Atlantic Coast Pipeline - NC detail sheets rev 1 cm 10202017

GENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09/170
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS NOTED
10/20/2017SR
10/20/2017CM
1 1 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC

--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
36" SILT-SAVER
PRIORITY 2 FABRIC26"
22"
24"
6' MAX O.C.Black Band
TRENCH
FRONT ELEVATION
4' LONG WOOD POST (OAK)
SPACED AT 6'-0"
26"
22"
24"
8"
4"
10' TO TOE
OF SLOPE
FABRIC TO BE 24" ABOVE GROUND
WITH "J" IN TRENCH
FLOW
4" x 8"
Trench
SIDE VIEW
TOE IN AND COMPACT BACKFILL
4 STAPLES
(1" x 13
4")
BONDING STRIP
(1" x 3
8" x 24")
POST (OAK)
(1 1
8" x 1 1
8" x 48")
(OR EQUAL DENSITY)
GROUND LINE
BOTTOM OF
TRENCH LINE
REPAIR DETAIL
ATTACHING TWO SILT
FENCES
WHEN TRENCHING IS
USED
PLAN VIEW
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
ENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09./20170
“”“”
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS SHOWN
10/20/2017SR
10/20/2017CM
12 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC
SEAL
--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
ENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09/20170
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS SHOWN
10/20/2017SR
10/20/2017CM
13 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC
SEAL
--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
ENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09/170
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS SHOWN
10/20/2017SR
10/20/2017CM
14 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC
SEAL
--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
MAINTENANCE
1.THE DEVELOPER/OWNER SHALL BE RESPONSIBLE FOR MAINTENANCE OF THE FILTER CURTAIN
FOR THE DURATION OF THE PROJECT IN ORDER TO ENSURE THE CONTINUOUS PROTECTION OF
THE WATERCOURSE.
2.SHOULD REPAIRS TO THE GEOTEXTILE FABRIC BECOME NECESSARY, THERE ARE NORMALLY
REPAIR KITS AVAILABLE FROM THE MANUFACTURERS; MANUFACTURER'S INSTRUCTIONS MUST
BE FOLLOWED TO ENSURE THE ADEQUACY OF THE REPAIR.
3.WHEN THE CURTAIN IS NO LONGER REQUIRED AS DETERMINED BY THE INSPECTOR, THE
CURTAIN AND RELATED COMPONENTS SHALL BE REMOVED IN SUCH A MANNER TO MINIMIZE
TURBIDITY. REMAINING SEDIMENT SHALL BE SUFFICIENTLY SETTLED BEFORE REMOVING THE
CURTIAN. SEDIMENT MAY BE REMOVED AND THE ORIGINAL DEPTH (OR PLAN ELEVATION)
RESTORED. AND SPOILS MUST BE TAKEN TO UPLAND AREA AND BE STABILIZED.
CONSTRUCTION SPECIFICATIONS
1.BARRIERS SHOULD BE A BRIGHT COLOR (YELLOW OR 'INTERNATIONAL" ORANGE ARE
RECOMMENDED) THAT WILL ATTRACT THE ATTENTION OF NEARBY BOATERS.
2.THE CURTAIN FABRIC MUST MEET THE MINIMUM REQUIREMENTS NOTED IN THE TABLE BELOW.
3.SEAMS IN THE FABRIC SHALL BE EITHER VULCANIZED WELDED OR SEWN, AND SHALL DEVELOP
THE FULL STRENGTH OF THE FABRIC.
4.FLOATATION DEVICES SHALL BE FLEXIBLE, BUOYANT UNITS CONTAINED IN AN INDIVIDUAL
FLOATATION SLEEVE OR COLLAR ATTACHED TO THE CURTAIN. BUOYANCY PROVIDED BY THE
FLOATATION UNITS SHALL BE SUFFICIENT TO SUPPORT THE WEIGHT OF THE CURTAIN AND
MAINTAIN A FREEBOARD OF AT LEAST 3 INCHES ABOVE THE WATER SURFACE LEVEL.
SEEDING AND MULCHING
SEE SEED MIXES, SOIL AMENDMENTS, AND MULCH SPECIFICATIONS SPECIFIED IN THE ACP RESTORATION AND REHABILITATION PLAN.
1.SEEDBED PREPARATION: AREAS TO BE SEEDED SHALL BE DISKED TO A DEPTH OF 4-IN TO 6-IN WHENEVER FEASIBLE, AND
SMOOTHLY GRADED.
2.IN TOPSOILED AREAS, SOIL TO BE REDISTRIBUTED EVENLY AND STABILIZED PRIOR TO SEEDING.
3.STABILIZATION MEASURES SHALL BE INITIATED AS SOON AS PRACTICABLE IN PORTIONS OF THE SITE WHERE CONSTRUCTION
ACTIVITIES HAVE TEMPORARILY OR PERMANENTLY CEASED, BUT IN NO CASE MORE THAN 21 DAYS AFTER THE CONSTRUCTION
ACTIVITY IN THAT PORTION OF THE SITE HAS PERMANENTLY CEASED.
4.WHERE THE INITIATION OF STABILIZATION MEASURES WITHIN 7 DAYS AFTER CONSTRUCTION ACTIVITY TEMPORARILY OR
PERMANENTLY CEASES IS PRECLUDED BY SNOW COVER, STABILIZATION MEASURES SHALL BE INITIATED AS SOON AS
CONDITIONS ALLOW.
5.WHERE CONSTRUCTION ACTIVITY WILL RESUME ON A PORTION OF THE SITE WITHIN 21 DAYS FROM WHEN ACTIVITIES CEASED
(E.G., THE TOTAL TIME PERIOD THAT CONSTRUCTION ACTIVITY IS TEMPORARILY HALTED IS LESS THAN 21 DAYS), THEN
STABILIZATION MEASURES DO NOT HAVE TO BE INITIATED ON THAT PORTION OF THE SITE BY THE SEVENTH DAY AFTER
CONSTRUCTION ACTIVITIES HAVE TEMPORARILY CEASED.
6.AREAS WHERE THE SEED HAS FAILED TO GERMINATE ADEQUATELY (UNIFORM PERENNIAL VEGETATIVE COVER WITH A DENSITY
OF 70%) WITHIN 30 DAYS, SEEDING AND MULCHING MUST BE RE-SEEDED IMMEDIATELY, OR AS SOON AS WEATHER PERMITS.
NOTES:
1. WATER PUMPED OUT OF TRENCH SHALL NOT BE DISCHARGED INTO WATERWAYS. WATER SHALL
BE DISCHARGED INTO A FILTER BAG OR DEWATERING STRUCTURE.
2. PUMP SHALL BE CONTROLLED SO THAT DISCHARGE DOES NOT OVERFLOW DEWATERING
STRUCTURE.
3. PUMP SUCTION HOSE MUST NOT BE ALLOWED TO COME IN CONTACT WITH TRENCH BOTTOM.
PROVISIONS MUST BE MADE TO ELEVATE THE SUCTION HOSE TO AT LEAST ONE FOOT ABOVE
THE BOTTOM OF THE PIPE TRENCH UNTIL BOTTOM DEWATERING IS NECESSARY.
4. DEWATERING SHALL NOT OCCUR DURING TIMES OF HEAVY RAINFALL EXCEPT AS REQUIRED TO
PREVENT FLOODING OF CONSTRUCTION EQUIPMENT LOCATED IN BORE PITS AND TRENCHES.
5. PUMPS UTILIZED DURING DEWATERING SHALL BE PLACED WITHIN SECONDARY CONTAINMENT
IF POSITIONED WITHIN 100 FEET OF A WETLAND OR WATERBODY.
MAINTENANCE
1.INSPECT CHECK DAMS AND CHANNELS AT LEAST WEEKLY AND AFTER EACH SIGNIFICANT (0.5
INCH OR GREATER) RAINFALL EVENT AND REPAIR IMMEDIATELY. CLEAN OUT SEDIMENT, STRAW,
LIMBS, OR OTHER DEBRIS THAT COULD CLOG THE CHANNEL WHEN NEEDED.
2.ANTICIPATE SUBMERGENCE AND DEPOSITION ABOVE THE CHECK DAM AND EROSION FROM
HIGH FLOWS AROUND THE EDGES OF THE DAM. CORRECT ALL DAMAGE IMMDIATELY. IF
SIGNIFICANT EROSION OCCURS BETWEEN DAMS, ADDITIONAL MEASURES CAN BE TAKEN, SUCH
AS INSTALLING A PROTECTIVE RIPRAP LINER IN THAT PORTION OF THE CHANNEL.
3.REMOVE SEDIMENT ACCUMULATED BEHIND THE DAMS AS NEEDED TO PREVENT DAMAGE TO
CHANNEL VEGETATION, ALLOW THE CHANNEL TO DRAIN THROUGH THE STONE CHECK DAM,
AND PREVENT LARGE FLOWS FROM CARRYING SEDIMENT OVER THE DAM. ADD STONE TO DAMS
AS NEEDED TO MAINTAIN DESIGN HEIGHT AND CROSS SECTION.
CONSTRUCTION SPECIFICATIONS
1.PLACE STONE TO THE LINES AND DIMENSIONS SHOWN IN THE PLAN ON A FILTER FABRIC
FOUNDATION
2.KEEP THE CENTER STONE SECTION AT LEAST 9 INCHES BELOW NATURAL GROUND LEVEL WHERE
THE DAM ABUTS THE CHANNEL BANKS.
3.EXTEND STONE AT LEAST 1.5 FEET BEYOND THE DITCH BANK TO KEEP WATER FROM CUTTING
AROUND THE ENDS OF THE CHECK DAM.
4.SET SPACING BETWEEN THE DAMS TO ASSURE THAT THE ELEVATION AT THE TOP OF THE LOWER
DAM IS THE SAME AS THE TOE ELEVATION OF THE UPPER DAM.
5.PROTECT THE CHANNEL AFTER THE LOWEST CHECK DAM FROM HEAVY FLOW THAT COULD
CAUSE EROSION.
6.MAKE SURE THAT THE CHANNEL REACH ABOVE THE MOST UPSTREAM DAM IS STABLE.
7.ENSURE THAT OTHER AREAS OF THE CHANNEL, SUCH AS CULVERT ENTRANCES BELOW THE
CHECK DAMS, ARE NOT SUBJECT TO DAMAGE OR BLOCKAGE FROM THE DISPLACED STONES.
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
ENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09/170
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS SHOWN
10/06/2017SR
10/20/2017CM
15 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC
SEAL
--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
MAINTENANCE
1.MANY OF THE RECOMMENDED PERMANENT GRASS SPECIES MAY REQUIRE TWO YEARS FOR
ESTABLISHMENT, DEPENDING ON THE SITE CONDITIONS. INSPECT SEEDED AREAS FOR FAILURE
AND MAKE NECESSARY REPAIRS, SOIL AMENDMENTS, AND RESEEDINGS. IF WEEDY EXOTIC
SPECIES HAVE OVERTAKEN THE AREA AFTER THE FIRST GROWING SEASON, THE INVADING
SPECIES MUST BE ERADICATED TO ALLOW NATIVE SPECIES TO GROW. NATIVE VEGETATIONS
ARE DIFFICULT TO MANAGE AND TAKE LONGER TO ESTABLISH. MONITOR THE SITE UNTIL LONG
TERM STABILITY HAS BEEN ESTABLISHED.
RIPARIAN SEEDBED PREPARATION
1.Disturbed soils within riparian areas must be amended to provide an optimum environment for seed
germination and seedling growth. The surface soil must be loose enough for water infiltration and root
penetration. The pH of the soil must be such that it is not toxic and nutrients are available. Riparian areas are
generally considered rich in nutrients due to flooding and deposition, however, these areas can be highly
variable (i.e., narrow steep corridors in the mountains, artificial fill material on top of alluvial floodplains in the
Piedmont). Soil analysis should be performed to determine nutrient and lime needs of each site. Appropriate
levels of phosphorus and potassium are critical for permanent seed establishment. Appropriate pH levels are
between 5.5 and 7. Riparian buffers regulated for nutrient management may be limited to a single application
of fertilizer. Construction activities within the riparian area can greatly compact soils. Suitable mechanical
means such as disking, raking, or harrowing must be employed to loosen the compacted soil prior to
seeding.
