Biodiversity Guide - The Intertwine

egional conservation strategybiodiversity guideAppendix I Watershedsbut serves as Portland’s water supply, joins theSandy at Dodge Park (RM 18). Between Dodgeand Oxbow parks (at RM 13), another gorgelimits road access. The Sandy slows and meandersthrough Oxbow Regional Park and Dabney StatePark (RM 6) and collects the significant tributariesGordon, Trout, and Beaver creeks. North ofInterstate 84, the Sandy River Delta, which isowned and managed by the U.S. Forest Service,totals 1,500 acres at the river’s confluence with theColumbia.Streamflow in the Sandy River ranges fromhundreds to tens of thousands of cubic feet persecond within a single reach. Intense rain-onsnowevents cause dramatic flows, movement ofglacial and large woody debris, bank erosion, andchannel migration, particularly in late winter.Native American UseNative Americans used the Sandy River for huntingand fishing, and the river formed part of atrail system between the Columbia and areas tothe east. Lewis and Clark recorded a ClackamasIndian village near the current site of PortlandInternational Airport. Portions of the upper basinare currently co-managed with the ConfederatedTribes of Warm Springs for harvest of traditionalfoods.Modern SettlementThe Sandy was a key link in modern settlementtransportation routes. Wagon trains first crossedthe area in 1840, and the Barlow Road officiallyopened in 1846. By the early 1900s railroadservice made the Sandy a production zone fortimber and gravel. The Mt. Hood Loop Highway’scompletion in the 1920s created additionalaccess, and in 1952 the highway became part ofU.S. Highway 26. The Historic Columbia RiverHighway follows the Sandy’s lower reaches. Sinceits construction in the 1950s, Interstate 84 hascrossed the Sandy at Troutdale.Timber harvest began in the lower Sandy inthe 1850s and had intensified by the early 20thcentury. Forest Service roads expanded beginningin the 1950s, eventually totaling more than 550miles. Logging in floodplain and riparian areasconverted mixed fir, hemlock, and cedar coniferforests to higher concentrations of alder. Thisreduced shade and recruitment of natural largewood and increased sediment loads into streams.Sandy River fish have been harvested since themid-1800s. By the 1870s, harvesting and habitatmodification had caused declines in salmon andsteelhead populations. Spring Chinook harvestpeaked on the Columbia at 43 million pounds in1873. By the 1940s, the harvest of all ColumbiaRiver salmon species was substantially depressed.Historical and Current VegetationHistorically, the Sandy River subbasin wascovered almost entirely by coniferous forest (82percent) and burned forest (16 percent), makingit the most heavily forested basin in the greaterPortland-Vancouver region. Virtually no prairieor oak was recorded in the General Land Officesurveys. Increases in prairie and oak in the ecologicalsystem life form (ESLF) data created forthe U.S. Geological Survey’s (USGS) Gap AnalysisProgram probably are due to misclassification.About 20 percent of the basin was converted toagriculture and 10 percent to urban uses (portionsof Gresham, Sandy, and Troutdale), mostlywithin the greater Portland-Vancouver region.Much of the Sandy Basin remains forested.Although the lower Sandy is dominated by young,privately owned forest, more than half the basin’sforest is more than 150 years old, particularly onfederal lands in the Bull Run, Salmon, and upperbasin wilderness. Approximately 74 percent ofthe basin, including nearly the entire upper basin,is managed by the U.S. Forest Service-Mt. HoodNational Forest (approximately 70 percent) andthe Bureau of Land Management (BLM). TheSalmon River is a tier-one watershed under theNorthwest Forest Plan and is managed for wildsalmon and steelhead, bull trout, and residentfish. About 3 percent of the watershed is ownedby the Portland Water Bureau and other local,state, and regional governmental entities.In contrast with the upper watershed, theportion of the Sandy River watershed that iswithin the greater Portland-Vancouver region(approximately 23 percent of the watershed)is primarily privately owned and includes thecities of Troutdale, Gresham, and Sandy. Privateconservation ownership totals about 2,000 acres,which are concentrated along the mainstemSandy. Other private ownership is a mixture ofagriculture (especially nurseries), small lot forest,and residential land. Most streambanks alongthe middle and lower Sandy are privately owned,with residential subdivisions dotting sectionsalong the upper and middle river. Developedneighborhoods, manufactured home parks, andseveral private summer camps are located withinthe lower basin. Agriculture is the designatedland use for about 15,000 acres (5 percent of thewatershed), with rural residential and otherzoning designations at 13,545 acres (4 percent).Less than 10% are classified as urban.Less than 5 percent of the Sandy Basin lieswithin the urban growth boundary. However,the human population in most areas of theSandy Basin has increased substantially in recentdecades, although it still totals less than 100,000.From 1980 to 2000 alone, the combined populationsof Troutdale, Sandy, and Gresham grew 162percent.Recreation is a major human use and importanteconomic driver within the basin. Significantportions of the upper basin are managed forrecreation, and the Sandy provides opportunitiesfor angling, hiking, swimming, boating, kayaking,biking, skiing, and nature study. Salmon andsteelhead in the Sandy support popular sportfisheries that account for a large percentage ofregional angling opportunities.Regional SignificanceDespite significant changes in land use and otherhuman alterations, the Sandy Basin supportsnumerous sensitive species. Evaluations by stateand federal agencies and The Nature Conservancyhas identified as many as 90 species of concernthat are or potentially are present in the Sandy.The Sandy’s vegetative cover falls into 12 covertype categories, as defined by the Oregon NaturalHeritage Program’s Oregon Gap Project. TheSandy Delta alone has seven habitat types, includingforest, savanna, upland and wetland forestscrub-shrub, and upland and wetland meadow.The Sandy River and its tributaries support adiverse assemblage of 22 native and 19 introducedfish species, including Lower Columbia Riverspring and fall Chinook salmon and coho salmonand winter steelhead. Other native fish speciesof ecological or cultural significance that maybe found in the basin include coastal cutthroattrout, Pacific lamprey, mountain whitefish, smelt,and resident rainbow trout, bull trout, and whitesturgeon. The majority of the introduced speciesin the basin are found in the lower river near theSandy Delta’s slower, warmer flows. Pacific smelt,which once were a popular game fish, were listedas threatened in 2010.The Sandy and its tributaries represent anchorhabitat for federally listed Chinook and cohosalmon and steelhead. The lower mainstemreaches of Sandy River are particularly importantfor recovery of late-run fall Chinook, while upperbasin reaches are critical for coho recovery. TheSandy River also provides key habitat for nativespring Chinook and winter steelhead. The Sandy’slocation downstream of the federal dams on256 257