BPSA Flow Management Efforts & Round 8.1 Flow Projections

COG staff - Presentation to WRTC September 6, 2013

COGs Round 8.2 Cooperative Forecast & Regional Wastewater Flow Projections1Overview9/6/13WRTC2COGs Wastewater Treatment PlantsFocus on Major Plants (defined as => 2 mgd)20 Including both Dale Service Corp plantsService Area (SA) maps being confirmed/updatedSAs shown for Majors, though Other still being refinedCOGs Regional Cooperative Forecast ProcessRound 8.2 recently adopted by COG BoardCOGs Regional Wastewater Flow Forecast Model (RWFFM)Basic assumptionsDemographic trends for MajorsFlow projections Unadjusted & AdjustedRemaining regional capacity9/6/13WRTC3

COGs RegionalCooperative Forecast Process9/6/13WRTC4Round 8.2 Cooperative Forecast adopted by COG Board on July 10, 2013Demographic projections are based on Jurisdictions forecasts and are within 3 percent of the econometric model projectionsPopulation, employment, and householdsDemographic information is allocated from Transportation Analysis Zones (TAZs) to the appropriate wastewater service areas (i.e., sewersheds and sub-sewersheds)

4COGs RWFFM Basic Assumptions9/6/13WRTC5Regional model grown from original Blue Plains workWastewater projections derived employment & households and Flow Factors (not population)Black & Veatch updated Base Year Flows (BYF) & flow factors for Blue Plains in 20102009 BYFs are actual annual average flows I/I rate of 44% of incremental sanitary flow remained the sameUsed Ffx #s for VA plants & WSSC #s for MD plantsTable ES-2 2009 Approved Flow FactorsCategoryFairfax CountyWSSCLoudounWater DistrictDullesVAViennaVAHousehold (gpd/unit)150180185170NA170Employment (gpd/employee)302825254821-50

9/6/13WRTC6COG Total5 millionCOG Major WWTPs & Unadjusted Flow Projections (Draft)9/6/13WRTC7Unadjusted flows reflect only impact of demographic trends

COG Major WWTPs & Unadjusted Flow Projections (Draft)9/6/13WRTC8

Unadjusted flows reflect only impact of demographic trendsTotal Regional Capacity (for Majors) 776 mgdCOG Major WWTPs & Adjusted Flow Projections (Draft)9/6/13WRTC9Adjusted flows reflect impact of (significant) flow reductions & flow diversionsTotal Regional Capacity (for Majors) 776 mgd

718 mgd = 93% of Total Capacity9/6/13WRTC10

COGs Region Forward and Economy Forward initiativesNext Steps9/6/13WRTC11Continue to verify with WWTP operators:WWTP service area mapsFlow projections/assumptionsRefine maps re: septic/distributed systems vs. non-sewered areasPresent overall/regional findings to CBPC (9/20/13)Region ForwardReport on percent wastewater capacity findingsOverall RACs on WWTP Service AreasFlow vs. Load Capacity AnalysisOutgrowth of work being done for Blue Plains Users

Wrap-up9/6/13WRTC12Questions?Ideas?

Additional presentations:COGs Cooperative Forecast processCOGs RWFFMCBPs use to characterize/project growth

Many thanks for teamed effort Mukhtar Ibrahim, Nasser Ameen, & Lana Sindler

Contact: Tanya Spano (202) 962-3776 / tspano@mwcog.org