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NEW ENGLAND COUNCIL ON<br />
FOREST ENGINEERING<br />
CASE STUDY<br />
MARCH 6, 2012
CONSTRUCTING A<br />
TEMPORARY ACCESS ROAD<br />
ACROSS AN ATLANTIC<br />
WHITE CEDAR ORGANIC<br />
BOG FOR THE PURPOSE OF<br />
MINING GRAVEL
TEMPORARY BOG CROSSING<br />
THE FOLLOWING SLIDES ARE OF A<br />
PROPOSED ACCESS ROAD THAT<br />
WILL CROSS SEVERAL WETLANDS TO<br />
ACCESS A GRAVEL DEPOSIT<br />
ONE OF THE WETLANDS HAS AN<br />
EXEMPLARY PLANT COMMUNITY<br />
THAT IS RARE IN MAINE AS<br />
DESIGNATED BY MNAP
TEMPORARY BOG CROSSING<br />
THE PROJECT HAS RECEIVED A PERMIT<br />
FROM THE DEP AND ACOE BUT AT LAST<br />
CHECK IS WAITING FOR LOCAL PERMITS<br />
AND/OR THE ECONOMY<br />
THE APPLICANT WAS HOPING TO BEGIN<br />
CONSTRUCTION OF THE ACCESS ROAD<br />
THIS WINTER OR SPRING BUT WORK HAS<br />
NOT YET STARTED
TEMPORARY BOG CROSSING<br />
ONE OF THE WETLANDS THAT THE ACCESS<br />
ROAD WILL CROSS IS AN ORGANIC BOG –<br />
THE CROSSING IS REQUIRED TO MINIMIZE<br />
DISTURBANCE TO THE WETLAND AND ITS<br />
HYDROLOGY<br />
THE ACCESS ROAD IS PROPOSED TO BE<br />
REMOVED AFTER THE GRAVEL IS<br />
EXCAVATED
TEMPORARY BOG CROSSING<br />
THE APPLICANT AND THE<br />
REGULATORS SHARE ONE<br />
IMPORTANT GOAL:<br />
NEITHER WANT THE ROAD TO SINK TO<br />
ANY APPRECIABLE DEGREE
TEMPORARY BOG CROSSING<br />
THE SITE CONTAINS A NUMBER OF RIDGES<br />
OF GRAVEL WITH LOW WETLAND AREAS IN<br />
BETWEEN THE GRAVEL RIDGES<br />
GROUNDWATER INFILTRATES THE GRAVEL<br />
RIDGES AND SEEPS OUT AT THE<br />
INTERFACE OF A DENSER MINERAL SOIL<br />
AND THE GRAVEL ABOVE
SITE MAP OF ACCESS ROAD<br />
AND GRAVEL DEPOSIT
TOPO MAP OF THE SITE
FIRST WETLAND CROSSING<br />
SITE
SECOND WETLAND CROSSING<br />
SITE – ORGANIC BOG
NOTE LIVE SPHAGNUM MOSS<br />
ON THE GROUND SURFACE
RUBBER TIRE – OBLIGATE<br />
WETLAND SPECIES
LONGEST/MOST SIGNIFICANT<br />
WETLAND CROSSING<br />
THE LONGEST WETLAND CROSSING SITE IS<br />
THE MOST COMPLEX; IT CONTAINS<br />
THREE DIFFERENT CONDITIONS:<br />
1. FIRM PEAT COVERED WITH RED MAPLE<br />
LEAVES<br />
2. COVERED WITH LIVE SPHAGNUM MOSS<br />
WITH OPEN WATER POCKETS<br />
3. LIVE SPHAGNUM WITH OPEN WATER<br />
POCKETS AND FLOWING WATER
FIRM PEAT COVERED WITH RED<br />
MAPLE LEAVES
LIVE SPHAGNUM WITH OPEN<br />
WATER POCKETS
TRANSITION FROM RED MAPLE<br />
LEAF TO LIVE SPHAGNUM TYPE
NOTE OPEN WATER POCKETS
SHOVEL PIT EXCAVATED INTO<br />
PEAT<br />
IMMEDIATELY BENEATH THE LIVE<br />
SPHAGNUM MOSS WAS A 10”-12”<br />
PEAT LAYER THAT WAS FRIABLE AND<br />
SATURATED TO THE SURFACE<br />
IMMEDIATELY BELOW THE SATURATED<br />
PEAT LAYER WAS A MUCH FIRMER<br />
PEAT THAT WAS MOIST BUT NOT AS<br />