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
ENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09/170
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS SHOWN
10/20/2017SR
10/20/2017CM
16 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC
SEAL
--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
PIPE OUTLET TO FLAT AREA - NO WELL DEFINED CHANNEL PIPE OUTLET TO WELL DEFINED CHANNEL
MAINTENANCE
1.INSPECT RIPRAP OUTLET STRUCTURES WEEKLY AND AFTER SIGNIFICANT (0.5 INCH OR
GREATER) RAINFALL EVENTS TO SEE IF ANY EROSION AROUND OR BELOW THE RIPRAP HAS
TAKEN PLACE, OR IF STONES HAVE BEEN DISLODGED. IMMEDIATELY MAKE ALL NEEDED
REPAIRS TO PREVENT FURTHER DAMAGE.
CONSTRUCTION SPECIFICATIONS
1.ENSURE THAT THE SUBGRADE FOR THE FILTER AND RIPRAP FOLLOWS THE REQUIRED LINES AND
GRADES SHOWN IN THE PLAN. COMPACT ANY FILL REQUIRED IN THE SUBGRADE TO THE DENSITY
OF THE SURROUNDING UNDISTURBED MATERIAL. LOW AREAS IN THE SUBGRADE ON
UNDISTURBED SOIL MAY ALSO BE FILLED BY INCREASING THE RIPRAP THICKNESS.
2.THE RIPRAP AND GRAVEL FILTER MUST CONFORM TO THE SPECIFIED GRADING LIMITS SHOWN ON
THE PLANS.
3.FILTER CLOTH, WHEN USED, MUST MEET DESIGN REQUIREMENTS AND BE PROPERLY PROTECTED
FROM PUNCHING OR TEARING DURING INSTALLATION. REPAIR ANY DAMAGE BY REMOVING THE
RIPRAP AND PLACING ANOTHER PIECE OF FILTER CLOTH OVER THE DAMAGED AREA. ALL
CONNECTING JOINTS SHOULD OVERLAP SO THE TOP LAYER IS ABOVE THE DOWNSTREAM LAYER
A MINIMUM OF 1 FOOT. IF THE DAMAGE IS EXTENSIVE, REPLACE THE ENTIRE FILTER CLOTH.
4.RIPRAP MAY BE PLACED BY EQUIPMENT, BUT TAKE CARE TO AVOID DAMAGING THE FILTER.
5.THE MINIMUM THICKNESS OF THE RIPRAP SHOULD BE 1.5 TIMES THE MAX. STONE DIAMETER.
6.RIPRAP MAY BE FILED STONE OR ROUGH QUARRY STONE. IT SHOULD BE HARD, ANGULAR,
HIGHLY WEATHER-RESISTANT AND WELL GRADED.
7.CONSTRUCT THE APRON ON ZERO GRAD WITH NO OVERFILL AT THE END. MAKE THE TOP OF THE
RIPRAP AT THE DOWNSTREAM END LEVEL WITH THE RECEIVING AREA OR SLIGHTLY BELOW IT.
8.ENSURE THAT THE APRON IS PROPERLY ALIGNED WITH THE RECIEVING STREAM AND
PREFERABLY STRAIGHT THROUGHOUT ITS LENGTH. IF A CURVE IS NEEDED TO FIT THE SITE
CONDITIONS, PLACE IT IN THE UPPER SECTION OF THE APRON.
9.IMMEDIATELY AFTER CONSTRUCTION, STABILIZE ALL DISTURBED AREAS WITH VEGETATION.
MAINTENANCE
1.INSPECT ROCK PIPE INLET PROTECTION AT LEAST WEEKLY AND AFTER EACH SIGNIFICANT (0.5
INCH OR GREATER) RAINFALL EVENT AND REPAIR IMMEDIATELY. REMOVE SEDIMENT AND
RESTORE THE SEDIMENT STORAGE AREA TO ITS ORIGINAL DIMENSIONS WHEN THE SEDIMENT
HAS ACCUMULATED TO ONE-HALF THE DESIGN DEPTH OF THE TRAP. PLACE THE SEDIMENT
THAT IS REMOVED IN THE DESIGNATED DISPOSAL AREA AND REPLACE THE CONTAMINATED
PART OF THE GRAVEL FACING.
2.CHECK THE STRUCTURE FOR DAMAGE. ANY RIPRAP DISPLACED FROM THE STONE HORSESHOE
MUST BE REPLACED IMMEDIATELY.
3.AFTER ALL THE SEDIMENT-PRODUCING AREAS HAVE BEEN PERMANENTLY STABILIZED, REMOVE
THE STRUCTURE AND ALL THE UNSTABLE SEDIMENT. SMOOTH THE AREA TO BLEND WITH
ADJOINING AREAS AND PROVIDE PERMANENT GROUND COVER.
CONSTRUCTION SPECIFICATIONS
1.CLEAR THE AREA OF ALL DEBRIS THAT MIGHT HINDER THE EXCAVATION AND DISPOSAL OF
SPOILS.
2.INSTALL THE CLASS B OR CLASS I RIPRAP IN A SEMI-CIRCLE AROUND THE PIPE INLET. THE STONE
SHOULD BE BUILT UP HIGHER ON EACH END WHERE IT TIES INTO THE EMBANKMENT. THE
MINIMUM CREST WIDTH OF THE RIPRAP SHOULD BE 3 FEET, WITH A MINIMUM BOTTOM WIDTH OF
11 FEET. THE MINIMUM HEIGHT SHOULD BE 2 FEET, BUT ALSO 1 FOOT LOWER THAN THE
SHOULDER OF THE EMBANKMENT OR DIVERSIONS.
3.A 1 FOOT THICK LAYER OF NC DOT #5 OR #57 STONE SHOULD BE PLACED ON THE OUTSIDE SLOPE
OF THE RIPRAP.
4.THE SEDIMENT STORAGE AREA SHOULD BE EXCAVATED AROUND THE OUTSIDE OF THE STONE
HORSESHOE 18 INCHES BELOW NATURAL GRADE.
5.WHEN THE CONTRIBUTING DRAINAGE AREA HAS BEEN STABILIZED, FILL DEPRESSION AND
ESTABLISH FINAL GRADING ELEVATIONS, COMPACT AREA PROPERLY, AND STABILIZE WITH
GROUND COVER.
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
ENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09/170
EROSION AND SEDIMENT CONTROL PLAN NARRATIVE
THE EROSION AND SEDIMENT (E&S) CONTROL MEASURES FOR THE PIPELINE CONSTRUCTION ACTIVITIES PRIMARILY CONSIST OF BUT ARE
NOT LIMITED TO COMPOST FILTER SOCK, BELTED SILT RETENTION FENCE, SUPER SILT FENCE, SLOPE BREAKERS, AND TEMPORARY AND
PERMANENT SEEDING AND MULCHING. BEST MANAGEMENT PRACTICES (BMP) SPECIFICATIONS FOR THE E&S CONTROL PLAN (E&SCP) ARE TO
BE UTILIZED BY THE CONSTRUCTION CONTRACTOR ACCORDING TO THE PROVIDED PLAN.
GENERAL CONSTRUCTION NOTES:
1.DISCHARGING SEDIMENT LADEN WATER WHICH WILL CAUSE OR CONTRIBUTE TO THE DEGRADATION OF A BENEFICIAL USE OF A WATER
OF THE STATE FROM THE CONSTRUCTION SITE, A DEWATERING SITE, OR SEDIMENT BASINTRAP INTO ANY SURFACE WATER WITHOUT
FILTRATION OR EQUIVALENT TREATMENT IS PROHIBITED.
2.THE DISCHARGER SHALL AMEND THE EROSION & SEDIMENT CONTROL PLAN WHENEVER THERE IS A CHANGE IN THE CONSTRUCTION OR
OPERATIONS, WHICH MAY EFFECT THE DISCHARGE OF POLLUTANTS TO SURFACE WATERS OR GROUNDWATER.
3.DISCHARGES ORIGINATING FROM OFF-SITE SOURCES, WHICH FLOW THROUGH OR ACROSS THE AREAS DISTURBED BY CONSTRUCTION,
MAY BE DIVERTED AROUND THE ACTIVE CONSTRUCTION AREA WHENEVER POSSIBLE.
4.PERFORM PERMANENT OR TEMPORARY SOIL STABILIZATION WITHIN 7 DAYS WHEN SITE IS AT FINAL GRADE AND ON SITES THAT ARE
NOT AT FINAL GRADE, BUT WILL REMAIN DORMANT FOR MORE THAN 14 DAYS.
5.DUE TO VARYING SITE CONDITIONS, ADDITIONAL SEDIMENT CONTROL BMPS MAY BE NECESSARY BEYOND THE MEASURES SHOWN ON
THE E&S CONTROL PLAN.
6.CONTACT THE DEMLR RALEIGH REGIONAL OFFICE (CONTACT NUMBER: [phone]) OR FAYETTEVILLE REGIONAL OFFICE (CONTACT
NUMBER: [phone]) AT LEAST 48 HOURS PRIOR TO COMMENCING IN LAND DISTURBING ACTIVITY FOR EACH SECTION OF THE
PROJECT.
7.STAGING AREAS, ASSEMBLY AREAS, TEMPORARY EQUIPMENT AND NON-HAZARDOUS MATERIAL STORAGE AREAS SHALL BE LOCATED
OUTSIDE 100-YR FLOOD ZONES. HAZARDOUS MATERIAL STORAGE AREAS SHALL BE LOCATED AT LEAST 100 FEET BACK FROM SURFACE
WATER BODIES.
8.EQUIPMENT STORAGE IN CONSTRUCTION STAGING AREAS SHALL BE LOCATED A MINIMUM OF 100 FEET AWAY FROM WETLAND EDGE.
9.AT MINIMUM, ALL BMPS ARE TO BE INSPECTED ONCE EVERY SEVEN CALENDAR DAYS AND WITHIN 24 HOURS AFTER ANY STORM EVENT
GREATER THAN 0.5-INCH PER 24-HOUR PERIOD DURING THE ENTIRE PROJECT. A WRITTEN REPORT MUST ALSO BE COMPLETED,
DOCUMENTING EACH INSPECTION AND, IF NECESSARY, ANY REPAIR, REPLACEMENT OR MAINTENANCE ACTIVITY.
10.THE CONTRACTOR SHALL TAKE PRECAUTIONARY MEASURES TO PROTECT ANY EXISTING FACILITY SHOWN ON THE DRAWINGS, AND ANY
OTHER WHICH IS NOT ON RECORD OR NOT SHOWN ON THE DRAWINGS. THE CONTRACTOR SHALL POTHOLE EXISTING UTILITIES AT THE
POINTS OF CONNECTION AND ALL UTILITY CROSSINGS TO DETERMINE EXACT LOCATIONS PRIOR TO THE START OF WORK. ANY
DISCREPANCIES BETWEEN THESE DRAWINGS AND EXISTING CONDITIONS SHALL BE REPORTED TO THE ENGINEER OF RECORD
IMMEDIATELY.
11.ALL WORK WITHIN A PUBLIC RIGHT-OF-WAY SHALL BE COORDINATED WITH THE AGENCY HAVING JURISDICTION.
12.ALL REQUIRED PERMITS MUST BE OBTAINED PRIOR TO STARTING WORK.
13.DURING CONSTRUCTION, THE CONTRACTOR SHALL BE RESPONSIBLE FOR CONSTRUCTION, STABILIZATION AND MAINTENANCE OF ALL
EXISTING AND PROPOSED SITE EROSION & SEDIMENTATION CONTROL DEVICES AND FACILITIES.
14.THE CONTRACTOR AGREES THAT IN ACCORDANCE WITH GENERALLY ACCEPTED CONSTRUCTION PRACTICES, THE CONTRACTOR WILL
BE REQUIRED TO ASSUME SOLE AND COMPLETE RESPONSIBILITY FOR JOB SITE CONDITIONS DURING THE COURSE OF CONSTRUCTION
OF THE PROJECT, INCLUDING EROSION & SEDIMENTATION DEVICES AND SAFETY OF ALL PERSONS AND PROPERTY; THAT THIS
REQUIREMENT SHALL BE MADE TO APPLY CONTINUOUSLY AND NOT BE LIMITED TO NORMAL WORKING HOURS, AND CONSTRUCTION
CONTRACTOR FURTHER AGREES TO DEFEND, INDEMNIFY AND HOLD THE ENGINEER OF RECORD HARMLESS OF ANY AND ALL LIABILITY,
REAL OR ALLEGED, IN CONNECTION WITH THE PERFORMANCE OF WORK ON THIS PROJECT, EXCEPTING LIABILITY ARISING FROM THE
SOLE NEGLIGENCE OF ENGINEER OF RECORD.
