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HomeMy WebLinkAboutHearing notes 12.4.202512/3/2025 Comment from engineering: Replace 3 manholes labelled "Sewer" with manholes labelled "Drain". 1 is in the grass and 2 others are adjacent to a handicap parking space 11/21/2025 COC request: Ongoing general conditions 15, 21-26, SC 2-3. Catch basins mostly as specified in plan, except for one near the East entrance on 6A which is ~10' further West than on approved plan. CB in middle of East property boundary on lawn is a little overgrown. Downspout from the bank to the West drains to the CB on this property via an unsecured hose. Plants mostly conform to landscape plan, except along 6A where they are more sparse. 3/3/2022 New material was submitted in response to the peer review comments. We had the Town Engineer review the remaining items to be addressed. She has the following comments: Providing sustainable drainage infrastructure for continuous treatment is the key to success for managing the water quality requirements in the Stormwater Regulations. Reviewing the response to ESS comments and application material see the following suggestions: • Pretreatment Requirement of 44% TSS removal o As noted in ESS’s response letter, the Massachusetts Stormwater Handbook does not provide clear direction if two deep sump catch basins/drain manholes in-line would receive the same TSS removal of 25%/each yielding the 44% TSS removal goal. With that being said, an additional pretreatment option should be considered.  Option 1: Provide bi-annual sweeping of the parking lots areas. This would provide up to 10% TSS removal.  Option 2: Substitute each drain manhole for a Stormceptor STC or equivalent oil/water separator (Recommended Pretreatment Option by Massachusetts Stormwater Handbook). • While the handbook only assigns 25% TSS removal, Stormceptor performance testing yields 76% to 93% TSS removal.  Option 3: DCE to perform TSS removal testing during a storm event at another site they have designed and provide results to the commission. • Infiltration Rate o The site’s test holes yielding 3-4’ deep of loamy sand and notes that these unsuitable soils will be removed prior to construction of drainage. With the completion of this work, the infiltration rates analyzed will be sufficient. • O&M Plan o O&M plan dated 6/2021 notes that catch basin cleaning would occur once every two years under the Estimated Operations and Maintenance Budget. This does not meet the Massachusetts Stormwater Handbook guidelines, which states cleanings should occur four times a year or when the sump is 50% full or 2’ as noted in the O&M plan. Understanding this may not be feasible, the Owner should provide quarterly inspections and retain records to identify the depth of sediment below the outlet pipe. Based on those results, the Owner should clean the catch basins upon 50% sediment depth or once every two years. o O&M also includes street sweeping, but it was not included in the TSS calculations. It notes that it will be completed on or about April 1st. The Massachusetts Stormwater Handbook guidelines suggests twice a year, which is required to credit the 10% TSS removal noted in Option 1 above. The Commission will need to decide which of the three TSS removal options the wish to see implemented. I have requested the other items be addressed in the O&M plan. With consideration of these items we should be ready to issue the permit. 2/17/2022 No applicant response received. Payment required for Peer review 2.3/2022 No applicant response received. Payment required for Peer review 1.20.2022 Peer review comments received 1/19/2022. Recommend continuing for applicant response. 1.6.2022 New material submitted for review by the peer reviewer. Get Dan Ojala to agree to a continuance to review the new material. Comments should be received by 1.13.2022 for review at the January 20 meeting. 12/16/2021 No new material received. November 30/2021 No new material as yet November 16, 2021 Request to continue to December 2 to receive updated material November 4, 2021 Request to continue to November 18 to receive updated material October 21, 2021 The Peer review found the application to be incomplete and not to meet the stormwater standards. Dan Ojala wishes to provide a response before and at the meeting as they are under time pressure. I will forward his response if I receive it before the meeting.