Massachusetts Water Resources Authority Combined Sewer Overflow Control Plan Annual Progress Report 2015 Table 2: Long-Term CSO Control Plan by Receiving Water CSO Discharge Goals (Typical Year Rainfall) Capital Cost* Receiving Water Projects* Volume (millions) Activations (million gallons) Alewife Brook/Upper 7 untreated 7.3 • Cambridge/Alewife Sewer Separation $ 108.3 Mystic River • MWR003 Gate and Rindge Siphon Relief and 3 treated @ 3.5 • Interceptor Connections Upgrades Somerville • Connection/Floatables at Outfall SOM01A Marginal • Somerville Baffle Manhole Separation • Cambridge Floatables Control (portion) Mystic River/Chelsea 4 untreated 1.1 • Somerville Marginal CSO Facility Upgrade 92.0 Creek Confluence and • Hydraulic Relief at BOS017 Chelsea Creek and 39 treated 57.1 • BOS019 Storage Conduit @ Somerville • Chelsea Trunk Sewer Replacement Marginal • Chelsea Branch Sewer Relief • CHE008 Outfall Repairs • East Boston Branch Sewer Relief (portion) Charles River 3 untreated 6.8 • Cottage Farm CSO Facility Upgrade 88.8 (including Stony • Stony Brook Sewer Separation Brook and Back Bay and 2 treated @ 6.3 • Hydraulic Relief at CAM005 Fens) Cottage Farm • Cottage Farm Brookline Connection and Inflow Controls • Brookline Sewer Separation • Bulfinch Triangle Sewer Separation • MWRA Outfall Closings and Floatables Control • Cambridge Floatables Control (portion) Inner Harbor 6 untreated 9.1 • Prison Point CSO Facility Upgrade 47.5 • Prison Point Optimization and 17 treated 243.0 • East Boston Branch Sewer Relief (portion) @ Prison Point Fort Point Channel 3 untreated 2.5 • Union Park Treatment Facility 62.4 • BOS072-073 Sewer Separation and System and 17 treated 71.4 Optimization @ Union Park • BWSC Floatables Control • Lower Dorchester Brook Sewer Modifications Constitution Beach Eliminate • Constitution Beach Sewer Separation 3.7 North Dorchester Bay Eliminate • N. Dorchester Bay Storage Tunnel and Related 253.8 Facilities • Pleasure Bay Storm Drain Improvements • Morrissey Blvd Storm Drain Reserved Channel 3 untreated 1.5 • Reserved Channel Sewer Separation 70.6 South Dorchester Bay Eliminate • Fox Point CSO Facility Upgrade (interim) 126.8 • Commercial Pt. CSO Facility Upgrade (interim) • South Dorchester Bay Sewer Separation Neponset River Eliminate • Neponset River Sewer Separation 2.5 Regional • Planning, Technical Support and Land Acquisition 50.3 TOTAL 410 $ 906.6 Treated Portion 381 *Floatables controls are recommended at remaining outfalls and are included in the listed projects and capital budgets. 19 .