16 38 47Terraces 22T 3 17 39 48Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Field Strips orDivided Slopes 7T 1 5 13 16Terraces 7T 1 5 13 17MinimumTillage 7T 1 5 13 16Terraces 18T 3 14 33 41MinimumTillage 7T 1 5 13Field Strips orDivided Slopes 18T 3 14 33 4116Terraces 6T 1 4 11 14Field Strips orDivided Slopes 6T 1 4 11 14Terraces 6T 1 4 11 14MinimumTillage 6T 1 4 11 14Field Strips orDivided Slopes 6T 1 4 11 14MinimumTillage 6T 1 4 11 14105

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill Erosion15”–18” Annual PrecipitationField Strips orDivided Slopes 26T 3 20 48 58Stubble Mulch 10T 1 8 19 23WHEAT-FALLOW-30T 4 23 56 68Terraces 26T 3 20 49 59Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Stubble Mulch 9T 1 7 16 20Terraces 22T 3 17 42 50Field Strips orDivided Slopes 9T 1 7 16 20Terraces 9T 1 7 16 20Stubble Mulch 9T 1 7 17 20Field Strips orDivided Slopes 22T 3 17 42 50Terraces 8T 1 6 14 17Stubble Mulch 8T 1 6 14 17Terraces 8T 1 6 14 17Field Strips orDivided Slopes 8T 1 6 14 17Field Strips orDivided Slopes 8T 1 6 14 17Stubble Mulch 8T 1 6 14 17107

MAJOR APPLICABLE ROTATIONSMore than 18” Annual PrecipitationAverage Annual SoilErosion Rates—Tons/AcreMORE THAN 18”WHEAT-4 YEARSPrecipitation ALFALFA-4 YEARS 4 TONSANNUALGRAIN10 TONSWHEAT-BARLEY-PEAS11 TONSWHEAT-PEAS20 TONSThe above erosion rates reflect the influence of the rotation with a management system generally as follows: Conservationpractices have not been applied. Fall seed germination is generally late; crop residues have been incorporated into the soiland not left on the surface. Tillage has reduced most clods to a very small size.109

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill ErosionAbove 18” Annual PrecipitationWHEAT-PEAS 4 Yrs.-4TALFALFA 4Yrs.1 3 6 9Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 MinimumTillage 1TField Strips orDivided Slopes 3TTerraces 4T1 1 2 31 2 5 71 3 5 8111

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill ErosionAbove 18” Annual PrecipitationMinimumTillage 3T 1 2 5 7ANNUAL GRAIN-10T3 8 16 23Field Strips orDivided Slopes 8T 2 6 12 17Terraces 9T 3 7 14 21Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Field Strips orDivided Slopes 2T 1 2 4 5Terraces 3T 1 2 5 6MinimumTillage 2T 1 2 4 5Terraces 7T 2 5 11 16MinimumTillage 3T 1 2 5 6Field Strips orDivided Slopes 7T 2 5 11 16Terraces 2T 1 2 4 5Field Strips orDivided Slopes 2T 1 2 4 5Terraces 2T 1 2 4 5MinimumTillage 2T 1 2 4 5Field Strips orDivided Slopes 2T 1 2 4 5MinimumTillage 2T 1 2 4 5113

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill ErosionAbove 18” Annual PrecipitationMinimumTillage 5T 1 5 8 13WHEAT-BARLEY-11TPEAS4 9 18 26Field Strips orDivided Slopes 8T 3 7 14 20Terraces 10T 4 8 16 23Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Field Strips ofDivided Slopes 4T 2 4 8 12Terraces 4T 1 2 7 9MinimumTillage 4T 2 4 8 12Terraces 7T 3 6 13 18MinimumTillage 4T 1 2 7 9Field Strips orDivided Slopes 7T 3 6 13 18Terraces 3T 1 3 6 8Field Strips orDivided Slopes 3T 1 3 6 8Terraces 3T 1 3 6 8MinimumTillage 3T 1 3 6 8Field Strips orDivided Slopes 3T 1 3 6 8MinimumTillage 2T 1 3 6 8115

CONSERVATION PRACTICE EFFECTSTo Reduce Sheet and Rill ErosionAbove 18” Annual PrecipitationMinimumTillage 7T 2 5 9 13WHEAT-PEAS-20T6 16 32 45Field Strips orDivided Slopes 15T 5 12 24 34Terraces 18T 5 14 29 41Low Surface ResidueLate Fall GerminationExcess Soil PulverizationFarming Without Regard to Slope“This information is not site specific and individuallocations may, due to site, climate, management,cultural, and similar experience valuesmeasurably different than those shown.”U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977 Field Strips ofDivided Slopes 5T 2 4 7 10Terraces 5T 2 4 8 12MinimumTillage 5T 2 4 7 10Terraces 14T 4 11 22 31MinimumTillage 5T 2 4 8 12Field Strips orDivided Slopes 14T 4 11 22 31Terraces 4T 1 3 6 9Field Strips orDivided Slopes 4T 1 3 6 9Terraces 4T 1 3 6 9MinimumTillage 4T 1 3 6 9Field Strips orDivided Slopes 4T 1 3 6 9MinimumTillage 4T 1 3 6 9117

Practice DescriptionThe branch charts list conservation practicesthat are commonly accepted and do reducesheet and rill erosion. The list is short. Otherpractices could be applied, such as contourstrips, but the physical difficulties and economiccosts limited their consideration. The effectivenessof other conservation practices not shownhere can be determined readily, however.It should be noted that all practices are notequally effective in reducing soil erosion onvarying classes of land. Classes II and III landsmay not require or respond to practices necessaryon steeper lands.The following conservation practice sheetsshow the practices that are most effective, whythey are effective, where they can be used, andthings to consider in their use.119

Minimum TillageCloddy soil surface was created by limitingnumber and speed of tillage operations.WHATLimiting the number and speed of tillage operations to preserve clods andcrop residues for soil protection.WHY1. To improve intake of soil moisture.2. To maintain a rough soil surface.3. To reduce tillage costs.4. To protect fall planted crops fromwinter winds.WHEREOn all cropland where crops are growntwo years or more in succession.THINGS TO CONSIDER1. Timing of tillage operations to maintaincloddy surface.2. Adequate weed control.3. The need for adequate surface residues.120

Stubble Mulch TillageFall chiseling as the first operation to spreadstraw and weed seeds and to open to soilsurface for moisture intake.WHATYear-round management of crop residuesto keep protective cover on soilsurface.WHY1. To provide continuous surface cover tosoil which will prevent wind and watererosion.2. To maintain soil binding characteristicsas long as possible.3. To maintain good moisture intake andsave soil moisture.WHEREOn all dry cropland to be summerfallowed.THINGS TO CONSIDER1. Adequate clearance of tillage equipment.2. Time tillage operations to retainmaximum surface residues.3. Weed control during wet periods.4. Need for extra nitrogen during first fewyears.5. Need for the right drill to seed inmulch.121

Field StripsField strips of grain and fallow gives protectionfrom runoff on this slope.WHATTwo or more strips of one or morecrops alternated with grass or fallowacross a slope to reduce erosion.WHEREOn sloping dry cropland.WHY1. Altering cover conditions on a slope soprotective cover absorbs runoff frommore erosive strips.2. To improve soil moisture intake ability.3. To reduce snow drifting.4. To reduce grain fire hazard.5. To reduce fuel costs.THINGS TO CONSIDER1. Change strip edge location every twoyears to prevent formation of ridges.2. Extra weed control at strip edges isneeded.3. Field access needs to be planned.4. More management is needed to usefall stubble for livestock.5. Use of grass strips in the system.122

Divided Slope FarmingWheat grown on upper slope, includinghilltop, with dry peas on lower slople.WHATUse of more than one crop or fieldcondition to divide slopes.WHEREOn sloping dry cropland.WHY1. Altering cover conditions on a slopeso protective cover on part of the slopeabsorb runoff from more erosive portionsof the slope.2. To give surface protection to half ofthe slope at all times.3. To keep tillage operations more nearlyon the contour.THINGS TO CONSIDER1. Moving the cropline every secondyear to avoid ridges or dead furrows.2. Extra weed control may be necessarywhere slope divides.3. Field access needs planning.4. If moldboard plow is used, turn furrowuphill.5. Use of tillage implements other thanmoldboard plow.123

TerracesTerraces were installed to safety dispose of runoff water.WHATA series of channels with supportingridges across a slope to carry runoffwater to a protected outlet.WHEREOn cropland field where slopes areless than 20 percent and suitable outletscan be provided.WHY1. To reduce the length of a slope andcarry runoff water to a protected outlet.2. To provide a cross slope line for tillageoperations.3. To reduce sediment in runoff water.4. To prevent gully development.THINGS TO CONSIDER1. Suitable outlets must be planned forgradient terraces.2. Field access must be considered.3. Tillage near terrace may cause ridgesto form.4. Tillage will reduce terrace height.5. Periodic maintenance is required.6. Spacing of terraces and width of tillageequipment.7. All field operations will change andshould follow rather than cross terraces.124

Retirement From CultivationGrass seeded on eroded hilltops preventloss of soil and water.WHATSeeding grass and/or legumes orplanting trees on areas subject to higherosion hazard, to provide permanentprotective cover.WHEREOn all steep cropland that is subject tosevere water or tillage erosion.WHY1. To provide continuous protective coverto soil surface.2. To hold winter snow and reduce drifting.3. To reduce deposition of eroded soil onproductive lower slopes.THINGS TO CONSIDER1. Soil slips can occur. Plow furrowshould be turned uphill against thegrass vegetation.2. Extra weed control may be needednext to the grass seeding.3. Field access must be planned.125

No-Till FarmingSeeding winter wheat into a stand of undisturbed stubblewith a special built heavy duty drill.WHATNo-Till Farming—Seeding a cropdirectly into a seedbed of undisturbedcrop residues.WHEREOn all dryland croplands of theintermediate and high precipitationzones.WHY1. Soil surface is never exposed to windand water erosion.2. Soil structure is maintained.3. Soil surface is always ready for intakeof moisture.4. Soil tillage is eliminated.THINGS TO CONSIDER1. Adequate establishment of stand.2. Reliance on herbicides for weed control.3. Availability of proper drill.4. Low plant vigor.5. Limited research.126

Grass WaterwayGrass seeded in field waterway to provide aprotected area for runoff water.WHATAn area for disposal of field runoffwater that is protected by vegetation.WHEREIn field areas where runoff water concentrates,that need protection againstgully erosion.WHY1. To protect areas of concentrated flowagainst gully erosion.2. To provide safe crossing with fieldequipment.3. To provide a protected outlet for disposalof runoff water from terraces.4. To provide a filter strip to remove siltsfrom runoff water.THINGS TO CONSIDER1. Amount of runoff water that will flow init.2. Adequate soil moisture for construction.3. Good moisture at waterway seedingtime.4. Proper design, construction andmaintenance.5. Proper tillage to avoid ridges whichmay form at edge of grass.6. Need for fertilizer and cutting of grass.7. Damage to grass by equipment travel.8. Need for hydraulic equipment.127

Analysis of the branching charts, whichfollow page 85 shows that some conservationpractices are much more effective than others.Minimum tillage and/or stubble mulch onsummerfallow ground will reduce erosion ratesby approximately 35 percent over systems with“no conservation management”.Retirement of Class IV and VI land can reduceerosion rates by 50 percent. These areas encompass14 percent of the land in the 12-15 inchprecipitation zone, 27 percent of the land in the15-18 inch precipitation zone, and 20 percent ofthe land in the over 18 inch precipitation zone.If these areas are retired from cultivation, it isexpected that an additional 10-15 percent of theland would have to be retired also because offield access problems caused by the retirement.No-till farming can be one of the most effectivepractices for erosion control. Since it is nowin the early development stage, more researchand testing are needed before this practice canbe widely recommended or applied. For thesereasons it has not been included on the branchingcharts. No-till farming can reduce erosionrates to: 2 tons per acre in 12-15 inch precipitationzone, slightly over 2 tons per acre in 15-18inch precipitation zone and roughly over 1 tonper acre in the over 18 inch precipitation zone.Occasional (every other or every third year)use of no-till shows much promise. Studies areunderway on improvement of no-till farmingequipment to make the practice feasible.Debris basins (barriers or dams constructedacross a waterway or at other suitable locationsto collect silt or sediment) can have beneficiallong-term effects, they do not stop erosion butcollect sediment before it becomes a problem indownstream areas. If other good land treatmentpractices are not applied, they usually fill withsilt soon after construction. Construction costsare generally high.128

RESOURCEEVALUATION

Resource EvaluationThe effects of applying conservation practiceson cropland are discussed in this chapter.The present condition (1975 cost-pricebase) is considered to be representative offuture conditions if conservation measures arenot applied. Future technological gains areexpected to be offset by losses of productivitybecause of soil erosion.For the 1975 base year, gross receipts fromthe 1,221,000 acres of cropland were estimatedto be 148 million. These gross receipts areassociated with a predicted annual sheet andrill erosion loss of 17.6 million tons. Approximatelyone ton of soil was lost for every $8.40 ofincome received.This chapter will discuss and display theeffects of conservation treatment for eachprecipitation zone. In addition, a present conditionor future without action alternative, analternative utilizing high residue management,an alternative providing the highest possibleon-farm net income, and a maximum erosionreduction alternative for each precipitation zoneare discussed and displayed.A recommended plan for implementation hasnot been selected since the various alternativeswill be used in development of state and localwater quality programs. Selection of a recommendedplan would be inappropriate since thevarious alternatives will be used as decisionsare made in implementing these programs. AsPL 92-500 is implemented, various best managementpractices will be developed for the basin.The alternatives presented can be used to evaluatethe potential environmental and economicimpacts of those practices. Within the limitationsof the study, one alternative has been identifiedas providing the greatest contribution towardsenvironmental quality (EQ). The alternative thathas the greatest contribution to economic developmenthas also been identified (ED).Following the discussion and display of thefour alternatives for each precipitation zone is asection which discusses no till farming, conclusions,and implementation proposals.131

Effects of ConservationTreatment LowPrecipitation Zone(12-15 inch annual precipitation)If high residue management were appliedreduction of erosion could be equal to thelevel possible from applying both terracesand divided slopes. 1 By applying high residuemanagement returns could be increased. Themaximum erosion reduction treatment 2 is highresidue management with divided slopes andterraces. With this treatment, erosion couldbe reduced to 5 tons, a 62 percent reduction.Returns would be reduced $9 from the maximumlevel which would be achieved at the 8tons per acre erosion level (a 46 percent reductionfrom present conditions) with all highresidue management.Wildlife habitat values in this precipitationzone are very low. Under present conditions,most cropland areas are estimated to have wildlifehabitat values of less than 1 percent of thosethat could be expected if the area were managedfor optimum wildlife habitat conditions. Inthe sample plot, approximately 99 percent of thearea is used for crop production and only about1 percent of the area has herbaceous cover. Presentmanagement of the cropland provides somefood for wildlife. Lack of cover is the primarylimiting factor. In addition, there is very littlewater available for wildlife. The application ofmost conservation practices will have very littleeffect on wildlife populations because the areawill continue to lack permanent cover and permanentsources of drinking water.1 Divided slopes, also includes field strips where appropriate.2 Maximum Erosion Reduction; the maximum level possible withoutland retirement. (table) pg. 142132

Table 14. Effect of Conservation Treatment In Low Precipitation Zone-Palouse River BasinTreatmentErosionRateTons/Ac.GrossReceipts$/Ac.ProductionCost $/Ac. 1Returns$/Ac.Wildlife NumberHabitat Avian% Optimum 2 Species 2Present CroppingSystems & ResidueManagement Level 13 74 33 41 .2 8w/Terraces 12 74 39 35 .2-.5 8-9w/Divided Slopes 3 10 74 36 38 .2-.5 8-9w/Terraces &Divided Slopes 8 76 31 45 .5-.6 10-11w/High ResidueManagement 7 76 37 39 .5-.6 10-11w/High ResidueManagement &Divided Slopes 3 6 76 34 41 .5-.6 10-11w/High ResidueManagement &Divided Slopes 3& Terraces 5 76 40 36 .6 111 Land cost of $39/acre have not been included in this table2 Compiled from G-9 evaluation plot3 Field stripcropping will be applied where applicable133

Alternatives Analysis andComparisonsThe Present Or Future Without Alternativeindicates that over 90 percent of the 120,000acres is in a wheat-fallow cropping system.Presently, two-thirds of the operators using thiscropping system are using better than averageresidue management; one third of the farms areretaining far less than the needed amount ofresidue required to stubble mulch.The 10,000 acres of recrop barley is managedone half with minimum tillage and one halfwith a lower quality residue management.The Second Alternative: Increasing ManagementTo The Optimum Level. (E.D.) SCS fieldstudies indicate high residue management usuallyresults in more moisture being available forcrop production and reductions in the number oftillage operations. This reduces production costs.With annual grain, maintaining high residuelevels requires fewer tillage operations; therefore,a savings in machinery and labor costs isachieved. Increased chemical costs offset thesesavings. This alternative provided the highestlevel of economic development.The Third Alternative: High Residue,Increased—Wheat—Barley—Fallow. Thisalternative allowed shifts in cropping systemsas well as shifts in conservation practices. Alinear program developed by the Economics,Statistics, and Cooperatives Service (ESCS) wasused to analyze these conditions. The computerprogram selected the cropping system thatwould provide the highest possible return toland, capital and management for each erosionlevel.Using this system, it is concluded that thehighest possible economic return could beachieved when the erosion rate was about 8tons per acre. This would result in a 46 percenterosion reduction. For this system, 40 percentof the cropland would be in a wheat-stubblemulch fallow system. Wheat-barley-stubblemulch fallow would occupy the remaining 60percent of the cropland.Alternative Four—The Maximum ErosionReduction. (E.Q.) This alternative includedmaintaining present cropping systems, butincreasing management to the optimum level,installing strips and terraces wherever possible,and seeding out all the Class IV e and VI e landplus 10 percent of the Class III land adjacentto the Class IV e and VI e land. Terraces can beinstalled on an estimated 50 percent of the cropland.Erosion reduction rates and cost figureshave been prorated on all acres in the precipitationzone. Fifty percent of the acres receiveno benefit from terraces yet they have beenincluded in the erosion and cost computations.In areas where terraces can be installed, theyare a cost effective method of erosion reduction.For purposes of analysis, it has been assumedthat terraces will cost about $6 per acre and willprovide no benefit other than erosion control.No increase in yield has been attributed to fieldstrips or divided slope farming. Labor machinerycosts will increase 10 percent. An amortized installationcost of $1 per acre has been included. Fieldstrips or divided slopes are applicable to all croppingsequences except annual grain.Within the limits of the study, this alternativeprovides the greatest contribution to environmentalquality. (See table 15)134