15.AS SITE SPECIFIC CONDITIONS MAY WARRANT, THE E&SC PLAN MAY REQUIRE MINOR MODIFICATIONS TO ENSURE PROPER PROTECTION
OF RECEIVING WATERS. THE RESPECTIVE PROJECT ENVIRONMENTAL INSPECTOR (EI) WILL IDENTIFY SITE SPECIFIC AREAS WHERE A
CERTAIN BMP MODIFICATION(S) IS NECESSARY TO EITHER OMIT OR ENHANCE BMPS IN SUCH AREAS. THIS PROCESS ENTAILS THE EI TO
IDENTIFY LOCATIONS WHERE BMPS WILL NEED TO BE ALTERED, SUBSTITUTED OR OMITTED AND CONTACT THE DOMINION GAS
COMPLIANCE SPECIALIST TO REVIEW PROPOSED CHANGES. UPON REVIEW AND APPROVAL BY THE DOMINION COMPLIANCE SPECIALIST,
THE EI WILL REDLINE, DATE, AND SIGN THE E&SCP DRAWING(S) DEPICTING THE REDLINE CHANGE(S). ONCE THIS PROCESS IS
COMPLETED, THE EI WILL NOTIFY NCDEQ OF SUCH MINOR MODIFICATION REDLINE AMENDMENTS AS REQUIRED BY THE GENERAL
PERMIT.
SEQUENCE OF CONSTRUCTION
1. A PRE-CONSTRUCTION MEETING SHOULD TAKE PLACE PRIOR TO START OF CONSTRUCTION ACTIVITIES.
2. BEGIN CLEARING AND GRUBBING SITE. CLEAR AND GRUB ONLY THOSE AREAS NECESSARY FOR INSTALLATION OF THE EROSION CONTROL
MEASURES.
3. INSTALL SILT FENCE AS SHOWN ON THE PLANS.
4. ONCE EROSION CONTROL MEASURES HAVE BEEN INSTALLED AND PRIOR TO SEDIMENT REMOVAL ACTIVITIES, THE SITE IS TO BE INSPECTED
BY NCDENR - LAND QUALITY.
5. GRADE SITE ACCORDING TO CONTRACT DOCUMENTS. MAINTAIN EROSION CONTROL DEVICES AS NEEDED.
6. INSTALL STORM DRAINAGE AS INDICATED ON PLANS.
7. GRASS OR OTHERWISE STABILIZE ALL AREAS AS THEY ARE BROUGHT TO FINAL GRADES.
8. THE CONTRACTOR SHALL DILIGENTLY AND CONTINUOUSLY MAINTAIN ALL EROSION CONTROL DEVICES AND STRUCTURES TO MINIMIZE
EROSION. INSPECT AND REPAIR MEASURES AFTER EACH RAINFALL AND AS NEEDED THROUGHOUT THE PROJECT.
9. CONTRACTOR TO LEAVE ALL EROSION CONTROL DEVICES IN PLACE AT THE CONCLUSION OF THIS CONTRACT. CONTRACTOR IS TO
CLEAN-OUT, REPAIR AND GRASS STABILIZE ALL DENUDED AREAS. ALL AREAS WILL BE RETURNED TO THE STATE OF EXISTING CONDITIONS
PRIOR TO CONTRACT AS A MINIMUM.
10. IT IS THE CONTRACTOR'S RESPONSIBILITY TO CONTAIN SEDIMENT ONSITE. ADDITIONAL EROSION CONTROL MEASURES MAY BE REQUIRED BY
THE ENGINEER.
11. ALL EROSION CONTROL MEASURES TO BE IN ACCORDANCE WITH THE NORTH CAROLINA EROSION AND SEDIMENT CONTROL PLANNING AND
DESIGN REQUIREMENTS AND LAND DEVELOPMENT STANDARDS.
MAINTENANCE SCHEDULE
AFTER FULL REVEGETATION HAS BEEN ACHIEVED, ALL BMPS WILL BE REMOVED AND ANY LAND DISTURBED BY REMOVAL WILL BE
PERMANENTLY STABILIZED. UNLESS OTHERWISE SPECIFIED, ALL MAINTENANCE MUST BE COMPLETED IMMEDIATELY AFTER AN INSPECTION
IDENTIFIES THAT A BMP IS NOT FUNCTIONING AS REQUIRED.
·THE ROW AND ESC DEVICES WILL BE INSPECTED DAILY AT THE ACTIVE CONSTRUCTION SITE AND AT LEAST ONCE EVERY SEVEN
CALENDAR DAYS FOR ACTIVELY DISTURBED AREAS, 14 CALENDAR DAYS FOR RESTORED AREAS, AND WITHIN 24 HOURS AFTER ANY
STORM EVENT GREATER THAN ONE-HALF-INCH PER 24-HOUR PERIOD.
·SEDIMENT MUST BE REMOVED WHERE ACCUMULATION REACHES ONE-HALF THE ABOVE GROUND HEIGHT OF THE CONTROL MEASURE.
·EROSION CONTROL MEASURES, WHICH HAVE BEEN UNDERMINED OR TOPPED, SHALL BE REPAIRED IMMEDIATELY.
·OTHER REQUIRED REPAIRS OR MAINTENANCE SHALL BE MADE IMMEDIATELY.
·TEMPORARY AND PERMANENT E&S CONTROL BMPS SHALL BE MAINTAINED AND REPAIRED AS NEEDED TO ASSURE CONTINUED
PERFORMANCE OF THEIR INTENDED FUNCTION.
·A SELF-INSPECTION AND COMPLETION OF SELF-INSPECTION FORM IS REQUIRED AFTER EACH PHASE OF CONSTRUCTION IS COMPLETED.
SELF-INSPECTION FORM CAN BE FOUND HERE: http://deq.nc.gov/about/divisions/energy-mineral-land-resources/erosion-sediment-control/forms
MATERIAL WASTE HANDLING AND RECYCLING
1.SOLID WASTE DISPOSAL SHALL BE HANDLED THROUGH ONE OF THE LOCAL LICENSED WASTE MANAGEMENT PROVIDERS AND PERMITTED
DISPOSAL FACILITIES. THE CONTRACTOR WILL PROVIDE MOBILE AND COVERED WASTE RECEPTACLES AS NEEDED ALONG THE PROJECT
LIMITS. CONTRACTOR SHALL ALSO PROVIDE A COVERED DUMPSTER FOR CONSOLIDATION OF WASTE FOR PICK UP AND DISPOSAL FOR
THE DURATION OF THE PROJECT. ALL SOLID WASTE SHALL BE DISPOSED OF AT A LICENSED PERMITTED MUNICIPAL LANDFILL.
2.THE CONTRACTOR WILL BE RESPONSIBLE FOR ANY PERMITS AN DOR DISPOSAL FEES. THE CONTRACTOR SHALL BE SOLELY
RESPONSIBLE TO ASSURE THAT ALL MATERIALS AREA HANDLED AND DISPOSED OF IN ACCORDANCE WITH APPLICABLE LAWS, RULES,
AND REGULATIONS, INCLUDING BUT NOT LIMITED TO THOSE ISSUED BY THE ENVIRONMENTAL PROTECTION AGENCY, NCDEQ, AND
OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION.
3.CONTRACTOR SHALL PRACTICE GOOD HOUSEKEEPING FOR THE DURATION OF THE PROJECT INCLUDING THE ROUTINE REMOVAL AND
DISPOSAL OF SOLID WASTE.
4.CONTRACTOR SHALL KEEP RECORDS OF PROPER SOLID WASTE DISPOSAL AND PROVIDE COPIES TO THE EI.
POLLUTANT CONTROLS
·SPILLS OCCURRING DURING CONSTRUCTION, OPERATION, AND MAINTENANCE ARE TO BE REPORTED IMMEDIATELY TO THE
MONITORING CENTER IN ACCORDANCE WITH DOMINION POLICIES, PLANS, AND PROCEDURES. DOMINION'S ENVIRONMENTAL
HEALTH AND SAFETY DEPARTMENT WILL BE RESPONSIBLE FOR CONTACTING THE APPROPRIATE AGENCIES, EXCEPT AS PROVIDED
FOR BELOW.
·ANY FACILITY OWNER/OPERATOR WHO IS SUBJECT TO THE SPCC RULE MUST COMPLY WITH THE REPORTING REQUIREMENTS
FOUND IN 40 CFR 112.4. A DISCHARGE MUST BE REPORTED TO THE EPA REGIONAL ADMINISTRATOR (RA) WHEN THERE IS A
DISCHARGE OF:
··MORE THAN 1,000 GALLONS OF OIL IN A SINGLE DISCHARGE TO NAVIGABLE WATERS OR ADJOINING SHORELINES,
··MORE THAN 42 GALLONS OF OIL IN EACH OF TWO DISCHARGES TO NAVIGABLE WATERS OR ADJOINING SHORELINES OCCURRING
WITHIN ANY TWELVE-MONTH PERIOD.
·IF A DOMINION REPRESENTATIVE CANNOT BE PROMPTLY CONTACTED AND THE SPILL HAS IMPACTED WATER, THE PERSON
DISCOVERING THE SPILL OR RELEASE WILL CONTACT THE NATIONAL RESPONSE CENTER AT 1-800-424-8802 AND REPORT THE
RELEASE. THAT PERSON WILL CONTINUE CALLING DOMINION UNTIL A REPRESENTATIVE IS REACHED.
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS SHOWN
10/20/2017SR
10/20/2017CM
17 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC
BMP INSTALLATION AND REMOVAL SEQUENCE
CONSTRUCTION MUST BE IN ACCORDANCE WITH THE FOLLOWING SEQUENCE. THIS SEQUENCE IS DESIGNED TO MINIMIZE SOIL EROSION
AND SEDIMENTATION. THE CONTRACTOR MAY DEVIATE SLIGHTLY FROM THE STAGING OF PERMANENT SITE IMPROVEMENTS, BUT NO
DEVIATION FROM THE RELATIVE ORDER OF EROSION AND SEDIMENTATION CONTROL MEASURES WILL BE ALLOWED.
THE STAGING OF EARTHMOVING ACTIVITIES FOR THIS PROJECT IS A GENERAL DESCRIPTION OF THE WORK REQUIRED. ALL WORK SHALL
BE COMPLETED IN ACCORDANCE WITH COMPANY STANDARDS, THE NORTH CAROLINA DEPARTMENT OF ENVIRONMENTAL QUALITY
REGULATIONS AND ALL OTHER APPLICABLE FEDERAL, STATE OR LOCAL REQUIREMENTS.
THE APPROVED EROSION AND SEDIMENTATION CONTROL PLAN INCLUDING THE SOIL EROSION CONTROL DRAWINGS AND NARRATIVE
SHALL BE AVAILABLE ON SITE AT ALL TIMES DURING EARTH DISTURBANCE.
1.STAKE AND/OR FLAG ALL LIMITS OF DISTURBANCE FOR CONSTRUCTION ACTIVITIES, CLEARLY IDENTIFYING WETLAND AND STREAM
EDGES. INSTALL SIGNS TO DESIGNATE THE AREA TO IDENTIFY IMPORTANT PROJECT ATTRIBUTES SUCH AS WETLANDSTREAM
BOUNDS, EXCLUSION AREAS ETC.
2.INSTALL ROCK CONSTRUCTION ENTRANCES IMMEDIATELY BEFORE INITIAL DISTURBANCES. THE ROCK CONSTRUCTION
ENTRANCES TO BE UNDERLAIN BY FILTER FABRIC. ALL CONSTRUCTION TRAFFIC SHOULD USE ONLY ROCK CONSTRUCTION
ENTRANCE FOR INGRESS AND EGRESS. ALL MUD OR SEDIMENT TRACKED ONTO THE EXISTING ROADWAY SHALL BE REMOVED BY
THE CONTRACTOR AS NECESSARY.
3.INSTALL SILT FENCE AND COMPOST FILTER SOCKS AS NECESSARY ALONG THE ACCESS ROADS TO PREVENT SEDIMENT LADEN
RUNOFF FROM ENTERING DOWNSTREAM WATER BODIES. MAINTAIN THE ACCESS ROADS AS REQUIRED, ASSOCIATED DITCHES,
AND NECESSARY OUTLET PROTECTION.
4.PRIOR TO AND SIMULTANEOUS WITH GRADING AND EXCAVATION, INSTALL REMAINING EROSION CONTROL DEVICES (ECD) SHOWN
ON THE PLANS.
