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DC Water moves forward with planning to dramatically improve the health of the Potomac

October 25, 2018

Public invited to comment on Environmental Assessment for proposed Potomac River Tunnel

WASHINGTON – Interested in the health of Washington D.C.'s waterways? DC Water invites the public to comment on an Environmental Assessment (EA) for the proposed Potomac River Tunnel. This project is designed to reduce combined sewer overflows to the Potomac River as part of the $2.7 billion DC Clean Rivers Project. Comments will be accepted on the EA through November 30, 2018.

DC Water is proposing to construct the Potomac River Tunnel in the District primarily on National Park Service (NPS) land within Chesapeake and Ohio Canal National Historical Park, Rock Creek Park and National Mall and Memorial Parks. The EA is a required milestone before DC Water can finalize plans for how and where it will construct the associated infrastructure.

The project consists of a large-diameter deep sewer tunnel, diversion facilities, drop shafts and support structures to capture flows from existing combined sewer overflows along the Potomac River and transport them to the Blue Plains Advanced Wastewater Treatment Plan for treatment. The EA evaluates impacts based on a range of options for each facility proposed for construction, with a preferred option presented for each structure.

Attend an Open House
DC Water and the NPS invite the public to an open house public meeting to learn more about the project, the EA and to ask questions of project staff.
When: Wednesday, November 14, 2018, from 6 – 8 p.m.
Where: West End Library 2301 L St. NW, Washington, DC 20037

For more information or for individuals requiring special assistance at the open house please contact DC Clean Rivers Project Public Outreach at (202) 787-4717 or by email at

How to Comment
The preferred manner for providing comments is via an online form on the NPS Planning, Environment, and Public Comment (PEPC) website, used by the agency to manage official correspondence and analyze public comment in the planning process. From the project website

Comments may also be submitted in writing to:
ATTN: Potomac River Tunnel EA
DC Clean Rivers Project
Blue Plains Advanced Wastewater Treatment Plant
5000 Overlook Avenue, SW
Washington, DC 20032
Comments must be provided electronically or postmarked by November 30, 2018, to receive consideration. Please be aware that the entire comment submitted – including personal identifying information such as address, phone number, and email address – may be made publicly available. Requests to withhold such personal identifying information from public release will be considered, but there is no guarantee that they will be withheld.

How to Obtain the EA
The EA can be downloaded from the NPS project webpage at Hard copies of the EA can also be found at the following District libraries:

  • Southwest Library, 900 Wesley Place SW
  • West End Library, 2301 L Street NW
  • Georgetown Library, 3260 R Street NW

Palisades Library, 4901 V Street NW

The DC Clean Rivers Project is DC Water’s ongoing program to reduce combined sewer overflows (CSOs) 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 water during heavy rainfalls before it ever reaches our rivers. Ultimately, it will improve water quality within the Chesapeake Bay watershed by lessening the volume of CSOs that enter the waterways. CSOs impair water quality by increasing water bacteria levels, contributing to low dissolved oxygen in water, increasing the potential for fish stress or fish kills and impacts to other aquatic life, and increasing the amount of trash in waterways. The proposed controls are estimated to reduce CSOs to the Potomac River by 93 percent by volume and limit their frequency from approximately 74 events to 4 events in a year of average rainfall.

More information can be found at: