The Shoreline Storage Tunnel (SST) Project is part of Project Clean Lake, a $3 billion, 25-year program NEORSD began in 2011 to meet Clean Water Act standards and address water quality issues. Project Clean Lake will eliminate 4 billion gallons of wet weather combined sewer overflows (CSOs) released each year into Lake Erie and its tributaries in the Greater Cleveland area.
The SST Project is a 23-foot diameter storage tunnel approximately 14,100 feet and is the first phase of CSO control measures required at this location under Consent Decree Control Measure 7. DLZ led the CCTV inspection and condition assessment of 2,500 feet of sewer, including repair recommendations for a variety of shapes that include circular, egg, arch, and rectangular sewers ranging from 15- to 120-inches in diameter.
The primary focus of the sewer rehabilitation on the SST Project includes the assessment and repair recommendations for an existing 120-inch diameter circular brick sewer with a longitudinal fracture in the crown. The existing sewer is critical for the overall success of Control Measure 7, which is to serve as a tunnel conveyance sewer to relieve 750 MGD of flow from the existing Easterly Main Branch Interceptor during the design rainfall event. It reduces the overall Control Measure 7 estimated construction cost by over $80 million by providing relief of the existing interceptor through the current sewer system. Rehabilitation of the existing sewer included an assessment of cost and overall constructability, including a variety of construction methods and materials.