11/15/2012 SEWER COMMISSION Minutes

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It is important to note the following caveats: • The focus of this step is to identify the discharge locations and volumes so they can be incorporated into a scenario including considerations for maximum month and peak day conditions required for facilities design. • All these options are based on the assumption that private facilities will be owned and operated in the future by the Town or District. Town/District should continue with negotiations with all of these facilities. • All these options are based on the assumption that the recharge sites can accommodate the flows (at all conditions: average, maximum month, peak day);the Town/District will need to verify this as part of preliminary design,final design,or as an amendment to this project. • Recharge to the Keeter Property assumes there is a distribution of treated recharge to several watersheds including directly to Nantucket Sound. USGS modeling efforts may provide a clearer estimation of the distribution of this nitrogen load. • This assumes that Towns will manage their respective loads or be willing to enter into agreements regarding regional facilities. • Nitrogen concentrations from septic systems at 23.63 mg/L are based on MEP/DEP findings: • Nitrogen concentrations from I/A systems are assumed to be 19 mg/L based on current MassDEP permitting and the findings of the Barnstable County study; however it is understood that some of these facilities may be able to achieve much higher treatment performance, however a conservative approach was selected. • Flows are based on those in the unified database and build-out information developed previously. It is also understood that MEP has been developing the full Waquoit Bay Watershed TMDL, and therefore adjustment may be required to address changes related to those findings as an amendmentto this project. • The development of the recommended plan is where the implementation and phasing approach of the project will be developed, which will focus on addressing current wastewater needs with the understanding that proposed facilities will need to be able to accommodate future growth. • It is understood that the current economic climate and population trends across the Cape are flat; however any future plan will have to consider that over a 20 year period these conditions will change,and will need to be flexible in both a positive(growth)and negative(declining)direction. Per the 2010 Census, Barnstable County saw a 2.9% decrease in population while Mashpee experienced a growth of almost 9%over that same period. 5 MEP Data The Unified Database is being transmitted to MEP with additional columns provided with correlation to Tables 1 through 3, indicating the flows.With this information and a data disk with the unified database and some additional columns to pull the data, we are requesting that the MEP model be run on the following options: 7