SATURATED AS THE TOP LAYER
PEAT PROFILE<br />
THE TOP PEAT LAYER THAT WAS<br />
SATURATED HAD GRANULAR<br />
STRUCTURE AND MANY PLANT<br />
ROOTS<br />
THE LOWER LAYER OF PEAT HAD<br />
MASSIVE OR PLATY STRUCTURE AND<br />
NO ROOTS
HYDROLOGY OBSERVATIONS<br />
IT APPEARD TO ME AS THOUGH WATER<br />
WAS PONDING ON THE FIRMER AND<br />
MASSIVE PEAT LAYER AND ANY<br />
MOVEMENT OF SIGNIFICANCE WAS<br />
OCCURRING IN THE TOP PEAT LAYER<br />
NO WATER MOVEMENT WAS<br />
OBSERVED IN THE OPEN WATER<br />
POCKETS OR THE SHOVEL PIT
COMPARISON OF PEAT LAYERS<br />
SATURATION
SATURATED UPPER PEAT<br />
LAYER
MORE DENSE AND LESS<br />
SATURATED LOWER PEAT
LIVE SPHAGNUM WITH MOVING<br />
WATER
NOTE PICTURE PLANTS IN<br />
WATER
NOTE INTERCONNECTEDNESS<br />
OF OPEN WATER POCKETS
WATER MOVEMENT
WATER MOVEMENT
GRAVEL RIDGE AT<br />
WETLAND/UPLAND BOUNDARY
STANDARDS FOR ROADS ON<br />
ORGANIC SOILS<br />
• MOST OF US HAVE VERY LITTLE<br />
EXPERIENCE WITH THE<br />
CONSTRUCTION OF ROADS OVER<br />
ORGANIC SOILS – PARTICULARLY<br />
WHEN THE ROADS CAN NOT<br />
CONNECT WITH THE MINERAL SOIL<br />
BELOW AND HAVE TO BE REMOVED<br />
AFTER A FEW YEARS
ORGANIC SOIL UNDER ROAD<br />
TO WEST QUODDY HEAD
SELECTION OF CRITERIA FOR<br />
ACCESS ROAD BOG CROSSING<br />
THE CONSULTANT SEARCHED FOR<br />
INFORMATION ON HOW BEST TO<br />
CONSTRUCT SUCH AN ACCESS ROAD BUT<br />
DID NOT FIND MUCH USEFUL INFORMATION<br />
I WAS CONSULTED AND THIOUGH I HAD NO<br />
HARD DATA – PROVIDED A<br />
RECOMMENDATION BASED ON<br />
KNOWLEDGE, LOGIC AND REASONING
ACCESS ROAD BOG CROSSING<br />
CONSTRUCTION DETAILS<br />
• CUT TREES BUT LEAVE STUMPS AND<br />
ROOTS IN PLACE FOR STRUCTURAL<br />
SUPPORT IN A 36 FOOT WIDE PATH<br />
• LAY SLASH DOWN BETWEEN STUMPS FOR<br />
ADDED SUPPORT-USE SLASH FROM<br />
ADJACENT UPLANDS IF NECESSARY<br />
• LEVEL ROAD AND SHOULDER FOOTPRINT,<br />
TO THE TOP OF STUMPS, WITH STUMP<br />
GRINDINGS OR WOOD CHIPS -<br />
ESSENTIALLY MAKING A MATTRESS
ACCESS ROAD BOG CROSSING<br />
CONSTRUCTION DETAILS<br />
• LAY FILTER FABRIC ON LEVELED ROAD AND<br />
SHOULDER FOOTPRINT<br />
• LAY A LAYER OF 36 FOOT LONG LOGS DOWN ON<br />
FILTER FABRIC ALTERNATING BUTT AND TOPS SO<br />
THAT THE THICKNESS AND SUPPORT IS SIMILAR<br />
OVER THE ENTIRE LAYER PERPENDICULAR TO<br />
THE DIRECTION OF THE ROAD<br />
• CABLE LOGS TOGETHER TO FORM A MATT OR<br />
MATTS<br />
• LAY ANOTHER LAYER OF LOGS DOWN ON THE<br />
TOP OF THE FIRST LAYER OF LOGS IN A SIMILAR<br />
MANNER TO THE FIRST LAYER BUT THEY DO NOT<br />
NEED TO BE CABLED TOGETHER
ACCESS ROAD BOG CROSSING<br />
CONSTRUCTION DETAILS<br />
• THE TWO LAYERS OF LOGS WILL<br />
PROVIDE ADDED STRENGTH TO<br />