Table 15. Effects of AlternativesAnd Comparisons To Future WithoutEconomic Development Environmental Quality Social Well-BeingLow Precipitation Beneficial Adverse Beneficial & Adverse Beneficial & AdverseALT #1 Future without action Gross Receipts 1$ MillionsCost 2 3 4$ Millions73,000 acres ofwheat-stubble mulchfallow37,000 acres ofwheat-fallow5,000 acres ofmininum-till barley5,000 acres of barleyThe value to producersof outputs of goodsand services5.52.6.4.48.95.02.8.4.41. Predicted average annualsheet and rill erosion of 1.5,million tons per year.2. Sediment delivery rate of 18%3. Sediment yield to streams of.3 million tons per year4. Wildlife habitat value of .2%of optimum5. Number of Avian speciesexpected, 8/100 ac.6. Use of 1.5 million gallons offuel7. Use of 3.4 million pounds offertilizerThe value of on-farmresources required. 8.6Net effects. .3ALT #2Future without actioncrops5 with highresidue management110,000 acres ofwheat-stubble mulchfallow10,000 acres ofminimum-till barleyThe value to producersof outputs of goodsand services.The value of on-farmresources required.Net beneficialeffects.Net effects comparedto future without.8.4.79.1.6.37.6.98.51. Predicted average annualsheet and rill erosion to .9million tons; a 40% reduction.2. Sediment yield to streamsof .2 million tons; a reductionof .1 million tons.3. Wildlife habitat percent ofoptimum increased from .2to .6; a 4% increase.4. Number of Avian species increasefrom 8 to 11; anincrease of 3/100 ac.5. Use of 1.5 million gallonsof fuel. No change.6. Use of 3.3 million poundsof fertilizer; a decrease of.1 million.7. Possibility of future waterquality improvement.1. Produce 3 millionbushels of wheat1. Produce 3 millionbushels of wheat.2. Average incomeincrease fromfuture without.3. Risk of cropfailure decreases.4. Requires moretechnically-skilledoperators.5. Increase ofeducationalrequirements6. Increased dependenceonchemical weedcontrol.ALT #3High residue, includewheat-barley-fallow44,000 acres of wheatstubblemulch fallow76,000 acres of wheatbarley-stubblemulchfallowThe value to producersor output of goods andservices.3.35.79.03.05.81. Predicted average annualsheet and rill erosion reducedto 1 million tons; a36% reduction.2. Wildlife habitat percent ofoptimum increased .2 to .6;an increase of .4.3. Number of Avain speciesthe value of on-farm8.8increased 3 to 11/100 ac.resources required.4. Fuel use 1.5 million gallons.No change.Net effects .25. Fertilizer use decrease .3Net effects compared-.1million pounds to 3.1 millionto future without.pounds.6. Sediment yield to streams of.2 million tons; a reductionof .1 million tons.7. Possibility of future waterquality improvement.1. Reduce wheatproduction .4million bushels to2.6 bushels.2. Average incomeincreases.3. Risk of crop failureincreases.4. Require additionaltechnical ability.5. Increase educationalrequirements.6. Increase barleyproduction.7. Sensitivity totimeliness ofoperation increased.8. Poor conservationfarmers will have tofind new vocations136

Table 15. Effects of AlternativesAnd Comparisons To Future WithoutEconomic Development Environmental Quality Social Well-BeingLow Precipitation Beneficial Adverse Beneficial & Adverse Beneficial & AdverseALT #4Maximum erosionreduction,6 Seed out10% Class III, ClassIV, and all Class VIlands will be seededout.78,000 acres of wheatstubblemulch fallow.5.39 5.4 1. Removal of 35,000 acres ofhighly erosive cropland7,000 acres ofminimum-till barley35,000 acres of grassseedings..5 .61.7from production.2. Reduce predicted averageannual soil loss to about .2million tons per year. A reductionof 1.3 million tons;The value to producers6.4of outputs of goodsan 84% reduction.and services.3. Wildlife habitat would increaseto 4% of optimum;a 3.8 increase.The value of on-farmresources required.7.74. Acreage below seeded-outareas may erode at higherrates.5. Number of Avian species increasesto15; an increaseNet effects -1.3Net effects compared-1.6of 7/100 acres.to future without.6. Use of fuel decreases to 1.4million gallons; a .1 milliongallondecrease.7. Fertilizer use decreases to 2.3million pounds of fertilizer; a1.1 million-pound decrease.8. A sediment yield of less than.1 million tons per acre peryear; a .2 million-ton reduction.1. Eliminate theequivalent acreageof 35 farmsfrom production.2. Average incomedecreases.3. Risk of crop failuredecreasesfrom futurewithout.4. May require someoperators withhigh percentagesof Class IV and VIlands to findother means ofobtaining income.5. Reduce wheatproduction .6million bushels to2.4 millionbushels.1 Average Annual2 May require capital expenditure of $25,000 per 1,000 acre operating unitfor stubble mulch equipment.3 Excludes cost of managerial ability, risk, and any additional cost tooperators with mulitple holdings.4 Includes land cost based on current market value.5 Within the limitations of this study, this alternative is the EconomicDevelopment Plan.6 Within the limitations of this study, this alternative is the EnvironmentalQuality Plan.137

Effects of ConservationTreatment IntermediatePrecipitation Zone(15-18 inch annual precipitation)In the intermediate precipitation zone, specifiedchanges in cropping sequence were analyzedalong with increments of land treatmentapplication.A three ton per acre soil loss reduction couldbe obtained by adding terraces, stripcroppingor switching from a two year wheat-fallowsequence to a three year wheat-barley-fallowcropping sequence. Use of stripcropping orterraces would reduce income. Changing toa three year cropping system would increasereturns $4 per acre. If a wheat-barley-fallowsequence is utilized; all slopes are divided andterraces are applied on all acres that can beterraced, erosion would be reduced to 15 tonsper acre and income reduced $7 per acre fromthe present system. It is not possible to achievemore than a 25 percent reduction in predictedsheet and rill erosion rates unless the amount ofhigh residue management is increased.If the present cropping system is maintainedand minimum tillage or stubble mulching isused on those acres presently not being treated,erosion could be reduced over 50 percent andincome would increase $5 per acre. With highmanagement, changing from wheat-fallow towheat-barley-fallow is just as effective for erosioncontrol as adding stripcropping or terraces.However, from a net return stand-point, changingcropping sequences is the most favorable. Ifcropping system changes, high residue management,stripcropping and terraces are applied,erosion can be reduced to 4 tons per acre.Returns would be increased $1 per acre fromthe present status at this maximum erosionreduction level.As in other areas of the Palouse River Basin,wildlife population in this precipitation zone islimited by lack of permanent cover and drinkingwater. In the plots studied, only about 0.5percent of the area has herbaceous cover andabout 0.4 percent has shrubby or tree-typecover. Drinking water that is available to wildlifeuse is generally distributed at one-fourth toone-half mile intervals.Application of conservation practices otherthan increase of areas with vegetative cover willhave limited beneficial impacts on wildlife.138

Table 16. Effect of Conservation Treatment, Intermediate Precipitation Zone—Palouse River BasinTreatmentErosionRateTons/Ac.GrossReceipts$/Ac.Production ReturnsCost $/Ac. 1 $/Ac.Wildlife Number%Optimum 2 Species 2Habitat AvianPresent Condition 20 92 32 60 2.2 12w/Divided Slopes 3 17 93 34 59 2.2-3 12wTerraces 17 93 38 55 2.2-3 12Transfer W-F toW-B-F 17 107 37 64 2.2-3 12w/Divided Slopes 3& Terraces14 93 40 53 2.2-3 12Minimum TillageStubble Mulch 9 96 31 65 2.2-3 12w/Divided Slopes 3 8 101 34 67 2.2-3 12Transfer W-F toW-B-F 8 106 36 70 2.2-3 12w/Terraces 8 100 37 63 2.2-3 12Transfer W-F toW-B-F &Divided Slope 3 6 107 39 68 2.2-3 12w/Terraces &Divided Slopes 3 4 101 40 61 3.1 121 Land cost of $59/acre have not been included2 Compiled from G-1 evaluation plot3 Field stripcropping will be applied where applicable139

Alternatives Analysis andComparisonsAlternative I. Present Condition (Future WithoutAction) A wheat-fallow cropping systemis used on 65 percent of the cropland in themedium precipitation zone. Forty percent of theoperators using the wheat-fallow system utilizehigh residue management. Thirty-four percentof the cropland is in the less erosive wheat-barley-fallowcropping system. Sixty percent of theoperators use the wheat-barley-fallow systemwith high residue management. Only about1 percent of the area is in a wheat-barley-peacropping system. This alternative produces grossreceipts, of $92 per acre. Production costs are $32per acre and the predicted average annual sheetand rill erosion rate is estimated at 20 tons peracre.Alternative II. Present Cropping System withHigh Residue Management Returns increasedfor all crops except annual grain when minimumtillage or stubble mulch were applied. Becauseof increased chemical cost, returns were reducedby a dollar per acre for the annual grain.If the present cropping system is maintainedand minimum tillage or stubble mulchingis used on acres not being treated presently,erosion could be reduced over 50 percent andincome would increase $5 per acre.Alternative III. Maximum Income (E.D.) Alternative.The third alternative was developed byutilizing the ESCS linear program to developsolutions and emphasizing achievement of thehighest level of net return for various levelsof erosion reduction. Pea or lentil acreage wasrestricted to zero acres. To achieve maximumincome levels in this precipitation zone, a croppingsequence of high residue wheat-barleystubblemulch fallow produced the highest netreturns. Returns would increase to $70 per acreand erosion would decrease to about 13 tons peracre; a 45 percent reduction in soil loss. Withinthe limits of the study, this alternative providesthe highest level of economic development.Alternative IV. Maximum Erosion Reduction(E.Q.) Alternative. For erosion reduction andwildlife habitat benefits, the retirement of themost erosive areas from cultivation offers thegreatest potential for development of environmentalquality alternative.The relationships described with variouslevels of conservation application are consistentwith the relationships described for the low precipitationzone. The only exception is terraceswhich can protect 20 percent of the cropland inthis precipitation zone.If all Class IV and V land were retired fromcultivation and high residue management,terraces and stripcropping or divided slopefarming were applied to all remaining croplandin this precipitation zone, the predicted averageannual soil loss would be 4 tons per acreper year. Net returns would be $47 per acre; areduction of $18 per acre (28 percent) below thepresent condition.Wildlife habitat values would increase fromthe present estimated level of 2.2 percent ofoptimum to 15.8 percent of optimum. Numbersof different bird species could be expected todouble from present conditions with this alternative.(See table 17)140

Table 17. Effects of AlternativesAnd Comparisons To Future WithoutEconomic Development Environmental Quality Social Well-BeingMedium Precipitation Beneficial Adverse Beneficial & Adverse Beneficial & AdverseALT #1ALT #2Future withoutactionGross Receipts 1$ MillionsCost 2 3 4$ Millions90,000 acres of wheatstubblemulch fallow147,000 acres ofwheat-fallow72,000 acres of wheatbarley-fallow8.112.17.67.913.06.91. Predicted average annualsheet and rill erosion rate of7.2 million tons per year.2. Estimated sediment deliveryrate to streams of 15.6% or asediment yield of 1.1 million51,000 avres of wheatbarley-fallow5.5 5.0tons.3. Wildlife habitat value of 2.2%of optimum.1,000 acres of wheatbarley-peaswith.1 .14. Number of Avian speciesexpected, 12/100 ac.minimum tillage5. Use of 5 million gallons of1,000 acres of.1 .1fuel.wheat-barley-peas6. Use of 10.5 million pounds ofThe value to producers33.5fertilizer.of outputs of goodsand services.The value of on-farm33.0resources required.Net effects. .5Future without cropswith all high residuemanagement.237,000 acres ofwheat-stubble mulchfallow123,000 acres ofwheat-barley-stubblemulch fallow2,000 acres of wheatbarley-peasminimumtillage.The value to producersof outputs of goodsand services.The value of on-farmresources required.Net effects. 1.7Net effects comparedto future without.21.313.0.320.811.8.31. Predicted average annualsheet and rill erosion rate 3.3million tons per year; a reductionof 3.9 tons from futurewithout a 55% reduction.2. A sediment yield of .5 milliontons; a .6 million-ton reduction3. A wildlife habitat value of 3%;increase of .8%.34.64. Number of Avian species expected,12/100 ac. No change.5. Use of 4.2 million gallons of32.9fuel; decrease of .8 million.6. Use of 11.2 million pounds offertilizer; increase of .7 millionpounds.1.27. Increase use of insecticidesand herbicides will occur.1. Produce 10.5million bushels ofwheat.1. Increase wheatproduction to 11.2million bushels.2. Average incomeincreases.3. Risk of cropfailure decreases.4. Require additionaltechnical ability.5. Increase educationalrequirements.6. Sensitivity totimeliness ofoperation increases.7. Poor conservationfarmers will haveto find new vocations.8. Possible need of$25,000 per farmfor new equipment.142

Table 17. Effects of AlternativesAnd Comparisons To Future WithoutEconomic Development Environmental Quality Social Well-BeingMedium Precipitation Beneficial Adverse Beneficial & Adverse Beneficial & AdverseALT #3ALT #4Maximum incomealternative 5362,000 acres of38.6 34.8wheat-barley-stubblemulch fallow.The value to producers 38.6of outputs of goodsand services.The value of on-farm34.8resources required.Net effects 3.8Net effects comparedto future without.3.3Maximum erosionreduction future6without croppingsystem with highresidue managementwith divided slopesand terraces and 10%of the Class III lands,and all of the Class IVand Class VI seedingout.150,000 acres wheat16.8 14.5stubble mulch fallowwith terraces anddivided slopes78,000 acreas wheatbarley-stubble9.6 8.2mulchfallow with terracesand divided slope1,000 acres of minimum.1 .1till wheat-barley-peas with terraces anddivided slope133,000 acres of grass9.0seeded on the 16% ofthe Class III, all of theClass IV, and Class VIlands.Value to producers of26.5outputs of goods andservices.Value of on-farm31.8resources requiredNet effects -5.3Net effects comparedto future without.-5.81. Predicted averagesheet and rill erosion rate of2.9 million tons per year. Areduction of 4.3 million tonsfrom the future without; a 62%reduction2. Estimated sediment yield tostreams of .5 million tons.3. Wildlife habitat value of 3%;increase of .8%.4. Number of Avian species,12/100 ac.5. Use of 5.6 million gallons offuel; a decrease of 1.1 milliongallons.6. Use of 13.2 million pounds offertilizer; increase of 2 millionpounds.7. Increase use of insecticidesand herbicides.1. Predicted average anualsheet and rill erosion rate 1.4million tons per year. A reductionof 5.8 million tons fromfuture with an 80% reduction.2. Estimated sediment yield tostreams of .2 million tons; areduction of .9 million tons.3. Wildlife habitat value of20.5%.; an increase of 18.3%.4. Number of Avian species,23/100 ac; an increase of 11.5. Use of 3.9 million gallons offuel; a decrease of 1.1 milliongallons.6. Use of 7 million pounds offertilizer; a decrease of 3.5million pounds.7. Increase use of insecticidesand herbicides.1. Decrease wheatproduction to 8million bushelsper year.2. Average incomeincreases.3. Risk of cropfailure increaases.4. Additionaltechnical ablilityrequired.5. Sensitivity totimeliness ofoperation increases6. Poorer conservationfarmers will probablyhave to find differentmeans of employment.1. Decrease ofwheat productionto 7 millionbushels of wheat.2. Average incomedecreases.3. Risk of cropfailure decreases.4. Loss of acreageequivalent to 133farms.5. 250 or more farmsmay be reduced tonon-economic units.6. Some economies ofsize will be lost.7. Operators shouldbe able to manageremaining acres ata higher level.8. Opportunity forupland bird huntingwould increase.1 Average Annual2 May require capital expenditures of $25,000 per 1,000 acre operating unitfor stubble mulch equipment.3 Excludes cost for managerial ability, risk, and any additional cost tooperators with multiple holdings.4 Production cost does not reflect additional cost to operator withmultiple holdings.5 Within the limitations of this study, this alternative is the EconomicDevelopment Plan.143

Effects of ConservationTreatment HighPrecipitation Zone(over 18 inch annual precipitation)In the high precipitation zone, an erosion rateof 6 tons per acre per year could be achieved bystripcropping and replacing fallow with recropwheat without any improvement in management(Table 18). This cropping system wouldretain returns at present levels, but have $18less return than if the fallow had been replacedby additional acres of peas. The system withpeas would have had an erosion rate of 7 tonsper acre and returns of $99 per acre.If all acres could be managed with high residuesystems, net returns would increase $8 peracre from the wheat-pea system with correctmanagement skills.There are at least eight systems that will havean erosion rate of less than 5 tons per acre. Highresidue wheat-pea systems with stripcroppingwill have returns of $104 per acre, an increase innet returns of $23 per acre over present conditions.Wildlife habitat values in this precipitationzone range from 0.8 percent to 32 percent ofoptimum. The areas with the lowest values arenearly devoid of herbaceous cover and are lackingin potential sources of food and water forwildlife. The areas with the highest values havemixed vegetative cover including 25 percentof the area in non-cropland uses. These acresalso have better management for wildlife uses.Water for wildlife is usually more easily accessiblein these areas. (See table 18)144

Table 18. Effect of Conservation Treatment—High Precipitation ZonePalouse River BasinTreatmentErosionRateTons/Ac.GrossReceipts$/Ac.Production ReturnsCost $/Ac. 1 $/Ac. Wildlife habitat % Optimum 21 2 3 4Present Condition 14 143 60 830.8-1.1Replace Fallow w/ Peas 10 167 68 99 0.8-1.0 1.2-2.0 12 28w/Terrace & replacefallow w/ peas 8 167 73 94 0.8-1.0 1.2-2.0 12 28w/Divided Slopes3replace falloww/ peas 7 167 68 99 0.8-1.0 1.2-2.0 12 28w/Terraces & Dividedslopes & replace falloww/peas 7 167 76 91 0.8-1.0 1.2-2.0 12 28Transfer from fallow torecrop wheat 7 153 70 83 1.4-1.6 2.4-2.6 18-19 27-28w/Divided slope &transfer fallow to recropwheat 6 153 72 81 1.4-1.6 2.4-2.6 18-19 27-28w/Terraces & transferfallow to recrop wheat 6 153 76 77 1.4-1.6 2.4-2.6 18-19 27-28w/Terraces & Dividedslopes & transfer fallowto recrop wheat 6 153 78 75 1.4-1.6 2.4-2.6 18-19 27-282-2.417.6321 Land cost of $59/acre have not been included2Compiled from G-1 evaluation plot3Field stripcropping will be applied where applicable145

Table 18. Effect of Conservation Treatment, High Precipitation Zone—Palouse River Basin (Continued)TreatmentErosionRateTons/Ac.GrossReceipts$/Ac.Production ReturnsCost $/Ac. 1 $/Ac. Wildlife habitat % Optimum 2HIGH RAINFALL ZONE 1 2 3 4Minimum TillageReplace fallow w/peas5 175 68 107 0.8-1.0 1.2-2.0 12 28Add recrop wheat 4 158 71 87 1.4-1.7 1.4-1.6 18-19 27-28w/Divided slope & transferfrom fallow to recropwheatw/Terraces & transferfrom fallow to recropwheatw/Terraces & Dividedslopes & transfer fallowto recrop wheatw/Divided slope &replace fallow w/peasw/Terraces & replacefallow w/peasw/Terraces & Dividedslopes & replace falloww/peas4 157 72 85 1.4-1.7 2.4-5.6 18-19 27-284 158 77 81 1.4-1.7 2.4-2.6 18-19 27-284 157 78 79 1.4-1.7 2.4-2.6 18-19 27-284 175 71 104 0.8-1.0 1.2-2.0 12 284 175 74 101 0.8-1.0 1.2-2.0 12 283 175 76 98 0.8-1.0 1.2-2.0 12 281 Land cost of $59/acre have not been included2 Compiled from G-1 evaluation plot3 Field stripcropping will be applied where applicable146

