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Home My WebLink About25009_East Side Truck Svc_Utility Trench Dam Install Rpt_20230718AO Atlantic Shores Environmental Services, Ltd. July 18, 2023 Ms. Stephanie Graham NCDEQ 217 West Jones Street Raleigh, North Carolina 27603 Reference: Documentation of Stormwater Vapor Dam Installation Eastside Trucking Fayetteville, North Carolina Brownfield Project No. 25009-21-026 Dear Ms. Graham, The purpose of this letter is to document the installation of two vapor dams for the stormwater conduits east of catch basin DI-(B3). This mitigation system was mixed and installed in accordance with the attached drawing prepared by ECS dated June 28, 2023. Cheryl Moody, PE of Atlantic Shores Environmental (ASE) observed the installation of the two barriers on June 29, 2023 (See attached photographs). South Atlantic Environmental Drilling and Construction Company preformed the work. The concrete slurry was placed into the forms that were constructed around the pipes. The slurry was placed in lifts and agitated manually to ensure all voids were filled before placing another lift. If there are questions regarding this submittal, or there is a need for further information, please contact us at 910-371-5980. Respectfully submitted, ATLANTIC SHORES ENVIRONMENTAL SERVICES, LTD. iCARo�%', Q'•''ES•Sj'••�i Cheryl J. Moody, PE ; =:'oF 0 9 ; Ryan Kramer Principal Engineer - oSEoos r = Sr. Project Manager Enclosures: Photographs Drawing 175-1 Venture Drive, Belville NC 28451 P:(910)371-5980 -A Woman Owned Business - License No. C-4762 Documentation of Stormwater Vapor Dam Installation Eastside Trucking Fayetteville, North Carolina Brownfield Project No. 25009-21-026 Photograph 1 — View of southern vapor dam form Photograph 2 — View of southern vapor dam installation July 18, 2023 Documentation of Stormwater Vapor Dam Installation Eastside Trucking Fayetteville, North Carolina Brownfield Project No. 25009-21-026 July 18, 2023 Photograph 3 — View of southern vapor dam installation Photograph 4 — View of northern vapor dam form V 2 Documentation of Stormwater Vapor Dam Installation Eastside Trucking Fayetteville, North Carolina Brownfield Project No. 25009-21-026 Photograph 5 — View of northern vapor dam installation Photograph 6 — View of northern vapor dam installation July 18, 2023 Utility Trench Vapor Mitigation Design Spring Hill Suites 520 Judson Church Road Fayetteville, Cumberland County, NC 28312 =:a� SEAL ,' q� G I N g; •' r��trnS C j I s �ss� DATE: June 28, 2023 PREPARED 9Y- ECS Southeast, LLP 5260 Greens Dairy Road - Raleigh, NC 27616 Phone: 919-861-9910 ecs southeast 6260 Greens Dairy Rd. Raleigh, NC 27616 NC Registered Engineering Firm F-1078 DRAWING LIST PAGE(S) DESCRIPTION 0 COVER 1 NOTES AND DETAIL 2 SITE PLAN 1. APPLICABILITY 1.1.GENERAL 1.1.1. The purpose of this Utility Trench Vapor Mitigation Design at the proposed development is to manage vapor gas migrating through the utility trench. 1.1.2. All wall and building systems shown are for clarification purposes only. These plans are only for layout and construction of the Utility Trench Vapor Mitigation Design. Civil layouts, structural details, and other information pertaining to the design was referenced from the available plans supplied to ECS Southeast. The design may be modified by ECS, as pCE IMPACTED AREA - SPRINGHILL SUITES necessary, to accommodate construction restraints. 