5.COMMENCE GRADING AND ASSOCIATED CUT AND FILL SLOPES. THE EARTH MOVING ACTIVITY SHALL BEGIN IN AREA OF CUT SO THAT
THE CUTS CAN BE PLACED IN AREAS OF FILL. REMOVE TOPSOIL FROM AREAS TO RECEIVE FILL PRIOR TO FILLING.
6.FINALIZE UTILITY INSTALLATION AND ROADWAY GRADES AND PLACE TOPSOIL ON THE CUT AND FILL AREAS. STABILIZE CUT AND
FILL SLOPES, AFTER PLACEMENT OF STOCKPILED TOPSOIL ON EXCAVATED SLOPES, AND AS DIRECTED.
7.RE-DISTRIBUTION OF WET SEDIMENT FROM DEVICES AND FACILITIES SHALL ONLY BE PERMITTED UPHILL OF AN EFFECTIVE
SEDIMENT CONTROL DEVICE OR FACILITY. SEDIMENT LADEN RUNOFF SHALL NOT BE ALLOWED TO FLOW DIRECTLY INTO WATER
BODIES.
8.ANY EXPOSED TOPSOIL PILES SHOULD BE STABILIZED & SEEDED PER THE PERMIT REGULATIONS, AND BY TABLES SHOWN ON THE
APPROVED EROSION CONTROL PLANS AND MULCHED WITH STRAW AS SPECIFIED BY THE PROJECT OWNER.
9.UPON MINIMUM 70% UNIFORM PERENNIAL VEGETATIVE GROWTH, REMOVE TEMPORARY SEDIMENT CONTROLS. REMOVE
ACCUMULATED SEDIMENTS WITHIN THE TRAPS, RE-GRADE TRAPS TO FINAL CONTOURS. STABILIZE SITE PER THE PLANS.
SEAL
EROSION AND SEDIMENT CONTROL DETAIL NOTES
1.THE DETAILS ON EROSION AND SEDIMENT CONTROL DETAIL SHEETS 1 THROUGH 3 CORRESPOND TO E&S CONTROL MEASURES
SPECIFICALLY IDENTIFIED ON THE E&SC PLAN. DETAILS ON SHEET 4 CORRESPONDS TO E&S CONTROL MEASURES THAT WHILE NOT
SPECIFICALLY IDENTIFIED ON THE E&SC PLANS, COULD POTENTIALLY BE REQUIRED.
--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
·SOIL STABILIZATION SHALL BE ACHIEVED ON ANY AREA OF THE SITE WHERE LAND-DISTURBING ACTIVITIES HAVE
TEMPORARILY OR PERMANENTLY CEASED ACCORDING TO THE FOLLOWING SCHEDULE:
··ALL PERIMETER DIKES, SWALES DITCHES, PERIMETER SLOPES AND SLOPES STEEPER THAN 3 HORIZONTAL TO 1
VERTICAL (3:1) SHALL BE PROVIDED TEMPORARY OR PERMANENT STABILIZATION WITH GROUND COVER AS SOON AS
PRACTICABLE BUT IN ANY EVENT WITHIN 7 CALENDAR DAYS FROM THE LAST LAND DISTURBING ACTIVITY.
··ALL OTHER DISTURBED AREAS SHALL BE PROVIDED TEMPORARY OR PERMANENT STABILIZATION WITH GROUND COVER
AS SOON AS PRACTICABLE BUT IN ANY EVENT WITHIN 14 CALENDAR DAYS FROM THE LAST LAND DISTURBING ACTIVITY.
·CONDITIONS - IN MEETING THE STABILIZATION REQUIREMENTS ABOVE, THE FOLLOWING CONDITIONS OR EXEMPTIONS
SHALL APPLY.
··EXTENSIONS OF TIME MAY BE APPROVED BY THE PERMITTING AUTHORITY BASED ON WEATHER OR OTHER
SITE-SPECIFIC CONDITIONS THAT MAKE COMPLIANCE IMPRACTICABLE.
··ALL SLOPES 50' IN LENGTH OR GREATER SHALL APPLY THE GROUND COVER WITHIN 7 DAYS EXCEPT WHEN THE SLOPE
IS FLATTER THAN 4:1. SLOPES LESS THAN 50' SHALL APPLY GROUND COVER WITHIN 14 DAYS EXCEPT WHEN SLOPES
ARE STEEPER THAN 3:1, THE 7-DAY REQUIREMENT APPLIES.
··ANY SLOPED AREA FLATTER THAN 4:1 SHALL BE EXEMPT FROM THE 7-DAY GROUND COVER REQUIREMENT.
··SLOPES 10' OR LESS SHALL BE EXEMPT FROM THE 7-DAY GROUND COVER REQUIREMENT EXCEPT WHEN THE SLOPE IS
STEEPER THAN 2:1.
··ALTHOUGH STABILIZATION IS USUALLY SPECIFIED AS GROUND COVER, OTHER METHODS, SUCH AS CHEMICAL
STABILIZATION, MAY BE ALLOWED ON A CASE-BY-CASE BASIS
··FOR PORTIONS OF PROJECTS WITHIN THE SEDIMENT CONTROL COMMISSION-DEFINED "HIGH QUALITY WATER ZONE"
(15A NCAC 04A. 0105), STABILIZATION WITH GROUND COVER SHALL BE ACHIEVED AS SOON AS PRACTICABLE BUT IN ANY
EVENT ON ALL AREAS OF THE SITE WITHIN 7 CALENDAR DAYS FROM THE LAST LAND DISTURBING ACT.
··PORTIONS OF THE SITE THAT ARE LOWER IN ELEVATION THAN ADJACENT DISCHARGE LOCATIONS AND ARE NOT
EXPECTED TO DISCHARGE DURING CONSTRUCTION MAY BE EXEMPT FROM THE TEMPORARY GROUND COVER
REQUIREMENTS IF IDENTIFIED ON THE APPROVED E&SC PLAN OR ADDED BY THE PERMITTING AUTHORITY.
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
ENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09/170
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS SHOWN
10/20/2017SR
10/20/2017CM
18 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC
SEAL
--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
GENERAL PIPELINE CONSTRUCTION
PIPELINE CONSTRUCTION WORKSPACE REQUIREMENTS ARE A FUNCTION OF PIPE DIAMETER, EQUIPMENT SIZE, TOPOGRAPHY, GEOLOGICAL ROCK FORMATIONS,
LOCATION OF CONSTRUCTION SUCH AS AT ROAD CROSSINGS OR RIVER CROSSINGS, PIPELINE CROSSOVERS, METHODS OF CONSTRUCTION SUCH AS BORING OR
OPEN-CUT CONSTRUCTION, OR EXISTING SOIL CONDITIONS ENCOUNTERED DURING CONSTRUCTION. AS THE DIAMETER OF THE PIPELINE BEING INSTALLED INCREASES,
SO DOES THE DEPTH OF TRENCH, EXCAVATED SPOIL MATERIAL, EQUIPMENT SIZE, AND ULTIMATELY THE AMOUNT OF CONSTRUCTION WORK SPACE THAT WILL BE
REQUIRED TO CONSTRUCT A PROJECT. ALL WORKSPACE LOCATIONS FOR A GIVEN PROJECT WILL BE SHOWN ON THE CONSTRUCTION ALIGNMENT SHEETS.
ADDITIONAL CONSTRUCTION RIGHT-OF-WAY (ROW) MAY BE REQUIRED AT SPECIFIC LOCATIONS INCLUDING, BUT NOT LIMITED TO, STEEP SIDE OR VERTICAL SLOPES,
ROAD CROSSINGS, PIPELINE CROSSOVERS, AREAS REQUIRING SUPPLEMENTAL TOPSOIL SEGREGATION, AND STAGING AREAS ASSOCIATED WITH WETLAND AND
WATERBODY CROSSINGS.
ALL CONSTRUCTION ACTIVITIES, INCLUDING STAGING AREAS AND ADDITIONAL SPOIL STORAGE AREAS, ARE RESTRICTED TO THE CONSTRUCTION ROW LIMITS IDENTIFIED
ON THE CONSTRUCTION ALIGNMENT SHEETS, EXCEPT FOR SPECIFIC ACTIVITIES IN LIMITED, NON-WETLAND, AND NON-RIPARIAN AREAS THAT ARE ALLOWED BY THE FERC
PLAN AND PROCEDURES (I.E., SLOPE BREAKERS, ENERGY-DISSIPATING DEVICES, DEWATERING STRUCTURES, AND DRAIN TILE SYSTEM REPAIRS). USE OF THESE LIMITED
AREAS IS SUBJECT TO LANDOWNER OR LAND MANAGEMENT AGENCY APPROVAL AND COMPLIANCE WITH ALL APPLICABLE SURVEY, PERMIT, AND REPORTING
REQUIREMENTS; THEREFORE, PRIOR DOMINION ENERGY TRANSMISSION INC. (DETI) APPROVAL IS REQUIRED TO USE THESE AREAS. IN SOME CASES, FEDERAL, STATE,
AND LOCAL PERMITS AND AUTHORIZATIONS MAY REQUIRE ADDITIONAL APPROVALS.
CROSS-COUNTRY PIPELINE CONSTRUCTION TYPICALLY PROCEEDS IN ASSEMBLY LINE FASHION, WITH MULTIPLE STAGES OF CONSTRUCTION OCCURRING
SIMULTANEOUSLY AT DIFFERENT LOCATIONS TO MINIMIZE THE TIME NEEDED TO COMPLETE THE PROJECT. THE STAGES OF CONSTRUCTION INCLUDE: SURVEY AND
FLAGGING, CLEARING AND MOWING, GRUBBING AND GRADING, TRENCHING, PIPE ASSEMBLY (INCLUDING STRINGING, BENDING, WELDING, TESTING, COATING, AND
LOWERING-IN), BACKFILLING, HYDROSTATIC TESTING, FINAL GRADING, AND RESTORATION. EROSION AND SEDIMENT CONTROL (ESC) MEASURES TO BE UTILIZED ALONG
THE PIPELINE ALIGNMENT ARE DEPICTED ON THE CONSTRUCTION ALIGNMENT SHEETS.
SITE PREPARATION
·SURVEY AND FLAG THE CONSTRUCTION ROW AND MARK ENVIRONMENTALLY SENSITIVE AREAS.
·INSTALL ROCK CONSTRUCTION ENTRANCES.
·INSTALL SAFETY FENCES PRIOR TO ESC INSTALLATION.
·CONDUCT INITIAL CLEARING, LIMITED TO THAT NECESSARY TO INSTALL TEMPORARY SEDIMENT BARRIERS.
·INSTALL PERIMETER ESCS PRIOR TO ANY BULK EARTH-MOVING ACTIVITY (ROAD GRADING, ROAD USE, LOG SKIDDING, ETC.).
·CONDUCT PROGRESSIVE CLEARING WITH INSTALLATION OF TEMPORARY SEDIMENT BARRIERS AND TEMPORARY EQUIPMENT BRIDGES KEEPING PACE WITH
CLEARING.
·MODIFY ACCESS ROADS BY GRADING AND INSTALLING STONE WHERE NEEDED.
·GRADE THE ROW AND SEGREGATE TOPSOIL WHERE NECESSARY.
·INSTALL TEMPORARY SLOPE BREAKERS, ALSO REFERRED TO AS TEMPORARY ROW DIVERSIONS OR WATER BARS, AS NEEDED TO REDUCE RUNOFF VELOCITY AND
DIVERT WATER OFF THE CONSTRUCTION ROW.
PIPE INSTALLATION
·EXCAVATE TRENCH TO ACCOMMODATE NEW PIPELINE SEGMENT.
·STRING PIPE, BEND THE PIPE JOINTS.
·WELD THE PIPE, INSPECT WELDS.
·LOWER THE PIPE INTO THE TRENCH.
·INSTALL PERMANENT TRENCH PLUGS.
·BACKFILL THE TRENCH.
·INSTALL HYDROSTATIC TEST DEWATERING STRUCTURES.
·HYDROSTATICALLY TEST THE PIPE AND DEWATER.
·BRING THE PIPELINE TO GAS SERVICE.
·FINAL GRADE ROW AND TEMPORARY WORKSPACES TO ORIGINAL CONTOURS TO THE EXTENT PRACTICABLE.
·INSTALL PERMANENT INTERCEPTOR DIKES.
·REPLACE SEGREGATED TOPSOIL.
RESTORATION
·CONDUCT ROW RESTORATION AND CLEANUP. AS SOON AS SLOPES, CHANNELS, DITCHES, AND OTHER DISTURBED AREAS REACH FINAL GRADE, THEY WILL BE
STABILIZED WITHIN THE TIMEFRAME SPECIFIED.