Alternatives Analysis andComparisonsAlternative I. Present Condition Or FutureWithout Action. The wheat-pea cropping systemutilizes the largest amount of acreage in thehigher precipitation zone. Over 40 percent ofthe cropland is in this system. About 50 percentof the wheat-pea acreage receives high residuemanagement treatment. Another 40 percent ofthe cropland is in a wheat-barley-fallow croppingsystem. Sixty-five percent of this systemis managed by maintaining necessary cropresidues and clod sizes. Recrop wheat occupiesthe remaining 20 percent of this zone. Thepredicted annual sheet and rill erosion rate is 12tons per acre. Gross receipts are $143 per acre.Production cost is $60 per acre.Alternative II. High Residue Management. Thisalternative for the high precipitation area variedslightly from the second alternative of the othertwo precipitation zones. In this zone, there aresummerfallow acres in the present situation.From a resource protection standpoint, summerfallowshould be utilized only as a methodof handling severe weed problems that cannotbe controlled by other methods. Therefore,wheat-fallow and wheat-barley-fallow croppingsequences have not been included as alternatives.Recrop wheat has been used to replace fallowin alternative II and IV. With high residueand the replacement of fallow, a 4 tons per acrepredicted average annual sheet and rill erosionrate could be achieved—a 67 percent reduction.With this alternative, gross receipts could beincreased $15 per acre from the present condition.Production cost would increase $11 peracre.Alternative III. Maximum Income (E.D.)Alternative. This alternative would utilize ahigh residue wheat-pea cropping system on all739,000 acres in the precipitation zone. This systemwould have net returns of $136 per acre ($53above present conditions) and a predicted erosionrate of 8 tons per acre per year—a 43 percenterosion reduction from the present condition.Alternative IV. Maximum Erosion Reduction(E.Q.) Alternative. This alternative of the highprecipitation zone reveals that retirement of10 percent of the Class III land and all ClassIV e and Class VI e land would involve retiringapproximately 20 percent of the cropland in thearea from production.This alternative also includes transferringsummerfallow acreages to recrop grain, stripcropping,and installing terraces on all landswhere they can be used. This alternative wouldresult in a predicted erosion rate of 2 tons peracre per year and net returns of less than $50per acre. (A net return reduction of about 40percent from present levels.)Wildlife habitat values would increase andthe numbers of bird species would nearlydouble from present levels. For this analysis,it has been assumed that income would not begenerated from seeded-out land.147

Table 19. Effects of AlternativesAnd Comparisons To Future WithoutEconomic Development Environmental Quality Social Well-BeingHigh Precipitation Beneficial Adverse Beneficial & Adverse Beneficial & AdverseALT #1Future withoutaction91,000 acres of recropwinter wheat withminimum tillage50,000 acres of recropwinter wheat188,000 acres ofwheat-barley-stubblemulch fallow100,000 acres ofwheat-barley-fallow149,000 acres ofwheat-peas withminimum tillage161,000 acres ofwheat-peasThe value to producersof outputs of goodsand services.The value of on-farmresources required.Net effects 2.4Gross Receipts 1$ MillionsCost 2 3 4$ Millions12.5 14.3 1. Predicted average annualsheet and rill erosion loss rateof 12 tons per acre per year,6.2 7.8 or 8.8 million tons per year.2. A sediment delivery rate of19.9 23.0 28.75%, or a sediment yield tostreams of 2.5 million tonsper year.9.8 12.6 3. Wildlife habitat value of 3%of optimum.30.4 22.0 4. Number of Avian speciesexpected, 12/100 ac.5. Use of 13.2 million gallons26.9 23.6 of fuel.6. Use of 55.6 million pounds of105.7fertilizer each year.103.31. Produce 23.2million bushels ofwheat.ALT #2Future without cropswith all high residuemanagement andfallow acres replacedwith recrop winterwheat.333,000 acres of recrop45.6 52.2winter wheat withminimum tillage288,000 acres of46.9 41.0wheat-barley-peas withminimum tillage118,000 acres of24.1 17.4wheat-peas withminimum tillageThe value to producers116.6of outputs of goodsand services.The value of on-farm110.6resources required.Net effects 6.0Net effects compared3.6to future without.1. Predicted average annualsheet and rill erosion loss rateof 4 tons per acre, or 3.3million tons annual. This is a5.5 million-ton reduction; a67% reduction.2. An estimated sediment yieldto streams of .9 million tonsper year;a reduction of 1.6million tons each year.3. Wildlife habitat value of 4%of optimum; a 1% increase.4. Number of Avian speciesexpected, 12/100 ac.No change.5. Use of 16.9 million gallons offuel; an increase of 3.7 milliongallons.6. Use of 69.6 million pounds offertilizer each year; an increaseof 14.1 million pounds.7. Increase use of herbicidesand insecticides.1. Production increaseto 27.4million bushels ofwheat; an increaseof 4.2 millionbushels each year.2. Average incomeincreases.3. Risk of cropfailure increases.4. Additionaltechnical abilityrequired.5. Sensitivity totimeliness ofoperationincreases.6. Poor conservationfarmers will havedifficulty contunuingto farm.1 Average Annual2 May require capital expenditure of $25,000 per 1,000 acre operating unitfor stubble mulch equipment.3 Excludes cost for managerial ability, risk and any additional cost tooperators within multiple holdings.4 Production cost does not reflect additional cost to operatorwith multiple holdings.148

Table 19. Effects of AlternativesAnd Comparisons To Future WithoutEconomic Development Environmental Quality Social Well-BeingALT #3ALT #4High Precipitation Beneficial Adverse Beneficial & Adverse Beneficial & AdverseMaximum incomealternative 5739,000 acres of150.9 109.3wheat-peas withminimum tillageThe value to producers 150.9of outputs of goodsand services.The value of on-farm109.3resources required.Net effects. 41.6Net effects compared39.2to future without.Maximum erosionreduction 6233,000 acres of31.9 38.1recrop winter wheatwith minimum tillageand terraces, dividedslopes or strips if awinter wheat-springwheat system is used.202,000 acres of32.7 30.6wheat-barley-peas withminimum tillage, terraces,and divided slopes.83,000 acres of16.9 13.0wheat-peas withminimum tillage, terraces,and divided slopes.221,000 acres of19.3grass that would beseeded on Class IV,Class VI, and adjacentClass III areas.The value to producers 81.6of outputs of goods andservices.The value of on-farm101.0resources required.Net effects. -19.4Net effects comparedto future without.-21.81. Predicted average annualsheet and rill erosion of 5.5million tons per year. This isa reduction of 3.3 million tons;a 37% reduction.2. Sediment yield to streams ispredicted to be 1.6 milliontons per year; a reduction of.9 million tons.3. Wildlife habitat value of3%. No change.4. Number of Avian speciesexpected, 12/100 ac. No change.5. Use of 15 million gallons offuel; increase of 1.8 milliongallons.6. Use of 37.5 million pounds offertilizer; a decrease of 18.1million pounds.7. Increase use of insecticidesand herbicides.8. Risk of high erosion ratesoccurring increases if highresidue management cannotbe applied because of weatherfactors.1. Predicted average annualsheet and rill erosion rate of 2tons per acre or 1.5 milliontons per year; an 83%reduction.2. Sediment yield to streamswould be .4 million tons peryear; a reduction of 2.1million tons.3. Wildlife habitat value wouldincrease to 16% of optimum;an increase of 13%.4. Number of Avian speciesincreases to 21 species/100ac; an increase of 9species/100 ac.5. Use of 13.3 million gallons offuel; an increase of .1 milliongallons.6. Use of 51.8 million pounds offertilizer; a decrease of 3.8million pounds.7. Decrease use of herbicidesand insecticides.1. Production increasesfromfuture without to25.9 millionbushels of wheat;a 2.7 millionbushel increase.2. Price of peas andlentils would sooncollapse underintense supplypressure.3. In the short run,income wouldincrease.4. High residuemanagementwould be difficultto achieve formost operators.5. Early seedemergence wouldbe difficult toachieve.6. Sensitivity totimliness ofoperationincreases sharply.7. Increasingdependence onchemical weedcontrol.1. Production of 19.2million bushels ofwheat; a reductionof 4 million bushelsof wheat annually.2. Average incomedecreases.3. Risk of cropfailure decreases.4. Loss of acreageequivalent toabout 275 farms.5. 800 or more farmsmay be reducedto non-economicunits.6. Some economiesof size will be lost.7. Operators shouldbe able to manageremaining acres ata higher level.8. Oportunity forupland bird huntingwould increase.5 Within the limitations of this study, this alternative is the EconomicDevelopment Plan.6 Within the limitations of this study, this alternative is theEnvironmental Quality Plan.149

Table 20. Effects of Various Levels of Erosion Reduction on Cropland, Palouse River BasinEROSION REDUCTION LEVELEffectsUnits Present 30% 40% 60% 70%74%Maximum50% LandRetirementErosion Tons/Acre 14.5 10 8 5.5 4.4 3.8 7.3CroplandWheat 1,000 acres 598 485 653 736 736 736 449Barley 1,000 acres 159 191 131 15 180 186 119Peas/Lentils 1,000 acres 159 191 191 191 191 185 119Fallow 1,000 acres 305 354 246 279 114 114 229Grass/Trees 1,000 acres 0 0 0 0 0 0 305Total 1,000 acres 1,221 1,221 1,221 1,221 1,221 1,221 1,221Cropland Managementw/o Minimum Tillage 1,000 acres 668 0 0 0 135 0 507with Minimum Tillage 1,000 acres 546 1,221 1,221 1,221 1,086 1,221 409Field Strips or Divided Slopes 1,000 acres 0 0 0 440 552 0 0Terraces 1,000 acres 0 0 0 0 362 517 0Field Strips or Divided Slopesand Terraces 1,000 acres 0 0 0 440 22 704 0Gross Receipts Million $ʼs 158 164 175 173 166 165 132Cost of Production Million $ʼs 61 58 69 72 78 82 45Conservation Costs Million $ʼs 0 0 0 4 5 10 1Returns to Land, Labor, Capital,and Management Million $ʼs 97 106 106 101 88 83 87Wildlife Habitat ValueAll Land % of Optimum 12 13 13 14 15 16 19Cropland Only % of Optimum 6 7 7 8 8 9 18Avian SpeciesAll Land No/100 acres 125 130 140 155 155 160 190Cropland Only No/100 acres 96 115 115 125 125 130 180Highway and Road DitchMaintanance Costs $1,000 1,000 700 600 400 300 260 500150

No-Till AnalysisNo-till farming 1 , which is actually very minimaltillage, may offer the greatest opportunityfor erosion control in the Palouse River Basin. Itis difficult to analyze because of the amount ofvariation between systems used. Results of fieldtrials used in the region vary from outstandingto disastrous.The no-till drill does not have any comparativeadvantage in operation efficiency. It takesjust as much time to seed a field with one heavy12’ no-till drill as it does to perform normal tillageand seeding operations with conventionalequipment.With present technology, the most successfuluse has been in the high precipitation zonewhere no-till drills are used to seed winterwheat following minimum-till spring wheat.In this area, yields have been comparable orhigher than conventional systems with noincrease in production costs. Rodent problemssometimes have been serious with no-till farming.In the low and medium precipitation area,where fallowing is required, weed control onno-till fields is often ineffective or prohibitivelyexpensive. For chemical fallow, a herbicide billof $30 to $50 per acre is not uncommon at thepresent time. Erosion rates are predicted to beless than 3 tons per acre on fields where no-tiltfarming systems are used.1 For practice description, see page 80Conclusions1. Reduction in summerfallow acreagethrough increases in acreage in smallgrain crops can reduce erosion rates 50percent in the high precipitation zone.2. Changes in tillage methods (increaseduse of minimum tillage on annual graincrop rotations and stubble mulch onsummerfallow land) can reduce erosionmore than 40 percent in the low precipitationzone and 55 percent in themedium precipitation zone.3. Returns can be increased throughimproved tillage methods which resultin reduced costs and improved yields.Reductions in acreage of summerfallowcan also result in increased returns.4. As maximum levels of erosion reductionare achieved, returns will decrease.5. Capital expenditures increase asfarmers shift to different crops or tofarming systems which require differentequipment, and as additional conservationpractices are applied to the land.6. The retirement of highly erosive areas tograss, would result in an estimated 18percent reduction in production and a50 percent reduction in erosion. It wouldresult in significant improvement inwildlife habitat and increases in wildlifepopulation.7. Terraces, divided slope farming, andstripcropping systems will have to beapplied to all cropland areas wherethey can be used if annual erosion ratesare to be reduced to an average of 5 tonsper acre if the level of managementcannot be increased.8. Conservation practices other thanplanting of additional cover will havelittle effect on wildlife.ImplementationAlternative methods of reducing erosion andsediment, their effectiveness and costs, havebeen presented in this report. These alternativescan, be used as decisions are made on what willbe done to solve the problems of the basin. Aswater quality programs are developed and bestmanagement practices are selected, the alternativescan be used in evaluation of their potentialimpacts and effectiveness in reaching waterquality goals. The major question remaining iswhat kind of an implementation program willbe necessary to get these erosion control measuresapplied to the land. An implementationprogram for a 10-year period is presented here.An effective information-education programmust be one of the first steps to a successfulimplementation program. The program shouldinclude: demonstrations of farm equipment,farming techniques, and effects of farmingoperations in relation to erosion control. Thereshould be direct contact between farmers andextension specialists. The program also shouldinclude farm tours, television, and radio programs.All available, including new, informationregarding conservation practices should bemade available to the land user. It is estimated151

that a good information-education programwill cost $100,000 the first year and $50,000 foreach remaining year of the 10-year period. (SeeFigure 11).Additional technical assistance will beneeded. Concentrated assistance in planningand application of conservation practices is anessential part of this proposal. As conservationtechnicians concentrate on working withindividual farmers in getting conservation onthe land, it will require more time per farmerassisted. If erosion rates are to be reduced by 30percent, it is estimated that only 10-20 farmerscould be assisted per man-year. If greater ratesof erosion reduction are to be achieved, evenmore technical assistance will be needed. It isestimated that increased technical assistancewill cost from $180,000 to $250,000 per year.Additional field evaluation of conservationpractices on specific sites is needed. The neededinformation can be acquired through continuingstudies of conservation practices as theyare applied to the land through field trials andinterviews. Cost of gathering this data is estimatedat $100,000 per year. Information neededin this assessment will remain constant, whilethe items evaluated will vary during the 10-year period.A cost-sharing program is needed for farmerswho apply conservation practices. The amountof funds needed for cost-sharing will dependon levels of erosion reduction desired (e.g., toachieve a 30 percent reduction will cost lessthan a 70 percent reduction). It is estimated that$1.2 million will be needed for cost-sharing toachieve a 30-40 percent reduction in soil loss;$13 million will be needed if a 70 percent reductionis to be achieved.Additional legislation and regulation neededprobably will vary, depending on the successof the other implementation methods. If higherlevels of erosion reduction are to be achieved, itis expected that increased legislative and regulatoryaction will be needed.A redirection in research programs is needed.Research on development of new grain varietiesshould be directed towards types that canproduce well, with no-till, minimum tillage,and stubble mulch tillage systems. New andimproved tillage and seeding equipment isneeded. Data is needed on the effects of conservationpractices on crop yields. Cost of anexpanded research effort to meet these needs isestimated at $200,000 per year.If erosion levels are to be achieved, manyfarmers will find it necessary to purchaseimplements that are less destructive thanthose they are presently using. With increasingamounts of erosion reduction, more and morefarmers will have to change to different kinds oftillage implements. These changes will becomean important part of the annual cost of thisimplementation program.Figure 11Palouse Implementation Proposal 2 Annual Cost152

THEIDAHOPALOUSE

The Idaho PalouseTo achieve the purposes of this study, theentire Palouse River Basin has been addressedin other portions of this report. This sectionhas been written to document the erosion andsedimentation rates from the Idaho portion ofthe basin and to present more detailed analysisof data regarding Idaho forested areas. This wasdone because of the need to present the data bystate as well as hydrologic boundaries.Nearly 17 percent—353,625 acres—of thePalouse Basin is in Idaho. Approximately 10 percentof the total sediment yield from the basinoriginates in Idaho. Table 21 and 22 show totalsoil erosion and sediment delivery from Idaho.Table 21. Total Annual Soil Erosion—PalouseRiver Basin—Idaho—With Existing Land UseLand Use 1AcresAverage AnnualSoil Erosion(Tons)Forest 162,597 70,594Cropland 169,733 1,717,704Pasture and Rangeland 17,112 25,500Other Land 4,183 6,000Total 353,625 1,819,7941 Includes stream channels in the four land use categories.Table 22. Total Sediment Delivery—Palouse River Basin—Idaho—Existing Land UseLand Use 1Delivery rate(percent)Sediment Deliver(tons)Forest 13 9,304Cropland 29 498,134Pasture and Rangeland 25 6,375Other Land 25 1,500Stream Channels 90 20,744Total 536,057155

CroplandFourteen percent (170,000 acres) of thecropland in the basin is in Idaho. This land, theproblems and alternative treatments have beendescribed in other portions of this report. Specificrecommendations have not been presentedhere, alternative cropping systems and conservationpractices displayed in Chapter V areadaptable to these lands. Maps on pages 19, 21,45, 47, and 67 are of particular interest in relationto data presented in this section. Erosion bysoil association is presented and may be of useto the state as well as for basin wide analysis.Table 23. Average Annual Soil Erosion From Croplandby Soil Association—Idaho Portion, Palouse River BasinSoil AssociationAcresAvg. AnnualSoil ErosionTotal AnnualSoil Erosion(tons/acre) (tons)Palouse-Thatuna 87,370 11 960,070Palouse-Thatuna-Naff 23,000 12 276,000Palouse-Thatuna-Tekoa 4,000 12 48,000Larkin-Southwick 37,354 7 261,478Freeman-Joel-Taney 10,517 12 126,204Helmer 3,000 6 18,000Santa-Carlington 4,492 6 26,952Total 169,733 1,716,704Average = 10 tons per acre per yearForest LandsForest lands in the Idaho portion of thePalouse River Basin total 162,597 acres or about8 percent of the entire river basin. These forestlands contribute about 41 percent of the meanannual stream flow of the entire basin, as measurednear Hooper, Washington. Average erosionfrom these lands is about 70,594 tons per year.Approximately 13 percent, or 9,304 tons, of thiserosion enters waterways as fluvial sediment.Primary areas of erosion are the stream systemand timber harvest. The principal sourceof sediment is the 139 miles of stream channel,with an average of 8,654 tons per year 50 percentof the total sediment from forested lands ofthe Idaho basin.Although 17,958 tons per year of sedimentfrom these forest lands and stream channels issignificant, it amounts to less than 1 percent ofthe annual sediment discharged by the PalouseRiver into the Snake River below Hooper,Washington.Mean annual gross erosion from forestedlands in Idaho is equivalent to 275 tons persquare mile; sediment averages 70 tons persquare mile; sediment averages 70 tons persquare mile per year. These rates are quite lowcompared with agricultural lands which arecontinuously disturbed by annual cropping.Table 24 summarizes gross erosion and sedimentby forest land use.157

Table 24.Gross Erosion and Sediment by Forest Land UseMapColorLand Use Type % Acres Mean ErosionRate T/AcS.D RatioPercentGross ErosionTons/YearGross SedimentTons/YearPink High Elev CC 2 3,251 3.95 15 12,830.6 1,877.1Yellow High Roading 3 4,877 3.47 19 16,915.8 3,255.1Red Placer Mining 1 195 1.73 88 336.6 296.2Dark Blue High Elev PC 6 9,756 .82 14 7,990.5 1,080.3Light Green Low Elev PC 1 1,219 1.10 21 7,337.6 280.9Olive Meadow Flats 1 488 .77 10 376.2 37.6Light Blue High Elev SC 4 6,503 .57 23 3727.6 843.7Dark Green High Elev SC 22 36,357 .19 10 6,959.0 683.0Orange High Elev DC 42 69,058 .13 08 9,204.5 748.8Purple Low Elev DC 19 30,893 .06 11 1,806.1 200.9Stream Erosion 139 Mi. 65.5 Tons/Mi. 95 9,110.0 8,654.0TOTAL 100 162,597 GROSS TONS 70,594.5Erosion17,957.6SedimentMEAN TONS/ACRE/YEAR .43 .11GROSS SEDMENTDELIVERY RATION = .25CC = ClearcutPC = Partial CutSC = Sparse CoverDC = Dense CoverSD = Sediment DeliveryNOManagementForest management in the Idaho Palousevaries, partly because of ownership (Table 25).About 94,000 acres, or 58 percent, of the basinis professionally managed. The remainderreceives varying management depending uponowner interest. The Idaho State Departmentof Public Lands is actively involved in a farmforestry program directed to many of the ownersof small, private woodlands which make upmore than 68,000 acres in the basin.In addition, the Soil Conservation Serviceand the conservation districts provide on-siteland use planning assistance to private woodlandowners.Several silvicultural systems are used. Clearcutting and seed-tree systems are the commonregeneration methods. Nearly all forests areunder an even-aged management regime.Several intermediate cuts are used, includingover- wood removal, special selection cuts andsalvage. Salvage of white pine diseased byblister rust, Douglas-fir and grand fir killed bytussock moth and other dead and diseased treesaccounts for up to a third of the acreage loggedduring a year. Though the acreage cutover variesfrom year-to-year, it probably has averagedabout 1,000 acres annually. During an “average”year, 300 acres would be clear cut, seedtrees would be left on 110 acres, and variousintermediate cuts would be performed on theremaining 590 acres.Timber stand records and observations indicateapproximately 4,000 acres—less than 3 percent—ofall forest ownerships are inadequatelystocked and in need of site preparation work.158

