Design and Implementation of a Water Quality Field Monitoring Program in Support of CSO Long Term Control Planning

Abstract

In 1999, The Metropolitan Sewer District of Greater Cincinnati, Ohio (MSD) began negotiations with the United States Department of Justice, the United States Environmental Protection Agency, and the State of Ohio to create a program to address sanitary sewer overflows (SSO) and combined sewer overflows (CSO). The resulting document, the Consent Decree, formally outlined a process that MSD would follow and that government agencies could recognize and support. MSD had been addressing removal and reduction of SSOs and CSOs prior to the Consent Decree negotiations, but the Consent Decree defined a time frame as well for MSD. The Consent Decree required MSD to update the CSO Long Term Control Plan (LTCP). An important component of the CSO LTCP Update is the assessment of CSO control alternatives with respect to receiving water quality. As such, a field program was designed and implemented to support water quality modeling and CSO planning objectives. The field program would coincide with the water recreation season, starting in May and ending in October. The field program contained several components associated with dry and wet weather sampling and monitoring as outlined by the Consent Decree; Ohio River sampling, source characterization (CSO, SSO and Storm), and tributary sampling and continuous monitoring. This paper discusses the continuous monitoring component of the tributary sampling and monitoring program. Starting with the conceptual plan described by the Consent Decree, it outlines the process of converting a conceptual ideal into a workable field program including the installation, maintenance, data management and demobilization activities. Specific examples of unique site limitations are provided with the solutions tried and the resulting outcomes.