Case Study: Real Time Control Strategies for CSO Control

The City of Indianapolis Department of Public Works (DPW) developed the CSO Long Term Control Plan (LTCP) in 2007, which identifies the role of real time control (RTC) of wetweather flows in overall CSO control effort and discusses the need for effective RTC strategies. The DPW adopted a practical “walk before you run” strategy that progresses stepwise from localized to regional to system-wide RTC measures to produce an effective system tailored to DPW's needs. This incremental approach is designed to verify benefits at each stage and to ensure proper operations and maintenance support is in place prior to implementation.DPW completed the first phase of RTC evaluations in 2005. This resulted in a set of early action projects (EAP) that used RTCs to achieve in-system storage and reduction of CSOs. In the recently completed second phase, DPW evaluated and enhanced the performance of the 11 EAP, established the guidelines for additional RTC projects based on the lessons learned and identified additional RTC projects within the existing system to maximize the in-system storage. In addition, the second phase effort includes a strategy for implementing RTC in DPW's system as a component of major LTCP projects, such as the deep tunnel and its components, which will be constructed through 2025. This technical paper provides a comprehensive case study on the overall approach used for the RTC integration into long-term CSO control efforts.