DC Water Submits Practicability Assessment for Potomac River Green Infrastructure Project

August 27, 2020

DC Water has submitted to the US Environmental Protection Agency (EPA) the Practicability Assessment for the Potomac River Green Infrastructure (GI) project as required under the terms of the 2016 Amended Consent Decree.  The Practicability Assessment evaluates the first set of GI projects in the Potomac River sewershed and identifies DC Water’s proposed plan to control combined sewer overflow (CSO) to the Potomac River.

DC Water is implementing the Clean Rivers Project to control CSOs to our waterways and to improve water quality.  The project will provide a 96% reduction in CSOs system-wide when completed. 

On January 14, 2016, DC Water, in conjunction with the United States Environmental Protection Agency, United States Department of Justice, and the District Government signed a modification to the 2005 Long Term Control Plan (LTCP) Consent Decree to evaluate innovative GI practices to control CSO Outfalls 027, 028 and 029 in the Potomac River instead of building additional storage within the Potomac Tunnel.

The modification required constructing a GI demonstration project in the Potomac River sewershed and then evaluating the results to determine the best path forward for controlling CSOs.  DC Water has completed the evaluation and determined that implementation of GI in the Potomac River sewershed is not practicable from a constructability, public acceptability, and cost to ratepayers’ perspective.

David L. Gadis, CEO and General Manager, of DC Water stated, “DC Water has determined that extending the Potomac River Tunnel was the most practical and cost effective approach to addressing CSOs in the Potomac sewershed.  DC Water remains dedicated in finding the best solutions that meets the needs of our ratepayers.  Our commitment to Green Infrastructure in the District has not changed, and we will continue to implement these practices when and where it makes sense.”   

A copy of the Potomac River Practicability Assessment can be found on DC Water’s website at www.dcwater.com/green.  A determination for this recommended approach is pending EPA review. Per the terms of the Consent Decree, EPA has 180 days to review the Practicability Assessment. Earlier this year, DC Water submitted the Rock Creek Practicability Assessment, and determination of the recommended approach is still pending EPA review.