·APPLY SOIL AMENDMENTS, PERMANENT SEED, MULCH, AND/OR EROSION CONTROL FABRIC.
·RESTORE TEMPORARY ACCESS ROADS OR ANY PAVED SURFACES TO ORIGINAL CONDITION.
·REMOVE TEMPORARY SEDIMENT BARRIERS FROM AN AREA WHEN REPLACED BY PERMANENT EROSION CONTROL MEASURES OR WHEN THE AREA HAS BEEN
SUCCESSFULLY RESTORED TO UNIFORM PERENNIAL VEGETATION. TEMPORARY EROSION CONTROL BMPS WILL NOT BE REMOVED UNTIL INSPECTION BY THE EI (EI)
TO CONFIRM SITE STABILIZATION.
·ENGAGE A QUALIFIED DRAIN TILE SPECIALIST, AS NEEDED, TO CONDUCT OR MONITOR REPAIRS TO DRAIN TILE SYSTEMS AFFECTED BY CONSTRUCTION.
WETLAND CROSSING
PROCEDURES USED TO INSTALL A PIPELINE ACROSS WETLANDS VARY DEPENDING ON THE LEVEL OF SOIL STABILITY AND SATURATION ENCOUNTERED DURING
CONSTRUCTION. DETI WILL COMPLY WITH USACE PERMIT TERMS AND CONDITIONS. IT WILL ASSEMBLE THE PIPELINE IN AN UPLAND AREA UNLESS THE
WETLAND IS DRY ENOUGH TO ADEQUATELY SUPPORT SKIDS AND PIPE. DETI WILL USE “PUSH-PULL” OR “FLOAT” TECHNIQUES TO PLACE THE PIPE IN THE TRENCH
WHERE WATER AND OTHER SITE CONDITIONS ALLOW.
THE FOLLOWING BEST MANAGEMENT PRACTICES (BMPS) ARE TO BE EMPLOYED DURING STANDARD WETLAND CROSSINGS:
·ASSEMBLE THE PIPELINE IN AN UPLAND AREA UNLESS THE WETLAND IS DRY ENOUGH TO ADEQUATELY SUPPORT SKIDS AND PIPE.
·DO NOT USE ROCK, SOIL IMPORTED FROM OUTSIDE THE WETLAND, TREE STUMPS, OR BRUSH RIPRAP TO STABILIZE THE ROW.
·PERFORM TOPSOIL SEGREGATION, INCLUDING SEGREGATING THE SURFICIAL 12 INCHES OF TOPSOIL FROM THE AREA DISTURBED BY TRENCHING, EXCEPT IN
AREAS WHERE STANDING WATER IS PRESENT OR SOILS ARE SATURATED. IMMEDIATELY AFTER BACKFILLING IS COMPLETE, RESTORE THE SEGREGATED
TOPSOIL TO ITS ORIGINAL LOCATION.
·IF REQUIRED, DEWATERING SHOULD BE CONDUCTED AS DESCRIBED BELOW.
·MINIMIZE THE LENGTH OF TIME THAT TOPSOIL IS SEGREGATED AND THE TRENCH IS OPEN. DO NOT TRENCH THE WETLAND UNTIL THE PIPELINE IS ASSEMBLED
AND READY FOR LOWERING-IN.
·INSTALL PERMANENT TRENCH BREAKERS AT THE WETLAND BOUNDARIES AND/OR SEAL THE TRENCH BOTTOM AS NECESSARY TO MAINTAIN THE ORIGINAL
WETLAND HYDROLOGY AT LOCATIONS WHERE THE PIPELINE TRENCH MAY DRAIN A WETLAND.
·INSTALL A PERMANENT SLOPE BREAKER AND A TRENCH BREAKER AT THE BASE OF SLOPES NEAR THE BOUNDARY BETWEEN THE WETLAND AND ADJACENT
UPLAND AREAS FOR EACH WETLAND CROSSED.
·INSTALL A PERMANENT SLOPE BREAKER ACROSS THE CONSTRUCTION ROW AT THE BASE OF SLOPES GREATER THAN 5 PERCENT WHERE THE BASE OF THE
SLOPE IS LESS THAN 50 FEET FROM THE WETLAND, OR AS NEEDED TO PREVENT SEDIMENT TRANSPORT INTO THE WETLAND. IN SOME AREAS, AN EARTHEN
BERM MAY BE SUITABLE AS A SEDIMENT BARRIER ADJACENT TO THE WETLAND.
·WHEN REQUIRED, ADDITIONAL FILL MATERIAL IMPORTED FROM OFF THE ROW MUST BE APPROVED BY THE EI.
·PRE-CONSTRUCTION WETLAND CONTOURS AND FLOW REGIMES WILL BE RESTORED TO THE EXTENT PRACTICAL.
WETLAND CLEANUP AND RESTORATION
·FOR EACH WETLAND CROSSED, DETI WILL INSTALL A TRENCH BREAKER AT THE BASE OF SLOPES NEAR THE BOUNDARY BETWEEN THE WETLAND AND
ADJACENT UPLAND AREAS. IT WILL INSTALL A PERMANENT SLOPE BREAKER ACROSS THE CONSTRUCTION ROW AT THE BASE OF SLOPES GREATER THAN 5
PERCENT WHERE THE BASE OF THE SLOPE IS LESS THAN 50 FEET FROM THE WETLAND, OR AS NEEDED TO PREVENT SEDIMENT TRANSPORT INTO THE
WETLAND. IN SOME AREAS, AN EARTHEN BERM MAY BE SUITABLE AS A SEDIMENT BARRIER ADJACENT TO THE WETLAND.
·RESTORE PRE-CONSTRUCTION WETLAND CONTOURS TO MAINTAIN THE WETLAND HYDROLOGY.
·REVEGETATION AND PERMANENT ROW MAINTENANCE PROCEDURES AS WELL AS THE USE OF LIME, MULCH, OR FERTILIZER IN WETLAND AREAS IS ADDRESSED
IN THE FERC RESTORATION AND REHABILITATION PLAN.
·DETI WILL NOT USE HERBICIDES OR PESTICIDES IN OR WITHIN 100 FEET OF A WETLAND, EXCEPT AS ALLOWED BY THE APPROPRIATE FEDERAL OR STATE
AGENCY.
·REMOVE PROJECT-RELATED MATERIAL USED TO SUPPORT EQUIPMENT ON THE CONSTRUCTION ROW, INCLUDING TIMBER MATTING AND PREFABRICATED
EQUIPMENT MATS, UPON COMPLETION OF CONSTRUCTION.
·REMOVE TEMPORARY SEDIMENT BARRIERS LOCATED AT THE BOUNDARY BETWEEN WETLAND AND ADJACENT UPLAND AREAS AFTER UPLAND REVEGETATION
AND STABILIZATION OF ADJACENT UPLAND AREAS ARE SUCCESSFUL.
·WITHIN 3 YEARS AFTER CONSTRUCTION, FILE A REPORT WITH FERC IDENTIFYING THE STATUS OF THE WETLAND REVEGETATION EFFORTS AND DOCUMENTING
SUCCESS.
STREAM CROSSING
·THE TEMPORARY WATERWAY CROSSING WILL BE AT RIGHT ANGLES TO THE STREAM. WHERE APPROACH CONDITIONS DICTATE, THE CROSSING MAY VARY 15
DEGREES FROM A LINE DRAWN PERPENDICULAR TO THE CENTER LINE OF THE STREAM AT THE INTENDED CROSSING LOCATION.
·EQUIPMENT BRIDGES MAY BE INSTALLED AND USED WHERE NEEDED TO ALLOW EQUIPMENT ACCESS ACROSS WATERBODIES. EQUIPMENT BRIDGES WILL BE
ABLE TO WITHSTAND THE ANTICIPATED LOADING OF THE CONSTRUCTION TRAFFIC, HAVE ONE TRAFFIC LANE, AND HAVE THE MINIMUM WIDTH OF 12 FEET
WITH A MAXIMUM WIDTH OF 20 FEET.
·PERMANENT OR TEMPORARY SOIL STABILIZATION SHALL BE APPLIED TO DENUDED AREAS WITHIN 7 DAYS AFTER FINAL GRADE IS REACHED ON ANY PORTION
OF THE SITE. THE AREAS DISTURBED DURING INSTALLATION WILL BE STABILIZED WITHIN 7 DAYS OF THAT DISTURBANCE IN ACCORDANCE WITH NC DEQ
REQUIREMENTS.
·INTERMITTENT AND PERENNIAL STREAMS WILL BE CROSSED USING PROPERLY DESIGNED AND CONSTRUCTED STRUCTURES INSTALLED AT RIGHT ANGLES TO
THE ACCESS ROAD.
·STRUCTURES WILL NOT IMPEDE FISH PASSAGE OR STREAM FLOW.
·APPROACHES TO STREAM CROSSINGS WILL BE STABILIZED WITH GRAVEL, MULCH OR OTHER SUITABLE MATERIAL FOR A MINIMUM DISTANCE OF 50 FEET ON
EACH SIDE OF THE CROSSING, OR TO THE TOP OF THE GRADE THAT IS CONTRIBUTING SEDIMENT TO THE STREAM CROSSING.
·UNTIL THE EQUIPMENT BRIDGE IS INSTALLED, ONLY CLEARING EQUIPMENT AND EQUIPMENT NECESSARY FOR INSTALLATION OF EQUIPMENT BRIDGES MAY
CROSS THE WATERBODY, AND THE NUMBER OF CROSSINGS WILL BE LIMITED TO ONE CROSSING PER PIECE OF EQUIPMENT, UNLESS OTHERWISE AUTHORIZED
BY THE APPROPRIATE PERMITTING AGENCY. EI APPROVAL IS REQUIRED PRIOR TO EQUIPMENT CROSSING A WATERBODY WITHOUT AN EQUIPMENT BRIDGE.
·CONSTRUCT AND MAINTAIN EQUIPMENT BRIDGES THAT ALLOW UNRESTRICTED FLOW AND PREVENT SEDIMENT FROM ENTERING THE WATERBODY.
·DO NOT USE SOIL TO CONSTRUCT OR STABILIZE EQUIPMENT BRIDGES.
·DESIGN AND MAINTAIN EQUIPMENT BRIDGES TO PREVENT SEDIMENT FROM ENTERING THE WATERBODY.
·REMOVE TEMPORARY EQUIPMENT BRIDGES AS SOON AS PRACTICABLE AFTER SEEDING.
·IF THERE WILL BE MORE THAN 1 MONTH BETWEEN FINAL CLEANUP AND THE BEGINNING OF PERMANENT SEEDING AND REASONABLE ALTERNATIVE ACCESS
TO THE ROW IS AVAILABLE, REMOVE TEMPORARY EQUIPMENT BRIDGES AS SOON AS PRACTICABLE AFTER FINAL CLEANUP.
TRENCH DEWATERING
·CONDUCT DEWATERING (ON OR OFF THE CONSTRUCTION ROW) IN SUCH A MANNER THAT DOES NOT CAUSE EROSION AND DOES NOT RESULT IN SILT-LADEN
WATER FLOWING INTO ANY WATERBODY, WETLAND, OR OFF-SITE PROPERTY.
·ELEVATE AND SCREEN THE INTAKE OF EACH HOSE USED TO WITHDRAW THE WATER FROM THE TRENCH TO MINIMIZE PUMPING OF DEPOSITED SEDIMENTS.
·A DEWATERING BAG MAY NOT BE NEEDED IF THERE IS A WELL-STABILIZED, VEGETATED AREA ON SITE TO WHICH WATER CAN BE DISCHARGED. THE AREA
MUST BE STABILIZED SO THAT IT CAN FILTER SEDIMENT AND AT THE SAME TIME WITHSTAND THE VELOCITY OF THE DISCHARGED WATER WITHOUT ERODING.
·REMOVE DEWATERING STRUCTURES AS SOON AS PRACTICABLE AFTER THE COMPLETION OF DEWATERING ACTIVITIES.
