Session 11E: It Is Easy Being Green: Spend Less Green with Green Infrastructure

摘要

In 2005 Louisville and Jefferson County Metropolitan Sewer District entered into a ConsentDecree with the United States Environmental Protection Agency (EPA). In 2009 MSDsubmitted the Integrated Overflow Abatement Plan (IOAP) to address Sanitary Sewer Overflows(SSOs) as well as Combined Sewer Overflows (CSOs). As part of the IOAP, MSD performed abenefit/cost analysis for each overflow location to determine the highest value overflowreduction project in an average rainfall year. In order to reduce CSO frequencies, MSD modeledsolution alternatives for CSO abatement and then completed a cost benefit analysis for eachalternative to determine the solution with the best cost benefit ratio. The best solutions wereimplemented into the Long Term Control Plan. Many of these solutions involve large storagebasins that capture overflows at the end of the pipe. As a part of the IOAP, MSD also committedto incorporate ‘green’ solutions to help downsize the downstream gray solutions, where thissituation was cost effective. MSD defines green solutions as those that capture storm waterbefore it enters the Combined Sewer System (CSS) and allow it to infiltrate into the ground.Gray solutions are defined as those that capture or reduce overflow volume and frequencythrough conveyance and storage of water once it has entered the MSD sewer system. Thepurpose of this paper is to describe how Louisville MSD creatively sought out, investigated, andpursued opportunities to incorporate green infrastructure into an overflow abatement plan.