Advancements in smart sensing and control technologies have enabled urban drainage engineers to retrofit stormwater storage facilities with actuated valves and gates, addressing flooding and water quality issues throughout the watershed. However, effectively controlling these distributed storage assets to mitigate flooding at downstream outlets while preventing overflow at upstream storage ponds poses a significant challenge. In this study, we simulated and assessed under different real-time control scenarios (local individual downstream control and system-level multiple control) in balancing flooding mitigation at downstream outlets and water quality improvements at upstream storage units, such as detention ponds. Using an established urban stormwater drainage model in Ann Arbor, Michigan, USA, we examined changes in peak water depth, outflow, and total suspended solids. We find the outflow from the detention pond is the most important hydraulic indicator for control rule set-up. Our results further demonstrate that system-level control shaves peak water depth up to 7.3%, reducing flood duration up to 34% and removes up to 67% of total suspended solids, compared with the baseline uncontrolled system. However, the system-level control scenario does not always outperform the individual downstream control scenario, particularly in alleviating flooding duration at the most downstream outlet. This research enhances the understanding of real-time control methods for developing adaptive stormwater management solutions that address both water quantity and quality challenges.

A document by Jiada Li. Click on the document to view its contents.

Green stormwater infrastructure (GI)  is widely adopted for addressing urban flooding challenges. Another rising solution that is complementary to, but distinguishable from GI, is smart real-time control (RTC). However, the outcomes of the battle between RTC and GI has been unknown.  This research compares the performance of RTC and GI to mitigate the climatic and urbanized influences on historical and future urban floods; a case study located in Sugar House neighborhood of Salt Lake City, Utah, USA, was provided. Results show that RTC and GI have comparable performance to reduce the historical flooding severity from 2001-2015, but RTC outperforms GI for improving flooding resilience in the future. Especially from 2085 to 2099, RTC maintains the system service level against future climatic and urbanized disturbances better than GI. This work improves the understanding about how RTC brings benefits for controlling future urban floods.

Assessing the resilience of urban drainage systems requires the consideration of future threats that will disrupt the system performance and trigger urban flooding failures. However, most existing resilience assessments of urban drainage systems rarely consider the uncertainties from future urban redevelopment and climate change, which leads to the underestimation of future disturbances toward system performance. This paper fills in the gap of assessing the combined and relative impacts of future impervious land cover and rainfall changes on flooding resilience in the context of a densely-infilled urban catchment severed by an urban drainage system in Salt Lake City, Utah, the USA. An event-based flooding resilience index is proposed to measure climatic and urbanized impacts on flooding resilience from system-level to junction-level, enabling engineers to harvests high-resolution infrastructure adaptation strategies at the vulnerable spots. Impact comparison shows that imperious urban surface induces more effects on the system performance curves by magnifying the maximum failure level, lengthening the recovery duration, and aggravating the flooding severity than future rainfall changes. A nonlinear logarithm resilience correlation is found, and this finding shows that flooding resilience is more sensitive to the land imperviousness change due to urban redevelopment than rainfall intensity change in the case study. This research work predicts the system response to the uncertainties induced by climate change and urban redevelopment, improving the understanding of impacts analysis and contributing to the advancement of resilient urban drainage systems in changing environments.

Traditional stormwater control measures are designed to handle system loadings induced by fixed-size storm events. However, climate change is predicted to alter the frequency and intensity of flooding events, stimulating the need to explore another more adaptive flooding solution like real-time control (RTC). This study assesses the performance of RTC to mitigate impacts of climate change on urban flooding resilience. A simulated, yet realistic, urban drainage system in Salt Lake City, Utah, USA, shows that RTC improves the flooding resilience by up to 17% under climatic rainfall changes. Compared with green stormwatrer infrastructure (GSI), RTC exhibits a lower resistibility, lower flooding failure level, and higher recovery rate in system performance curves. Results articulate that keeping RTC’s performance consistent under ‘back-to-back’ storms requires a tradeoff between upstream dynamical operation and downstream flooding functionality loss. This research suggests that RTC provides a new path towards smart and resilient stormwater management strategy.

Jiada Li1*, Carly Hansen2, Steven Burian31Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA2 Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA3Department of Civil, Construction, and Environmental Engineering, University of Alabama, Tuscaloosa, AL USA