HarvestingSeveral logging systems are used in theBasin. Generally, tractors are used to skid logson level ground and on slopes up to 30 to 40percent. On steeper ground, cable systems areused, the most common being the Idaho “jammer”.In jammer skidding, logs are draggedacross the ground usually not more than 300feet. Occasionally, tower height and topographyenable one end of a log to be lifted. Parallelroads are necessary about every 350-400 feet.Both systems result in a considerable grounddisturbance for roads and skid trails. This disturbedground—particularly roads builton steeper slopes—is susceptible to erosionand the source of some sediment reachingstreams from forest lands.There is a trend toward using logging systemsthat are less damaging to water quality.Systems capable of fully suspending logs forlonger distances are beginning to be used. Thispermits longer distances between roads (over1000 feet) and less soil disturbance betweenthem. Implementation of the Forest PracticesAct also tends to lessen soil erosion and sedimentationof streams. The Act prescribes practiceswhich will minimize sedimentation ofstreams. The Act is administered by the IdahoState Department of Public Lands. (See table 25)Table 25. Land Ownership Idaho—Palouse Forest LandOwnershipApproximateAcresPercentSmall Private 68,667 42Industrial Forest 20,950 13State of Idaho 19,430 12Bureau of Land Management 260National Forest 53,290 33Vegetative CoverThe North and South Forks of the PalouseRiver Basin in Idaho contain 162,597 acres offorest land; of this, 2,411 acres are composedprimarily of moderately wide, gently slopingdepositional land along third and fourth orderstream 1 bottoms. The remaining acreage is gentlyrollng to steep, deeply dissected land.Following is a list of forest land areas differentiatedaccording to vegetative ecosystems: aPlant Community Acres Percent1. Western redcedar, grand fir—pachistimaDouglas-fir-ninebark and Ponderosa pine—wheatgrass112,192 692. Western hemlock—pachistima 4,878 33. Western redcedar, grand fir—pachistimaDouglas-fir—ninebark 26,015 164. Grand fir—western redcedar—pachistima 14,634 95. Semi-wet meadow—ponderosa pine—Hawthorne 4,878 3TOTAL ACRES 162,597 1001 Horton-Strahler Stream Classification System. Where the smallest headwater streams are the first order. When two 1st order streams jointhe downstream segment becomes a second order stream, etc.159

Stream Channel StabilityForested lands within the study area contain139 miles of perennial stream channel.Stability of this distribution system for the waterresource of the Basin varies as follows: b(See table 26)Table 26. Channel Erosion and Sediment Rates by Stability ClassChannelStabilityClassNumberMilesMean ErosionRateTons/Mile/YearGross ErosionTons/YearGross SedimentTons/Year*Good 35 10 350 332Fair 76 60 4,560 4,332Poor 28 150 4,200 3,990TOTAL 139 9,110 8,654** .95 sediment delivery ratioThere is a proven relationship betweenstream channel stability, erosion, and resultingoffsite sedimentation c . This is a dynamic processwhich depends on volume of stream flow.Channel erosion potential and sediment ratesalso vary by land form. In the North Fork of thePalouse, higher erosion rates occur on depositionalland forms, such as valley bottoms wheremany stream banks have fine textured soils andtree roots and rocks are lacking. The high rateof stream bank erosion in these areas often hasbeen accelerated by cattle trampling the soil.From the gross erosion standpoint, the erosionfrom stream channels on forest lands in theIdaho Palouse Basin is low and comprisesonly 13 percent of the total erosion from forestlands. However, from the gross sediment standpoint,the fluvial sediment from stream channelsis high, comprising 48 percent of the gross sedimentderived from forested lands in the IdahoPalouse Basin.Placer mining for gold in the North Fork ofthe Palouse River headwaters caused severechannel scouring and stream bank vegetationloss on four miles of third order stream channel.Since most of the fine textured materials havesince eroded, suspended sediment loads fromthe area are currently low. However, lack ofchannel stabilization does result in high bedloadconcentrations during annual peak discharge.160

117º00SPOKANE CO.LINCOLN CO.Palouse RiverBasinADAMS CO.FRANKLIN CO.WHITMAN CO.BENEWAH CO.LATAH CO.NEZ PERCE CO.WASHINGTONIDAHOSAINTCreekJOECreek116º45BENEWAH COUNTYLATAH COUNTYCr.116º3047º00LOCATION MAPDeepNATIONALMeadow95GoldPotlatchFORESTCr.Princeton116º30Hatter Cr.FlanniganMoscow46º45116º45StabilitySTREAM STABILITY, EROSION, AND SEDIMENTATIONMilesErosion RateAve. Tons/MileGross ElevationTons/YearGross SedimentTons/YearGood 35 10 350 332Fair 76 60 4,560 4,332WHITMAN COUNTYLATAH COUNTY95Poor 28 150 4,200 3990Very PoorNon Forested LandsTotal 139 9,110 8654*Forest Land* .95 sediment delivery ratio-forested lands only.NEZGenessePERCE CO.River Basin Boundary117º00FOREST LANDSTREAM STABILITY, EROSION,AND SEDIMENTATIONPALOUSE RIVER BASINIDAHO AND WASHINGTONJANUARY 19775 05SCALE 1: 500,00010 MILESSource:Base map prepared by SCS, WTSC Carto. Unit from State Staff compilation.Thematic detail compiled by USFS, S&PF, Region 6 from survey based onUSFA April 1975 stream survey procedure, publication number R1-75-002U.S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE USDA-SCS-PORTLAND, OR. 1977M7-OL-23732-4161

ClimateFollowing are average air temperatures inIdaho forest lands of the North Fork of thePalouse Basin. d (See table 27)Table 27. Average Air Temperatures—Idaho Forest LandsElevationAnnualAverageJanuaryAverageJulyAverageLow Elevation < 2500ʼ 47.4ºF 30.1ºF 66.3ºFHigh Elevation < 2500ʼ 42.0ºF 27.4ºF 58.2ºFChange of air temperature decreases 2.5ºF foreach 1,000 foot rise in elevation. In mountaincanyons, however, cold air drainage is oftenblocked, leaving localized cold air pocketswhich can produce frost conditions. Air temperatureis a primary cause of short growing seasons,which make these forest lands unsuitedfor agricultural crops.Mean annual precipitation on Idaho Palouseforest lands range from 25 inches at the lowerelevation to 50 inches along the high peaks andridges. Generally, there is a seven inch increasein mean annual precipitation with each 1,000foot rise in elevation e . However, geographicconditions strongly affect local precipitation,particularly in snow country. (Table 28)Snow normally comprises 40 percent of theannual precipitation at the lower forest landelevations. It contributes 60-70 percent of thetotal annual precipitation at higher levels.Precipitation Intensity—The following arethe approximate storm frequencies for the forestlands within the North Fork of the PalouseRiver. gReturnFrequency(Years)DurationAmount(Inches)10 30 min. .625 30 min. .650 30 min. .710 1 hour .725 1 hour .850 1 hour .910 24 hour 2.2525 24 hour 2.650 24 hour 3.0Table 28. Annual Palouse River Basin—Idaho ForestsPrecipitation Occurrences fMonthPercent ofAnnual Precip.MonthPercent ofAnnual Precip.January 12.0 July 1.8February 9.6 August 2.1March 9.5 September 4.5April 7.6 October 9.0May 6.1 November 13.2June 8.4 December 16.2163

Water YieldMean annual water yield from forested landsalong the North Fork of the Palouse Riverranges from 5 to 30 acre inches per year. Annualstream flow is about 178,856 acre feet. h Thisstream flow amounts to about 1.1 foot per yearper acre, which is equal to about 83 percent ofthe mean annual flow of the Palouse River atColfax, Washington and 41 percent of the meanannual Palouse River discharge at Hooper,Washington. i,jFigure 12 shows the relationship betweenmean annual runoff and elevation for theforested lands of the North Fork Palouse Riverin Idaho. The regression is based on the bestavailable information using Thornwaite’s waterbalance computer model.Where: RO = P - ETWhen:RO = Annual RunoffP = Annual PrecipitationET = Annual Evapo-Transpiration lossThere have been minor increases in wateryield from forested acres recently converted toagriculture. Water yield also has increased onabout 5,000 acres of forest land as a result oftimber harvest activities. Generally, areas areso dispersed and hydrologic recovery so fastthat total increase in water yield from forestlands, under present management, amountsto less than 1,800 acre feet per year. This representsonly a 1 percent increase (Figure 13).Uncontrolled timber harvest could increase thewater yield and change the water quality situationdramatically from its present condition.Compared to other forested watersheds inNorth Idaho, the North Fork Palouse Basin producesrelatively little water primarily becausethere are no extensive areas of high countrywhich receive great amounts of precipitation. 1However, in terms of the entire Palouse RiverBasin, the forest land water yield from Idaho isextremely significant.1 White Pine Planning Unit Multiple Use Plan 1975, FinalEnvironmental Impact Statement, U.S. Forest Service.164

Figure 14Average Discharge—1,000 CFSPalouse River, Potlatch, Idaho 1966-1972Figure 14 depicts the annual discharge andfluctuation of the Palouse River at Potlatch,Idaho. Normally, the peak flow occurs in lateMatch to April. The early peak discharge occurslargely because of the lower elevation andwarm, south-facing slopes on which snow meltsearly.165

FloodingAnnual stream flows in forested lands of theNorth and South Forks of the Palouse Riverfluctuate extremely (Figure 15). The flood plainof forested land is small because, normally,stream channels are deeply incised. However,this is frequently complicated by the natural andpeople-caused debris and log jams whichrestrict high flows. Floods occur periodically insmall communities which are on depositionallands, particularly following rain or snow inlate December through February.Figure 15CubicFeet Per Sec.50Total Monthly Discharge—1000CFSPalouse River, Potlatch, Idaho4540353025201510501967 1968 1969 1970 1971YEARSThe flow of the North Fork Palouse River atPotlatch varies greatly from year-to-year andwithin the year. 1 For Example, in water year1973 the following flows were observed andcompared with the record event (USGS Station# 13345).TimeParameterInstantaneous DischargeAmountDateWater Year 1973 Minimum Flow .07 CFS Sept. 24,1973Water Year 1973 Mean Flow 96.70 CFSWater Year 1973 Maximum Flow 1850 CFS Dec. 22, 197311-year Record Minimum Flow .07 CFS Sept. 24, 197311-year Record Maximum Flow 6100 CFS Jan. 21, 19721 Surface Water Supply of the United States, 1950-1975. WSP#2134, Part 13 Snake River Basin, U.S. Geological Survey.166

ErosionErosion rates on forest lands of the NorthFork Palouse River in Idaho are based on identificationof land types: groups of land havingsimilar vegetation patterns, soil types, slopehydrology, bedrock type and structure, andgeomorphic processes. These land types werecorrelated with land form and present land useto arrive at 10 distinct erosion contributionareas. Erosion rates are based on research data,field examinations, aerial photo interpretations,and field plots. See erosion-sediment map (page161) for site locations. (See table 29)The channel system contributes only 13percent of the mean annual erosion but has thehighest sediment delivery rate.Table 29. Mean Annual Erosion, Idaho Forest LandsMapColor% ofAreaAcresMean Erosion RateTons/Acre/YearGross ErosionTons/YearPink 2 3,251 3.95 12,830.6Yellow 3 4,877 3.47 16,915.8Red 1 195 1.73 336.6Dark blue 6 9,756 .82 7,990.5Light green 1 1,219 1.10 1,337.6Olive 1 488 .77 376.2Light blue 4 6,503 .57 3,727.6Dark green 22 36,357 .19 6,959.0Orange 42 69,058 .13 9,204.5Purple 19 30,893 .06 1,806.1Channel Erosion 139 miles 65.5 Tons/Mile 9,110.0TOTAL 100% 162,597 Acres 70,594.5 TonsWeighted mean erosion rate = .43 Tons/Acre/Year = 275 Tons/sq. Mile167

SedimentApproximately 25 percent of the mean annualerosion ends up in the stream system as fluvialsediment and is accounted for as follows:Table 30. Gross Sediment Delivery—Idaho Forest AreasMapColor% ofAreaAcresSediment DeliveryRatio - PercentGross SedimentTons Per YearPink 2 3,251 15 1,877.1Yellow 3 4,877 19 3,255.1Red 1 195 88 296.2Dark blue 6 9,756 09 1080.3Light green 1 1,219 21 280.9Olive 1 488 10 37.6Light blue 4 6,503 23 843.7Dark green 22 36,357 10 683.0Orange 42 69,058 08 748.8Purple 19 30,893 11 200.9Stream Channels 139 Miles 95 8,654.0TOTAL 100% 162,597 Acres 17,957.6 TonsWeighted mean sediment rate = .11 Tons/Acre/Year = 70 Tons/Sq. MileAlthough the forest stream channels contributeonly 13 percent of the gross erosion from forestedlands, they do contribute 48 percent of thegross sediment. The 8,654 tons per year of channelsediment, though substantial, is much lessthan for typical streams on agricultural land.This channel sediment averages 62.26 tons permile per year. Fifty percent of the gross mean annualsediment from the channel system on forestland moves as bedload sediment, rather thanas suspended sediment; primarily because ofsteep channel gradient, material size and shape.The following table shows comparativeamounts of sediment from the Idaho Palouseforest land—162,597 acres—and the total sedimentfrom all of the Palouse Basin: 2.1 millionacres. Idaho forest lands thus comprise about8 percent of the Palouse River Basin. The tablebelow contains mean annual data and is basedon USGS Water Supply Paper #1899C1.Table 31. Idaho Forest and Palouse River BasinMean AnnualSediment—TonsMean AnnualSediment—TonsPer Square MileForest Lands Idaho 17,957 70Palouse River @ Colfax 360,000 730Palouse River @ Mouth 1,580,000 480The above data indicates that forested landsin Idaho contribute only one percent of themean annual sediment yield of the PalouseRiver at its confluence with the Snake River.They also have the lowest mean annual sedimentrate per square mile—only 10 percentof the sediment yield of the Palouse River atColfax, Washington.168

Bedload Component ofGross SedimentThe clearwater National Forest hydrologisthas measured suspended sediment and bedloadat three forested subwatersheds in the NorthFork of the Palouse River. They are DisaltoCreek, Wagner Gulch, and Stephens Creek.In 1975, gross sediment from these watershedsranged from .03 to .08 tons per acre peryear. Bedload sediment ranged from 11 to 76percent and averaged 50 percent. Bedloadmakes up a high percent of the sediment instreams containing small, rounded gravels,with a steep channel gradient. The transportdistance of bedload is much less than the suspendedsediment. Bedload normally settles tothe channel bottom at its first encounter witha low gradient depositional land form. Frequentlybedload causes channel blockage inthe low gradient valley streams which in turncauses accumulated bank scouring to the valley(fine texture) streambanks.1 Sediment Transport by Streams in the PalouseRiver Basin, Washington and Idaho. 1961-1965, WaterSupply Paper 1899C, U.S. Geologic Survey.Table 32. Feneral Descriptionof Past Land Use and CoverWithin Erosion Map UnitsMAPREFERENCECOLORPinkGENERAL DESCRIPTIONThis area is roaded, in thehigher elevations, generallyon SW aspects which havebeen clearcut—steep, highrunoff areas.RedDark blueOliveLight blueDark greenOrangePurpleThis depositional land typehas been severely scouredduring early-day gold placermining.These areas are at higherelevations and have beenpartial cut at various intensities.These are wide, alluvial, forestedmeadow lands, oftengrazed and contain scouredstreambanks. Soils are lowin rock content along streambanks.These are high elevationareas containing relativelysparse forest due to soilaspect.These areas are at the lowerelevations and have sparseforest cover due to soil,aspect, and precipitationconditions.These areas are at thehigher elevations and containdense forest cover.These areas are at the lowerelevations and have predominantlydense forest coverdue to available moisture.YellowThese areas have an unusuallyhigh density of roads onsteep slopes with high precipitationand runoff rates.MAPREFERENCECOLORGENERAL DESCRIPTION169

116º45WASHINGTONIDAHO47º00116º45EROSION AND SEDIMENT YIELDSWHITMAN COUNTYLATAH COUNTY117º00BENEWAH CO.LOCATIONMAPIdaho PortionPalouse River BasinLATAH CO.NEZ PERCE CO.SAINTCreekJOECreekBENEWAH COUNTYLATAH COUNTYCr.NATIONALMeadow116º30Deep95GoldPotlatchFORESTCr.FlanniganHatter Cr.Princeton116º30Moscow9546º45Land Use Type % AcresMean ErosionTons/YearS.D. RatioPercentGross ErosionTons/YearGross SedimentTons/YearHigh Elev. CC 2 3,251 3.95 15 12,830.6 1,844.1High Roading 3 4,877 3.47 19 16,915.8 3,255.1Placer Mining

Water QualityWater quality, a relative term, has real meaningonly when applied to a specific use of water.Table 33 is a summary of water quality datacollected from selected forested tributaries tothe North Fork of the Palouse River in July,1974. It demonstrates the relatively high qualitywater from forest lands.Table 33. Water Quality Data - Palouse River Basin Idaho StreamsStationLocationsParametersJerome Cr.Strychninc Cr.Bonami Cr.Palouse R.Palouse R.Graves Cr.Wagner Gu.N. F. Palouse R.EldoradoN. F. Palouse R.W. Pine Cr.Disalto Cr.Secuda CFlat Cr.ConductivityMmos/cm 42 25 35 35 55 40 88 32 17 25 26 28 40 65Water Temp.F 52 54 52 59 54 50 59 52 46 50 52 46 58 59HardnessMg/I 20 10 10 15 15 10 30 10 10 20 10 10 10 10NitratesMg/I 12 14 14 4 6 8 9 3 8 7 6 10 5 3NitritesMg/I .008 0 .01 0 .1 .1 .1 0 .04 .01 0 0 .002 0PhosphatesMg/I 4 .7 .1 .1 .45 .1 .05 .8 .4 .1 .1 3.2 .1 .15ChloridesMg/I 5 5 5 5 5 2.5 10 5 5 5 5 15 5 5SulfatesMg/I 8 3 0 0 2.5 5 0 0 2 1 8 3 8 10DissolvedOxygen %Mg/IDissolvedOxygen %Saturation7 9 9 8 - - - - - - - 10 9 972 91 90 87 - - - - - - - 92 86 98pH 6.3 6.4 6.4 6.4 6.5 6.4 6.5 6.4 6.8 6.3 6.5 6.2 6.7 8.4Ironppm - - - - - - .1 - - - - - - -Total Dis.Solids Mg/I 34 20 29 29 44 33 72 26 14 20 21 23 33 53Water Quality Data—Bovill-Palouse Planning Unit—July 1974Source: Clearwater National Forest173

