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HomeMy WebLinkAboutResponse to commentsGreen Seal Environmental, LLC ENGINEERING | ENVIRONMENTAL | LAND SURVEY 114 State Road, Bldg. B, Sagamore Beach, MA 02562 T: 508.888.6034 F: 508.888.1506 www.gseenv.com October 22, 2024 Mr. Edwin Hoopes, Chairman Yarmouth Conservation Commission C/O Brittany DiRienzo, Conservation Administrator 1146 Route 28 Yarmouth, MA 02664 RE: Response to Engineering Review of Stormwater Management Permit Application 228 Route 28 Mr. Hoopes and Commissioners, Green Seal Environmental, LLC (GSE) has prepared this letter in response to the Engineering Review letter dated October 8, 2024 by Weston & Sampson. For the purposes of these response, the original comment is in italics, and our response is in bold. Where Weston & Sampson indicated that a reviewed item meets the standard or otherwise needs no comment, that item is not included in this response. 2.05(2) Good Housekeeping Procedures We have noted the following in our review related to this standard: • This standard requires provisions for car washing to occur “on lawns or pervious areas using biodegradable and phosphate free detergent.” This is not discussed in the O&M plan. We recommend that the engineer address the item noted above. Both the Construction and Long-Term Pollution Prevention Plans have been revised to address this comment. There will be no car or other vehicle washing on the property. A car wash business is located 2 miles from the property where residents can wash their vehicles offsite. The contractor will wash their vehicles offsite as well. 2.05(3) Stormwater Management Systems Design We have noted the following in our review related to this standard: • This standard requires the use of NOAA Atlas 14 rainfall data for stormwater modeling, or alternative datasets at the discretion of the commission. It does not appear that the Engineer has used NOAA Atlas 14 data in the analysis. We recommend the Engineer revise the calculations to reflect the NOAA Atlas 14 data. It is our understanding that NOAA Atlas 14 rainfall distributions for Northeastern states is referred to as “NOAA 10” in the hydrology software used, HydroCAD. We have used this rainfall data in our analysis. A partial print of HydroCAD’s Rainfall Tables is attached that documents this relationship. Green Seal Environmental, LLC ENGINEERING | ENVIRONMENTAL | LAND SURVEY 114 State Road, Bldg. B, Sagamore Beach, MA 02562 T: 508.888.6034 F: 508.888.1506 www.gseenv.com 2.06(2) Stormwater Pollution Prevention Plan (SWPPP) Submission The project will disturb more than one acre of land, therefore it will be subject to coverage under the NPDES Construction General Permit. Under this section, the applicant is required to submit a complete copy of the SWPPP for the project. We recommend that the applicant submit a copy of the SWPPP. The commission may wish to consider adopting a condition of approval requiring the submission of the SWPPP prior to any ground disturbing activity since the contractor will ultimately be the party responsible for the SWPPP. The Applicant respectfully requests that the submittal of the SWPPP be a condition of approval before any ground disturbance begins. As stated, this document is tied in with the site contractor, who will be selected shortly before construction. 2.06(4) Erosion and Sedimentation Control Plan Content We have noted the following in our review related to this standard: • This standard calls for a description of how fueling of vehicles/equipment and fuel/chemical storage will be conducted. This was not found on the plan. The engineer should address this. • This standard calls for the identification of “trees with a caliper twelve (12) inches diameter breast height or larger, noting specimen trees and forest communities.” This was not found in the submitted materials. We recommend that the applicant either clarify whether this is applicable, submit the applicable information, or request a waiver from the commission if that is the applicant’s intent. • A description of procedures for construction vehicle fueling, temporary chemical storage and construction vehicle washing/washout was not found. The engineer should address this. Descriptions of fueling, chemical storage, construction vehicle washing, and washout (typically concrete) have been added to the Construction Pollution Prevention Plan. The site has little tree cover, and most of the trees are smaller incipient growth in the wetland buffer zone where there has been extensive disturbance in the recent past. Some more substantial trees are located along the abutting sidelines and overlap the property lines. A number of these trees have been flagged for preservation and approach the 12-inch caliper criteria. These are shown on the Site Plan. 2.07(1) Stand-alone O&M plan requirements We have noted the following in our review related to this standard: • The O&M plan is currently formatted as a chapter within the stormwater report. The commission may wish to advise whether it is desirable to have it separated as a “stand-alone” report. In our response with have attached revised versions of the Construction and Long-Term Pollution Prevention plans, effectively making them stand-alone reports if the Commission wants them separate. Green Seal Environmental, LLC ENGINEERING | ENVIRONMENTAL | LAND SURVEY 114 State Road, Bldg. B, Sagamore Beach, MA 02562 T: 508.888.6034 F: 508.888.1506 www.gseenv.com Massachusetts Stormwater Handbook Compliance Review Standard 8: Construction Period Pollution Prevention and Erosion/Sedimentation Control The engineer has provided an erosion and sedimentation control plan. Since the site will disturb more than one acre, a Stormwater Pollution Prevention Plan (SWPPP) will be required to obtain coverage under the NPDES Construction General Permit. The town’s standards related to this are more stringent. Provided that the applicant addresses the preceding comments, this standard from the Handbook will be satisfied. Standard 9: Operations & Maintenance Plan A long-term pollution prevention and operations and maintenance plan have been provided. Further comments that related to this standard are provided above under the analysis of the town’s similar standard. Provided that those comments are addressed, this standard from the Handbook will be satisfied. We believe that these comments have been addressed in the Construction and Long-term documents. Standard 10: Illicit Discharge Compliance Statement The Engineer has stated that an Illicit Discharge Compliance Statement will be signed by the responsible party prior to the start of construction. The Commission may wish to include this as a condition of approval for the project. The property owner has provided the attached Illicit Discharge Statement as required. General Comments: • Trench drains were proposed on the grading and drainage plan. The Engineer should provide a detail of the proposed trench drains. A typical detail of the trench drains proposed has been added to the construction detail sheet (Sheet D- 4) attached. Sincerely, Green Seal Environmental, LLC Jack O’Leary PG CPESC Attachments as noted