Cleveland's $3B Project Clean Lake Features Large-Scale Storage Tunnels

"Work for Project Clean Lake began in 2011, but we actually started the planning years before, in 1995," said Devona Marshall, NEORSD's director of engineering and construction. "The sewer district was created in 1972, and with decades of infrastructure investments to manage combined sewer overflow, such as construction of interceptor sewers, auto-regulators, weir modifications and a prior tunnel project, we were well-equipped to plan for the future." The focus of Project Clean Lake is construction of large-scale storage tunnels and treatment plant enhancements.

A total of seven tunnels are being built, ranging from 2 to 5 mi. in length, as deep as 300 ft. underground and as much as 24 ft. in diameter, large enough to park a semi-truck. A consent decree involving the EPA, Department of Justice, state of Ohio and the sewer district outlining the plan to reduce combined sewer overflows was initially approved by the sewer district board of trustees in December 2010.

It became official approximately six months later. Out of 82 planned projects involving multiple contractors and subcontractors, 72 are completed or active as of January 2023. Euclid Creek Tunnel, Dugway Storage Tunnel and Doan Valley Tunnel are already operational.

Once the electrical substation for the Westerly Tunnel dewatering pump station is complete, it will go online. Design for the Southerly Storage Tunnel began in 2021, with design starting for Big Creek Tunnel next year. Crews are currently mining the Shoreline Storage Tunnel.

"Every tunneling job creates unique situations for the contractor, and this is the first ‘soft ground' tunnel for our program," said Ryan Sullivan, construction supervisor of NEORSD. "The four previous tunnels were all excavated through Chagrin Shale, which is rock. "The geology of this tunnel's location dictates that the tunnel needed to be in the silts, clays and sands above the bedrock. While similar equipment and techniques are used for both, there are slight differences the contractor had to change for this tunnel." With most of the tunnel work taking place 150 ft. below ground, weather does not have a noticeable effect on the work or the crews; however, the process is extremely time-consuming.

"The tunneling itself takes the most time," said Sullivan. "The removal of 310,000 cubic yards – 120 feet below ground and more than 15,000 feet in length – doesn't happen quickly." For the Shoreline Storage Tunnel, crews have been working at the main mining site for years. With construction of four deep tunnels required to send flows to the Easterly Wastewater Treatment Plant, this site is where the Shoreline Storage Tunnel and Dugway Storage Tunnels intersect.

Prior to construction of the Shoreline Storage Tunnel, all the deep tunnels have been single-pass tunnels, except for one leg of the Doan Valley Storage Tunnel. This means the tunnel is mined and lined using a single piece of equipment — a tunnel boring machine (TBM). For the Shoreline Storage Tunnel, workers are using a Herrenknecht S-1312 tunnel boring machine — 26-ft.

Earth Pressure Balance TBM. Mining has just begun on this project, with crews still learning the ins and outs of the TBM. Other equipment has included a H+E continuous conveyor; H+E vertical conveyor; Imperial radial stacking conveyor; Siemens grout plant; Delta cooling towers water cooling plant; Atlas Copco air compressors and backup generators (GA 160, GA 110, XATS1050); Reimers System Inc. hyperbaric medical lock and shuttle (7806D and 5406D); and a Spendrup 125 ventilation fan. A Techni-Metal Systems multi service vehicle also has been on site, along with a Liebherr HS 885 HD 150-ton crane; a SANY SY500H 120,000-lb. excavator; a Cat 950 wheel loader; a SANY STH1256 telehandler; a Cat 259D skid steer; a Genie z45/25j manlift; a Generac Industrial 500 kW backup generator; a Cat 320D 60,000-lb. excavator; a Cat 308E 20,000-lb. excavator; a Manitowoc 888 230-ton crane; and a Liebherr LB 35 drilling rig.

The main material being used in the construction of the tunnel is precast concrete tunnel segments made in Macedonia, Ohio. The program also includes significant green infrastructure investment, such as stormwater control measures to store, infiltrate and evapotranspirate stormwater before it even makes its way to the combined sewer system. This could reduce the long-term cost, while enhancing neighborhoods, providing economic development opportunities and rebuilding the community.

"The sewer district implements green infrastructure across our programs where it's the right solution for the problem at hand," said Kyle Dreyfuss-Wells, NEORSD's chief executive officer. "Our green infrastructure policy lays out this commitment, and we work to ensure green infrastructure is integrated into our work and demonstrates the most effective applications of this technology."

Project Clean Lake is funded through sewer use fees paid for wastewater treatment. Frank Greenland, former planning manager and current director of watershed programs at the sewer district, said being part of such a major undertaking is extremely gratifying.

"This is our job, but also our commitment to the residents of northeast Ohio. In addition to Project Clean Lake, we have a robust regional stormwater management program that will further benefit the region for decades to come." "Our work is fascinating," added Dreyfuss-Wells. "We serve 63 communities, with 750 employees to protect water quality and public health in the Lake Erie watershed.

With a $190 million annual operating budget and $216 million in annual construction, we deal with engineering, environmental science, hydrology, industrial technology, finance, public policy, legal issues and deeply personal issues as folks are impacted by flooding, erosion and water quality concerns." According to Marshall, "It's very rewarding to see Project Clean Lake come to fruition.

To date, the work completed under the consent decree has led to elimination of about 1.7 billion gal. of overflow from discharging into the environment each year, with the reduction of another 300 million by the end of 2023."

Marshall noted that the work is challenging, but not overwhelming. "We have a talented team here at the sewer district in charge of planning and managing projects, so we are able to meet the deadlines outlined in the consent decree. In addition, we are regularly looking for value-added engineering opportunities and sound project management to ensure we are delivering projects both efficiently and cost effectively."

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