Simulation and assessment of long-term stormwater basin performance under real-time control retrofits

The use of real-time control (RTC) as an adaptation technique for improving stormwater systems has been gaining attention in recent years for its ability to enhance water quality treatment and quantity management. An RTC retrofit of seven existing detention basins was simulated for a small (162 ha), an urbanized watershed in Blacksburg, VA. Two heuristic, reactive control algorithms were tested for their ability to improve hydraulic conditions at each facility and the watershed outlet through manipulation of an actuated valve. For 24-hour design storms, RTC only reduced peak flows at certain facilities for events with a return period of 2 years or less. For larger design storms, RTC maintained or increased peak flow rates. During a 15-year historic rainfall simulation, RTC retrofitting reduced the total duration of erosive flows for most facilities; however, the duration of high intensity flows increased, or remained unchanged. This result was also reflected at the watershed outlet.