Laserfiche WebLink
Environmental 1?ngincers/Consultants <br /> ,19 Vdel,c[3ill Ro;ld <br /> ,�1r5V[11i '✓E�d:ti.t.'ll kl3a't.,(�J,1{:�... <br /> (61 I)°)6.1.Y°)�)'{ <br /> 1'cztt;Stfll'.(6,1J) 52 1) .111)1 <br /> i xx: (6 1 ) 4,Q )i J <br /> MEMORANDUM F� mail; i,io(d. )sp=a,i�a�tir>« z,,;i:,z�:,.<<,�,� <br /> To: Tom Fudala, Chair Date: December 16, 2010 <br /> Mashpee Sewer Commissioners <br /> c: <br /> From: Pio Lombardo, P.E. 7 <br /> Lombardo Associates, Inc. ( AI) <br /> Re: Comments on Mashpee Se er ommission Proposed Sewer Plan <br /> Overview&Summary <br /> Lombardo Associates, Inc (LAI) has reviewed the Mashpee Sewer Commission's Proposed Sewer <br /> Plan to formulate a planning level opinion on how it compares to Scenario 3R, which is the only <br /> scenario that will, per MEP analysis, meet the TMDL required threshold nitrogen concentrations in <br /> the applicable subwatersheds within the Eastern Waquoit Bay and Popponesset Bay watersheds. <br /> This analysis considered the following: <br /> 1. The number of parcels sewered within the TMDL subwatersheds in the Proposed Plan vs. <br /> Scenario 3R. <br /> 2. The relative increase or decrease in discharged treated effluent to each subwatershed in the <br /> Proposed Plan vs. Scenario 3R. <br /> 3. The excess capacity each subwatershed had per the MEP analysis of Scenario 3R. <br /> This analysis will determine if the Proposed Plan removes the same, more or less nitrogen than the <br /> LAI Scenario 3R, which has passed MEP review for TMDL compliance in all subwatersheds. For <br /> subwatersheds where less nitrogen removal appears to be planned, LAI will comment on the <br /> excess capacity and if it is likely to be exceeded, resulting in non-compliance. <br /> Table 5 from MEP's December 15, 2009 Technical Memo and Table 3 from MEP's February 9, <br /> 2010 Technical Memo shows the results of the MEP model runs for the 5 scenarios, including <br /> Scenario 3R. <br /> Ockway Bay, Jehu Pond Hamblin Pond <br /> These subwatersheds appear to have similar nitrogen removal to Scenario 3R. Any variance are <br /> small at most, and as seen on Tables 3 and 5 there is ample excess capacity in Scenario 3R. <br /> Shoestrina Bay <br /> LAI's Scenario 3R removes 100% of the Barnstable portion of this subwatershed. However, there <br /> is sufficient excess capacity in this subwatershed to withstand less than 100% removal. As long as <br /> Barnstable removes most of the nitrogen within its portion of the Shoestring Bay subwatershed, <br /> TMDL compliance should not be compromised. <br /> YAProjects-Closed\@6235 Town of Mashpee\@Reports&Memos\101216 LAI Review of Current Plan Memo.docx <br />