DC Water mobilizes to Prevent Major Sewer Line Collapse into Rock Creek

This year DC Water’s Contractors began an 18 month project to perform field investigations, surveys, and routine inspections of the sanitary sewer and manholes in Rock Creek Park. They found that a sector of the Rock Creek Main Interceptor that collects sewage from trunk lines in various neighborhoods and directs it towards DC Water's Blue Plains Advanced Wastewater Treatment Plant had a significant crack and was in danger of collapse. 

The Rock Creek Main Interceptor has a six foot diameter and generally follows Beach Drive north to south carrying as much as 100 million gallons of wastewater a day and could cause significant environmental harm to Rock Creek if a failure occurred.

DC Water’s Contractors using a closed-circuit camera system, video showed a 200-foot long fracture in the brick-lined tunnel ceiling. The compromised section of pipe is located in an embankment, near 26th Street and Pennsylvania Avenue Northwest. The sewer line carries combined stormwater and wastewater from Maryland and DC to the Potomac and Main Pumping stations. 

“We cannot run the risk of a failure that could cause a major discharge of sewage into Rock Creek and harm this natural resource,” said DC Water CEO and General Manager David Gadis. “We were fortunate to find this before it was too late, due in large part to our proactive approach that includes routine inspections of our aging infrastructure.”

Parts of DC Water’s sanitary sewer system were first built more than 200 years ago, and this section dates back to the late 1800’s. For decades DC Water neglected maintaining their water and sewer pipes infrastructure. In the 21st century DC water has made a massive investment in improving and replacing their infrastructure and become far more proactive. In 2021 they estimated that their Comprehensive Infrastructure Repair, Rehabilitation and Replacement Program would cost $319 million. The system wide inspections are part of this program.

For safety, DC Water has fenced off the area to restrict access until work can begin. Construction is not expected to impact traffic on Rock Creek Parkway and the bridge on Pennsylvania Avenue which crosses over the affected area.

An engineering analysis is underway to evaluate the cause of the fracture, and whether there are any other structural issues that must be addressed to stabilize the pipe. This will provide a better understanding of the underlying issues, and the scope of work necessary for repairs. A number of options are being considered and will likely include extensive construction. This may include building a diversion from the Rock Creek Main Interceptor to another sewer line, isolating or pumping out sewer discharges, or reinforcing the tunnel with steel rebar and high pressure concrete. 

The timeline for construction and repairs will be determined once planning and design work is completed.