Deep Rock Tunnel Connector Pump Station

Completed in 2019 by Southland Contracting, the Deep Rock Tunnel Connector Pump Station Project was an effort to improve the water quality for the residents of the City of Indianapolis, the owner needed a combined sewer overflow (CSO) collection system at multiple locations. The main function was to construct a pump station to empty the tunnel system and deliver the flow to the Southport Advanced Wastewater Treatment Plant (SAWWTP). Three CSOs capture sewage from the city’s largest overflow points and then transport it to the underground Deep Rock Tunnel Connector Pump Station (DRTC PS), where it is then pumped to the SAWWTP. The project is currently delivering 54 MGD of the planned 270 MGD of CSO storage for treatment, as well as accommodating future connections to other tunnels in the overall system. The project consisted of a subterranean pump station, 60 feet wide by 98 feet long by 66 feet tall, constructed 275 feet below ground. Access to the pump station occurs through a 275-foot deep by 44-foot inside diameter (ID) main access shaft. An additional equipment shaft, 279 feet deep by 23 feet in diameter, was constructed and lined with cast-in-place concrete. A 6-foot ID tunnel connects the existing screen and grit shaft to the new pump room 180 feet away. The team mined the shafts and tunnel through rock, excavating 60,800 tons of rock throughout the duration of the project.