HomeMy WebLinkAboutResponses to engineering comments (07-16-2025)
112 State Road / N. Dartmouth MA 02747
Tel: (508) 858-5040 / Fax: (508) 858-5041 / www.choubahgroup.com
July 16, 2025
Ms. Brittany DiRienzo, Conservation Administrator
Yarmouth Conservation Commission
1146 Route 28
Yarmouth, MA 02664
Re: Proposed Gasoline filling station with
convenience store, a drive thru & residential apartments
1272-1276 & 1282 Route 28
Yarmouth, MA 02664
Applicant/Owner:
Ekaterina & Family, LLC
1282 Route 28
Yarmouth, MA 02664
CEG# 20-586
Dear Ms. DiRienzo,
Attached please find revised Plans and revised Stormwater Report and supporting documents for
the proposed gasoline filling station and residential apartments at 1272 -1276 & 1282 Route 28. Revised
Plans and supporting documents are to address Peer Review comments dated June 27, 2025, by
Comprehensive Environmental Incorporated (responses to comments are in Bold italic below each
comment).
Stormwater Comments:
1. The development proposes three subsurface infiltration systems designed to completely infiltrate
runoff generated from the 100-year storm event, however, the following assessments must be performed
to ensure the system will function properly:
a.
Test pit must be performed at the location and soil layer of all proposed infiltration systems to confirm
infiltration capacity. A test pit was not performed at the location of System #1 or #3.
The systems locations have been adjusted and moved as close as is practical to the location of the test
pits for systems 1 and 2. Proposed System 3 is in proximity of the existing fueling pad and fuel tanks.
It is not feasible to perform a test pits as the gasoline filling station is still operating. The test pits for
this system is approximately 25’ feet from the system.
A total of 7 test pits were performed within this small site, soil profile and infiltration rates were
consistent for all test pits across the board in all locations. We do not anticipate any changes to
ground elevation or soil infiltration rates. In addition a note has been added to the drainage plans for
the design engineer to inspect bottom of all infiltration systems during construction and to confirm
groundwater elevation and soil infiltration rates are consistent with design values and to make any
adjustment to the systems if needed.
b.
A mounding analysis is required when the vertical separation from the bottom of an exfiltration system
to estimated seasonal high groundwater is less than four (4) feet and the recharge system is proposed to
attenuate the peak discharge from a 10-year or higher 24-hour storm (e.g., 10-year, 25-year, 50-year, or
100-year 24-hour storm). The average separation to estimated seasonal high groundwater is just below 4
feet (El. 16.11) based on the test pits provided. The bottom of the stormwater chambers for System #1,
2, & 3 is at El. 20.00.
Bottom of all infiltration systems were raised to elevation 20.15 to provide 4 feet of separation from
groundwater elevation at 16.11. A mounding analysis is no longer needed (refer to revised plans and
stormwater report).
c. Note, per the Yarmouth Stormwater Regulations, the estimated seasonal high groundwater elevation
must be adjusted using the Cape Cod Commission adjustment method (Technical Bulletin 92- 001, as
amended) in areas to be used for stormwater infiltration.
Mottles was used to establish high groundwater elevation (EL. 16.11) and therefore no adjustment is
needed per the Cape Cod Commission adjustment method (refer to test pits data).
2. Per the Yarmouth Stormwater Regulations, redevelopment projects must achieve 50% total
phosphorus (TP) and 30% total nitrogen (TN) removal in addition to 80% TSS removal from all
impervious area under post-construction conditions. Please document how the project meets TP and TN
removal requirements in the Stormwater Report.
A 100% removal rate for both Total Phosphorus and Total Nitrogen was targeted in the design of the
infiltration systems on site (refer to Appendix “C” of the revised Stormwater Report). This is in
addition to the pavement sweeping, leaf’s removal and cleaning of the catch basins to be performed
twice per year.
3. Note the following information on the erosion and sediment control plan:
a. For the subsurface infiltration systems, accomplish any required excavation with equipment placed
just outside of this area. If the size of the area intended for exfiltration is too large to accommodate this
approach, use trucks with low pressure tires to minimize compaction. Keep the area above and
immediately surrounding the subsurface structure roped off to all construction vehicles until the final
cover is installed (either paving or landscaping).
A note to the Erosion and Sediment Control Plan & Drainage Plan has been added as suggested
(refer to revised plans).
b. Per the Yarmouth Stormwater Regulations, a description of vehicles and equipment fueling
procedures, including how fuels and other vehicle maintenance substances will be stored and handled
during construction.
A fueling detail of construction equipment has been added to the Erosion Control Details and Notes
Sheet #2 as suggested (refer to revised plans).
4. Note the following information in the O&M plan.
a. The proposed Grading and Drainage Plan does not include Infiltration Ditches. If infiltration ditches
are not proposed, the O&M plan should remove this reference in the inspection and maintenance
procedures.
This has been removed as suggested (refer to revised O&M Plan).
b. Restrictions on the application of fertilizers are required per Section 2.05(2)d of the Yarmouth
Stormwater Regulations.
Notes have been added to the O&M Plan as suggested (refer to revised O&M Plan).
We kindly ask that you contact this office if you have any questions or need additional information.
Sincerely,
Choubah Engineering Group, P.C.
Halim A. Choubah, P.E.
Halim A. Choubah, P.E., President
Cc: File, Barbara Hanson, Jay Imad