·REMOVE DEWATERING STRUCTURES AS SOON AS PRACTICABLE AFTER THE COMPLETION OF DEWATERING ACTIVITIES. IF SEDIMENT BUILD-UP PREVENTS THE
BAG FROM FUNCTIONING PROPERLY, OR THE BAG BECOMES HALF FULL OF SEDIMENT
SITE INSPECTION FREQUENCY FOR SENSITIVE AREAS
EROSION AND SEDIMENT CONTROL INSPECTIONS WILL BE IN ACCORDANCE WITH NC GUIDELINES. INSPECTIONS WILL BE PERFORMED AT LEAST ONCE PER 7
CALENDAR DAYS AND WITHIN 24 HOURS OF A RAINFALL EVENT GREATER THAN 0.5 INCHES PER 24 HOUR PERIOD. THE DEPARTMENT OF ENERGY, MINING, AND
LAND RESOURCES (DEMLR) MONITORING FORM WILL BE USED TO DOCUMENT INSPECTIONS.
TIMBER MATS
DETI UTILIZES CONSTRUCTION TIMBER MATS TO PROVIDE ACCESS THROUGH AREAS SUCH AS WETLANDS AND WATERBODIES, SOME AGRICULTURAL FIELDS,
STEEP SLOPES, AND OTHER AREAS AS DETERMINED BY THE CONSTRUCTION SUPERVISOR. THIS PRACTICE REDUCES SOIL COMPACTION AND PROVIDES A STABLE
TRAVEL LANE FOR CONTRACTORS ALONG THE PROJECT ROW, THUS MINIMIZING LAND DISTURBANCE. THE MATERIALS USED TO CONSTRUCT THE TIMBER
MATTING WILL BE ABLE TO WITHSTAND THE ANTICIPATED LOADING OF THE CONSTRUCTION TRAFFIC. THE TIMBER MATS OVER WATERBODY CROSSINGS WILL
BE CLEANED AT THE END OF EACH DAY AND WHERE EXCESS ACCUMULATION OF SEDIMENT THE TIMBER MATS WILL BE CLEANED OFF THROUGHOUT EACH DAY.
THE USE OF CONSTRUCTION TIMBER MAY GENERALLY NOT CONSTITUTE SOIL DISTURBANCE OR A CHANGE IN HYDROLOGY. THEREFORE, THE INSTALLATION OF
TIMBER MAT ACCESS ROADS AND WORK PADS IS NOT CONSIDERED A REGULATED LAND-DISTURBING ACTIVITY.
TRENCH PLUGS/BREAKERS
TRENCH PLUGS WILL BE USED AT ALL STREAM, RIVER, WETLAND OR OTHER WATERBODY CROSSINGS, AS NECESSARY, TO PREVENT DIVERSION OF WATER INTO
UPLAND PORTIONS OF THE PIPELINE TRENCH AND TO KEEP ANY ACCUMULATED TRENCH WATER OUT OF THE WATERBODY. TOPSOIL WILL NOT BE USED TO FILL
SACKS FOR TRENCH PLUGS. TRENCH PLUGS WILL BE OF SUFFICIENT SIZE TO WITHSTAND UPSLOPE WATER PRESSURE.
·PERMANENT SACKS OF SUBSOIL OR SAND, POLYURETHANE FOAM, BENTONITE CLAY, OR POSSIBLY CEMENT (IN AREAS OF STEEP TERRAIN) BAGS INSTALLED
AROUND THE PIPE WILL REMAIN IN THE TRENCH TO PREVENT SUBSURFACE CHANNELING OF WATER ALONG THE TRENCH. TOPSOIL WILL NOT BE USED IN
TRENCH BREAKERS. TRENCH BREAKERS ARE NOT EMPLOYED IN TRENCHLESS PIPELINE CONSTRUCTION SUCH AS HORIZONTAL DIRECTIONAL DRILL (HDD) OR
FOR NON-LINEAR FACILITIES (E.G., COMPRESSOR STATIONS, M&R STATIONS).
·THE NEED FOR AND SPACING OF TRENCH BREAKERS WILL BE INDICATED ON THE CONSTRUCTION ALIGNMENT SHEETS. TRENCH BREAKERS WILL BE INSTALLED
AT THE SAME SPACING AS AND UPSLOPE OF PERMANENT SLOPE BREAKERS UNLESS DETERMINED OTHERWISE BY THE CERTIFYING PROFESSIONAL ENGINEER.
·IN AGRICULTURAL FIELDS AND RESIDENTIAL AREAS WHERE SLOPE BREAKERS ARE NOT TYPICALLY REQUIRED, TRENCH BREAKERS WILL BE INSTALLED AT THE
SAME SPACING AS IF PERMANENT SLOPE BREAKERS WERE REQUIRED. IN AGRICULTURAL LANDS, TRENCH BREAKERS WILL BE INSTALLED TO A DEPTH THAT
DOES NOT ENCROACH INTO THE TYPICAL PLOW ZONE.
PERMANENT TRENCH BREAKERS WILL BE INSTALLED AT THE BASE OF SLOPES GREATER THAN 5 PERCENT WHERE THE BASE OF THE SLOPE IS LESS THAN 50 FEET
FROM A WATERBODY OR WETLAND AND WHERE NEEDED TO AVOID DRAINING A WATERBODY OR WETLAND.
TURBIDITY CURTAINS
TURBIDITY CURTAINS WILL BE INSTALLED DOWNSTREAM OF THE STREAM CROSSING AS NECESSARY TO MINIMIZE SUSPENDED SOLIDS IN THE WATER.
·A TYPE I, II, OR III CURTAIN WILL BE SELECTED BASED ON THE FLOW CONDITION. IN MOST SITUATIONS, TURBIDITY CURTAINS SHOULD NOT BE INSTALLED
ACROSS CHANNEL FLOWS.
·TURBIDITY CURTAINS WILL EXTEND THE ENTIRE DEPTH OF THE WATERCOURSE WHEN THE WATERCOURSE IS NOT SUBJECT TO TIDAL ACTION AND/OR
SIGNIFICANT WIND AND WAVE FORCES.
·IN TIDAL AND/OR WIND AND WAVE ACTION SITUATIONS, THE CURTAIN WILL NEVER TOUCH THE BOTTOM. THE CURTAIN WILL HAVE A MINIMUM 1-FOOT GAP
BETWEEN THE WEIGHTED LOWER END OF THE SKIRT AND THE BOTTOM AT “MEAN” LOW WATER.
·IN TIDAL AND/OR WIND AND WAVE ACTION SITUATIONS, THE CURTAIN DEPTH WILL NOT BE LOWER THAN 10 TO12 FEET BELOW THE SURFACE.
·TURBIDITY CURTAINS WILL BE LOCATED PARALLEL TO THE DIRECTION OF FLOW OF A MOVING WATERBODY.
·A MINIMUM CONTINUOUS SPAN OF 50 FEET BETWEEN JOINTS AND A MAXIMUM SPAN OF 100 FEET BETWEEN JOINTS (ANCHOR OR STAKE LOCATIONS) IS A
GOOD RULE OF THUMB.
·THE ENDS OF THE CURTAIN SHOULD EXTEND WELL UP TO THE SHORELINE AND SECURED FIRMLY TO THE SHORELINE, PREFERABLY TO RIGID BODIES SUCH AS
TREES OR PILES.
·WHEN THERE IS SPECIFIC NEED TO EXTEND THE CURTAIN TO THE BOTTOM OF THE WATERCOURSE IN TIDAL OR MOVING WATER CONDITIONS, A HEAVY
WOVEN PERVIOUS FILTER FABRIC MAY BE SUBSTITUTED FOR THE NORMALLY RECOMMENDED IMPERVIOUS GEOTEXTILE.
·BARRIERS WILL BE OF BRIGHT COLORS TO ATTRACT THE ATTENTION OF NEARBY BOATERS.
·SEAMS IN THE FABRIC WILL BE EITHER VULCANIZED WELDED OR SEWN AND WILL DEVELOP THE FULL STRENGTH OF THE FABRIC.
·THE LOAD LINES WILL BE FABRICATED INTO THE BOTTOM OF ALL FLOATING CURTAINS. TYPE-II AND III MUST HAVE LOAD LINES ALSO FABRICATED INTO THE
TOP OF THE FABRIC.
·EXTERNAL ANCHORS MAY CONSIST OF WOODEN OR METAL STAKES FOR TYPE I CURTAINS; TYPE-II AND III SHOULD USE BOTTOM ANCHORS.
·ONCE THE CURTAIN IS NO LONGER REQUIRED, AS DETERMINED BY THE EI, THE CURTAIN AND RELATED COMPONENTS WILL BE REMOVED IN SUCH A MANNER
AS TO MINIMIZE TURBIDITY. SEDIMENT MAY BE REMOVED AND THE ORIGINAL DEPTH RESTORED. ANY SPOILS WILL BE TAKEN TO AN UPLAND AREA AND
STABILIZED.
TRENCH DEWATERING
DETI UTILIZES GEOTEXTILE BAGS FOR DEWATERING AND VELOCITY REDUCTION ON A MAJORITY OF PIPELINE CONSTRUCTION PROJECTS. THE PURPOSE,
DEFINITION, CONDITIONS OF APPLICATION AND PLANNING CONSIDERATIONS ARE IDENTICAL. DESIGN CRITERIA AND SPECIFICATIONS VARY BY DEWATERING
BAG MANUFACTURER; A VARIETY OF GEOTEXTILE DEWATERING BAG PRODUCTS ARE AVAILABLE ON THE MARKET. THE MANUFACTURERS' GUIDANCE ON THE
USE, DESIGN, SIZING, MAINTENANCE, AND APPLICATION OF THE GEOTEXTILE DEWATERING BAG WILL BE FOLLOWED.
·CONDUCT DEWATERING (ON OR OFF THE CONSTRUCTION ROW) IN SUCH A MANNER THAT DOES NOT CAUSE EROSION AND DOES NOT RESULT IN SILT-LADEN
WATER FLOWING INTO ANY WATERBODY, WETLAND, OR OFF-SITE PROPERTY.
·ELEVATE AND SCREEN THE INTAKE OF EACH HOSE USED TO WITHDRAW THE WATER FROM THE TRENCH TO MINIMIZE PUMPING OF DEPOSITED SEDIMENTS.
·A DEWATERING BAG MAY NOT BE NEEDED IF THERE IS A WELL-STABILIZED, VEGETATED AREA ON SITE TO WHICH WATER CAN BE DISCHARGED. THE AREA
MUST BE STABILIZED SO THAT IT CAN FILTER SEDIMENT AND AT THE SAME TIME WITHSTAND THE VELOCITY OF THE DISCHARGED WATER WITHOUT ERODING.
A MINIMUM FILTERING LENGTH OF 75 FEET MUST BE AVAILABLE IN ORDER FOR SUCH A METHOD TO BE FEASIBLE.
·REMOVE DEWATERING STRUCTURES AS SOON AS PRACTICABLE AFTER THE COMPLETION OF DEWATERING ACTIVITIES.
·REMOVE DEWATERING STRUCTURES AS SOON AS PRACTICABLE AFTER THE COMPLETION OF DEWATERING ACTIVITIES. IF SEDIMENT BUILD-UP PREVENTS THE
BAG FROM FUNCTIONING PROPERLY, OR THE BAG BECOMES HALF FULL OF SEDIMENT, DISCARD AND REPLACE WITH A NEW BAG.
WATERBARS (TEMPORARY/PERMANENT)
·TEMPORARY WATERBARS WILL BE INSTALLED PRIOR TO PIPELINE INSTALLATION.
·PERMANENT WATERBARS WILL BE INSTALLED AT THE COMPLETION OF PIPELINE INSTALLATION.
·WATERBARS WILL BE INSTALLED IN ACCORDANCE WITH NC EROSION AND SEDIMENT CONTROL SPECIFICATIONS.
STREAM BANK STABILIZATION AT PIPE COMPLETION
·EROSION CONTROL MATTING SHALL BE PLACED ON THE BANKS OF THE FLOWING STREAMS WHERE VEGETATION HAS BEEN REMOVED OR AS DIRECTED BY THE
EI.
·EROSION CONTROL MATTING SHALL MEET THE REQUIREMENTS SPECIFIED IN THE PLAN.
·STAPLES SHALL BE MADE OF AT LEAST 11 GAUGE WIRE, U-SHAPED WITH 6” LEGS AND A 1” CROWN. STAPLES SHALL BE DRIVEN INTO THE GROUND FOR THE
FULL EFFECT OF THE STAPLE LEGS. ALTERNATIVELY, 1” DIA. WOODEN PEGS 6” LONG AND BEVELED MAY BE USED TO SECURE MATTING.
·MATTING SHALL BE INSTALLED PER MANUFACTURERS SPECIFICATIONS OR AS STATED BELOW:
·EXTEND TOP OF BLANKET 2 FEET PAST THE UPPER EDGE OF THE HIGH WATER MARK. IF A SLOPE BREAKER IS PRESENT, ON THE APPROACH SLOPE, BEGIN THE
BLANKET ON THE UPHILL SIDE OF THE SLOPE BREAKER.