The water quality data in Table 34 is fromU.S. Geologic Survey records and portrays thechange in water quality as flows approach theSnake River.Table 34. Comparative Water Quality AnalysisParameterNorth Fork Palouseat Potlatch, ID.Lower Palouseat Hooper, WASample Date 9-23-74 9-16-74Stream Flow (CFS) 6.6 54.0Dissolved Sodium (PPM) 5.8 26.0Dissolved Potassium (PPM) 1.9 4.7Alkalinity (PPM) 39.0 173.0Dissolved Sulfate (PPM) 3.7 14.0Dissolved Chloride (PPM) 1.4 9.4Nitrite & Nitrate (PPM) .13 .87Total Phosphorus (PPM) .20 .25Hardness (PPM) 32.0 150.0Specific Conductance (micro mho) 78.0 390.0Field pH (Units) 7.4 8.4PPM = Parts Per Million—a measure of concentrationSource USGS, September 1974174

Typical forest land stream channel having“good” stability despite the steep slopingground on the right side.Typical alluvial valley depositional land formbeing used for pasture. The channel bankstability at this point is “very poor” due to thelack of bank rock and brush root wads.175

Road encroachmenton stream systemcauses stream bankerosion and increasessediment deliveryrate from road surfaces.Encroachment of agriculture cropping practicesto the edge of the stream system increases bankerosion and removes the sediment filter ofgrass and brush.176

Remains of early day goldmining. Typical of red areaon erosion-sediment map.(page 171)Forest land is typical of dark green coloredareas on erosion-sediment map. Note intermingledagriculture lands and effective use ofgrassed waterway in foreground.177

Temporary road with erosionevident. Located in Douglas-firninebark habitat type typicalof the light blue area on theerosion map.Road cut bank sloughing during spring runoff.Note ditch sedimentation. Typical of yelloware on erosion-sediment map.178

Forested meadow and meadow depositionalland type. Note scoured stream banks ofpasture land, flood damage, and attempt tocorrect problem. Rip-rap material too small.This are is typical of olive colored area onerosion-sediment map. Flooding of forestedmeadow land during April 1976. Unsurfacedroads along major streams have a highsediment delivery ration.179

Western redcedar pachistima habitattype—typical of the orange colorederosion-sediment map area. Notegood stream channel stability evenat high runoff.Ponderosapine-wheatgrasshabitat typetypical ofthe purple mapcolored area.180

Literature Cited:a Idaho-Washington RC&D Project. May 1974, U.S. Dept. ofAgriculture pp 23-31.b Stream Channel Stability Evaluation. 1975, NorthernRegion, Hydrologist U.S. Forest Service.c Hydrology of Northeast Washington. 1975, Clif Benoit,Colville, National Forest, U.S. Forest Service.d Climatological Handbook-Columbia Basin States.September 1969, Meterology Committee, Pacific Northwest River Basins Commission.e Water Yield Maps for Idaho. March 1968, Marvin Rosa,Agricultural Research Service publication #41-141, U.S.Dept. of Agriculture.f Unpublished Hydrologic Data. August 1976, MelvinBennett, Hydrologist, U.S. Forest Service, Orofino, Idaho.g Climatological Handbook—Columbia Basin States.September 1969, Meterology Committee, Pacific NorthwestRiver Basins Commission.h Water Yield Maps for Idaho. March 1968, Marvin Rosa,Agricultural Research Service Publication #41-141, U.S.Dept. of Agriculture.i Surface Water Supply of the United States, 1950-1975.WSP #2134, Part 13 Snake River Basin, U.S. GeologicalSurvey.j U.S Geological Survey Water Quality Data. 1972-1974Stream Gage #13345000 (Palouse River near Potlatch,Idaho).181

AGENCY ACTIVITIES

Agency ActivitesSoil Conservation ServiceSCS became active in the Palouse River Basinin 1935, five years before the first conservationdistricts in the area were organized. Major SCSactivities have included technical assistance toindividual farmers and groups of farmers planningand applying conservation on the landthrough Soil and Water Conservation Districts.This extensive assistance is available to all farmersin the basin.Soil surveys have been completed for theentire basin and reports have been publishedfor Adams and Spokane Counties. The LatahCounty, Idaho soil survey is completed. TheWhitman County survey is being prepared forpublication.All of the Idaho Basin and Spokane County iswithin the Idaho-Washington Resource Conservationand Development project.SCS also assists the Agricultural Stabilization& Conservation Service with the technicalaspects of conservation practice cost-sharingprograms, including site inspection, beforepractice installation and follow up inspection ofcompleted practices.Small Watershed Project (PL-566). The potentialin the Palouse Basin for a small watershedproject is expected to be high. The number ofconventional projects involving channel workand major structures for flood control is limited.Instead, the anticipated PL-566 projects wouldinvolve installation of small conservation measuresthroughout community watersheds. Themeasures would include terraces, diversions,grassed waterways, debris basin, stripcropping,and grade stabilization structures.Installation of recommended conservationmeasures would have a significant effect on erosion,sedimentation, and water quality within awatershed area. Presently, much of the conservationwork is being installed on a piecemealbasis. If an overall plan could be developedover a larger area, a more orderly, integratedand efficient system could be installed.Under the PL-566 program, combinationsof measures would be analyzed and sponsorswould select a recommended plan of action.Through the small watershed program, SCSwould then assist with technical and possiblefinancial assistance, if money was not availablethrough other programs.RC & D Potential for the Basin. Where basinareas are now within the RC & D area (LatahCounty, Idaho and Spokane County, Washington)SCS can accelerate technical and financialassistance. Measures would include criticalerosion area, flood prevention, farm irrigation,land drainage, soil and water management foragricultural pollution, water-based fish andwildlife recreation developments for public use,and water quality management. Acceleratedplanning also is available for forestry measuresand practices.Conservation DistrictsLegal subdivisions of state governmentDisticts coordinate soil and water conservationprograms within their jurisdictions.In the Palouse River Basin, there are countywideconservation districts in all but WhitmanCounty, which is served by four separate conservationdistricts.Conservation districts focus particularly onsevere erosion problems. They provide necessarylocal leadership to work with conservationplanning and application. SCS provides a majorpart of its technical assistance through conservationdistricts.Approximately 700 farmers are cooperatorswith basin Conservation Districts. With SCStechnical assistance, these farmers have developed400 conservation plans on over 700,000acres of basin farmland.Although SCS assistance is provided tofarmers in applying numerous conservationpractices, some are more commonly used inthe area. Following is a listing of some of thesepractices which had been applied as of September30, 1977 in Whitman County.Pond (Number) 210Grassed Waterway or Outlet 12,895(acres)Minimum Tillage (acres) 44,196Stripcropping (acres) 46,292Terraces (feet) 31,537Subsurface Drain (feet) 5,980,429185

Conservation districts also are involved ineducating people of the basin about conservationneeds of the area. Effects of these effortshave not been readily apparent under pastvoluntary programs. The broad impact of thisis being reccognized, as districts cooperate indevelopment of county water quality plans.In the future, districts should play an evenstronger role in basin conservation activities.New state and national laws have given districtsgreater authority and responsibility. TheFederal Water Pollution Control Act has playeda major role in strengthening the mission ofdistricts. As districts work to meet guidelinesof this act, people are increasingly motivated touse the assistance districts can provide. As bestmanagement practices are applied to the land,district leaders believe people will continue toseek leadership from their local conservationdistrict. The most effective incentives possiblewill be needed to get conservation on the land.Districts are arousing concern about keepingwater quality planning for non-point pollutioncontrol at the local level. As the energy crisisintensifies, districts will become more involvedin increasing public awareness of resourceproblems and the need to solve them throughconservation measures.Department of Ecology,State of WashingtonDOE is responsible for planning, managementand regulation for water and related landresources of the state. DOE coordinates federaland state grants for planning and construction.Floodwater damage, shoreline management,coastal zone management, water quality, andwater rights are among their resource managementresponsibilities.DOE has played a major role in initiatingaction, obtaining funds, and giving coordinationand leadership for water quality planningin the Washington portion of the basin. Thedepartment works through the State ConservationCommission, local conservation districtsand water quality committees on developmentof best management practices to meet nationalwater quality guidelines. DOE is expected tocontinue playing a significant role as best managementpractices are applied to basin land.The Washington StateConservation CommissionAn agency of state government, the commissionadministers legal and program activities ofthe 52 conservation districts located in Washington’s39 counties.The Commission’s functions are describedunder Chapter 89.08 RCW. The ConservationCommission is housed in and attached to theDepartment of Ecology (DOE) for administrativeand fiscal purposes. Program operation isindependent and guided by policy developedby the Commission members.A brief list of activities may better illustratethe Conservation Commission’s role relative toother conservation agencies:1. The Conservation Commission hascontracted with the DOE to developan implemental plan for water qualityimprovement in dryland agriculture.2. The commission has personnel inthe field to assist individual conservationdistricts in program development,specific problems, and specific projectsrelated to natural renewable resources.3. The commission sponsors andconducts training conferences, e.g.:a. To acquaint conservation districtsupervisors with duties, responsibilities,and opportunities.b. To explain and implement uniformaccounting procedures with conservationdistricts.c. To give motivational training.4. The commission is responsible to seethat supervisor elections are conductedand appoints two of the local fivememberboard of supervisors in eachdistrict.5. The commission conducts regularmeetings throughout the state, focusedon understanding the complex problemsand opportunities of Washington’s naturalrenewable resources. Periodic commission/conservationdistrict board interaction around the state is carried out toallow a better mutual understanding ofpriority resource problems andopportunities.186

6. The commission develops job descriptions,recruitment, and training programsfor district employees.7. The commission interacts and coordinatesprograms with the federal and statenatural resource agencies.Forest ServiceThe role of the Forest Service in the PalouseBasin includes administration of the nationalForest System, cooperative State Forestry programs,and assistance to private forest owners.Basin National Forest lands are managedby the District Ranger of the Palouse RangerDistrict as part of the Clearwater National Forest.Forest land in the Palouse Ranger District ismanaged for a variety of uses, forest productsand services.The Clearwater National Forest is currentlyupdating management plans to reflect needsdetermined under the Forest and RangelandRenewable Resources Planning Act Assessment,and planning requirement of the national ForestManagement Act of 1976 (PL-94-588) whichamends it.The Forest Service state and private forestrymission is directed toward the following goals:to meet future demands for forest resourcesto extend available supplies and servicesto efficiently plan uses of land and waterresourcesto apply researchto maintain and enhance the environmentA variety of programs are designed to achievethese goals: improved harvesting and marketingof forest products; fire prevention andcontrol, and reduction of losses from insects anddiseases. Principal coordinating partner is theIdaho State Forester who—through cooperativeagreements—provides technical assistanceto private forest owners. The state forester alsoparticipates with the Forest Service in the insectand disease management program.The Forest Service, in partnership with thestate forester, also gives private forest ownerstechnical assistance through the Resource Conservationand Development Program (RC&D).The RC&D Program is developed by local residentsof the area, acting as sponsors.Cooperative forestry programs probablyafford small private woodland owners the bestopportunity for improving forest managementand water quality while increasing forest productivity.RC&D, in particular, is a deliverysystem with potential that far exceeds recentfunding levels.Department of Lands,State of IdahoThe State of Idaho has an active program onthe 67 percent of the forest land in State or privateownership. This program includes responsibilitiesfor timber management, grazing, andminerals on State land, cooperative servicesin timber management and fire protection onprivate lands. The Department of lands administersthe State’s fire hazard reduction programwith about six to eight positions in the PalouseBasin. These same people serve as an initialattack force under the cooperative fire program.The Department also administers the State’sinterests in navigable streams.Economics, Statistics andCooperatives ServiceESCS conducts national and regionalresearch, planning, and technical consultation.Other ESCS services relate to economic andinstitutional factors and policy on use, conservation,development, management, and controlof natural resources. This includes determiningthe extent, geographic distribution, productivity,quality, and contribution of natural resourcesto regional and national economic activity andgrowth. ESCS studies resource requirements,development potentials, and resource investmenteconomics; impacts of technology andeconomics on use of natural resources; resourceincome distribution and valuation; and recreationaluse of resources. The agency participatesin departmental and interagency efforts toformulate policies, plans, and programs for theuse, preservation, and development of naturalresources.The Cooperative Extension ServiceCES has long been active in reduction of sedimentand erosion. During the mid-1930’s, extensionagents helped the Soil Conservation Serviceselect farms for demonstration and testing ofconservation programs throughout the basin.187

Local county extension agents assisted localfarmers in formation of Conservation Districtsunder State Enabling Acts, passed in Washingtonand Idaho in the late 1930’s. After districtsorganized, county agents were involved inarrangements for election of district supervisors,formulation of district programs and workplans, arranging district annual meetings andassisting in district information and educationactivities. In 1944, county agents assisted inorganizing Washington’s first district associationin Whitman County. They also helped withdistrict newsletters. In the 1950’s, an extensionspecialist was assigned to work with districts inWhitman county.The Cooperative Extension Service has establishednumerous field trials and demonstrationsof how to control weeds without increasing erosionhazards on cropland. Field trials and demonstrationshave been broadened in recent yearsto include work on no-till farming systems.Recent federal legislation related to PublicLaw 92-500 gave the CES a major role in erosionand sedimentation control by cooperatingwith conservation districts in non-point pollutioncontrol programs. The CES, through localagents, Is cooperating with the SCS in assistingwith planning and implementation of Section208 of Public Law 92-500. CES helps organizeCounty public awareness programs and workswith county water quality committees. Thesewater quality committees were organized toencourage citizen input into county plans forreducing and eventually controlling non-pointsources of water pollution.The Agricultural Stabilization &Conservation ServiceASCS, through the Agricultural ConservationProgram, cost-shares with landownersand operators the installation of selected conservationpractices on agricultural land. Thesepractices include those which contribute to theconservation and development of soil, water,plant, wildlife, and other resources, as wellas practices which help to reduce or controlerosion, and chemical or animal-waste pollutants.This cost-sharing program is available toindividual farmers and ranchers and to groupsof landowners who have common problemstoo large or complex to be handled individually.ACP also cost-shares in the installation ofemergency conservation practices following anatural disaster. The Soil Conservation Serviceis responsible for providing technical assistancefor this program.The Agricultural Stabilization and ConservationService administers the USDA AgricultureFarm Program, relating to agriculture productioncontrol. ASCS administers the AgricultureCommodity Storage and Loan Program, andlong-term cost-share agreements and contracts,utilizing State and County Committees establishedunder Section 8(b) of the Soil Conservationand Domestic Allotment Act, as amended.Science and Eduction Administration,Federal ResearchSEA conducts research to find better ways ofstoring, saving, transporting, and using water.SEA researches both physical requirementsand effects of soil and water conservation. Thisresearch is oriented primarily toward scientificdetermination of the effectiveness and feasibilityof conservation practices: water management,including requirements and consumptiveuse of agricultural crops; sediment yield anddelivery rates; conservation cropping systemsand residue management, and hydraulic characteristicsof surface methods of irrigation.ARS has provided extensive assistance todevelopment of basin data for the UniversalSoil Loss Equation, which has been used extensivelyin this study. Continued work is neededwith the USLE to improve and refine this valuabletool. As improved land management systemsare applied to the land, SEA can assist instudying the effects of these systems. SEA canalso play a key role in testing and developingimproved tillage equipment—such as the no-tilldrill—which are needed to solve area erosionproblems. Research is needed also on tillageerosion problems.The Farmers Home AdministrationFmHA makes water development and soilconservation loans to eligible individual farmers,rural residents, groups of farmers and ruralcommunities. These loans are for developingwater supply systems for domestic, livestock,and irrigation use; and for carrying out soilconservation practices. Each loan is scheduledfor repayment according to the borrower’sability to repay, over a period of not more than40 years. Loans also are made to local organizationsto help finance projects and develop188

land and water resources in watershed plannedunder authority of Public Law 83-566. Eligiblelocal organizations include flood control districts,irrigation districts, drainage districts, andsimilar legal entities which have authority understate law to construct, maintain, and operateworks of improvement. These watershed loansare repayable over periods of up to 50 years.The major purposes of FmHA’s rural creditprograms are:1. To help build the family farm system, theeconomic and social base of many ruralcommunities.2. To expand business and industry, increaseincome and employment, and controllerabate pollution.3. To install water and waste disposalsystems and other community facilitiesthat will help rural areas upgrade thequality of living and promote economicdevelopment and growth.4. To provide or improve modest homesin suitable rural environments at pricesand on terms that families of low ormoderate incomes can afford.The University of Idaho andWashington State UniversityThese two institutions of higher learninghave contributed in three major ways to the jobof controlling soil erosion in the Palouse RiverBasin: conducting basic and applied researchrelated to various aspects of erosion control;educating and training students in agriculturaldisciplines related to soil conservation (thusmaking technicians available to the Soil ConservationService, Extension Service, Science andEducation Administration and other agencieswhich directly assist farmers in erosion control)and educating and training people who laterbecome farmers in the Palouse Basin.A specific example of research which aidedsoil conservation was development of Gaineswheat. Prior to development of Gaines byUSDA and University plant breeders in theearly 1960’s, wheat varieties then in use producedextra long, heavy straw which lodgedbadly on some sites. This made residue utilizationdifficult or impossible with equipment thenavailable. As a result, many farmers burnedthe straw after harvest. The new semi-dwarfvariety Gaines and its successors produce ashort, stiff straw and yield more grain per ton ofresidue than earlier varieties. A farmer is nowable to better utilize grain residues for erosioncontrol. Wheat breeders are currently workingto develop better spring wheat varieties; winterwheats which thrive in rough seedbeds, andother soil erosion control improvements.Research programs at the Universities haveimproved weed control methods compatiblewith erosion control needs. To a lesser degree,the institutions have worked on improved tillagemethods for soil and water conservation.Washington State University assists localConservation Districts in the Washington portionof the basin in yet another way. In 1953, anumber of Districts began helping cooperatingfarmers with moisture-nitrogen testing of soilsto guide fertilizing practices. The University hasassisted with this job. WSU provides technicaldirection for lab operation by: training Districtlab technicians; calibrating lab equipment; providingtechnical formulae for making tests andinterpreting results, and carrying out field teststo further improve the system.Idaho and Washington have fully organizedState Conservation Commissions. The Deans ofAgriculture from these Land Grant Universitiesare members of their respective State ConservationCommissions.189

