10/03/2022 SELECT BOARD Minutes - Laserfiche WebLink

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31, Mashpee Select Board Minutes October 3, 2022 APPOINTMENTS & HEARINGS Water Quality Presentation: Briann Howes_-_Univers' V of MassachusettswDartmouth: (continued) Dr. Howes reviewed the 2010-2021 data of estuarine monitoring in Waquoit Bay and Popponesset Bay. During this time 18 estuarine stations have been monitored with 4 sampling events in Waquoit Bay. In Popponesset Bay there are 16 estuarine stations with 4 sampling events. All sites have been over the TMDL nitrogen thresholds during this time span. Results from 2019 to 2021 show significant nitrogen enrichment in the upper tributaries, with moderately nitrogen enriched embayment's to the east. Quashnet was noted to be the worst tributary system on the Cape and within the south shore. Great River, Jehu and Hamblin Ponds have begun to worsen. The health index in Waquoit Bay is poor with improved water quality near the inlets. Phase II of the Town's sewering initiative is expected to improve upon this area. Nitrogen in salt water derives mostly from wastewater in the estuaries. Sewering would encompass approximately 85% of the fixable range. Popponesset Bay water quality results during the three year span also show large and significant enrichment in the upper tributaries with nutrient impairment throughout. There are no high water quality areas. Findings for Popponesset and Waquoit Bays show increase impairments with significant impairments in the upper tributary regions. There is gradual decline in the lower basins and frequency of phytoplankton blooms. Clear evidence indicate the declines are due to nitrogen enrichment within the bay waters. Dr. Howes indicated the results indicate the monitoring program has the ability to detect changes in response to the implementation of management alternatives. Phase I of the Town's Comprehensive Wastewater Management Plan will be tracked and water quality versus TMDL targets will be used to support management and regulatory compliance tracking. Discussion followed with regards to natural rainfall and the fluctuation during summer months. This year there was little rain. Although long term drought lowers the groundwater tables the absence of rain reduces nutrient flush and may reveal lower results in the 2022 study. Build -out scenarios were reviewed and recommended at a reasonable amount. Maintaining clean waters in Mashpee ponds has been a priority of the Select Board. The pilot studies have not encompassed fresh waters to date. Lakes require a more detailed water analysis. This would include study of the water meter data to review how much wastewater is generated. The Town is presently focused on the phosphorus levels both long and short term remediations. A brief discussion followed with regards to cesspools and the leaching impact. Larger leaching fields tend to slow phosphorus from entering ponds. It was noted that most marshes are built on fresh water to increase wetland boundaries and wetland buffers