SUPPORT THE GRAVEL ROAD<br />
SURFACE AND LOADED DUMP<br />
TRUCKS AND THE VOIDS BETWEEN<br />
THE LOGS WILL ALLOW WATER<br />
MOVEMENT THROUGH THE ROAD<br />
BASE SIMILAR TO A ROCK SANDWICH
ACCESS ROAD BOG CROSSING<br />
CONSTRUCTION DETAILS<br />
• 36 FOOT LONG LOGS WERE CHOSEN<br />
TO PROVIDE REASONABLE SUPPORT<br />
(NO FORMULA WAS USED TO MAKE<br />
THAT DETERMINATION) AND TO GIVE<br />
5 FEET OF CLEARANCE ALONG EACH<br />
SIDE OF THE ROAD FOR SNOW<br />
PLOWING ACCUMULATION-CABLING<br />
THE BOTTOM LAYER OF LOGS<br />
TOGETHER AS A MATT WILL PROVIDE<br />
ADDED STRENGTH
ACCESS ROAD BOG CROSSING<br />
CONSTRUCTION DETAILS<br />
• IN THE AREA OF THE LONGEST BOG<br />
CROSSING WHERE MOVING WATER<br />
WAS OBSERVED SOME OF THE TOP<br />
LAYER OF LOGS WILL BE REPLACED<br />
BY METAL PIPES OF A SIMILAR<br />
DIAMETER TO THE LOGS TO ACT AS<br />
SMALL CULVERTS THAT WILL<br />
SPREAD OUT THE WATER OVER THE<br />
ENTIRE AREA WHERE MOVING<br />
WATER WAS OBSERVED
ACCESS ROAD BOG CROSSING<br />
CONSTRUCTION DETAILS<br />
THE DEP AND ACOE WANTED TO INSTALL A<br />
CULVERT(S) TO MAINTAIN THE NATURAL<br />
HYDROLOGY BUT I FIGURED THEY WOULD<br />
JUST BECOME EMBEDDED IN THE PEAT<br />
AND NOT FUNCTION AS PLANNED<br />
THIS WAS REINFORCED AFTER STUDYING<br />
HOW THE HYDROLOGY WORKED IN THE<br />
BOG
ACCESS ROAD BOG CROSSING<br />
CONSTRUCTION DETAILS<br />
• PLACE A FILTER FABRIC ON TOP OF THE<br />
SECOND LAYER OF LOGS<br />
• ADD A FOOT OF GRAVEL 24 FEET WIDE ON<br />
TOP OF THE SECOND LAYER OF FILTER<br />
FABRIC (28’ WIDE AT BASE)<br />
• USE STUMP GRINDINGS FOR 4 FOOT<br />
SHOULDERS ON EACH SIDE OF THE ROAD<br />
TOO PREVENT GRAVEL FROM BEING<br />
PUSHED INTO THE ORGANIC BOG-STUMP<br />
GRINDINGS WILL BE SIMILAR TO THE<br />
WOODY MATERIAL ALREADY PART OF THE<br />
NATURAL BOG
BOG CROSSING ACCESS ROAD<br />
CROSS-SECTION
PERIODIC INSPECTIONS<br />
THE DEP AND ACOE ARE CONCERNED<br />
ABOUT THE POSSIBILITY OF<br />
SIGNIFICANT SUBSIDENCE OF THE<br />
ROAD AND RESULTING ALTERATION<br />
OF THE NATURAL HYDROLOGY<br />
THEY WILL BE REQUIRING THE<br />
APPLICANT TO PERIODICALLY CHECK<br />
THE ELEVATION OF THE ROAD
PERIODIC INSPECTIONS<br />
SHOULD THE ROAD SUBSIDE TO A<br />
SIGNIFICANT DEGREE<br />
THE BOG CROSSING SECTION OF THE<br />
ROAD MAY BE LIMITED TO ONE<br />
VEHICLE AT A TIME AND/OR LOAD<br />
LIMITS MAY BE APPLIED
DOCUMENTATION<br />
I INTEND TO PRIODICALLY VISIT THE<br />
SITE, AS DO A NUMBER OF OTHERS,<br />
AND WILL TAKE LOTS OF PHOTOS<br />
THEY MIGHT MAKE AN INTERESTING<br />
PRESENTATION AT A FUTURE<br />
NERCOFE MEETING
QUESTIONS
ROCK SANDWICHES<br />
AKA<br />
PERMEABLE ROAD BASE
WHAT IS A ROCK SANDWICH?<br />
IT IS A LAYER OF STONE OR CRUSHED ROCK<br />
