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Combined Sewer Service Area
Capital Improvement Program
Potomac River Outflow

Similar to many older communities in the Mid- Atlantic, Northeast, and Midwest portions of the country, a portion of the District of Columbia is served by a combined sewer system. Approximately one- third of the system is combined, mostly in the downtown and older parts of the city. In dry weather, the system delivers wastewater to the Blue Plains Wastewater Treatment Plant. In wet weather, storm water also enters the system, and if the conveyance capacity of the system is exceeded, the excess flow spills into the waterways of the District of Columbia. This discharge is called Combined Sewer Overflow (CSO). There are 60 permitted CSO outfalls in the District.

In FY 2003, WASA completed negotiations for a consent decree with a group of citizens and the United States government to settle a lawsuit alleging that the Authority was in violation of the Nine Minimum Control (NMC) provisions of the federal CSO Policy. This EarthJustice consent decree is pending approval by a federal judge. The purpose of the NMC projects is to reduce CSO's through proper operation and maintenance of the existing CSO control facilities. WASA had already undertaken a number of projects to comply with the NMC requirements. Under the terms of the consent decree, these projects must be completed by specific dates negotiated as part of the settlement agreement. The projects are identified in the CIP as the NMC projects. Among these are the CSO dry- weather overflow control structure upgrade project and the CSO event indicator project. A subset of the NMC projects, the pump station upgrade projects, are also part of the combined sewer system Long Term Control Plan. Under the consent decree, WASA has agreed to fund a supplemental environmental project, to be approved by U. S. Environmental Protection Agency (EPA).

As required by the EPA's CSO policy, WASA developed its Long Term Control Plan (LTCP), which was submitted to the EPA on August 1, 2002. Prior to submission to the EPA, the planning process included a comprehensive public information program, including the creation of a stakeholder advisory panel comprised of environmental organizations and others, presentation of the plan at a number of public meetings, and conducting a public hearing.

Among the benefits of the proposed plan, EPA requirements will be met or surpassed for both the average numbers of overflow events yearly and the percentage of combined sewage that is captured for treatment in the combined sewer system. When fully implemented, CSO overflows will be reduced by a projected 96 percent overall, (98 percent reduction on the Anacostia River), resulting in improved water quality and less debris in our nation's capital waterways. Overflow events would be reduced to two per year in the Anacostia River, four per year on the Potomac and Rock Creek, and one per year at Piney Branch.

Key components of the plan include:

  • Four large storage tunnels, which will allow the storage of CSO flows from storm events until they can be gradually sent to Blue Plains for treatment (with two tunnels located near the Anacostia River, one near the Potomac River and one near Rock Creek)
  • Targeted separation of combined sewers in several sections of the District
  • Consolidation and elimination of 13 of 59 outfalls, including four outfalls on the Anacostia River
  • Low impact development (LID) at WASA facilities and to encourage LID across the District

Recommendations have been included in the LTCP to address LID encouragement through a public education program and proposed changes in development / redevelopment regulations, such as building code provisions. WASA has begun the first phase of installation of several LID projects at the Bryant Street Pumping Station. In the next phase, LID opportunities at other WASA facilities will be identified. The purpose of these projects is to reduce CSO by delaying storm water runoff into the combined sewer system.

The final LTCP submitted to the EPA recommended projects costing $1.265 billion in FY 2001 dollars, or $2.6 billion in inflated dollars, assuming a 40- year implementation schedule. In FY 2003, the Authority received a $50 million appropriation from the U. S. Congress, with a 100 percent WASA match, for initial funding of the LTCP. There are preliminary indications that an additional $25 million to $35 million will be appropriated in FY 2004. Because it is unlikely that this outside funding will continue without implementation of the LTCP, the early year budgets have been included in the 10- year capital disbursement plan. Disbursements for LTCP projects have increased by $86.5 million, compared to last year's plan, due to projects scheduled to be underway during the current ten- year budget period. It is important to note that the projected disbursements are based on a 40- year implementation schedule, and therefore the majority of LTCP costs are not reflected in the current CIP and financial plan. Until a Board- approved financing plan is in place, WASA does not intend to begin LTCP work beyond $143 million of projects that were included in the CIP prior to the plan being submitted to the EPA.

Some of the LTCP projects included in the $143 million are:

  • Potomac Pumping Station rehabilitation, with a lifetime budget of $17.5 million, includes replacing pump motors, motor controls, adding variable speed drives, upgrading the electrical system and electrical feeders, and modifying the existing wet- wells and influent channels.
  • Main & "O" Street Pumping Stations rehabilitation has a project lifetime budget of $72.2 million, and includes rebuilding and upgrading sanitary pumps, upgrading electrical and ventilation systems, replacing screens and installing a screening handling system, and installing odor control systems.
  • East Side Pumping Station rehabilitation, with a lifetime budget totaling $18.5 million, provides for a new, above grade pumping station.
  • Poplar Point Pumping Station rehabilitation has a lifetime budget of $4.4 million, and provides for improvements that include structural and architectural repairs, HVAC upgrades, the addition of an odor control system, and electrical and lighting upgrades.

The work planned on the pump stations is required to maintain the stations at their rated capacities, improve station efficiency and will reduce combined sewer overflow to area rivers.

Additional CSO projects include:

  • Improvement and Modifications to Combined Sewer System Structures — Under this project, a number of CSO outfall structures will be improved and/ or modified to eliminate dry weather overflow of CSO. A construction contract was awarded and work has begun with completion scheduled for mid- 2004. This effort has a lifetime budget of $7.8 million.
  • Anacostia Sewer Separation — This is one of the early action projects proposed under the final LTCP. The project involves separating a small area on the east of the Anacostia River. The result will be two separate conveyance system, one for sanitary sewer and one for storm sewer, and elimination of CSO Outfall 006. Engineering design work on the project began in FY 2003. Lifetime budget for this work totals $3. 5 million.

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