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Page 28 • August 24, 2019 • www.constructionequipmentguide.com • CONSTRUCTION EQUIPMENT GUIDE NEORSD Expects to Finish DST By December 2019 Launched in 2011, Project Clean Lake is a $3 billion, 25-year plan to reduce CSO volumes affecting Lake Erie via the con- struction of seven storage tunnels, green infrastructure and three treat- ment plant improvements that will reduce CSO by four billion gallons annually. “When Cleveland entered into its consent decree in 2011, [the city] discharged an estimated 4.5 billion gallons of raw sewage into the lake,” noted Salini Impregilo. “Although the volume is half of what it was in the 1970s, the city needs to reduce it even more to meet standards set under the Clean Water Act.” “The Dugway series of sewer projects is extensive and critical to the future of clean water in the region” Elting said. “It is a network of sewers and tunnels being con- structed to reduce combined CSOs, ensuring a cleaner environ- ment for the Glenville neighbor- hood and beyond.” The Dugway work will create 32,000 ft. of new sewers ranging from three to 24 ft. in diameter. Dugway West was completed in August 2017 ($52 million) and Dugway South was substantially completed in August 2018 ($26 million). The Dugway East Interceptor Relief Sewer project ($11 million, completed in December 2011) also helps to mit- igate combined sewer overflows on Cleveland’s east side, but this project was completed prior to Project Clean Lake. The Dugway tunnels, along with the Euclid Creek Tunnel proj- ects (completed in 2015), will han- dle 950 million gallons annually. And the new tunnels are needed. “Cleveland’s earliest sewers are combined sewers,” stated a docu- ment distributed to local residents during public consultations. “Built around the turn of the 19th century, these sewers carry sewage and stormwater in a single pipe. During heavy rains, when there is a dra- matic increase of water flowing through the sewers, some of the combined wastewater and stormwater is allowed to overflow into area waterways to prevent urban flooding. This combined CSO harms our environment.” Design work for the DST was completed by a joint venture of MWH Americas Inc. and Mott MacDonald LLC. A design-bid-build contract was selected based on a combination of the NEORSD’s governing rules and the many geotechnical, proper- ty acquisition, flow monitoring, property and hydraulic work asso- ciated with the project. “Meeting our consent decree dates, CSO requirements, and avoiding the large claims by iden- tifying and investigating all of the major risk items were among the top challenges,” said the NEORSD’s Doug Lopata. “Via the Euclid Creek Tunnel project, we learned the importance of identify- ing utilities early on for either relo- cation or avoidance when possible.” The lifespan of the tunnel is approximately 100 years. The ini- tial boring had the DST at 27 ft. in diameter, but once the precast seg- mental concrete rings lined the walls, the internal diameter is close to 24 ft. The tunnel is between 200 to 230 ft. below ground and has six shafts of varying diameters and depths, along with a series of con- crete structures for the collection and transporting of wastewater and rainwater. Thus far, the Salini Impregilo/Lane Construction JV has completed the tunnel, six shafts — DST-1, DST-2, DST-4, DST-5. DST-7, and DST-8 — and four adits at DST-2, DST-4, DST-5, and DST-7. The remaining work includes lining the 200 ft. of the ECT tail tunnel, which covers the area from the DST-1 shaft to the ECT tail tunnel. Crews are current- ly prepping the work site. "The lining will be cast-in-place and should be completed in October,” explained Buck Depew, the NEORSD’s construction Northeast Ohio Regional Sewer District photo The TBM before mining, being brought to the mining tunnel shaft. Northeast Ohio Regional Sewer District photo Assembly of the Dugway Storage Tunnel project’s gantry crane. TUNNEL from page 1 see TUNNEL page 32 Northeast Ohio Regional Sewer District photo The TBM’s cutterhead in place in the mining shaft. “Meeting our consent decree dates, CSO requirements, and avoiding the large claims by identifying and investigating all of the major risk items were among the top challenges.” Doug Lopata Northeast Ohio Regional Sewer District