“SANDWICHED” BETWEEN 2 LAYERS OF<br />
FILTER FABRIC USED AS A ROAD BASE<br />
THOUGH THE DEP-BMP CALLS FOR A<br />
MINIMUM 12” THICK LAYER OF 3”-6”<br />
STONE, ACTUAL SANDWICH THICKNESS<br />
AND STONE DIAMETER CAN BE ADJUSTED<br />
ACCORDING TO SITE SPECIFIC<br />
CONDITIONS AND AVAILABILITY OF STONE
WHAT IS ITS PURPOSE<br />
*MAINTAINS NATURAL HYDROLOGY<br />
*STRENGTHENS ROAD BASE<br />
*PREVENTS FROST ACTION IN ROAD<br />
*REQUIRES LITTLE MAINTENANCE<br />
*LASTS INDEFINATELY<br />
*PREVENTS SCOURING ASSOCIATED<br />
WITH CONCENTRATED FLOW
PURPOSE<br />
*THEY DO NOT HEAVE<br />
*THEY DO NOT RUST<br />
*THEY DO NOT COLLAPSE<br />
*THEY DO NOT FREEZE DUE TO LATENT<br />
HEAT OF GROUNDWATER<br />
*ONLY REQUIRE SHALLOW DITCHES<br />
WHICH NEED MINIMAL MAINTENANCE<br />
*PUTS COLD CLEAN GROUNDWATER<br />
BACK INTO THE GROUND
WHERE SHOULD ROCK<br />
SANDWICHES BE USED<br />
ROCK SANDWICHES CAN BE USED ALMOST<br />
ANYWHERE BUT ARE DESIGNED TO BE<br />
USED PRIMARILLY IN TWO LOCATIONS:<br />
WETLAND CROSSINGS<br />
&<br />
CUTS BELOW THE GROUNDWATER TABLE
ROCK SANDWICHES IN<br />
WETLAND CROSSINGS<br />
ROCK SANDWICHES WORK WELL IN<br />
CROSSING MOST WETLANDS EXCEPT<br />
FOR WETLANDS THAT ARE ORGANIC<br />
BOGS<br />
PROVIDES EXCELLENT STRUCTURAL<br />
SUPPORT WHEN CROSSING<br />
WETLANDS
ROCK SANDWICHES IN CUT<br />
SLOPE ROADS<br />
ROCK SANDWICHES CAN BE USED IN<br />
ALMOST ANY CUT BUT ARE MOST<br />
EFFECTIVE IN CUTS BELOW THE<br />
SEASONAL GROUNDWATER TABLE<br />
MOST EFFECTIVE IN SOILS THAT HAVE<br />
HIGH PERMEABILITY AND A<br />
SHALLOW RESTRICTIVE LAYER OR<br />
ARE SHALLOW TO BEDROCK
ROCK SANDWICHES IN CUT<br />
SLOPE ROADS<br />
THE MOST BENEFICIAL SITES FOR<br />
ROCK SANDWICHES IN CUT SLOPE<br />
ROADS ARE:<br />
*STEEP SLOPES (THE STEEPER THE<br />
MORE BENEFICIAL)<br />
*SIGNIFICANT UPSLOPE WATERSHED<br />
(THE LARGER THE MORE<br />
BENEFICIAL)
ROCK SANDWICHES IN CUT<br />
SLOPE ROADS<br />
*RECONNECTING GROUNDWATER<br />
SEEPS<br />
*RECONNECTING ROCK FILLED<br />
CHANNELS (USE STONE SIZE SIMILAR<br />
TO THE NATURAL STONE IN THE<br />
ROCK FILLED CHANNEL)<br />
*RECONNECTING COARSE TEXTURED<br />
SUBSOIL LAYERS WHERE “PIPING” IS<br />
PRESENT
WHERE ROCK SANDWICH USE<br />
IS QUESTIONABLE<br />
ROCK SANDWICHES DO NOT PROVIDE<br />
THE SAME VALUE FOR ROAD CUTS IN<br />
SLOWLY PERMEABLE SOILS SUCH AS<br />
LACUSTRINE SEDIMENTS OR MARINE<br />
SEDIMENTS AS THEY DO IN MORE<br />
PERMEABLE SOILS SUCH AS SANDLY<br />
LOAM TO LOAMY SAND GLACIAL<br />
TILLS
ROCK SANDWICH ON LEVEL<br />
GROUND
ROCK SANDWICH ON SLOPING<br />
GROUND WITH CUT
September 23, 2011<br />
Mr. David Rocque<br />
Department of Agriculture<br />