·INSTALL BLANKETS ACROSS THE SLOPE IN THE DIRECTION OF THE WATER FLOW.
·ANCHOR THE UPSTREAM EDGE OF THE BLANKET INTO THE SLOPE USING A 6” DEEP TRENCH, DOUBLE STAPLE EVERY 12” BEFORE BACKFILLING AND
COMPACTING TRENCH.
·OVERLAP THE EDGES OF PARALLEL BLANKETS A MINIMUM OF 6”. PLACE THE UPPER BLANKET OVER THE LOWER BLANKET (SHINGLE STYLE) AND STAPLE EVERY
12” ALONG THE LENGTH OF THE EDGE. WHEN BLANKETS ENDS ARE ADJOINED, PLACE THE UPSTREAM BLANKET OVER THE DOWNSTREAM BLANKET (SHINGLE
STYLE) AND STAPLE EVERY 12” ALONG THE LENGTH OF THE EDGE
·STAPLE DOWN THE CENTER OF THE BLANKET, THREE STAPLES IN EVERY SQUARE YARD.
·IN LIVESTOCK AREAS WHERE EROSION CONTROL MATTING IS APPLIED TO THE STREAMBANKS, FENCING WILL BE USED IF NECESSARY TO EXCLUDED LIVESTOCK,
WITH PERMISSION OF THE LANDOWNER.
·MONITOR WASHOUTS, STAPLE INTEGRITY OR MAT MOVEMENT, REPLACE OR REPAIR AS NECESSARY.
·INSTALLATION MAY BE USED AT THE DISCRETION OF THE EI AT SEVERELY SLOPING ROAD BANKS, BUT MAY ONLY BE INSTALLED A MAXIMUM OF ONE BLANKET
WIDTH.
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
ENERAL NOTES AND COMMENTS:SYM.DATE BY REVISION INFORMATION PROJECT/TASK APP.
--ISSUED FOR PERMITTINGJR03/09/170
APP. FOR CONST.:
SCALE:
APP. FOR BID:
CHECKED:
DRAWN:
DIR/FILE:
DISTRICT:
TITLE:
COUNTY:DWG. NO.GROUP REV.STATE:
925 White Oaks Blvd. Bridgeport, West Virginia 26330 / 681-842-8000
Atlantic Coast Pipeline, LLC
AS SHOWN
10/20/2017SR
10/20/2017CM
19 OF 9ACP\North Carolina\Details
EROSION AND SEDIMENT CONTROL DETAILS
ATLANTIC COAST PIPELINE
NC
SEAL
--ISSUED IN RESPONSE to NCDEQ COMMENTSEB08/01/171
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017CM09/21/172
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM SEPTEMBER 21, 2017)CM10/06/20173
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ACCESS ROADS
DETI HAS IDENTIFIED ROADS WHICH WILL BE USED TO PROVIDE ACCESS TO THE PROPOSED ACP PIPELINE ROW AND OTHER
FACILITIES DURING CONSTRUCTION AND OPERATION OF THE PROJECTS. IN SOME CASES, EXISTING ROADS WILL REQUIRE
IMPROVEMENT (SUCH AS GRADING, GRAVELLING, REPLACING CULVERTS, MINOR WIDENING, AND/OR CLEARING OF
OVERHEAD VEGETATION) TO SAFELY ACCOMMODATE CONSTRUCTION EQUIPMENT AND VEHICLES. DETI ACCESS ROAD
LOCATIONS ARE SHOWN ON THE CONSTRUCTION ALIGNMENT SHEETS. TRAFFIC MANAGEMENT PLANS HAVE BEEN
DEVELOPED FOR THE PROPOSED PROJECT AND WILL BE IMPLEMENTED AND FOLLOWED DURING CONSTRUCTION TO REDUCE
IMPACT TO TRAFFIC FLOW. IT IS ANTICIPATED THE PROPOSED PROJECT WILL NOT IMPACT ROADS OR TRAFFIC DURING THE
CONSTRUCTION AND OPERATION OF THE PROJECT.
A CONSTRUCTION ENTRANCE WILL BE CONSTRUCTED AT ANY POINT WHERE CONSTRUCTION EQUIPMENT LEAVES THE ROW
AND ENTERS A PAVED PUBLIC ROAD OR OTHER PAVED SURFACE. TYPICALLY, A CONSTRUCTION ENTRANCE IS COMPRISED OF
FILTER FABRIC OVERLAIN BY 6 INCHES OF COARSE AGGREGATE EXTENDING A MINIMUM OF 100 FEET FROM THE EDGE OF
THE PAVEMENT. THE AREA OF THE ENTRANCE MUST BE EXCAVATED 3-INCHES PRIOR TO LAYING THE FILTER FABRIC
UNDERLINER. THE ENTRANCE MUST EXTEND THE FULL WIDTH OF THE VEHICULAR INGRESS AND EGRESS AREA AND HAVE A
MINIMUM 18-FOOT WIDTH. CONVEYANCE OF SURFACE WATER THROUGH CULVERTS UNDER THE ENTRANCE WILL BE
PROVIDED, AS NECESSARY.
THE CONSTRUCTION ENTRANCE MUST FUNCTION TO REMOVE MUD FROM VEHICLES AND EQUIPMENT LEAVING THE ROW.
AS MUD ACCUMULATES ON THE ENTRANCE, CLEAN STONE MUST BE ADDED OR THE TIRE MATS LIFTED AND SHAKEN TO
REMOVE MUD. ANY MUD THAT IS CARRIED ONTO THE PAVEMENT MUST BE THOROUGHLY REMOVED BY THE END OF THE
DAY BY SHOVELING OR SWEEPING. THE MUD WILL BE RETURNED TO THE ROW. THE USE OF WATER TO REMOVE SEDIMENT
TRACKED ONTO ROADWAYS IS PERMITTED ONLY AFTER SEDIMENT IS REMOVED AS STATED ABOVE.
MAINTENANCE OF THE CONSTRUCTION ENTRANCE MAY REQUIRE PERIODIC TOP DRESSING WITH ADDITIONAL STONE AND
CLEANOUT OF ANY STRUCTURES USED TO TRAP SEDIMENT. ADDITIONALLY, THE CONSTRUCTION ENTRANCE MAY NEED TO
BE SHOVELED THEN SWEPT, FOLLOWED BY WASHING OF THE ENTRANCE TO REMOVE ANY SEDIMENT BUILD UP. IF ANY
INADVERTENTLY SEDIMENT TRACKING OCCURS ON THE PUBLIC ROADWAY, THE ROAD WILL BE CLEANED THOROUGHLY BY
THE END OF EACH DAY.
DETI HAS IDENTIFIED BOTH PRIVATE AND PUBLIC ROADS WHICH WILL BE USED TO PROVIDE ACCESS TO THE PROPOSED ACP
PIPELINE ROW AND OTHER FACILITIES DURING CONSTRUCTION AND OPERATION OF THE PROJECT. IN SOME CASES, EXISTING
ROADS WILL REQUIRE IMPROVEMENT (SUCH AS GRADING, GRAVELLING, REPLACING OR INSTALLING CULVERTS, MINOR
WIDENING, AND/OR CLEARING OF OVERHEAD VEGETATION) TO SAFELY ACCOMMODATE CONSTRUCTION EQUIPMENT AND
VEHICLES. THE FOLLOWING CONDITIONS APPLY TO THE USE OF ACCESS ROADS:
·CONSTRUCTION ENTRANCES WILL HAVE STONE ACCESS ENTRANCE AND EXIT DRIVES AND PARKING AREAS TO REDUCE THE
TRACKING OF SEDIMENT ONTO PUBLIC OR PRIVATE ROADS. A CONSTRUCTION ENTRANCE WILL BE CONSTRUCTED AT ANY
POINT WHERE CONSTRUCTION EQUIPMENT LEAVES THE ROW AND ENTERS A PAVED PUBLIC ROAD OR OTHER PAVED
SURFACE.
·DURING CONSTRUCTION AND RESTORATION ACTIVITIES, ACCESS TO THE ROW IS LIMITED TO THE USE OF NEW OR
EXISTING ACCESS ROADS IDENTIFIED ON THE CONSTRUCTION ALIGNMENT SHEETS.
·TO THE EXTENT POSSIBLE, ACCESS THROUGH WETLANDS WILL BE LIMITED TO THE CONSTRUCTION ROW AND THOSE
EXISTING ROADS REQUIRING NO MODIFICATION OR IMPROVEMENTS, OTHER THAN ROUTINE REPAIR, AND POSING NO
IMPACT ON THE WETLAND.
·THE CONSTRUCTION ROW MAY BE USED FOR ACCESS ACROSS WETLANDS WHEN THE WETLAND SOIL IS FIRM ENOUGH TO
AVOID RUTTING OR THE CONSTRUCTION ROW HAS BEEN APPROPRIATELY STABILIZED TO AVOID RUTTING (E.G., TIMBER
MATTING). HOWEVER, ACCESS IS NOT ALLOWED THROUGH WETLANDS THAT WOULD NOT OTHERWISE BE IMPACTED BY
THE PROJECT.
·IN WETLANDS THAT CANNOT BE APPROPRIATELY STABILIZED, ALL CONSTRUCTION EQUIPMENT OTHER THAN THAT NEEDED
TO INSTALL THE WETLAND CROSSING WILL USE ACCESS ROADS LOCATED IN UPLAND AREAS. WHERE ACCESS ROADS IN
UPLAND AREAS DO NOT PROVIDE REASONABLE ACCESS, LIMIT ALL OTHER CONSTRUCTION EQUIPMENT TO ONE PASS
THROUGH THE WETLAND USING THE CONSTRUCTION ROW.
·MAINTAIN SAFE AND ACCESSIBLE CONDITIONS AT ALL ROAD CROSSINGS AND ACCESS POINTS DURING CONSTRUCTION
AND RESTORATION. ACCESS ROAD MAINTENANCE THROUGH THE CONSTRUCTION SEQUENCE MAY INCLUDE GRADING
AND THE ADDITION OF GRAVEL OR STONE WHEN NECESSARY.
·MAINTAIN ACCESS ROADS IN A STABLE MANNER TO PREVENT OFF-ROW IMPACTS, INCLUDING IMPACTS TO ADJACENT
AND/OR NEARBY SENSITIVE RESOURCE AREAS, AND IMPLEMENT ALL APPROPRIATE ESC MEASURES FOR
CONSTRUCTION/IMPROVEMENT OF ACCESS ROADS.
·IF EROSION IS OBSERVED ADJACENT TO ACCESS ROADS, IMMEDIATELY REPAIR, STABILIZE, OR IMPLEMENT ADDITIONAL ESC
MEASURES. ADDITIONAL MEASURES INCLUDE SILT FENCE, CHECK DAMS, OR EROSION CONTROL FABRIC. THE EI WILL
IMPLEMENT THE APPROPRIATE ESC MEASURE BASED UPON OBSERVED SITE CONDITIONS.
·MINIMIZE THE USE OF TRACKED EQUIPMENT ON PUBLIC ROADWAYS AND IN ACCORDANCE WITH REQUIREMENTS OF THE
MANAGING AGENCY.
·REMOVE ANY SOIL OR GRAVEL SPILLED OR TRACKED ONTO ROADWAYS DAILY OR MORE FREQUENT AS NECESSARY TO
MAINTAIN SAFE ROAD CONDITIONS.
·REPAIR ANY DAMAGES TO ROADWAY SURFACES, SHOULDERS, AND BAR DITCHES.
·IF CRUSHED STONE/ROCK ACCESS PADS ARE USED IN RESIDENTIAL OR AGRICULTURAL AREAS, STONE WILL BE PLACED ON
SYNTHETIC, NONWOVEN GEOTEXTILE FABRIC TO FACILITATE REMOVAL AFTER CONSTRUCTION.
·ALL ACCESS ROADS ACROSS A WATERBODY MUST USE AN EQUIPMENT BRIDGE.
·FOR ACCESS THROUGH A SATURATED WETLAND, USE TIMBER MATS OR AN EQUIVALENT UNLESS OTHERWISE AUTHORIZED
BY AGENCY PERMITS.
