DC Water at Work: Collaboration for Common Cause

As the District of Columbia’s (DC) largest tributary to the Anacostia River, Watts Branch has 5,500 acres of watershed in DC, and an additional 6,000 acres in Maryland, where its headwater originates. From 2018 to 2020, climate changes brought record shattering torrential storms, converting a calm creek into a white water in a couple hours. In early 2021, the inspection and enforcement staff of District of Columbia Department of Energy and Environment (DOEE) notified a DC Water engineers that a sanitary sewer manhole M-41235 was exposed from a significant washout in Watts Branch Stream in a community park. The same sewer had been lined two years prior, as part of a capital improvement project (CIP), and at the time of the lining, the manhole and sewer appeared to be about 6 ft behind the embankment. Upon an in-depth field and record evaluation, it was determined that the 24″ sanitary sewer inlet and outlet of the manhole could have been further exposed if urgent action was not implemented. DOEE and DC Water collaborated on strategizing on an expedited action to build a protection wall, in the approximate 8-ft washout zone in front of the sewer, to prevent undercutting of the sewer pipe. This wall leaves sufficient space for a permanent embankment to be designed, and constructed, by the creek owner in the future. The DOEE associate director demonstrated genuine stewardship by advising DC Water not to wait for a full-scale permitting to kick off the mitigation. This helped to avert a potential sanitary sewer overflow, SSO, while implementing best management practices, BMP. DC Water’s geo-structural engineer and emergency contractor implemented a design-build mitigation plan within a couple of weeks. The timely, proactive work completed in the spring of 2021 has already protected the sewer from being undercut during several torrential storms, including the one induced by Hurricane Ida. This presentation focuses on limited embankment protective work to protect buried sewer assets in sensitive areas, as a non-owner of the creek. It also shows collaboration between a regulatory agency and non-governmental municipal agency, and how both agencies used a goal-oriented, joint action to avert a catastrophic event in the interest of public and environment.