Assessing the role of SuDS in resilience enhancement of urban drainage system: A case study of Gurugram City, India.

The increasing frequency of urban floods worldwide due to rapid urbanization, frequent climatic extremes, or poor drainage conditions necessitates evaluating the performance of the urban drainage systems (UDS) and enhancing their resilience. In this study, a comprehensive assessment of the UDS of Gurugram City, India, through the concepts of sustainable drainage systems (SuDS) is presented. A stormwater management model (SWMM) was set up to model the existing UDS response to a design storm of a 5-year return period. The increase in percentage imperviousness (due to urbanization) and rainfall intensity (due to climate change) are considered the governing factors for functional failures. The results revealed climate change to be a more severe threat to UDS than urbanization, while their combinations can further worsen the repercussions. The structural failure was modelled using the single link-failure scenarios, where 3 and 12 conduits possessed low resilience and no resilience (severe), respectively. The role of SuDS in enhancing the resilience of UDS was assessed by simulating all these functional and structural failure scenarios for three SuDS-implemented conditions, i.e., only infiltration trenches (SuDS IT), only retention ponds (SuDS RP), and both of them together (SuDS IT+RP). The SuDS abated the flood magnitudes, delayed the time to peak flow, and stored an additional volume of water within the catchment, thereby justifying their efficacy to mitigate the pluvial flood and enhance the resilience of UDS. The findings of this study encourage implementing SuDS over the developing countries to bring down the frequency of urban floods. • The urban drainage system (UDS) of Gurugram City is comprehensively evaluated. • Functional and structural failure scenarios were analysed for their effects on resilience of UDS. • Compared the impacts of increase in imperviousness and rainfall intensity on UDS failure, and the latter is found to be a more serious threat. • The vulnerable conduits in the drainage networks of the city are identified. • The SuDS, viz., infiltration trenches and retention ponds were considered for mitigating the pluvial flood and enhancing the resilience of UDS. • SuDS has managed to delay and reduce the peak outflow from the catchment, assisting the catchment to store more water within it for sustainable use. [ABSTRACT FROM AUTHOR]