State of Maine<br />
Dear Dave,<br />
RE: Costing information for blanket 1.<br />
M & H Construction<br />
3039 Main Street Route 4 North ~ P.O. Box 565<br />
Rangeley, ME 04970<br />
207-864-5617<br />
I am very sorry we have no pictures of rock blankets actually being installed. I sent you some<br />
pictures but they should be at high water. If any of the pictures you could use further<br />
information please call me 446-4841 or 864-5617 x100. I will give you some general guidelines<br />
on cost of the rock blankets.<br />
For each 100 SF of the blanket at a depth of 18” rock and 6” of Type D gravel and 6” of surface<br />
gravel.<br />
Excavator 2 HR $110 HR Dump trucks 2 HR @ $65<br />
Non-woven fabric 22 SY @ $2.00 SY Rock 6” to 12” 6 CY @ $15.00 CY Del<br />
Gravel Type D 2 CY @ $10.50 CY Del ½” crushed gravel 2 CY @ $16.00 Del<br />
Sincerely,<br />
1. Excavate and have dump truck haul of to get a base for rock blanket.<br />
2. Place a layer of non-woven fabric, then place rip rap, then another layer of fabric,<br />
then type D gravel and then surface course of crushed.<br />
These do work very well keeping surface water from channeling but they work<br />
extremely well intercepting sub surface water and it is a big help keeping a building<br />
site dry.<br />
Kenneth J. Haley<br />
General Manager
ROCK SANDWICH<br />
INSTALLATION
ROCK SANDWICH<br />
INSTALLATION IN CUT
ROCK SANDWICH – WETLAND<br />
CROSSING
ROCK SANDWICH WETLAND<br />
CROSSING
ROCK SANDWICH – WETLAND<br />
CROSSING
ROCK SANDWICH – WETLAND<br />
CROSSING
ROCK SANDWICH WETLAND<br />
CROSSING IN WINTER
NOTE UNSTABILIZED MINERAL<br />
SOIL UPSLOPE OF ROCKS
DOWNSLOPE OF ROCK<br />
SANDWICH
ROAD ROCK SANDWICH AT<br />
WETLAND AND STREAM
SEASONAL STREAM ABOVE<br />
ROCK SANDWICH
ROCK SANDWICH UPSLOPE<br />
SIDE OF ROAD
ROCK SANDWICH DOWN SLOPE<br />
SIDE OF ROAD
SUBDIVISION ROAD WITH ROCK<br />
SANDWICH AT CUT
UPSLOPE SIDE OF ROAD WITH<br />
CUT AND ROCK SANDWICH
OVERFLOW CULVERT AT CUT<br />
AND ROCK SANDWICH
OVERFLOW CULVERT AT ROCK<br />
SANDWICH AND CUT
DOWNSLOPE SIDE OF ROAD ST<br />
CUT AND ROCK SANDWICH
DOWNSLOPE SIDE OF ROAD AT<br />
CUT AND ROCK SANDWICH
DOWNSLOPE SIDE OF ROCK<br />
SANDWICH NOTE WATER
UPSLOPE SIDE OF ROCK<br />
SANDWICH
UPSLOPE SIDE OF ROCK<br />
SANDWICH
DOWNSLOPE SIDE OF ROCK<br />
SANDWICH
ELLIOTSVILLE TWP ROAD<br />
ROCK SANDWICH UPSLOPE
ELLIOTSVILLE TWP ROCK<br />
SANDWICH DOWNSLOPE
DAVID P. ROCQUE<br />
STATE SOIL SCIENTIST<br />
MAINE DEPARTMENT OF AGRICULTURE<br />
STATE HOUSE STATION #28<br />
AUGUSTA, MAINE 04333<br />
PHONE: (207) 287-2666<br />
E-MAIL: DAVID.ROCQUE@MAINE .GOV
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