·LIMIT CONSTRUCTION EQUIPMENT OPERATING IN WETLAND AREAS TO THAT NEEDED TO CLEAR THE ROW, DIG THE
TRENCH, FABRICATE AND INSTALL THE PIPELINE, BACKFILL THE TRENCH, AND RESTORE THE CONSTRUCTION ROW. ALL
OTHER CONSTRUCTION EQUIPMENT WILL USE ACCESS ROADS LOCATED IN UPLAND AREAS TO THE MAXIMUM EXTENT
PRACTICAL.
·ROADS WILL BE SURFACED WITH STONE OR ANOTHER SUITABLE MATERIAL TO PROVIDE A NON-ERODIBLE RUNNING
SURFACE.
·CUT-BANKS AND FILL-SLOPES WILL BE STABILIZED AS SOON AS FEASIBLE TO A NON-ERODIBLE CONDITION USING
VEGETATION, ROCK, GEOTEXTILE MATERIAL, OR OTHER SUITABLE MATERIAL.
·SILT FENCE OR STONE OUTLET PROTECTION WILL BE CONSTRUCTED AT OUTLETS OF DRAINAGE STRUCTURES.
·WHEN ACCESS ROADS INTERSECT PUBLIC HIGHWAYS, THE CONTRACTOR WILL USE A COMBINATION OF GEOTEXTILE AND
STONE (TEMPORARY STONE CONSTRUCTION ENTRANCE) TO HELP KEEP MUD OFF HIGHWAY ENTRANCES. WHERE
SEDIMENT IS TRANSPORTED ONTO A PAVED OR PUBLIC ROAD SURFACE, THE ROAD SURFACE WILL BE CLEANED
THOROUGHLY AT THE END OF EACH DAY. SEDIMENT WILL BE REMOVED FROM THE ROADS BY SHOVELING OR SWEEPING
AND TRANSPORTED TO A SEDIMENT CONTROL DISPOSAL AREA. STREET WASHING WILL BE ALLOWED ONLY AFTER
SEDIMENT IS REMOVED IN THIS MANNER.
·ROADS WILL BE MAINTAINED SO THAT WATER CAN FLOW FREELY FROM THE ROAD SURFACE.
·TEMPORARY ACCESS ROADS WILL FOLLOW EXISTING CONTOURS AS MUCH AS POSSIBLE
--ISSUED IN RESPONSE to NCDEQ COMMENTS RECIEVED ON SEPTEMBER 15, 2017 (SUPERCEEDS REVISIONS FROM OCTOBER 06, 2017)CM10/20/20174
HORIZONTAL DIRECTIONAL DRILL (HDD)
THE HDD METHOD IS A PROCESS THAT ALLOWS FOR TRENCHLESS CONSTRUCTION BY DRILLING A HOLE BENEATH A SURFACE
FEATURE, SUCH AS A WATERBODY OR OTHER UNIQUE RESOURCE, AND INSTALLING A PREFABRICATED SEGMENT OF PIPELINE
THROUGH THE HOLE. THE METHOD AVOIDS DISTURBANCE TO THE SURFACE OF THE ROW BETWEEN THE ENTRY AND EXIT POINTS
OF THE DRILL. THE METHOD IS SOMETIMES USED TO INSTALL PIPELINES UNDERNEATH SENSITIVE RESOURCES OR AREAS THAT
PRESENT DIFFICULTIES ASSOCIATED WITH CONSTRUCTION OR ACCESS USING TYPICAL INSTALLATION METHODS. HDDS CAN
PROVIDE CERTAIN ADVANTAGES OVER TYPICAL CONSTRUCTION METHODS, SUCH AS AVOIDANCE OF SURFACE DISTURBANCE,
RIPARIAN TREE CLEARING, OR IN-STREAM CONSTRUCTION.
FOR EACH HDD CROSSING, ELECTRIC GRID GUIDE WIRES WILL BE LAID BY HAND ON THE GROUND ALONG THE PIPELINE
CENTERLINE TO CREATE AN ELECTROMAGNETIC SENSOR GRID. THE GRID WILL BE USED BY THE HDD OPERATOR TO STEER THE
DRILL HEAD DURING DRILLING. NO GROUND OR SURFACE DISTURBING ACTIVITIES WILL BE REQUIRED FOR INSTALLATION OF THE
GUIDE WIRES. IN THICKLY VEGETATED AREAS, HOWEVER, A SMALL PATHWAY MEASURING APPROXIMATELY 2 TO 3 FEET IN
WIDTH MAY NEED TO BE CUT WITH HAND TOOLS TO CREATE A PATH FOR THE WIRES.
TO COMPLETE EACH HDD, A DRILL RIG WILL BE PLACED ON THE ENTRY SIDE OF THE CROSSING AND A SMALL-DIAMETER PILOT
HOLE WILL BE DRILLED ALONG A PREDETERMINED PATH BENEATH THE WATERBODY USING A POWERED DRILL BIT. AS DRILLING
PROGRESSES, ADDITIONAL SEGMENTS OF DRILL PIPE WILL BE INSERTED INTO THE PILOT HOLE TO EXTEND THE LENGTH OF THE
DRILL. THE DRILL BIT WILL BE STEERED AND MONITORED THROUGHOUT THE PROCESS TO MAINTAIN THE DESIGNATED PATH OF
THE PILOT HOLE. ONCE THE PILOT HOLE IS COMPLETE, THE ELECTRIC SENSOR GRID WILL BE REMOVED AND THE HOLE WILL BE
ENLARGED TO ACCEPT THE PIPELINE.
TO ENLARGE THE PILOT HOLE, A LARGER REAMING TOOL WILL BE ATTACHED TO THE END OF THE DRILL ON THE EXIT SIDE OF THE
HOLE. THE REAMER WILL BE DRAWN BACK THROUGH THE PILOT HOLE TO THE DRILL RIG ON THE ENTRY SIDE OF THE HOLE.
DRILL PIPE SECTIONS WILL BE ADDED TO THE REAR OF THE REAMER AS IT PROGRESSES TOWARD THE RIG, ALLOWING A STRING
OF DRILL PIPE TO REMAIN IN THE HOLE AT ALL TIMES. SEVERAL PASSES WITH PROGRESSIVELY LARGER REAMING TOOLS WILL BE
REQUIRED TO ENLARGE THE HOLE TO A SUFFICIENT DIAMETER TO ACCOMMODATE THE PIPELINE. THE FINAL HOLE WILL BE
APPROXIMATELY 12 INCHES LARGER THAN THE PIPELINE TO BE INSTALLED.
THROUGHOUT THE DRILLING PROCESS, A FLUID MIXTURE CONSISTING OF WATER AND BENTONITE CLAY (A NATURALLY
OCCURRING MINERAL) WILL BE PUMPED INTO THE DRILL HOLE TO LUBRICATE THE BIT, TRANSPORT CUTTINGS TO THE SURFACE,
AND MAINTAIN THE INTEGRITY OF THE HOLE. WATER FOR THE MIXTURE WILL BE PUMPED FROM THE WATERBODY TO THE DRILL
SITE THROUGH A HOSE OR TEMPORARY NETWORK OF IRRIGATION-TYPE PIPING OR TRUCKED IN FROM ANOTHER SOURCE. THE
PUMP INTAKE WILL BE APPROPRIATELY SCREENED TO PREVENT ENTRAINMENT OF AQUATIC SPECIES. SMALL PITS WILL BE DUG
AT OR NEAR THE ENTRY AND EXIT POINTS FOR THE HDD TO TEMPORARILY STORE THE DRILLING FLUID AND CUTTINGS. THE FLUID
AND CUTTINGS WILL BE PUMPED FROM THE PITS TO AN ON-SITE RECYCLING UNIT WHERE THE FLUID WILL BE PROCESSED FOR
REUSE.
THE PIPELINE SEGMENT (ALSO CALLED A PULL SECTION) TO BE INSTALLED BENEATH THE SURFACE FEATURE WILL BE FABRICATED
ON THE ROW OR IN THE ADDITIONAL TEMPORARY WORK SPACE (ATWS) ON THE EXIT SIDE OF THE CROSSING WHILE THE DRILL
HOLE IS REAMED TO SIZE. THE PULL SECTION WILL BE INSPECTED AND HYDROSTATICALLY TESTED PRIOR TO INSTALLATION.
AS THE PIPELINE IS BEING INSTALLED, EXCESS DRILLING FLUID WILL BE COLLECTED AND INCORPORATED INTO THE SOIL IN AN
UPLAND AREA OR DISPOSED OF AT AN APPROPRIATE FACILITY. IF WATER IS LEFT OVER FROM THE DRILLING PROCESS, IT WILL BE
DISCHARGED INTO A WELL-VEGETATED UPLAND AREA OR AN ENERGY DISSIPATION/SEDIMENT FILTRATION DEVICE, SUCH AS A
GEOTEXTILE FILTER BAG, IN A MANNER THAT DOES NOT AFFECT FLOWING STREAMS OR OFF-SITE PROPERTY.
IF AN HDD CROSSING IS SUCCESSFUL, THERE ARE LITTLE TO NO IMPACTS ON THE SURFACE FEATURE BEING CROSSED. IF A
NATURAL FRACTURE OR WEAK AREA IN THE GROUND IS ENCOUNTERED DURING DRILLING, HOWEVER, AN INADVERTENT RETURN
OF DRILLING FLUID TO THE ENVIRONMENT COULD OCCUR. SUBSTRATE CONSISTING OF UNCONSOLIDATED GRAVEL, COARSE
SAND, OR FRACTURED BEDROCK COULD PRESENT CIRCUMSTANCES THAT INCREASE THE LIKELIHOOD OF AN INADVERTENT
RETURN. DEPENDING ON THE ORIENTATION OF THE NATURAL FRACTURE OR SUBSTRATE, THE DRILLING FLUID MAY MOVE
LATERALLY OR VERTICALLY FROM THE DRILL HOLE. IF THE DRILLING FLUID MOVES LATERALLY, THE RELEASE MAY NOT BE
EVIDENT ON THE GROUND. FOR AN INADVERTENT RETURN TO BE EVIDENT ON THE SURFACE, THERE MUST BE A PREFERENTIAL
PATHWAY EXTENDING VERTICALLY FROM THE DRILL HOLE TO THE SURFACE OF THE GROUND. THE VOLUME OF FLUID RELEASED
IN AN INADVERTENT RETURN IS DEPENDENT ON A NUMBER OF FACTORS, INCLUDING THE SIZE OF THE PATHWAY, THE
PERMEABILITY OF THE GEOLOGIC MATERIAL, THE VISCOSITY OF THE FLUID, AND THE PRESSURE OF THE HYDRAULIC DRILLING
SYSTEM.
DETI'S HORIZONTAL DIRECTIONAL DRILL FLUID MONITORING, OPERATIONS, AND CONTINGENCY PLAN (HDD PLAN), IDENTIFIES
TYPICAL CONTINGENCY MEASURES TO BE IMPLEMENTED IN THE EVENT OF A DRILL FAILURE, SUCH AS DRILLING ALONG A NEW
PATH, ABANDONING AND SEALING THE DRILL HOLE, AND IMPLEMENTING AN ALTERNATE CROSSING METHOD, AND DESCRIBES
THE PROCEDURES TO BE FOLLOWED IN THE EVENT OF AN INADVERTENT RETURN OF DRILLING FLUID. IF A RELEASE OCCURS ON
LAND, INCLUDING WITHIN A WETLAND, A SMALL PIT WILL BE EXCAVATED AT THE RELEASE SITE TO CONTAIN THE SPREAD OF THE
FLUID, AND A PUMP WILL BE USED TO TRANSFER THE FLUID FROM THE PIT INTO A CONTAINMENT VESSEL. IF AN INADVERTENT
RETURN OCCURS IN A WATERBODY, IT WILL BE MORE DIFFICULT TO CONTAIN BECAUSE THE FLUID WILL BE DISPERSED INTO THE
WATER AND CARRIED DOWNSTREAM. IN THIS SITUATION, AN ATTEMPT WILL BE MADE TO PLUG THE FLOW PATH BY ADDING
THICKENING AGENTS TO THE DRILLING FLUID, SUCH AS ADDITIONAL BENTONITE, COTTONSEED HULLS, OR OTHER
NON-HAZARDOUS MATERIALS. DETI WILL CONSULT WITH AND OBTAIN PERMISSION FROM THE APPROPRIATE STATE
REGULATORY AGENCIES REGARDING THE USE OF ADDITIVES DURING THE HDD (OR CONVENTIONAL BORE) PROCESS, AND
CONFIRM THAT ADDITIVES WILL NOT VIOLATE WATER QUALITY STANDARDS.