BIBLIOGRAPHY

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Lang, A. L. and Blakely, B. D. Crop rotation: Practical or pass’e? National Plant Food Institute,Washington, D.C.Leggett, G. E. Relationships between wheat yield, available moisture, and available nitrogen inEastern Washington dry land areas. Bulletin 609, Washington State University. December, 1959.Leggett, G. E., Reisenauer, H. M. and Nelson, W. L. Fertilization of dry land wheat in EasternWashington. Bulletin 602, Washington State University. March, 1959.Leggett, G. E, and Nelson, W. L. Wheat production as influenced by cropping sequence and nitrogenfertilization in the 10-15 inch rainfall area of Eastern Washington. Bulletin 608, WashingtonState University. 1960.Maldenhauer, W. C. and Onstad, C. A. Achieving specific soil loss levels. Journal of soil and waterconservation. 1975.McCool, D. K. and Papindick, R.I. Variation of suspended sediment load in the Palouse region ofthe Northwest. December, 1975.Michaelson, E. L. Economics of farm size in the Washington-Idaho wheat-pea area. Bulletin 52.May, 1967.Michaelson, E. L. Resource requirements, costs, and expected returns for alternative crop andlivestock enterprises, Palouse wheat-pea area. Bulletin 671. September, 1966.Miller, T. K. Grass is gold. Biographical history. 1969.Molnau, McCool, D. K., and Allmaras. Hydrology and erosion control research for the nonirrigatedareas of the Pacific Northwest. 1975.Molnau, Neilson, Chacho, and Watts. Sediment transport estimation in the Central Idahobatholith. 1975.Montana Cooperative Extension Service, and SCS (USDA) cooperating. Enterprise cost report forirrigated crops, Gallatin County. Circular 1122, Montana State University. January, 1971.Nairn, J. Evaluation of dry land crop rotation experiments at Sherman Branch ExperimentStation, Oregon. Miscellaneous Paper No. 23, Agricultural Experiment Station, Oregon StateCollege, Corvallis, Oregon.Neff, E. L. and Bloomsburg, G. L. Precipitation characteristics in the Palouse area of Idaho andWashington. Agricultural Research Service, USDA, 41-66. 1962.Nulan, J. Soils Handbook for Whitman County. 1959. Oakerman, G. Wildlife evaluation in thePalouse River Basin. 1976.Onstad, C. A., Piest, R. F., and Saxton, K. E. Watershed erosion model valuation for South-westIowa. 1976Onstad, C. A. and Foster, G. R. Erosion modeling in a watershed. ASAE, Vol. 18, No. 2, PL288-292. 1974.Oregon State University. Grass on diverted acres. Corvallis, Oregon, March, 1970. Oregon StateUniversity, University of Idaho and Washington State University. STEEP proposal. 1974.Owens, H. I., Paulling, J. R., and Gilden, R. O. Tillage alternative. Cut labor and time. Cut erosion.Stop pollution. Your decision. Extension Service, USDA. February, 1971.Pacific Northwest River Basins Commission. Columbia-North Pacific framework study. XVI. 1972.Pacific Northwest River Basins Commission. Climatological Handbook, Columbia Basin States, to1971. 3 Volumes.Parker, S. Exploring tour beyond the Rocky Mountains. Ithaca: New York. 1844.Pawson, W. W., Brough, O. L., Jr., Swanson, J. P., and Horner, G. M. Economics of croppingsystems and soil conservation in the Palouse Pacific Northwest Agricultural ExperimentStation Research Series. Bulletin 2, 1961.196

Pawson, W. W., Swanson, J. P., and Horner, G. M. Appendix to the report on effect of croprotations and fertilizer use on farm income and soil conservation in the Palousewheat-pea area. August, 1959.Perryman, C. and Brown, R. W. A grain farm beef enterprise (Costs and returns for a 50cow beef cow-calf enterprise). County Extension Service, Washington State University. EM2630, May, 1966.Perryman, C., Cable, A., Johnson, J., Roffler, R., and Minnick, E. Costs and returns: A beefcow-calf enterprise, Lewis County. Washington State University. June, 1965.Perryman, C., Cagle, A., Kelso, B., Roffler, R., and Minnick, E. Costs and returns of raisingdairy replacement heifers for Lewis County. Washington State University. EM 2424,June, 1964.Peterson, A. W. Economic development of the Columbia basin project compared with aneighboring dryland area. Washington State University. January, 1966.Peterson, A. W. and Swanson, J. P. Economic land use classification for Whitman County.1949. Platt, J. A. Whispers from Old Genesee. Moscow, Idaho, 1959.Potter, W. D. and Love, S. K. Hydrologic studies at the South Fork Palouse River demonstrationproject. USDA, SCS, Hydrologic Research Division. 1942.Poelker, R. J. and Bass, Irven O. Habitat Improvement—The Way to Higher Wildlife Populations inSoutheast Washington. Northwest Science 46(1): 25-31, 1972.Ringe, L. D. Geomorphology of the Palouse hills, Southern Washington. 1968. Roberts, F. M.Meeting of Palouse River steering committee. Dayton, Washington. 1975.Rookie, W. A. Progress report of the Bureau of Chemistry and Soils at The Palouse Northwest SoilErosion and Moisture Conservation Experiment Station. USDA in cooperation with the StateCollege of Washington. 1932.Rosenberry, P. E. and Moldenhauer, W. C. Economic implications of soil conservation. Journalof Soil and Water Conservation. Vol. 25, Number 6, November-December, 1971.Schreiber, D. L. and Bender, D. L. Obtaining overland flow resistance by optimization. ProceedingsASCE 98 (HY3): 420-446, 1972.Shelton, J. R. Effect of crop selection and rotation upon farm income in the Palouse dry croplandarea of Washington. Soil Conservation Service. September, 1974.Smith, H., Vandecaveye, S. C., and Kardos, L. T. Wheat production and properties of Palouse siltloam as affected by organic residues and fertilizers. Washington State University Bulletin 476.1946.Soil Conservation Service. The use of variable cost analysis in resource planning. Spokane,Washington, December, 1972.Soil Conservation Service, USDA. Columbia-North Pacific small watershed reconnaissancedata, Washington and Idaho. OR-93 and summaries. 1966.Soil Conservation Service, USDA. Conservation needs inventory—small watershed projects. 1967.Soil Conservation Service, USDA. Crop yield, soil loss and management tables for soils ofWhitman County. June,1976.Soil Conservation Service, USDA. Dryland conservation farming guide for the Lower ColumbiaBasin dryland farming area of Oregon-Washington.Soil Conservation Service, USDA. USLE Cropping system estimates for “C” values. 1976.Soil Conservation Service, USDA. Erosion sediment and related soil problems, and treatmentopportunities. December, 1975.Soil Conservation Service, USDA. General soil survey—Latah County, Idaho. 1969.197

Soil Conservation Service, USDA. Generalized plan for land treatment on 820 acres of land in thevicinity of Pullman, Washington. 1967.Soil Conservation Service, USDA. Generalized water erosion map—Columbia Plateau area ofIdaho, Oregon, and Washington. 1967.Soil Conservation Service, USDA. Idaho clean Water program. 1976.Soil Conservation Service, USDA. Land resource regions and major land resource area, UnitedStates. December, 1965.Soil Conservation Service, USDA. Major land resource area, State of Washington. September, 1963.Soil Conservation Service, USDA. Major problem areas for soil and water conservation in thedry-farmed grainlands of the Columbia-Snake Palouse area of the Pacific Northwest. 1972.Soil Conservation Service, USDA. Palouse soil and water accelerated project (Idaho). 1976.Soil Conservation Service, USDA. Plan of work, Snake River Basin—Idaho and Wyoming,Type IV survey. 1974.Soil Conservation Service, USDA. Plant science handbook, How to measure rill erosion.Washington, D.C.1968.Soil Conservation Service, USDA. Proposed Palouse regional environmental and conservationprogram. 1969.Soil Conservation Service, USDA. RC&D project plan supplement, annual plan and annualreport, Idaho-Washington. 1976.Soil Conservation Service, USDA. RC&D project plan, Idaho-Washington. 1974.Soil Conservation Service, USDA. Sheet and rill erosion control guide, State of Washington.May, 1976.Soil Conservation Service, USDA. Soil conditioning rating indices for major irrigated andnon-irrigated crops grown in the Western U.S. 1967.Soil Conservation Service, USDA. Soil survey—Adams County, Washington 1976.Soil Conservation Service, USDA. Soil survey manuscript, Whitman County, Washington. 1974.Soil Conservation Service, USDA. Soil survey—Spokane County, Washington. 1968.Soil Conservation Service, USDA. Studies of erosion-controlling forage plants. 1938.Soil Conservation Service, USDA. Washington conservation needs inventory. 1970.Soil Conservation Service, USDA. Wind erosion control guide, State of Washington. March, 1975.Stapleton, H. N. and Hinz, W. W. Increase farm profits through better machinery selection.Agricultural Experiment Station and University of Arizona, Tucson, Cooperative ExtensionService. Bulletin A-78.State Soil and Water Conservation Commission. Streambank erosion in Oregon: A report tothe 57th legislative assembly. 1973.Stephens, D. E. Conservation practices on wheat lands of the pacific Northwest. August, 1944.Stevlingson, D. J. and Everson, D. O. Spring and fall freezing temperatures in Idaho. IdahoAgricultural Experiment Station: Moscow. Bulletin 494. 1968.Swanson, J. P., Parrish, B. D., and Peterson, A. W. Economic land use classification for SpokaneCounty. Washington State University, 1949.Taylor, M. C. and Baker, V. W. Economic aspects of soil conservation in the Palouse wheat-pea area.Bulletin 494, October, 1947.198

Taylor, M. C. and Baker, V. W. Soil Conservation and farm income in the Palouse wheat-pea area.Bulletin 186. November, 1947.Technical NotesColfax Field Office3 Range seeding 195432 Agron. soil aggregation 195659 Agron. stubble mulch research 195777 PM alfalfa for Sw.CI. 195982 Agron. dryland wheat problems 195990 Agron. cloddy tillage 196091 PM increasing livestock 196094 Agron. grass sod, water 1961102 Agron. minimum tillage 1962103 Biol. Cons. & E L, EW 1963117 Agron. Fall Chiseling 1966Thurow, C., Foner, W., and Eriey, D. Performance controls for sensitive lands, a practical guide forlocal administrators. Environmental Protection Agency 600/5—75-005. 1975.U.S. Army, Corps of Engineers. Flood plain information: Pullman, Washington, South Fork ofPalouse and Missouri Flat Creek. March, 1969.U.S. Army, Corps of Engineers. Special flood hazard information, South Fork of Palouse River,Moscow, Idaho and vicinity. 1973.U.S. Army, Corps of Engineers. Sedimentation ranges, 1969-1973.U.S. Army, Corps of Engineers. Status reports—Palouse River Basin. May, 1972.U.S. Congress. Federal water pollution control act. Public Law 92-500. 1972.USDA. Survey report Big Bend-Palouse-Lower Snake subarea. 1954.USDI, Bureau of Reclamation. Lower Snake River basin, Idaho-Washington. May, 1972.USDI, Geological Survey. 1913-1974 Water resource data for Washington.USDI, Geological Survey. The channelled scablands of Eastern Washington. 1974.University of Idaho. Erosion research in Northern Idaho. Agricultural Engineering AnnualReport, 1974-75, pp 41-43.Walker, C. H. Application of a basin simulation model to USDA Type IV River Basin studies.Soil Conservation Service, Bozeman, Montana. October 2, 1975.Washington Crop and Livestock Reporting Service. Washington Agricultural Statistics. 1975.Washington State Department of ecology. STORET retrieval data, water quality monitoring. 1974.Washington State Department of Ecology. 1973 quality report—Palouse River 1970-1971. TechnicalReport No. 73-014 (also 74-75).Washington State Department of Ecology. Water quality report—Palouse River, December,1970-September, 1971.Washington State University. Annual weed control in winter wheat in Eastern Washington.Extension Bulletin 599. October, 1969.Washington State University. Continuous cropping, It’s best for the Palouse. Circular 391.September, 1975.199

Washington State University. Effects of time and method of applying nitrogen carriers onrill-irrigated gaines wheat. Washington Agricultural Experiment Station, Circular 463. May,1966.Washington State University. Forecasting crop yields, total production, and gross income for thePalouse wheat-pea area, 1970-1985. Bulletin 712. September, 1969.Washington State University. Impacts of energy price changes on food costs. Bulletin 822.April, 1976.Washington State University. Managing dryland alfalfa in Eastern Washington. 1970.Washington State University. Summaries of Research—2nd annual cons. research field day.ARS, CES. July 1, 1976.Washington State University. Soil losses on wheat farms in the Palouse wheat-pea area.Circular 255. September, 1954.Washington State University. Weather Palouse. Technical Bulletin 58.Watson, W. B. History and description of runoff studies at Moscow, Idaho. Soil ConservationService, USDA. Office of Research. 1943.Whitman County Agricultural Stabilization and Conservation Service. Crop production data,1973, 1975,1976.Whitman County. Comprehensive planning program. 1970.Whitman County Planning Commission. The comprehensive outdoor recreation plan for WhitmanCounty, Washington. 1966.Whitman County Regional Planning Council. Program development for non-point source waterpollution abatement. February, 1975,Whitman County Water Quality Committee. Grant proposal—Program cost summary demonstrationproject for development of a comprehensive program for abatement of non-point sourcewater pollution in rural areas. 1975.Whittlesay, N. K. and Colyar, L. Decision making under conditions of weather uncertainty inthe summerfallow—annual cropping area of Eastern Washington. Bulletin 58. March, 1968.Whittlesay, N. K. and Oehlschlaeger, R. E. Crop production budgets for dryland crops inEastern Washington. Circular 501. February, 1969.Wetter, F. Historical Notes—Palouse River basin. 1976.Yen, E. The determination of frozen ground probabilities from climatic and hydrologic data.M.S. Thesis, University of Idaho. 1975.200

RESOURCECONSERCATIONGLOSSARY

Glossaryabatement: The method of reducing the degree or intensity of pollution, also the use of such amethod.absorption: The penetration of a substance into or through another, such as the dissolving of asoluble gas in a liquid.acre-foot: The volume of water that will cover 1 acre to a depth of 1 foot.aeration: 1. The process of being supplied or impregnated with air. 2. In waste treatment theprocess used to foster biological and chemical purification. 3. In soils, the process by whichair in the soil is replenished by air from the atmosphere. In a well-aerated soil, the soil air issimilar in composition to the atmosphere above the soil. Poorly aerated soils usually containa much higher percentage of carbon dioxide and a correspondingly lower percentageof oxygen. The rate of aeration depends largely on the volume and continuity of pores inthe soil. The zone of aeration is the zone between the land surface and the water table.algal bloom: Proliferation of living algae on the surface of lakes, streams, or ponds; stimulatedby phosphate enrichment.alkalinity: The quality or state of being alkaline; the concentration of OH negative ions.alkali soil (obsolete): 1. A soil with a high degree of alkalinity (pH of 8.5 or higher) or with highexchangeable sodium content (15 percent or more of the exchange capacity) or both. 2. Asoil that contains sufficient alkali (sodium) to interfere with the growth of most crop plants.annual cropping: A system of growing crops on the same land each year as opposed to a systemwhich includes alternate years of crops with summerfallow.annual precipitation: The amount of atmospheric condensation, in the form of snow, sleet, hail,rain, dew, and fog, that falls on an area during a complete year.sediment discharge: The quantity of sediment that is carried past any cross section of astream during an annual period of time.aquatic environment: An ecosystem in which both plants and animals are adapted to livingcompletely under water—examples include lakes, streams, and ponds.aquifer: A geologic formation or structure that transmits water in sufficient quantity to supply theneeds for a water development; usually saturated sands, gravel, fractures, and cavernousand vesicular rock. The term water-bearing is sometimes used synonymously with aquiferwhen a stratum furnishes water for a specific use.artificial reforestation: Establishing a stand of trees by either tree seedlings or by direct seeding.basalt: A fine-grained, dark-colored rock commonly found beneath a large area of soils of thePalouse Country of Eastern Washington.bedload: The sediment (1) that moves by sliding, rolling, or skipping on or near thestreambed, or (2) that is moved by tractive or gravitational forces, or both, but at velocitiesless than those of the adjacent flow.berm: A shelf or flat area that breaks the continuity of a slope.cfs: A volume measurement of water—cubic feet per second.channeled scablands: A large area of Eastern Washington that has been denuded of soil, inmany places to bedrock, by glacial floodwaters of the past.203

chemical sprays: This term is most commonly used to describe the application of herbicides forannual or perennial weed control. Other forms of farm chemicals such as fertilizers, insecticides,and fungicides may also be applied as sprays.chinook: A warm southwest wind that usually causes a warming trend during winter and springmonths.cobbly loam: Soil material consisting of loam and from 15 to 35 percent rock fragments andcobbles 3 to 10 inches in size.conservation district: A public organization created under state enabling law as a special-purposedistrict to develop and carry out a program of soil, water, and related resource conservation,use, and development within its boundaries; usually a subdivision of state government with alocal governing body.conservation practices: These practices are used to control erosion, conserve water, protect plants,or generally improve soil, water, and plant resources.contour: 1. An imaginary line on the surface of the earth connecting points of the same elevation.2. A line drawn on a map connecting points of the same elevation.cost-share programs: National farm programs developed whereby the farmer and the U.S.Government share together in the cost of applying conservation practices on the farmers’land.crop residue: The portion of a plant or crop left in the field after harvest.crop rotation: The growing of different crops in recurring succession on the same land.crop sequence: The order in which crops occur in a cropping system or crop rotation.cropping systems: A sequence of crops adapted to a particular climatic area. It may include grassesand legumes in rotation, fallow, cover crops and the cultural and management measures neededto successfully grow these crops. A “conservation cropping system” is one which protects thesoil from erosion while growing these crops.cultivation: To prepare land by tilling of the soil for the production of crops.debris: The loose material arising from the disintegration of rocks and vegetative material;transportable by streams, ice, or floods.debris dam: A barrier built across a stream channel to retain rock, sand, gravel, silt, or othermaterial.delivery ratio: The percentage of gross erosion which will be delivered to a downstream pointof measurement.discharge—weighted mean concentration: The theoretical sediment concentration if all thewater and sediment passing a section during a time interval were mixed. Concentrationsare expressed in milligrams per liter.diversion: Individually designed channel and ridge across a hillside to protect an area fromhillside runoff.dryland farming: The practice of crop production in low rainfall areas without irrigation.ecology: The study of interrelationships of organisms to one another and to their environment.environment: The sum total of all the external conditions that may act upon an organism orcommunity to influence its development or existence.erodability: The ability or characteristics of a soil that causes it to wear or erode away by windor water action.204

erosion: The wearing away of the land surface by running water, wind, ice, or other geologicalagents, including such processes as gravitational creep. The following terms are used todescribe different types of water erosion.gully erosion: The erosion process whereby water accumulates in narrow channels or depressionsand, over short periods, removes the soil from this narrow area toconsiderable depths, ranging from 1 to 2 feet to as much as 75 to 100 feet.natural erosion: Wearing away of the earth’s surface by water, ice, or other natural agentsunder natural environmental conditions of climate, vegetation, etc., undisturbedby man.rill erosion: An erosion process in which numerous small channels only several inchesdeep are formed; occurs mainly on recently cultivated soils.sheet erosion: The removal of a fairly uniform layer of soil from the land surface by runoffwater.stream channel erosion: Lateral recessions of the streambanks and/or degradation of thestreams bottoms by stream flow action.tillage erosion: The downhill movement of soil by use of tillage implements for crop production.erosion rate: The amount or degree of wearing away of the land surface.erosive: Refers to wind or water having sufficient velocity to cause erosion. Not to be confusedwith erodible as a quality of soil.farm commodity programs: National farm programs developed to alleviate economic problemsresulting from over-production.fertilizer: Any organic or inorganic material of natural or synthetic origin that is added to a soil tosupply elements essential to plant growth.flood control: Methods or facilities for reducing flood flows.fluvial sediment: Sediments deposited by stream action.forb: A herbaceous plant which is not a grass, sedge, or rush.forest: A plant association predominantly of trees and other woody vegetation.forest management: Employing a number of practices such as planting, logging, fire, and diseasecontrol in such a way that desired goals of use and conservation are achieved.furrow slice: The soil in the plow layer that is over turned when a field is plowed.geological uplift: Elevation or pushing up of an extensive part of the earth’s surface relative tosome other part.glacial outwash: Cross-bedded gravel, sand, and silt deposited by water as it flowed fromglacial ice.glacial periods: Periods of alteration of the earth’s surface through erosion and deposition bymovement of glacial ice.gradient: Change of elevation, velocity, pressure, or other characteristics per unit length; slope.grassed waterway: A natural or constructed waterway, usually broad and shallow, covered witherosion-resistant grasses, used to conduct surface water from cropland.green manure crop: Any crop grown for the purpose of being turned under while green or soonafter maturity for soil improvement.groundwater: Phreatic water of subsurface water in the zone of saturation.205

