3.4 miles of
24-foot diameter tunnel
65 million gallons
of storage
Challenges
- The Northeast Ohio Regional Sewer District has embarked upon a comprehensive combined sewer overflow (CSO) program totaling approximately US$3.0 billion in projects.
- These will dramatically reduce the overflows from combined sewers in the District's entire service area.
- This project needs to reduce CSOs to both Euclid Creek and Lake Erie.
Solutions
- Overall project management and project administration was provided by Hatch, the program's lead consultant.
- The design of the tunnel lining, shafts and adit-to-tunnel design, and tunnel ventilation design were all provided by our experts.
- Our other responsibilities included cost estimation, risk analysis, tunnel-boring machine (TBM)specifications, data, reports, drawings, and technical specifications for our designs.
- Coordination and phasing of the work was done to allow the site to be shared with developers of the future pump station, power substation, and tunnel project.
Highlights
- Approximately 3.5 miles of 24-foot diameter tunnel 200 feet below grade in bedrock.
- Annular grouting through TBM tailshield in bedrock.
- 6,300 feet of near-surface consolidation sewers (microtunneling, open-shield TBM tunneling, hand mine and open-cut).
- 40-foot and 50-foot diameter finished-tunnel access and surge-suppression shafts.
- Three additional tunnel-access shafts and shaft-to-tunnel adits.
- Diversion structures, CSO connection structures, regulators, gate and gate control structures provided.
- Five Baffle-type drop structures used, one of which is 32 feet in diameter, the largest of its kind.