DC Water quickly developed and implemented a plan to collect and pump the effluent into the canal near Lock 13, let the water flow through Locks 13, 12, and 11, recapture it with a cofferdam above Lock 10, and return it through a set of short trenches back into the pipe below the breach. In five days DC Water completed this first step, thereby stopping most of the spillage into the river. There was some additional spillage Feb. 8, when some of the pumps were clogged by so-called "flushable" wipes. And it was later discovered that some sewage continued to leak through the lining of the canal and contaminate the river, causing DC Water to implement additional measures to collect much of this leakage and return it to the pipeline. Finally, on March 14, DC Water completed a temporary repair, allowing the sewage to flow through the pipeline again instead of through the canal. A more permanent repair is planned for later this year.
Approximately 250 million gallons of untreated sewage spilled into the Potomac as a result of this event. Water testing initially performed Jan. 23 by the Potomac Riverkeeper Network on the river near Lock 10 showed values that were 7,000 times above the standard limit for "safe" recreational activities of 410 MPN (Most Probable Number)/100 ml. Samples collected approximately four miles downstream at Fletchers Cove were approximately 60 times the "safe" standard at that time.
This disaster has been called one of the largest single sewage spills in U.S. history. And it could have been much worse had DC Water's engineers and crews not acted as quickly as they did to install the structures and equipment necessary to pump the spilling sewage into the C&O Canal and divert it back into the pipeline downstream of the breach. The location of the breach—next to the canal and not upstream of any active intake for drinking water—also was fortuitous. The timing of the spill—right before a major snowstorm and prolonged cold spell during which most portions of the Potomac were covered by ice—complicated the repair effort but also reduced the immediate effects of the spill on recreation (and perhaps on wildlife). But it remains to be seen what the long-term effects will be of bacteria that were deposited in cold water, literally under ice, as the water and underlying sediments warm up.
The Potomac Riverkeeper Network and a plethora of other organizations, including CCA, sprang into action to demand water testing by DC Water and state and local environmental and health agencies. And they also requested prompt actions to complete the repair, remediate the areas affected by the spill, determine the root cause of the spill, and take action to prevent future spills (including prompt completion of the program for rehabilitating the Potomac Interceptor). Notably, Potomac Riverkeeper Dean Naujoks arrived on the scene within four days to measure the toxicity of the effluent, before DC Water or any public agency did so. CCA and other organizations, as well as many individuals, wrote letters to DC Water and other relevant agencies, attended public meetings, testified before a DC Council subcommittee, and took other actions to bring attention to the spill and advocate for actions to protect the river and the people and wildlife that use it.
Responding to these efforts, DC Water, the Maryland Department of the Environment, the DC Department of Energy and Environment, and other agencies have stepped up their water testing activities and have increased their engagement with the public regarding responses to the spill. CCA submitted comments on DC Water's Environmental Rehabilitation Plan and requested:
- environmental testing of sediments in areas where paddlers frequently come in contact with the riverbed and riverbanks when entering and exiting the water, including at the Lock 10 takeout, in the Feeder Canal, in the C&O Canal between Lock 5 and Chain Bridge, and at Little Falls, and
- remediation of these sediments as needed to ensure they are safe for human contact.
With the exception of the area of the river near Lock 10, water test results generally have improved to levels that are below the 410 MPN threshold in most areas below the spill (including in the Feeder Canal near Lock 6 and in the river from Brookmont Dam to the tidal area below Little Falls), indicating that the waters are "safe" for recreation. As of March 17, DC, Montgomery County, and the Commonwealth of Virginia had lifted their recreational water advisories for most of the affected area, except for portions of the river close to the Maryland shoreline/Swainson's Island between Locks 8 and 11.
A CCA website page provides a comprehensive list of links to reports on the rupture, rehabilitation plans, water testing data, health advisories and CCA's and others' responses.
As warmer weather arrives and paddling activity increases, the CCA and its members will need to continue to monitor water quality data and the progress toward cleaning up areas affected by the spill when deciding the location of trips. And we will need to keep up the pressure on DC Water and other relevant agencies to continue testing water quality and publishing results, evaluate and remediate sediments that may be contacted by people or that may release contamination into the water, complete the project to rehabilitate the Potomac Interceptor, and take steps to identify the cause of this pipeline collapse and prevent similar events from happening in the future.