Federal, State, Regional, and City Resources Combine With a Common Goal: Create a Better Environment

PROJECT BACKGROUND A neighborhood within the City of Garfield Heights, OH, has a history of complex sewer system issues, including Basement Backups (BBUs), Combined Sewer Overflows (CSOs), sanitary/storm sewer cross-connections, and water quality issues within the surrounding stormwater receiving stream, Wolf Creek. This neighborhood is located directly upstream of Mill Creek, and along Wolf Creek and a recreational pond in the City's historic Garfield Park, which was established in 1894 by the City of Cleveland. During the 1960s, the park experienced water quality problems due to population growth in upstream communities. The Cleveland Metroparks took over ownership in the 1980s and have invested in restoration of the pond, currently scheduled to open in the summer of 2024. The Northeast Ohio Regional Sewer District (NEORSD) was established in 1972 and currently serves more than 1,000,000 residents. Made up of 63 member communities, including Garfield Heights, NEORSD collects and conveys wastewater, manages stormwater, and maintains CSOs throughout their service area. NEORSD conducted a Local Sewer System Evaluation Study (LSSES) to identify and provide solutions to water quality issues within Garfield Heights. The LSSES showed the neighborhood's sewer configuration is 15% combined sewer and 75% over/under or common standard sewer configuration, which are separated sewer systems that contribute to inflow/infiltration (I/I). Identified water quality issues included 160 reported BBUs and an estimated 56 CSO activations in a typical year, totaling 9.5 million gallons. Figure 1 shows the mix of combined, sanitary, and storm sewers in the project area. PROJECT OVERVIEW NEORSD received $2 million in federal and state appropriation dollars in 2023 to fund the CSO-249 Elimination Project and solve the lingering capacity and water quality issues, as well as direct more polluted flow to their Mill Creek CSO Tunnel. Using a 'Multi-Criteria Decision Analysis' tool (MCDA) during the project's planning phase, the project team evaluated costs and a range of benefits, including quantification of stormwater removed from the system, inflow volume to Mill Creek Tunnel, impact to private property and residents, number of BBUs relieved, and construction cost. Criteria were developed into a scoring tool to perform a more comprehensive assessment of alternatives and develop a final recommendation for capital improvements, using capacity, water quality, and level of service benefits considerations. Once construction is complete, the CSO-249 Elimination Project will successfully convert the outfall into a 'storm-only' conveyance system, eliminate seven Regulator structures that require routine maintenance, improve level of service at all locations within the project area, and reduce Typical Year overflows by over 6 million gallons. The project will also accomplish further sewer separation by diverting more than 1 million gallons of stormwater flow away from the Mill Creek Tunnel during the District's Typical Year, freeing CSO capacity for surrounding locations. The project's design phase began in mid-2023, and construction is anticipated to begin during the summer of 2024. DATA COLLECTION & PROBLEM IDENTIFICATION NEORSD, the City of Garfield Heights, and the County of Cuyahoga Heights worked collaboratively by sharing common data working toward a common, yet complex goal of solving capacity issues throughout the system. Some of this shared data included closed circuit television (CCTV), flow monitoring, water quality testing results, 3D inspection reports, as built record drawings, and basement backup reports. For the District, the cause of CSOs was determined to be due to a lack of conveyance capacity in the combined system whereas the basement backups are due to I/I in the separated system. Water quality testing was performed by the District throughout the project area to strategically bracket any illicit lateral connections to the storm sewer system. This information was used to identify viable sewers for performing sewer separation. For some sewers, the water quality results indicated that there was a substantial amount of E. coli greater than 15,000 MPN/100mL which helped narrow down viable solutions. Manhole inspections were performed to identify cross connections between the storm and CSO overflow system. Basement backup reports provided by Cuyahoga County, along with flow monitoring data were used to calibrate the hydraulic model, which was used as a tool for alternatives analysis. ALTERNATIVES ANALYSIS The MCDA screening tool was used to help identify solutions that would benefit all parties including NEORSD, the City of Garfield Height, and all residents who reside in the project area, and residents who recreationally use the downstream Garfield Park, taking socioeconomic factors into consideration. The project team's approach to alternatives analysis was to find shared problems and solutions for both agencies, which included the following steps: 1.) Identify common agency problems, 2.) Identify unique agency problems 3.) Identify common agency solutions, 4.) Establish solutions criteria and weighting, 5.) Run scoring tool and analyze results. The resulting scores were used to help narrow in on the preferred solution set. Figure 2 shows the results, including the high-scoring alternative in comparison and indicated that a blended solution would provide the best overall cost-versus-benefit.