Combined Sewage Overflow Example During Heavy Rains

Today the DC area was hit by around 3.4″ of rain within one hour, causing widespread flooding and inundation of many of the areas roads and public areas. One direct way that this rain can affect our rivers is by overloading our sewage systems and causing whats referred to as a “Combined Sewage Overflow (CSO)”. A CSO is when stormwater from the city’s roads flows into the same pipe as sewage from homes and offices and is forced to overflow into the rivers due to the shear volume of water. Around 1/3 of DC is served by this older combined sewage system that can cause these CSOs, potentially bringing sewage, trash, sediments, and other city pollutants into the rivers. DC Water is currently working on the Clean River’s Project which will aim to reduce the amount of overflows into all DC waters by 96%, and the Anacostia specifically by 98%. Unfortunately, with more intense storms becoming commonplace, these CSOs will continue until the Clean Rivers Project is complete; and even then it isn’t certain that all CSOs will be stopped. Check out the video below captured by Anacostia Riverkeeper Project Coordinator Robbie O’Donnell this morning to see what a Combined Sewage Overflow event looks like. This event took place around 10:00AM at the O St Pump house CSO outflow in Navy Yard on 7/8/2019.