Major investments in underground water infrastructure continue to advance across the United States as utilities work to improve environmental performance and system resilience. Construction has begun on the Piney Branch Tunnel, the final segment of Washington, D.C.'s Clean Rivers Project, marking another milestone in the region's long-term wastewater improvement program.
DC Water has started construction of the Piney Branch Tunnel beneath Rock Creek Park, launching the final phase of the DC Clean Rivers Project.
The underground tunnel is designed to capture combined sewer overflows generated during heavy rain events, helping prevent untreated wastewater from entering Rock Creek before ultimately reaching the Potomac River.
Clark is participating in the delivery of the infrastructure project as work progresses toward completion.
Upon completion, the Piney Branch Tunnel is expected to reduce sewage overflows into Rock Creek by approximately 96% during major storm events, supporting broader efforts to improve regional water quality and environmental protection.
The DC Clean Rivers Project is one of the nation's significant long-term combined sewer overflow mitigation programs, incorporating large underground storage tunnels and related utility infrastructure to modernize Washington's wastewater system.
Underground tunnel projects remain a critical component of municipal infrastructure investment as utilities address aging sewer systems, regulatory compliance and environmental goals. For construction owners and infrastructure contractors, projects such as the Piney Branch Tunnel demonstrate continued demand for large-scale civil construction, tunneling expertise and long-term water infrastructure upgrades.
Source: Clark Construction.