habitat: The environment in which the life needs of a plant or animal organism, population, orcommunity are supplied.herbicide: A chemical substance used for killing plants, especially weeds.humus: That more or less stable fraction of the soil organic matter remaining after the majorportion or added plant and animal residues have decomposed.intermediate cuts: Harvesting a portion of the merchantable trees from an immature stand of trees.intermittent streamflows: Streams which flow only during certain times when they receive waterfrom springs or from precipitation.lava flows: A stream of fluid or solidified fragmented lava which spews from an individual volcaniccone or from a fissure in relatively quiet fashion, with little or no explosive activity.leaching: The removal from the soil in solution of the more soluble materials by percolating waters.loess: Material transported and deposited by wind and consisting of predominantly silt-sizedparticles.mean annual stream flow: Discharges observed and average over a water year (Octoberthrough September).minimum tillage: The least amount of tillage required to create the proper soil condition for seedgermination and plant establishment.natural resources: Naturally occurring resources needed by an organism, population, or ecosystem,which, by their increasing availability up to an optimal or sufficient level, allow an increasingrate of energy conversion.natural revegetation: Natural re-establishment of plants; propagation of new plants over an area bynatural processes.no-tillage: A method of planting crops that involves no seedbed preparation other than openingthe soil for the purpose of placing the seed at the intended depth.noxious weeds: Plants that are undesirable because they conflict, restrict, or otherwise causeproblems under the present management objectives.nutrients: 1. Elements, or compounds, essential as raw materials for organism growth anddevelopment, such as carbon, oxygen, nitrogen, phosphorus, etc. 2. The dissolved solidsand gasses of the water of an area.overwood removal: Removing the tallest trees as a weeding, sanitation, or salvage operation.particle size: The diameter, in millimeters, of suspended sediment or bed sediment. A classificationrecommended by the Sub-committee on Sediment Terminology of the American GeophysicalUnion defines a particle having a diameter of less than 0.004 mm (millimeter) as clay, between0.004 and 0.062 mm as silt, and between 0.062 and 2.0 mm as sand.parameter: A quantity or constant whose value varies with the circumstances of its application.pasture: An area devoted to the production of forage, introduced or native, and harvested bygrazing.percolation: The downward movement of water through soil, especially the downward flow ofwater in saturated or nearly saturated soil at hydraulic gradients of the order of 1.0 or less.permeability: Capacity for transmitting a fluid. It is measured by the rate at which a fluid ofstandard viscosity can move through material in a given interval of time under a givenhydraulic gradient.pesticide: Any chemical agent used for control of specific organisms; such as insecticides, herbicides,fungicides, etc.206

planned grazing system: A system of grazing in which two or more grazing units are alternatelyrested in a planned sequence over a period of years. The resting period may be throughoutthe year or during the growing season of the key species.pollution: The condition caused by the presence in the environment of substances of suchcharacter and in such quantities that the quality of the environment is impaired or renderedoffensive to life.pond: A water impoundment made by constructing a dam or embankment, or by excavating apit or dugout.poorly drained soils: Are wet for long periods, are light gray, and generally mottled from thesurface downward, and have limited uses for crop production.proper grazing use: Grazing ranges and pastures in a manner that will maintain adequate cover forsoil protection and maintain or improve the quality and quantity of desirable vegetation.rangeland: Land on which the native vegetation (climax or natural potential) is predominantlygrasses, grass-like plants, forbs, or shrubs suitable for grazing or browsing use. Includeslands revegetated naturally or artificially to provide a forage cover that is managed likenative vegetation. Rangelands include natural grassland, savannas, shrublands, most deserts,tundra, alpine communities, coastal marshes, and wet meadows.range condition class: One of a series of arbitrary categories used to classify range condition,usually expressed as either excellent, good, fair, or poor.river basin: The area drained by a river and its branches.runoff (hydraulics): That portion of the precipitation on a drainage area that is discharged fromthe area in stream channels. Types include surface runoff, ground water runoff, or seepage.scour: To abrade and wear away; used to describe the wearing away of terrace or diversionchannels or stream beds.sediment: Solid material, both mineral and organic, that is in suspension, is being transported,or has been moved from its site of origin by air, water, gravity, or ice and has come to reston the earth’s surface either above or below sea level.sediment discharge: The quantity of sediment that is carried past any cross section of a stream in aunit of time. Basically, sediment discharge is made up of two components, suspended-sedimentdischarge and bedload discharge.sedimentary strata: Rock formed from sediment, such as conglomerate, sandstone, and shales, andformed of fragments of other rocks transported from their sources and deposited in water.sediment yield: The sediment discharge from a unit of drainage area, generally expressed in tons persquare mile.shrub communities: Vegetation which is dominated by shrubby species.silt: 1. A soil separate consisting of particles between 0.05 and 0.002 millimeter in equivalentdiameter. 2. A class of soil texture.silt loam: A soil textural class containing a large amount of silt and small quantities of sand andclay. See soil texture.silty clay: A soil textural class containing a relatively large amount of silt and clay and a smallamount of sand.silvicultural: The cultivation and care of trees in a forest.soil association: 1. A group of defined and named taxonomic soil units occurring together in anindividual and characteristic pattern over a geographic region, comparable to plant associationsin many ways. Sometimes called “natural land type.” 2. A mapping unit used on reconnaissance207

or generalized soil maps in which two or more defined taxonomic units occurring together in acharacteristic pattern are combined because the scale of the map or the purpose for which it isbeing made does not require delineation of the individual soils.soil moisture: Water retained in the soil for use by plants.soil organic matter: The organic fraction of the soil that includes plant and animal residues atvarious stages of decomposition, cells, and tissues of soil organisms, and substances synthesizedby the soil population. Commonly determined as the amount of organic materialcontained in a soil sample passed through a 2-millimeter sieve.soil productivity: The inherent capacity of a soil to produce a specified crop or sequence of crops inits normal environment.soil profile: A vertical section of the soil from the surface through all its horizons, including Chorizons.soil slip: Areas of varying size that have become saturated, and due to excessive steepness, haveslipped downhill—a small land-slide.soil structure: The combination or arrangement of primary soil particles into secondary particles,units, or peds. The secondary units are characterized and classified on the basis of size,shape, and degree of distinctness into classes, types, and grades, respectively.soil texture: The relative proportions of the various soil separates in a soil. The textural classesmay be modified by the addition of suitable adjectives when coarse fragments are presentin substantial amounts, for example, gravelly silt loam.spawning beds: Areas within a stream, lake or pond, usually containing gravel, upon or inwhich fish deposit eggs to complete their embryonic development.stagnated thicket: Very dense stands of trees, generally five to twenty-five feet high, where notrees are able to express dominance.stratification: The process of arrangement or composition in strata or layers.stream reaches: A length of stream channel selected for use in hydraulic or other computations.stripcropping: Growing crops in a systematic arrangement of strips or bands which serve asbarriers to wind and water erosion.structural treatments: A group of practices which control water after it has become runoff, such asterraces, waterways, drop structures, etc.stubble mulch: The stubble of crops or crop residues left essentially in place on the land as a surfacecover during fallow and the growing of a succeeding crop.stumpage value: The monetary value of the tree or timber stand before it is cut.subwatershed: A watershed subdivision of unspecified size that forms a convenient natural unit.See watershed.summerfallow: The tillage of uncropped land during the summer in order to control weeds andstore moisture in the soil for the growth of a later crop.super-saturated: Free water or water in excess of what the soil is capable of holding.supplemental irrigation: Water supplied to a crop when either rainfall or the principal irrigationsupply are inadequate to produce a crop.suspended sediment: The sediment that at any given time is maintained in suspension by theupward components of turbulent currents or that exists in suspension as a colloid.sustained yield: Managing a forest for continued production, where production is equal to theyield.208

terrace system: A series of terraces occupying a slope and discharging runoff into one or moreoutlet channels.tillage: The operation of implements through the soil to prepare seedbeds and root beds.tillage erosion: The downhill movement of surface soil, caused by tillage equipment when usingthem on sloping land.topography: The relative positions and elevations of the natural or man-made features of an areathat describe the configuration of its surface.topsoil: 1. Earthy material used as top-dressing for house lots, grounds for large buildings, gardens,road cuts, or similar areas. It has favorable characteristics for production of desired kinds ofvegetation or can be made favorable. 2. The surface plow layer of a soil; also called surface soil.3. The original or present dark-colored upper soil that ranges from a mere fraction of an inch totwo or three feet thick on different kinds of soil. 4. The original or present A horizon, varyingwidely among different kinds of soil. Applied to soils in the field, the term has no precisemeaning unless defined as to depth or productivity in relation to a specific kind of soil.toxicity: Quality, state, or degree of the harmful effect resulting from alteration of an environmentfactor.tributary: Secondary or branch of a stream, drain, or other channel that contributes flow to theprimary or main channel.understory vegetation: The vegetation, generally under fifteen feet in height, that grows beneath thetree canopy.universal soil loss equation: An equation used to design water erosion control systems: A =RKLSPC wherein A is average annual soil loss in tons per acre per year; R is the rainfallfactor; K is the soil credibility factor; L is the length of slope; S is the percent slope; P is theconservation practice factor; and C is the cropping and management factor. (T = soil losstolerance value that has been assigned each soil, expressed in tons per acre per year).upland game bird: Ground dwelling, chicken-like birds that are not necessarily dependent onwetlands for their survival—e.g. quail, pheasant, grouse, partridge.vegetation cover: The soil surface protection against rain drop or runoff erosion or wind erosionby living plant materials such as grasses, legumes, cereal grains, or other growing crops.velocities: As referred to here in the study, the speed at which water flows.volcanic activity: Pertaining to the phenomena of volcanic eruption, the explosive or quietemission of lava or volcanic gasses at the earth’s surface.water holding capacity: The amount of water that a given soil can hold.watershed area: All land and water within the confines of a drainage divide or a water problemarea consisting in whole or in part of land needing drainage or irrigation.wetland: Land where water on or near the soil surface is the dominant factor determining thetypes of plant and animal communities living in the soil or on its surface.wildlife: Undomesticated vertebrate animals, except fish, considered collectively.windbreak: 1. A living barrier of trees or combination of trees and shrubs located adjacent tofarm or ranch headquarters and designed to protect the area from cold or hot winds anddrifting snow. Also headquarters and livestock windbreaks.209

APPENDIX

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AppendixStudy MethodologyLiterature Search 1With two major agricultural universitieslocated within the basin and associated for each of the major soil association areas inIt was decided to select one evaluation arearesearch facilities connected with these universities,extensive data on the problems of were used. The areas used had previously beenthe basin. Areas of approximately 1,400 acresthe area and their effects are available. In selected by SCS soil scientist Herman Gentry asthis study, over 300 reference sources, most representative areas of the major soil associations.Each area is approximately 1.3 miles wideof which originated at the universities, werefound about the Palouse and related erosion by 1.7 miles long. Land ownership and operationof the areas varied from as few as three toproblems. Data from these sources has beenused extensively in this study to improve its as many as seven different farmers. Evaluationusefulness, scope, and accuracy. Available data area boundaries do not necessarily follow sectionlines or ownership boundaries. (See Figurewas also used in establishing study directionand intensity.16) Fifteen areas were evaluated.Field sheets used in the study include 8”/mile scale aerial photographs, soils surveymaps, and contour maps of each evaluationEvaluation Area Selection—Cropland area.Each farmer in each evaluation area wasinterviewed. 1 Data obtained from the farmersIn order to achieve study objectives, a processof utilizing evaluation areas as a base for ery usage, and farm operation inputs. Fiftyincluded cropping system, crop yields, machin-the study was used. The study areas used were farmers were interviewed.selected following discussions with cooperative Field data for use in universal soil loss equationcomputations was collected on each evalu-study leaders, Washington State University andUniversity of Idaho staff members, and personnelof the Agricultural Research Service and the the basin (see Figure 16, topographic diagram)ation area. Because of complex topography inCooperative Extension service with extensive and as influenced by the amount of cropland inexperience in the basin. Evaluation areas were the evaluation area, intensity of field study wasselected to meet the following criteria:varied (the more complex topography and areaswith high percentages of cropland received1. represent the soils of the basin;most intensive field analysis).2. adequately represent rainfall zones of thebasin;1 Exception: One farmer refused interview, and three could not be3. be large and numerous enough to providecontacted.sound and meaningful data;4. lend themselves to soil loss and economic The soil loss equation is expressed as: A =analysis;RKLSCP.5. be within the range of stream monitoring sta-A = average annual soil loss in tons/acre/tions;year.6. be representative of major soil erosion prob-R = rainfall and runoff factor.lem areas.K = soil erodibility factor.1 See Bibliography SectionLS = length and steepness of slope combination.C = cropping management factor.P = erosion control practice factor.213

All factors except the LS factor were availablefrom various published sources includingSheet and Rill Erosion Control Guide, State ofWashington, Whitman County Soil Survey, andsoil survey maps of the evaluation areas. Representativeslopes in each evaluation area wereselected and measured for use in determinationof LS (length and steepness) values. An averageof eight slopes were measured in each evaluationarea. Because of slope irregularity and/orsoil differentiation, all slopes were segmentedand soil loss analysis was made for each segment.Data from farm and field was assembled foruse in two major computer analysis programs.U.S.L.E. Computer Analysis—CroplandComputer analysis of soil loss rates wasconducted for each evaluation area in four programs.The first program evaluated each slopeand each slope segment for each farm in eachevaluation area. Soil loss rates were projectedfor 13 cropping-management systems (C values)and six conservation practices (P values). Analysiswas made for each slope with and withoutterrace installations. (See Figure 16 and Table 36).Analysis was also conducted to study effects ofretiring Class IV e and VI e land from cultivation.Figure A-1Major soils in the Palouse-Athena association and their relationship to thelandscape in the valley of Willow and Pine Creeks. location: NW cor. of blockdiagram is 2800 feet east of NE cor. of Sec. 9, T19N R45E.214

Table 35. Crop Rotations and Conservation PracticesItems Evaluated-C and P ValuesC ValueC1 Annual Winter Wheat, fall plow, fall disc500-1,000 lbs. residue .24C2 Annual Winter Wheat, fall chisel, fall disc 2,500 lbs. residue .08C3 Seeding out Class VI only .01C4 Seeding out class IV and VI .01C5 Winter Wheat--Peas, chisel wheat, chisel peas .18C6 Winter Wheat--Peas, fall plow wheat, any tillage peas .48C7C8Winter Wheat--Spring Grain--Peasfall chisel all crops .13W-P-W-P-3 to 5 years, Alfalfa and Grasschisel all crops, plow green manure .09C9 No till Winter Wheat .03C10C11C12Wheat-Fallow; No Stubble Mulch700 lbs. residue .37Wheat-Fallow, Stubble Mulch2,000 lbs. residue .13Wheat-Barley-Fallow, no stubble mulchMoldboard plow .27C13 Wheat-Barley-Fallow, stubble mulch fallow .15P1P2P3P4P5P6P7RKLS1RKLS2Existing conservation practicesUp and down hill farmingCross slope farmingContour farmingField stripcroppingContour stripcroppingDivided slope farmingLand without terracesLand with terraces215

Evaluation: G-8Average Slope: 14%Date: 2/15/77Table 36. Soil Loss Summary Table Per Evaluation AreaPalouse-Athena Soil AssociationAverageP (N)Annual Winter Wheat, Barley,AndPeasN Value Winter Wheat Wheat & PeasWheat-PeasAndAlfalfaNoTillC=0.24 C=0.08 C=0.18 C=0.48 C=0.26 C=0.09 C=0.03WITHOUT TERRACES AND WITHOUT GRASS1 0.85 7.82 2.6 5.86 15.64 8.47 2.92 0.972 1.00 8.71 2.89 6.53 17.43 9.44 3.26 1.083 0.83 7.64 2.54 5.73 15.29 8.28 2.86 0.944 0.71 6.95 2.31 5.21 13.91 7.53 2.60 0.865 0.54 5.52 1.83 4.14 11.06 5.99 2.06 0.686 0.36 3.73 1.24 2.79 7.47 4.04 1.39 0.45WITHOUT TERRACES AND WITH GRASS1 0.85 6.07 2.07 4.57 12.09 6.57 2.31 0.812 1.00 6.97 2.37 5.24 13.88 7.54 2.65 0.933 0.83 5.90 2.01 4.44 11.74 6.38 2.25 0.794 0.71 5.21 1.78 3.92 10.35 5.64 1.99 0.715 0.54 3.92 1.35 2.95 7.79 4.25 1.51 0.546 0.36 2.63 0.90 1.98 5.23 2.85 1.01 0.36WITH TERRACES AND WITHOUT GRASS1 0.85 7.21 2.40 5.40 14.44 7.81 2.70 0.892 1.00 7.97 2.65 5.97 15.95 8.63 2.98 0.983 0.83 7.05 2.34 5.28 14.11 7.64 2.64 0.874 0.71 6.48 2.15 4.86 12.98 7.02 2.42 0.805 0.54 5.18 1.72 3.88 10.36 5.61 1.93 0.636 0.36 3.50 1.16 2.62 7.00 3.78 1.30 0.43WITH TERRACES AND WITH GRASS1 0.85 5.47 1.87 4.12 10.88 5.92 2.09 0.742 1.00 6.23 2.12 4.69 12.39 6.74 2.37 0.833 0.83 5.31 1.81 4.00 10.56 5.75 2.03 0.724 0.71 4.74 1.62 3.57 9.42 5.13 1.82 0.655 0.54 3.58 1.23 2.69 7.03 3.87 1.37 0.496 0.36 2.40 0.82 1.81 4.76 2.59 0.92 0.33216

Program two provided summary data by slope,program three provided summary data by farm,and program four provided summary data byevaluation area. Major data output is predictedsoil loss rate by slope, farm, and evaluation area.Economic Computer AnalysisData collected during farm interviews wasconsolidated into three major rainfall zones foreconomic analysis. This consolidation was doneto reduce computer costs and considered desirablebecause of small differences in farmingsystems in the three major rainfall zones. Thezones used were under 15” annual rainfall, 15”-18” annual rainfall, and 18+” annual rainfall.Economic analysis was performed for allcropping-management systems, conservationpractices and use of terrace systems as performedin the USLE computer programs. Dataoutput includes net returns in fuel use $/acre,and gallons/acre, and fertilizer use in $/acre foreach alternative land management system andpotential supporting conservation practice.Linear Program—USLE and EconomicsA linear program was performed by ESCS,using USLE and economics computing programoutput to provide comparative data for alternativeland management systems on maximumfeasible net income, minimum feasible soil erosion,best technical (minimum soil loss plus bestfeasible economics), restricted fuel availabilityand restricted wheat price constraint programs.Linear programming was the techniqueused in analyzing the various land managementsystems in the Palouse. This technique ismathematical in nature and can be defined as amethod of maximizing, or minimizing, a linearfunction. Such a function consists of a number ofvariables subject to a number of restraints whichare stated in the form of linear inequalities.As an example, let us assume that a farmproduces two products, corn for silage (Xi) andbarley (Xz) which can be sold at prices of $3.64and $1.00 per cwt. respectively. Therefore Px, =$3.64, and Pxz = $1.00. Let it also be assumedthat the farm has available 600 acres of land (a),88,000 pounds of fertilizer (b), and 22,000 acreinchesof water (c).It is also assumed that one unit of Xi requires0.0033 units of a, 0.4500 units of b and 0.1500units of c. The problem facing the farmer is oneof producing the maximum amount of revenuefrom the sale of Xi and X2, consistent with thegiven prices of the crops and within the constraintsimposed by the existing supplies ofinputs. We assume further that the farmer cannotproduce negative amounts of the two crops,Xi and X2, and that he may not produce anyamount at all of one of the crops—i.e., Xi > 0and X2>0. Finally, the farmer knows that barley,X2, requires 0.0417 units of a, 6.25 units of b,and 1,4583 units of c.It is now possible to write the mathematicalequations which emphasize the constraints interms of inputs subject to which Xi and X2 mustbe produced. These are as follows:0.0033(X,) + 0.0417(X2) = 6000.4500(X,) + 6.2500(X2) = 88,0000.1500(Xi) + 1.4583(X2) = 22,000The combinations of linear functions andthe number of variables necessary to analyzethe alternative land management systems inthe Palouse resulted in a linear programmingproblem more complicated than the exampleshown above. First of all, three distinct precipitationzones were involved: less than 15-inches,15 to 18 inches, and greater than 18-inches.There were 13 distinct cropping patterns. Eachcropping pattern supplied erosion costs, totalproduction costs, total profit, yield, fuel requirements,fertilizer requirements, gross receipts,and the tons of erosion reduced by each landmanagement system. In addition, there was apossibility of 53 land management systems.The land management systems were separatedinto three major zones according to theamount of precipitation in each zone. Precipitationeffects the combinations of crops grown,the types of tillage systems and equipmentused, and the resulting soil loss and sedimentdelivery rates from each zone. The soil loss foreach management system was computed usingthe Universal Soil Loss Equation and the dataprovided by the Soil Conservation Service.Erosion control measures in the Palouse RiverBasin can be either nonstructural or structural,or a combination of the two. Nonstructural measuresinclude improved tillage systems, changesin cropping patterns, or combinations thereof.Structural measures include the use of terracing,stripcropping, and similar measures. Themanagement systems within the Basin consist ofmeasures that control erosion by the applicationof combinations of the following principles:217