1.2. SYSTEM COMPONENTS 1.2.1. The Utility Trench Vapor Mitigation Design construction shall consist of, but not be limited to, the following: 1.2.1.1. A trench dam consisting of a bentonite cement slurry shall be poured in place in the utility trench dam. The trench dam shall have a minimum length of 36 inches or twice the width of the trench. The cross section of the utility trench shall be backfilled to provide a minimum of 12 inches of trench dam material around the utility pipe. 1.2.1.2. The bentonite cement slurry shall consist of a minimum 4% Type II Portland cement and a minimum 2% powdered bentonite. The remaining mixture shall consist of soil, sand, and/or aggregate. The mixture shall include enough water to turn this mixture into a pourable slurry. The mixture shall include a water -reducing admixture which meets ASTM C494 (MasterPozzolith® 700) and an air -entraining admixture which meets ASTM C260 (MasterAir®AE 200). 1.2.1.3. The bentonite shall me mixed with water to fully hydrate prior to mixing with the cement. 1.3. SUBMITTALS 1.3.1. Information about the products shall be submitted to ECS for approval before they are installed. 1 A.INSPECTIONS AND TESTING 1.4.1. Construction Phase 1.4.0.1. Inspections shall be conducted under the direct supervision of a North Carolina licensed Professional Engineer to verify compliance with this design and to determine if the sealed utility barrier has been constructed between soil gas from the VOC impacted side of the utility trench to the Springhill Suites side of the utility trench. Inspections shall be conducted during the following: 1.4.0.1.1. During placement of trench dam material. 1.4.0.1.2. During placement of backfill material on either side and over the top of the trench dam. 1.5. STANDARD OF CARE AND LIMITATIONS 1.5.1 ECS's services will be performed in a manner consistent with generally accepted practices of the profession undertaken in similar designs in the same geographical area during the same time period. Please note that ECS does not warrant the work of third parties supplying information used in the preparation of the vapor mitigation system. These services were performed in accordance with the scope of work agreed with you, our client, as reflected in our proposal. ECS Southeast, LLP '`�• ° gx�3 5260 Greens Dairy Road Raleigh, NC 27616 Phone:919-861-9910 NC Registered Engineering Firm F-1078 )NC RETE STORM SEWER Plf ASPHALT GRAVEL SOIL BACKFILL ZONE OF BENTONITE CEMENT SLURRY (4%TYPE II PORTLAND CEMENT & 2% POWDERED BENTONITE) SEAL AROUND PENETRATION PIPE BEDDING MATERIAL BY OTHERS NOTES: 1. TRENCH DAM SHALL HAVE A MINIMUM LENGTH OF 36 INCHES OR TWICE THE WIDTH OF THE UTILITY TRENCH. 2. A MINIMUM OF 12 INCHES OF TRENCH DAM MATERIAL SHALL SURROUND THE UTILITY PIPE. AA SECTION ALONG STORM WATER 1 PIPING TRENCH "Vim Legend ICAN LLC. ■ Soil Gas Sample Point T, -Groundwater Monitoring Well • - Soil Sample Location Red Text Indicates Exceedance for Groundwater Green Text indicates Exceedance for Soil Vapor , "'II I f,,"" .��•`t-SH cn F?0(r . p •Qgssro-�L _ SEAL ry= 3 Y x$ ❑ 1G II • � - DROP INLET I $� • •- , •—STORM SEWER PIPE ND DROP INLET `STORM SEWER PIPE----- 10 - BENTONI I L CEMLNT SLURRY I RENC� f A BENTONITE CEMENTSLURRY TRENCH DAM PCE 5 3 /L� v 1 ND A DROP INLET PCE 21.7 µg/L PCE14.6 µg/ w 1 02 Ji STORM SEWER PIPE 15' $ P 19µg/L NDI. pPPROX' irrs� DROP INLET SG-51T1-55 (3.5') ND .70 µg/m3 �PC .4µg&�'❑ 7Q PWC 2Q - main eaE STORM SEWER PIPE Stormwaler maintenance y access easement f ;1 `20' WAT° R. 5 �. _ .,. 4EE❑aapOK 2�9ls' ORf DRABASIN. InrpGgSEM EA --.-._...- ., . 1rf�.� r -- f 287.2a371,5-4 n N ^- .. { .... .. ECS Southeast, LLP 5260 Greens Dairy Road Raleigh, NC 27616 Phone:919-861-9910 INC Registered Engineering Firm F-1078 Scale o�s� 3O 1 inch =30 R.