Clean Rivers Project

Restoring Our Rivers

The Clean Rivers Project is DC Water's ongoing program to reduce combined sewer overflows (CSO's) into the District's waterways - the Anacostia and Potomac Rivers and Rock Creek. The Project is a massive infrastructure and support program designed to capture and clean wastewater during rainfalls before it ever reaches our rivers.

Protecting Our District

With the Clean Rivers Project, DC Water will protect the public from chronic sewer flooding that has plagued many areas of the District since the early 1900's. It is also cleaning up our waterways, by reducing the pollutants that enter our rivers and can be harmful to our wildlife.

What are We Building?

The Clean Rivers Project is comprised of a system of deep tunnels, sewers and diversion facilities to capture CSO's and deliver them to DC Water’s Blue Plains Advanced Wastewater Treatment Plant. The Clean Rivers Project is also installing Green Infrastructure or "GI" to assist with the reduction of CSO's to the Potomac River and Rock Creek. The Anacostia River and Potomac River tunnel systems include more than 18 miles of tunnels that are larger than the Metro tunnels and are constructed more than 100 feet below the ground.

Clean Rivers System for Anacostia and Potomac Rivers and Rock Creek

How Does the System Work?

With the current sewer system, practically every time it rains, untreated sewage and rainwater (combined sewage) is discharged into the District’s rivers and creeks. The Clean Rivers project will install "diversion facilities" at strategic locations to capture this untreated sewage and divert it to the new 157 million gallon tunnel system where it will be stored and conveyed to the Blue Plains Advanced Wastewater Treatment Plant for treatment. Each diversion facility consists of a Diversion Chamber to intercept flow from the existing sewers, an Approach Channel to direct the flow and create a vortex, a Drop Shaft to drop the flow approximately 100 feet and an Adit to connect to the main tunnel system.

The entire system works by gravity, with no moving parts to direct and capture flow. During dry weather conditions, the existing sewer system will have the capability to deliver flow to Blue Plans for treatment through its existing Dam and Interceptor system. The tunnel system is designed to capture "wet weather" or combined sewage only.

Typical Clean Rivers Diversion Facility (click to enlarge)

What are the Benefits?

The DC Clean Rivers Project will reduce CSOs annually by 96 percent throughout the system and by 98 percent for the Anacostia River alone. In addition, the Project will reduce the chance of flooding in the areas it serves from approximately 50 percent to 7 percent (equivalent to a 15-year storm) in any given year and reduce nitrogen discharged to the Chesapeake Bay by approximately 1 million pounds per year.

A Drop's Life

Learn about the Clean Rivers Project from the perspective of a single water drop, in this 4-1/2-minute cartoon.

In This Section

Green Infrastructure

Important Links

What is a Combined Sewer Overflow?

Executive Summary of Current Plan (PDF 2.5 mb)

Current Plan, Full Document (PDF 39.0 mb)

Projects that are part of Clean Rivers (select "Clean Rivers" at this link)

Clean Rivers Environmental Assessment

Current Combined Sewer Overflow Controls

Combined Sewer Overflow or "CSO" controls have been implemented in the past. Prior to DC Water's creation in 1996, the District of Columbia Water and Sewer Utility Administration (WASUA) was responsible for the water and sewer system. In the 1950's, 60's and 70's, portions of the combined sewer system were separated to reduce CSO's. In the 1980s and early 1990s, WASUA constructed new facilities to control CSO's. Examples of such facilities include the Northeast Boundary Swirl Facility, which is a treatment facility located near RFK stadium. The facility can treat up to 400 million gallons per day of CSO from the Northeast Boundary drainage area. Another example is the inflatable dams, which are balloon-like devices installed in existing sewers. The dams are inflated to store combined sewer overflow in existing sewers to prevent overflows. There are 12 dams at 8 locations in the system. Other examples of prior CSO control activities include improvements to the Blue Plains Wastewater Treatment Plant, separation of portions of the combined sewer system and construction of a monitoring and control system for key components of the system. DC Water continues to operate these and other CSO control components of the combined sewer system.

Long Term Control Plan Development

The District's National Pollutant Discharge Elimination System (NPDES) permit issued by the U.S. Environmental Protection Agency (EPA) required the preparation of a Long-Term Control Plan (LTCP). The LTCP is a plan with a schedule to control CSO discharges to the area waterways. The LTCP planning effort began in 1998 and a draft of the LTCP was made available to the public and submitted to EPA and the District Department of Health in June 2001.

DC Water obtained public comments on the Draft LTCP in the summer and autumn of 2001 via public meetings, neighborhood meetings, a public hearing and by mail, fax and e-mail. Many comments were received. In August 2002, DC Water submitted a Final LTCP to EPA and the District Department of Health for approval. In response to public comments, the Final LTCP proposed significant reductions in CSO compared to the draft plan and was approved in December 2004.

In 2010, DC Water named the LTCP the Clean Rivers Project.

LTCP Documents:

Long-Term Control Plan Executive Summary (PDF 851 kb)

Long-Term Control Plan Highlights (PDF 1.5 mb)

Long-Term Control Plan (PDF 17.6 mb)

Long-Term Control Plan Consent Decree (PDF 2.7 mb)

Consent Decree Modification

On January 14, 2016, DC Water, in conjunction with the United States Environmental Protection Agency, United States Department of Justice and the District of Columbia executed a modification to the 2005 Long Term Control Plan (LTCP) Consent Decree to include innovative Green Infrastructure practices to achieve the reduction of combined sewer overflow volume by 96 percent system-wide (for the Anacostia and Potomac rivers and Rock Creek) and offer additional community benefits.

2016 Consent Decree Modification