SSO-700 Integrated Watershed Action Plan (IWAP) Water Quality Sampling Program: Purpose, Design, Implementation and Findings

The Metropolitan Sewer District of Greater Cincinnati (MSDGC) and Hamilton County, Ohio, are developing an Integrated Watershed Action Plan for the SSO 700 watershed, a 35 square mile watershed in the Greater Cincinnati area. The objectives of this work are to maximize improvement to water quality and meet Consent Decree SSO and CSO control requirements through an optimum combination of cost-effective and affordable gray infrastructure, sustainable infrastructure, and watershed-based controls. To support the development of project water quality models, an extensive water quality sampling program was conducted that included dry and wet weather in-stream sampling; wet weather source sampling of CSO, SSO, and stormwater; and in-stream flow monitoring. The program fully achieved the goals of collecting comprehensive and complete datasets to characterize pollutant sources and to produce well-calibrated watershed and surface water quality models. Ultimately, these models will be used to quantify MSDGC’s contribution to water quality impairment and demonstrate the mitigation of MSDGC’s contribution to impairment through the implementation of proposed projects.