HomeMy WebLinkAboutQuestions for DPW - Dewatering projectQuestions for DPW regarding the dewatering project at 45 Mitchells Way
• Provide a new delineation plan (aerial photo with delineation). The plan most recently supplied
last Thursday is ok, just put on the plan the name of the delineator and date of delineation, have
one of the engineers stamp the photo plan, and put a specific date on the plan (not just September
2025).
• Please submit, in written form, the alternatives analysis presented at the hearing.
Further Information Requested:
Assuming the discharged water will have some level PFAS and that Aunt Bettys also has some level, will
the impact of discharging increase potential harm to abutters?
Why was this location chosen to place the pump station? Is there a reasonable alternative?
Will the amount of water needed to be discharged lessen as the depth of the whole decreases? Please
provide a explanation with graph and figures showing why the pumping rate would diminish after the
initial two-week drawdown.
Is Aunt Betty’s Pond located within a FEMA-designated flood zone?
Please provide information from Mass DEP or an independent expert regarding the regulatory status
and/or prohibitions for, and ecological effects of discharging PFAS laden water to a wetland buffer.
For purposes of reducing the volume of pumped water, will DPW use a metal or vinyl sleeve in a manner
similar to a coffer dam when excavating and pumping water from the vertical shaft? If not, why is that
not a viable option?
What was the proposed work schedule (e.g., five days/week, one 8 or 10 hr shift) for this pumphouse
project? If only 5 days/week or less than about 10 hrs/day, can the work week and work day be
extended?
What is the estimated percentage of the settled “sediment free” pumped water that will be discharged into
the ground via the sedimentation basin? If not 100%, then what percentage of that water is likely to spill
out and over the top of the sediment basin, with resulting overflow over the vegetated buffer?
Where exactly is the C-5 monitoring well referenced by Mr. Cambareri? Please show on the monitoring
figure.
Where was the discharge site for the dewatering projects at Phinney’s Lane and Main Street Hyannis?
What was their proximity to wetlands? Was a similar sediment tank and basin used at those sites? Did
the pumped discharge at those sites overflow from the sedimentation basins or was all the water infiltrated
within those basins?
What happens if you pump at 900 gpm for the first week and don’t achieve the desired groundwater
level?
Would it be possible to discharge part of the water to the existing storm drains in the vicinity?