The Easterly Tunnel Dewatering Pump Station (TDPS) project was one of the largest combined sewer overflow (CSO) pump station projects in the U.S., and is a critical component to addressing CSOs in Cleveland. The project was the second major component scheduled as part of the $3B Easterly CSO Plan Improvements Program.

The previous Easterly collection system contained both combined and sanitary sewer overflows (CSO/SSO). The combined sewer system had regulators that diverted excess flows to local waterways and Lake Erie. Intercepted flows were routed to the Easterly Wastewater Treatment plant (Easterly WWTP) through three individual interceptors. NEORSD commissioned several studies aimed at reducing CSOs, which concluded that deep tunnels for CSO storage and an associate pump station were needed.

Designed by MWH and constructed by a joint venture led by Atkinson Underground, the TDPS provided the means to entirely dewater the storage tunnel system at the end of each wet weather event and pump combined sewage to the Easterly Interceptor for transport to the Easterly WWTP. The pump station is 230 feet underground—22 feet below the Euclid Creek Tunnel and Dugway Storage Tunnel CSO tunnel storage system invert (cavern)—and is approximately 185-feet-long by 45-feet-wide by 60-feet-high. The main shaft is approximately 45 feet in diameter and contains an elevator, main stairwell, and an equipment removal shaft. An auxiliary shaft—approximately 40 feet in diameter—houses the auxiliary stairwell pump discharge piping and HVAC ductwork.

Atkinson Underground’s role on the project was excavating both shafts and the pump station cavern.