EVOLVING ISSUES FOR CSO COMMUNITIES RELATED TO WET WEATHER AND WATER QUALITY STANDARDS

The Combined Sewer Overflow (CSO) Control Policy contains provisions for developing appropriate, site-specific NPDES requirements for all CSOs. The expectation of the CSO Policy was that long-term control plans (LTCPs) would be developed to meet water quality standards (WQS) and, where appropriate, States would revise their WQS to reflect the difficulty in achieving compliance with current bacterial standards in urban areas during wet weather events. However, WQS and designated use reviews have been or are being undertaken for only a few of the more than 900 communities with CSOs in the United States although in most cases LTCP implementation will not result in compliance with existing water quality standards. Furthermore, EPA will require all states to adopt new bacterial standards by 2003 as research indicates that current bacterial standards are not adequately protective of human health. The new standards were not anticipated by the CSO Policy, and therefore are not addressed by most existing LTCPs although LTCP implementation is a phased process often spanning 15 or more years.This paper discusses the difficulties CSO communities face in obtaining revisions to WQS to support the development of LTCPs that are cost-effective and protective of water quality and human health. The few approaches to revising WQS for CSO receiving waters that have been adopted by States are presented. A summary of the new EPA-recommended bacteria criteria for fresh and marine waters is provided, as well as the bacteria criteria for those States with CSOs that have moved to implement the EPA's new bacteria criteria. Finally, we present actions that CSO communities can consider taking to ensure they obtain the flexibility in their LTCP that was envisioned when the national CSO Policy was adopted in 1994.