Lexington and Payne CSO Basin: Improving Water Quality in Downtown Louisville
As part of its Integrated Overflow Abatement Plan (IOAP), the Louisville and Jefferson County Metropolitan Sewer District (Louisville MSD) retained Hazen and Sawyer to design a 13.7-million gallon combined sewer overflow (CSO) storage basin, an integral 16.5 mgd pump station, seven CSO diversion structures, and nearly 1-mile of large diameter interceptor sewer (ranging in size from 84-inch to 102-inch diameter).
Each of the existing CSO locations currently discharge into the South Fork Beargrass Creek Improved Channel, an existing concrete channel running through a congested urban area of central Louisville. The Lexington and Payne interceptor will be constructed underneath this concrete channel and will convey diverted flow from the nine existing CSO locations to the proposed CSO basin.
The Lexington and Payne CSO concrete basin will intermittently receive flow by gravity from nine nearby CSOs during storm events when the existing interceptor becomes surcharged. The facility will pump flows back to the interceptor when the storm event has subsided and the interceptor has sufficient capacity to convey these flows to the sewage treatment plant. This project is one of the largest of several CSO basin projects identified in Louisville MSD’s IOAP. The projects identified in the IOAP will bring Louisville MSD into compliance with the Clean Water Act (CWA) by eliminating unauthorized discharges from MSD’s separate sewer system, combined sewer system, and water quality treatment centers. The Lexington and Payne CSO Basin is currently under design with final construction completion anticipated by March 2020 at an estimated cost of approximately $62 million.
Project Outcomes and Benefits
- The CSO detention basin will be constructed underground to enhance operations, minimize visibility to the public, and preserve green space atop the basin.
- The CSO detention basin will be fully equipped with floor flushing systems, and odor control system, and operator walkways inside the basin.
- The pump station will include flow monitoring and emergency standby power.
- The interceptor will be constructed beneath the improved concrete channel to minimize excavation depth, utility conflicts, and impact to the public.
- The project will eliminate CSO discharge from nine CSOs during a typical year design storm currently discharging to the South Fork Beargrass Creek Improved Channel.
- The project will improve water quality in the South Fork Beargrass Creek, and receiving streams downstream.