The EasterlyTunnel Dewatering Pump Station (ETDPS) project is 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, Ohio.
The project is the second major component scheduled as part of the $3 billion (USD) Easterly CSO Plan Improvements Program. This project will enable the Northeast Ohio Regional Sewer District (NEORSD) to meet critical requirements associated with their Consent Decree, resulting in fiscally sound solutions for the community and meeting Board expectations. NEORSD selected MWH to provide design and construction administration services for this complex project.
Built around the turn of the nineteenth century, Greater Cleveland’s earliest sewer tunnels are combined sewers, carrying sewage, industrial waste, and stormwater in a single pipe. The 160 million-gallon-per-day (mgd) ETDPS will provide the means to entirely dewater the storage tunnels at the end of each wet weather event and pump combined sewage to the Easterly Interceptor for transport to the Easterly Wastewater Treatment Plant. The pump station, equipped with nine pumps, will enable these tunnels to capture flows in a controlled fashion that would have otherwise been discharged into surface waters causing urban flooding and discharges of sanitary sewage to the environment.
These nine pumps include:
- Main dewatering pumps
- Four 40-mgd vertical non-clog
- One 20-mgd vertical non-clog
- Final dewatering pumps
- Two 10-mgd horizontal non-clog
- Sump/emergency drainage pumps
- Two 1-mgd dry pit submersibles
Sump pumps are being designed to remove infiltrated groundwater and on-site generated wastewater, while also serving as emergency pumps during catastrophic flooding. The pump station will be 240-feet underground, 35-feet below the Euclid Creek Tunnel and Dugway Storage Tunnel CSO tunnel storage system invert (cavern), and will be approximately 140-feet-long by 56-feet-wide by 66-feet-high. Two egress shafts are provided, each 40-feet in diameter. Shafts also serve to accommodate room for discharge pipes, HVAC ductwork and electrical conduits.
The current plan proposes to dewater the tunnel in a 24-hour period in anticipation of back-to-back storm events. Flow from the tunnel storage will be pumped when influent flows recede and sufficient capacity has been restored to the Easterly Wastewater Treatment Plant following a wet weather event. Upon completion, the MWH team anticipates the ETDPS will be activated about 80-times-per-year; will completely fill about four-times-per-year; and the pumps will operate on average 340-hours-per-year.
Project start date – 3 January 2012
Scheduled completion date – 24 December 2015
Engineering design cost – $6.94M
Construction budget – $69.7M
- Alternative analysis
- Preliminary and final design
- Construction administration
- Coordination with stakeholders
Previous studies developed a Base Project Alternative for the project, estimated at roughly $96M. The first task MWH completed for NEORSD was identification of alternatives to the base project and a thorough evaluation. MWH identified three alternatives, one of which provides the client more than $25M in savings.
- Cleveland, Ohio, United States
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