MSDGC's Critical Assets Planning- The Pleasant Run Planning Challenge

Stated Purpose: The propose of this presentation is to summarize the planning approach for replacing and upgrading one of the Metropolitan Sewer District of Greater Cincinnati's (MSDGC) critical collection system assets – the Pleasant Run Force Main (FM) system. This presentation will provide an inside look at MSDGC's innovative planning approach for replacing the Pleasant Run FM system, the various alignment and coordination challenges, and the use of FLAMROC as MSDGC's planning tool for evaluation and final selection of alternatives. Benefits of Presentation: Several large cities have critical aging assets in heavily urban locations. Replacement and upgrades to these critical assets present various planning, design, and construction challenges. The Pleasant Run FM upgrades project is one such example of a planning challenge. The Pleasant Run FM's were originally constructed in the 1970's, have historically been maintenance intensive, and are considered to be among the most critical assets maintained by MSDGC due to the significant consequence of failure and large number of customers served. Sections of the force mains have been replaced and/or repaired frequently, and the lack of redundancy in the system presents one of the most significant environmental risks to MSDGC. There is currently no contingency plan to address failures which would result in large quantities of sewage overflowing into local streams or residential neighborhoods. The planning goal is to develop innovative cost feasible solutions that offer operational redundancy, 50-year asset life, and can be constructed with minimal interference to the existing system operation. Key take-aways from this presentation will include the development of alternatives through alignment challenges (such as avoiding a cemetery, crossing County boundaries, I-275 highway crossing, etc), coordination challenges of working with multiple local city governments and townships and their associated existing infrastructure (such as water main, storm sewers etc.) and the use of FLAMROC planning methodology for screening and final selection of alternatives. Project Description: This project is located in the Mill Creek sewer shed in Hamilton County, Ohio, between John Gray Road on the north, just south of Waycross Road on the south, the Pleasant Run West Pump Station (WPS) on the west, and the Pleasant Run East Pump Station (EPS) on the east. The EPS FM discharges to a 3,000-feet (ft) long, 16-inch diameter FM which runs along Hazelgrove Drive to Mill Road and discharges into the Central Pump Station (CPS). The WPS discharges into a 5,500-ft long, 24-inch diameter force main which runs under John Gray and Mill Roads to the CPS. The CPS repumps flow from the EPS and WPS into a 24-inch diameter force main which runs 7,000 feet under and along Mill Road to Gravity Sewer Manhole 30811002. Planning Approach Summary: Thirteen conveyance alternatives, and several sub-alternatives were evaluated to determine the best combination to convey wastewater from the Pleasant Run FM's to the downstream gravity sewer system. After narrowing down the alternatives into four options, the FLAMROC analysis evaluated alternatives on their Flexibility, Land Availability, Adaptability, Maintainability, Reliability, Operability, and Constructability (FLAMROC). The four alternatives listed below were found to be the most feasible and beneficial to MSDGC. 1. Alternative 1 (EPS to CPS, WPS to CPS, CPS to MH NO. 30811002) - One new FM from EPS to CPS (utilize existing force main) - Two new FM's from WPS to CPS - Two new FM's from CPS to MH - Rehab EPS, WPS and CPS - Equalization at WPS 2. Alternative 2 (EPS to WPS via force main, WPS to MH NO. 30811002) - Two new FM's from EPS to WPS - Two new FM's from WPS to MH - Rehab EPS - New WPS (demolish existing WPS) - Eliminate (demolish) CPS - Equalization at WPS 3. Alternative 3 (EPS to WPS via force main and gravity sewer, WPS to MH No. 30811002) - Two new FM's from EPS to high pt., 1 new dedicated gravity sewer from high pt. to WPS or upsize lower reach of existing downstream sewer to WPS to accommodate the added flow - Two new FM's from WPS to MH - Rehab EPS - New WPS (demolish existing WPS) - Eliminate (demolish) CPS - Equalization at WPS 4. Alternative 4 (EPS to WPS via deep gravity sewer, WPS to MH No. 30811002) - One new dedicated deep gravity sewer from the existing EPS site to WPS, including a majority of the gravity sewer installed via trenchless technology Two new FM's from WPS to MH - New WPS (and demolish existing WPS) - Eliminate (demolish) EPS - Eliminate (demolish) CPS - Eliminate (demolish) Kemper Mill Village Pump Station (KMPS) - Equalization at WPS. Based on FLAMROC scoring analysis, Alterative 2 (Figure 2) was eventually selected as the recommended alternative. This alternative includes the following components: - Rehabilitate the existing EPS - Install new dual FM from the existing EPS to the new WPS - Abandon in place the existing EPS FM - Construct new WPS - Demolish the existing WPS - Abandon in place the existing WPS FM - Construct new 300,000-gallon EQ Tank at WPS. - Install new dual FM from the new WPS to existing MH 30811002 - Demolish the existing CPS - Abandon in place the existing CPS FM The projected costs are as follows: - Total Construction Cost: $27,2,000,000 - Total Budgetary Cost: $49,308,000 - Net Present Value (NPV) / Life Cycle Cost: $39,400,000 - Equivalent Annual Life Cycle Cost: $2,500,000 Project Status of Completion: The planning phase was completed in the summer of 2021. The project is anticipated to take over five years from design through construction, with Design of Alternative 2 beginning in August 2021. Originality: This project had several creative and innovative solutions evaluated as part of alternative development. Alterative 4 proposed to build a deep gravity tunnel and install dual FM's in the same casing pipe as that of the gravity sewer. Alternative 2 proposed redundant force mains with cross over vaults to switch flows between dual force mains when needed. MSDGC's FLAMROC analysis was used to develop weighted scoring criteria for non-cost factors that were important to MSDGC.