In recognition of Infrastructure Week, the Northeast Ohio Regional Sewer District (NEORSD) invited area media for a tour of the Westerly Storage Tunnel on May 15. Westerly is the most recent large-diameter tunnel in the District’s 25-year, $3 billion Project Clean Lake, a CSO control plan that is cleaning up Lake Erie, the Cuyahoga River and other area waterways.
The Westerly Storage Tunnel contract was awarded last spring to a joint venture of Jay Dee–Obayashi, which bid $135 million. The project includes approximately 9,600 lf of 25-ft ID CSO storage tunnel excavated in rock and supported with a bolted, gasketed, one-pass steel fiber reinforced concrete segmental lining, being manufactured in nearby Macedonia, Ohio. The JV will be using a new Lovsuns TBM that is being built in China.
In addition to the tunnel, there are three deep shafts, with slurry walls built by Nicholson Construction:
– WST-1: 46-ft diameter online access shaft at the TBM retrieval site.
– WST-2: 12-ft diameter baffle drop structure, connected to the main tunnel via a 5-ft diameter, 50-ft long adit in rock.
– WST-3: 40-ft diameter baffle drop structure at the TBM launch site.
Ancillary work includes Gate Structure and Gate Control Structure, at both the WST-2 and WST-3 sites, to regulate flow entering the tunnel, approximately 90 lf of 46-in. diameter sewer, and miscellaneous modifications to existing sewers.
When completed, Westerly will reduce overflows from the Walworth Run Sewer, one of the District’s biggest CSO points. The sewer was a natural stream that was culverted more than a century ago.