• As work nears completion on the initial clean-up and temporary stabilization of the areas directly impacted by the Potomac Interceptor overflows, DC Water is beginning preparations for beautification and revegetation to restore native plants, trees, and shrubs.
• Before moving to the next phase of environmental rehabilitation, DC Water is working with the Environmental Protection Agency to conduct soil sampling to verify the clean-up efforts.
• As of today, the initial clean-up and temporary stabilization have been completed in the areas that include Culvert 12 (Rock Run Culvert), the tributary to the Potomac River, and shoreline. A small section remains in the drainage channel along Clara Barton Parkway and is expected to be completed this weekend.
• Crews continue to remove sludge and debris from the C & O Canal. Once complete, the next step will be to remove the soil in the canal down to the clay liner.
• DC Water is working with the National Park Service (NPS) and will rebuild the C & O Canal to its historic specifications in the sections between locks 10 and 14 that were used as a bypass to divert wastewater around the damaged pipe section and into the Potomac Interceptor further downstream.
• Rebuilding the C & O Canal will include restoring the clay liner, cleaning the historic locks according to NPS approved methods and standards, and reconstructing the lock gates.

With the emergency repair complete, and environmental rehabilitation transitioning to the beautification and revegetation, updates on the environmental rehabilitation will be provided weekly on Tuesdays and Thursdays and when key milestones are reached. Daily water quality sampling results will continue to be posted at dcwater.com/potomac-interceptor-collapse.

Water Quality Sampling Results

It's important to understand that rain, snow, heat, contaminated runoff, and natural sources of E. coli such as wildlife can cause higher bacteria levels in urban rivers such as the Potomac. For this reason, experts recommend avoiding the water for at least 48-72 hours after heavy rain. This is reflected in the data this week, where significant spikes are seen that coincide with heavy rainfall including areas upstream where measurements are unrelated to the overflow event.

As there have been no overflows to the river from the Potomac Interceptor for more than a month prior to completion of emergency repairs, fluctuations in measurements are more likely due to these other known factors.

For the Potomac River, historical water quality data shows E. coli levels may vary from a range as low as 10 MPN/100mL to as much as 5,000 MPN/100mL on a given day. A more detailed explanation is posted on the District Department of Energy and Environment (DOEE) website at doee.dc.gov/release/potomac-interceptor-update-and-faqs.

Sample results from March 9 - present. Past results may be found here.

For the latest updates and information, including how to provide feedback on the environmental rehabilitation, go to our dedicated Potomac Interceptor Response page.