1. Install conservation practices as requiredbecause of topography, soils and vegetativecover to reduce erosion.2. Retain and protect suitable existing vegetationwherever possible to retard runoff anderosion.3. Provided structural measures to accomodateincreased runoff resulting from changedsoil and surface conditions.4. Install permanent vegetative and structuralerosion control to stabilize critical erosionareas.5. Maintain vegetative and structural improvementsto insure their effectiveness.6. Adjust land use to assure that flatter, lesserosive lands are used for cultivated crops andsteeper Class IV e and VI e lands are used forpermanent grass crops.The above principles were incorporated intoeach rainfall zone by cropping pattern and managementsystem. Each combination examinedthe changes in agricultural production resultingfrom the regulation of erosion control rates.Evaluation Areas—RangelandUSLE projections for rangeland were performedin a manner very similar to that used oncropland. The three evaluation areas with majoracreages of rangeland were evaluated. Soil losspredictions for rangeland were prepared. Economicanalysis was not performed for rangelandareas because of good budget data alreadyavailable and the low soil loss rates projectedfor rangeland which obviated the need for considerationof alternative management systemsfor this land.Evaluation Area—Forest LandSmall areas of forest land are found in onlythree evaluation areas of the Palouse Basin inWashington. Soil loss rate predictions have beenprepared for these areas. The U.S. Forest Servicehas performed extensive analysis of soil lossand sediment delivery on forested portions ofthe basin in Idaho.Sediment yield can be defined as the effluentfrom a Soil Processing System. The “System” isa diffuse natural process known as soil erosion.This System is distributed in time and space,and can be accelerated or decelerated by a multitudeof factors, including the activities of man.The effluent from the Soil Processing System isa heterogeneous mixture of mineral and organicmatter ranging from small to large particles,with a variety of natural or acquired chemicaland biological properties.There has been concern in the United Statesfor sediment yield to streams and reservoirs forover 100 years. Only recently, however, have webegun to appreciate the water quality implicationsof sediment as a pollutant in the samecontext as effluent from industrial, sewage, andother point sources of pollution entering waterbodies. Likewise, we have become aware of theability of sediment to transport other pollutants.For instance, persistent chlorinated hydrocarbonssuch as Dieldrin have a low solubility inwater, but are strongly absorbed by soil particles.Phosphorus applied as a fertilizer is alsostrongly absorbed onto soil particles and movesto streams and other water bodies primarilyattached to sediment from erosion. Significantnitrogen-sediment relationships have beenillustrated by the Agriculture Research Servicein southwestern Iowa (1973).The procedures used for the forest land portionof the Palouse first involved an estimateof the gross erosion. This was accomplished byconstructing a mosaic of 1 inch = mile aerialphotography. The landforms were mappedusing standard procedures. They were furtheradjusted using existing slope, vegetation, soildisturbance, climatic, and geologic types; andgrouped into 10 distinct erosion producing units.Rates of erosion were established usingactual plot data as a basis to adjust researchfindings and output from the universal soil lossequation. Channel erosion was based on photocomparison and field survey of stream channelmorphology. The U.S. Forest Service, Region 1,procedure for stream channel stability determinationwas used and correlated with regressioncurves for channel erosion versus channel stabilityby Hydrologist, C. Benoit. Erosion rateswere adjusted to long-term climatic conditions,1960-1975 base. These erosion rates range from.06 to 3.95 tons/acre/year. A weighted averageof 65.5 tons per mile was used for the 139 milesof stream channel erosion to produce a grosserosion of 70,594.5 tons. Helli Smith bedloadsample data indicate that approximately 1/2 ofthe stream channel erosion is bedload and 1/2is suspended load.Fluvial sediment was determined by samplingstream flow over time using a DH-48 andDH-59 depth integrated sediment samplersaccording to U.S. Geological Survey recom-218

mended techniques. Again, a Helli Smith wasused for bedload. This data was compared withstream flow, producing a sediment-dischargeregression. This regression had a confidence R2value of .92. Mean annual runoff for each basinwas estimated using Idaho runoff isohyetalmaps developed by Dr. Marvin Rosa, U.S. AgricultureResearch Service. The timing of runoffwas based on the U. S. Geological Survey GaugingStation (13345) data for the Palouse. Thesesynthesized hydrographs were applied againstthe regression (sediment discharge) to developmean annual weighted gross sediment deliveryof 17,957.6 tons from all sources. This results inan overall sediment delivery ratio of .25; that is,1 out of every 4 tons of erosion leaves the forestland as fluvial sediment.These procedures are further documented inAgriculture Research Service publication S-40dated June 1975 and other references cited inHydrologist, C. Benoit’s report dated November1976 for the Palouse, Chapter VII of this report.Evaluation—Wildlife HabitatThe loss of wildlife habitat has been frequentlynoted, but seldom measured or theresults quantified. Therefore, an attempt wasmade to quantify and express numerically thevalue of wildlife habitat on the same sampleplots selected for evaluation in other portionsof this study. The evaluation of wildlife habitatwas based on three assumptions:(1) The abundance and distribution of waterand various vegetative types directly affectsthe total number of species as well as the totalwildlife population of any given area of land;(2) the value of any habitat or vegetative type ismodified by the management of the habitat; e.g.,types of tillage operations, grazing intensity,burning, use of herbicides and insecticides, etc.;and (3) when values for abundance, distributionand management are at optimum levels, thewildlife populations will also occur at optimumlevels. Optimum being the greatest diversityand density of wildlife attainable for a givenarea.A habitat evaluation technique proposed byThomas (1974) and later modified by Applegate(1974) was adopted for use. The “ThomasTechnique” predicts the relative value of wildlifehabitat based on the abundance, distributionand management of defined vegetativetypes. The technique was modified for use inthe Palouse by defining vegetative types ofimportance to wildlife in the Palouse area—e.g.,herbaceous vegetation, woody vegetation,and cropland; by expressing the importanceof wildlife drinking water; and by developingvegetation management values for managementsystems commonly used in the Palousearea. The validity of the Thomas Technique forpredicting habitat value was field tested byOakerman (1976). He found significant positivecorrelations between the predicted habitat valuesand wildlife diversity (r=.95) and predictedhabitat values and wildlife density (r=.82).The evolution of habitat value is performedby placing 20 random points on a photo-mosaicof the study area. The distance from each pointto herbaceous, woody or cropland vegetationis measured on the photo and field checkedto minimize errors in differentiating the threevegetative types from the photos. The mean distance(x) to each vegetative type is then calculated.During the field check, the managementof each of three vegetative types is noted, aswell as the distribution of water on the plot.The mean distance (x), management andwater distribution are then each assigned a relativevalue between one-tenth (0.1) and one (1.0);one-tenth representing little value for wildlifeand one representing an optimum value forwildlife (See Tables A,B). The relative values arethen “plugged into” the formula to arrive at anoverall habitat for each plot.An example of the habitat evaluation techniqueis:1,000 acres of land, of which (a) 750 acres iscropland—a wheat-fallow rotation, crop residuesincorporated by chiseling x distance .5,water available on the average of 1/2 mile; (b)200 acres is herbaceous vegetation—heavilygrazed pasture, x distance .3, water available219

on the average is less than 1/2 mile; (c) 50 acresis woody vegetation, an open windbreak witha heavy understory of grass that is ungrazed,overstory damaged by herbicide drift fromadjoining cropland, x distance 6.5, water availableon the average 1/2 mile. This is summarizedas follows:(1)Vegetationtype(2)Acreage(3)Abundance(4)Management(5)WaterAvailabilityAcreValue(2)x(3)x(4)x(5)Crop 750 .6 .5 1 225.0Herbaceous 200 1.0 .3 1 60.0Woody 50 .4 .4 1 8.01,000 293.0 acresHabitat Value 293/1000= 0.29This value (0.29) means that the habitatrequirements of wildlife found on the entireplot area could be satisfied, on 29% (293 acres)of that area, if conditions on the 293 acreswere optimum for wildlife. If, for example, theabundance and distribution of crop, herbaceous,and woody vegetation were adjusted toprovide optimum conditions for wildlife (seeTable A), with no change in management, all ofthe values in column 3 would become 1.0. Thiswould result in a habitat value of 0.43—or 430acres. On the other hand, if management wasimproved to a value of 1.0 for all vegetativetypes with no change in the abundance or distributionof vegetative types, the result wouldbe a habitat value of 0.67—or 670 acres.Table 37. Vegetation Abundance and Habitat Value for thePalouse River BasinPercent Abundance 0% 5% 10% 15% 20% 30% 40% 50% 60% 70% 80% 90% 100%Cropland 0 .4 .6 .7 .9 1.0 1.0 1.0 .9 .7 .5 .2 .1Herbaceous 0 .1 .4 .8 1.0 1.0 1.0 .9 .8 .7 .6 .5 .3Woody 0 .4 .5 .7 .9 1.0 1.0 .9 .8 .8 .7 .6 .4Acre Value (Abundance and Distribution) 1X Distancein 100 feet 0-0.1 0.2-0.4 0.6-0.8 1.0-1.2 1.4-1.6 1.8-2.0 2.5-3.0 4.0-5.0 6.0-7.0 8.0-9.0 10.0 11.0 12.0 13.0Cropland .1-.5 .6-.7 .8-1.0 1.0-1.0 1.0-1.0 1.0-1.0 1.0-.9 .7-.6 .6-.5 .4-.4 .3 .1 .1 .1Herbaceous .6-.6 .7-.8 .8-.9 .9-.9 .9-1.0 1.0-1.0 1.0-1.0 .8-.6 .5-.3 .1-.1 .1 .1 .1 .1Woody .4-.6 .7-.8 .9-.9 1.0-1.0 1.0-1.0 1.0-1.0 1.0-.9 .7-.5 .5-.4 .4-.3 .3 .1 .1 .11 Values for abundance and distribution are combined as suggested by Applegate (1974).220

Table 38. Habitat Management ValuesGrain and Seed Cropsa. Grain and seed crops managed specificallyfor wildlife—a portion of the crop leftunharvested; no till system or residue notdisturbed in fall; no spring plowing; nograzing.b. Same as “a”, except not specificallymanaged for wildlife.c. Crop residue chiseled in fall-springtillage does not include plowing.d. Crop residue fall disked or chopped—nospring plowinge. Crop residue fall plowedValue1.00.80.60.50.3(No value to exceed 1.0 or less than 0.1)Deduct0.1 for fallow in rotation0.2 for peas or lentils in rotation0.1 for moderate grazing of stubble0.2 for burning of crop residueAdd0.1 or 0.2 for stripcropping (depending on value of rotation to wildlife).221

Table 38. Habitat Management Values (Continued)Woody Vegetationa. A stand of woody vegetation that containsa combination of species, successional stages,and stocking levels, which is specificallymanaged for wildlife.b. Same as “a”, except not specifically managedfor wildlife.c. An even-age stand of moderate stocking witha heavy understory.d. An even-age mature stand of moderate to heavystocking with light understory.e. A decadent or overstocked even-aged stand thathas no understory.Value1.00.80.60.40.2(No value greater than 1.0 or less than 0.1)Deduct0.1 for stands where understory is grazed lightly0.2 for stands where shrubby vegetation is moderately hedged0.3 for stands where shrubby vegetation is severely hedged and patches of bare soil exist0.2 for stands where the overstory has been damaged by herbicides0.2 for stands where understory has been removed by fire0.2 for stands where cultivation is done up to the edge of the stand0.2 for stands where the cultivation has removed the understoryAdd0.2 for stands where fruit from planted trees is not harvested222

Table 38 Habitat Management Values (continuedHerbaceous Vegetationa. A stand composed of grasses, forbs, andlegumes specifically managed for wildlife.b. Same as “a”, except not managed specificallyfor wildlifec. Light to moderate grazing that does notsignificantly reduce the species compositionof vigor of the vegetation, cover not drasticallyreduced, utilization patchy.d. Proper use of the forage obtained under a grazingsystem, species composition reduced to those speciesthat can withstand grazing, all types of hay fieldsare included in this category, cover reduced to 4-6”tall at the end of the grazing season.e. Intensive use of the forage resource, speciescomposition reduced to those plants that areless palatable or can withstand heavy grazing,cover reduced to 2-4” at the end of the grazingseason, soil erosion not evident.f. Overuse of the forage resource, species compositionreduced to those annual and invading species that canwithstand the heavy grazing, cover reduced to 1-2”tall at the end of the grazing season, soil erosionevident.Value1.00.80.70.60.30.2(No value to exceed 1.0 or less than 0.1)Deduct 0.1 for stands where understory is grazed lightly0.2 for stands where shrubby vegetation is moderately hedged0.2 for grazing hay aftermath0.1 for spring burning0.2 for fall burning0.3 for fall burning of hay aftermathAdd0.1-0.2 for deferment grazing systems (depending on the level of utilization and the value of the systemfor wildlife)223

Table 39. Water Availability ValuesWater Availabilitya. Perennial water source distributed over and areaso that the average distance to water is less than1/8 of a mile.b. Water sources distributed over an area so thatthe average distance to water is greater than1/8 of a mile but less than 1/4 of a mile.c. Water sources distributed over an area so thatthe average distance to water is greater than1/4 of a mile but less than 1/2 of a mile.d. Water sources distributed over an area so thatthe average distance to water is greater than1/2 of a mile but less than 3/4 of a mile.e. Water sources distributed over an area so thatthe average distance to water is greater than3/4 of a mile but less than 1 mile.d. Water sources distributed over an area so that theaverage distance to water is greater than one mile.Value1.00.80.60.40.20.1(No value greater than 1.0 or less than 0.1)Deduct0.2 if only water sources are at an occupied farmstead0.2 if permanent cover (woody and herbaceous) does not adjoin the water source0.2 if cover adjoining the water source is reduced to under 1 ft. by grazing, cultivation, or mowingAdd0.1 if water sources are developed to increase accessibility or safety to wildlife (i.e., floating blocks oraccess and escape ramps installed on troughs and tanks224

Under present management systems, the habitatvalues and equivalent acreage for thirteen 1200acre study plots are presented below:Table 40. Habitat ValuesPlot No. Habitat Value Equivalent Acreage1 0.022 262 0.024 304 0.176 2115 0.012 146 0.320 3847 0.233 2808 0.022 279 0.004 510 0.023 2811 0.008 1012 0.443 53213 0.286 34315 0.021 26From these data, it can be concluded thatmany plots, under existing conditions, are ofvery little value to wildlife. As much wildlifecould be produced on 5 acres, under optimumconditions, as is presently being produced on the1200 acres in Plot 9. As much wildlife could beproduced on 14 acres and 10 acres, under optimumconditions, as is presently being producedon 1200 acres each in Plots 5 and 11 respectively.Applegate, Jones E.—Modification of SCSTechniques for Predicting Wildlife HabitatValue, Mimeographed Report of RutgersUniversity, 1974Oakerman, Grover—Wildlife Evaluation InThe Palouse River Basin, MimeographedReport of the Washington Game Department,1976Thomas, Carl H.— Predicting Land UseEffects on Wildlife Habitat, MimeographedReport of the Soil Conservation Service, 1974225

Habitat Values were recalculated for each ofthe thirteen study plots based on land managementalternatives proposed to reduce soil erosionto acceptable levels. The three broad soilconservation alternatives evaluated were:Alternative I. Remove crops from steep, erosiveClass IV and Class VI land. Place this acreage inpermanent herbaceous (grass/legume) cover.Assume that the present level of management,with regard to tillage operations, grazing, burning,pesticide use, etc.—will remain the same asit is at present.Plot No. Habitat Value Equivalent Acreage1 0.150 1802 0.059 714 0.348 4185 0.082 986 0.363 4367 0.246 2958 0.027 339 0.032 3810 0.167 20111 0.109 13112 0.443 53213 0.074 8915 0.158 189A comparison of these habitat values andequivalent acreages with those under existingconditions (Table 40), indicates a significantimprovement for wildlife.Alternative II. Improve the management ofcropland, herbaceous, and woody vegetation.Conservation practices applied to prevent excesssoil loss and deterioration of water quality—e.g.,minimum tillage, proper grazing use, no plowing,no burning, contour farming, stripcropping,etc. The abundance and distribution of cropland,woody and herbaceous vegetation are assumedto remain the same as they are at present.Plot No. Habitat Value Equivalent Acreage1 0.030 362 0.036 434 0.201 2415 0.031 386 0.355 4267 0.280 3358 0.067 809 0.006 710 0.119 14311 0.043 5112 0.538 64613 0.286 34315 0.031 38The application of soil and water conservationpractices improves the quality of habitat overexisting conditions. However, note that theimprovement is not as significant as those resultingfrom Alternative I.226

Alternative III. The third alternative evaluatedis a combination of Alternatives I and II,above. This alternative assumes that Class IVand Class VI land is converted to permanentherbaceous cover and extensive soil and waterconservation measures are applied to all lands.Plot No. Habitat Value Equivalent Acreage1 0.155 1862 0.089 1064 0.385 4635 0.113 1356 0.396 4757 0.295 4548 0.076 929 0.041 5010 0.270 32511 0.139 16612 0.538 64613 0.444 53315 0.205 245This alternative obviously provides the besthabitat conditions for wildlife, as well as providingprotection of soil and water resources.The equivalent acreage of value to wildlifeare presented below for comparison. It is interestingto note that the most significant improvementof wildlife habitat occurs as a resultcreating more permanent cover as shown inAlternative I. These data support very strongly,the contention that the limited amount of permanentvegetation in the Palouse, is the singlemost limiting factor for wildlife populations.Plot No.ExistingConditions Alternative I Alternative II Alternative III1 26 180 36 1862 30 71 43 1064 211 418 241 4635 14 98 38 1356 384 436 426 4757 280 295 335 4548 27 33 80 929 5 38 7 5010 28 201 143 32511 10 131 51 16612 532 532 646 64613 343 343 343 34315 26 189 38 245227

Evaluation—Sediment Delivery RatesData from sediment pond studies on 10ponds in and near the Palouse Basin has beenused to project sediment delivery ratios. Watershedsabove the 10 ponds studied vary from120-2,560 acres, with a mean of approximately300 acres. Additional sediment delivery datafrom extensive sediment delivery studies on theMissouri Flat Creek watershed near Pullmanhas also been used.Data Expansion ProceduresData from evaluation areas includes estimatedexisting soil loss rates and project soilloss rates with alternative land managementsystems in tons/acre/year. This data has beenexpanded to provide:a. projected soil loss rates by soil association/year;b. projected soil loss rates by land capabilityclass/year;c. projected soil loss rates by subwatershed/year;d. projected soil loss rates for the PalouseRiver Basin/year;e. projected soil loss rates by rainfall zone.Economic data expansion is minimal exceptfor purposes of comparing alternative landmanagement systems. Census data has beenused for overall economic analysis of the basin.Sediment yield studies have been expandedto show projected sediment yields by subwatershedand for the Palouse Basin.228