The Potomac River Tunnel (PRT) is the next major combined sewer overflow (CSO) control project that is part of the overall DC Clean Rivers Project. The purpose of the DC Clean Rivers Project is to control the CSOs to meet water quality standards in the Anacostia River, Potomac River, and Rock Creek by increasing the capacity of the sewer system. The PRT consists of a large-diameter deep tunnel under the Potomac River, seven CSO diversion facilities, drop shafts, and support structures to capture flows from existing CSOs along the Potomac River and convey them to the Blue Plains Advanced Wastewater Treatment Plant. With project completion in 2030, the 5.5-mile-long Potomac River Tunnel will provide a 93% reduction in the volume of CSOs to the Potomac River in an average year of rainfall.
Two tunnel boring machines (TBMs) will launch from the 60’ ID mining shaft at West Potomac Park. The northbound TBM will head towards CSO-029, passing through in-line shafts at CSO-022 (45’ ID) and CSO-028 (42’ ID), and terminating at the CSO-029 exit shaft (45’ ID). The southbound TBM will terminate at the existing JBAB drop shaft beneath the existing overflow structure. Ground improvement and temporary bulkheads inside the shaft will be used in conjunction with SEM techniques to connect the southbound tunnel to the existing JBAB infrastructure.
Gall Zeidler Consultants (GZ) is part of the Construction Management team, its services include design review, submittal review and technical input into the proposed solutions. GZ is presently providing on-site environmental compliance management services and will provide resident engineering and inspection services when tunneling starts.