Evaluating the Watershed-Scale Effects of Real Time Stormwater Control Using a Process-Based Modeling Approach

Abstract

Extreme storm intensity and frequency have increased over time as a result of climate change, making sustainable stormwater management a challenging task. The accurate development and application of hydrological models play a crucial role in water resources management and urban planning. The integration of Real Time control (RTC) with conventional Stormwater Green infrastructure (SGI) designs enhances their performance by enabling swift and context-sensitive responses to stormwater challenges. The dynamic control provided by RTC optimizes the efficiency of (SGI) practices, effectively addressing the increased runoff and decreased baseflow associated with urbanization.

In this study, we utilized a process-based hydrological model to evaluate the effects of integrating Real-time Control (RTC) into SGIs on the long-term hydrological. We created and calibrated a model representing the baseline condition of the selected watershed. To represent the watershed, it is discretized into 14 smaller sub-watersheds. Each sub-catchment is represented by previous and impervious catchments, two soil layers, groundwater, stream, surface water outlet, ground water outlet, and connectors that represent the interface between connected blocks. Subsequently, we analyzed multiple scenarios of implementing SGIs in the model to assess their enduring influence on alterations in hydrograph characteristics, specifically the streamflows associated with specified exceedance probabilities. The considered SGIs encompass basic stormwater ponds, along with SGIs featuring storage or engineered soil layers accompanied by underdrain pipes. For the RTC modeling, we developed two control schemes based on rain forecasts.

An optimization algorithm was used to identify the optimal parameters of the RTC schemes to minimize and maximize the flows corresponding to pre-determined exceedance probabilities. The results emphasized the benefits of employing real-time control strategies in stormwater management and urban resilience. Comparing passive and RTC scenarios, the results consistently demonstrated that RTC strategies achieved higher runoff reduction and increased baseflow compared to passive scenarios at all levels of SGI implementation.