A Real Time Control (RTC) Feasibility Study concluded that CSO control requirements for the City of Ottawa could be achieved through the implementation of a more efficient operating strategy at key flow regulators along the City's interceptor sewer system. The project provides a simple and costeffective solution that can be integrated within existing regulator structures, the existing SCADA system, and operating procedures. The system is designed to be robust with fail-safe features ensuring reliable performance under any event. The paper presents the work that was completed in optimizing the preferred real time control approach and highlights some of the more challenging and innovative elements of the design for the retrofit of these major flow regulators, the development of the operating philosophy and process control narratives, the selection of the control equipment and instruments, and the more detailed performance evaluation of the pre-design configuration done with the RTC model. Physical model testing of the largest and most important regulator, the Rideau Canal Regulator, was conducted to confirm the existing capacity and to provide the basis for developing a preferred option for increasing the flow capture rate at this site.