Impacts of site real-time adaptive control of water-sensitive urban designs on the stormwater trunk drainage system

Increased rainfall intensity due to climate change is expected to exacerbate flood inundation in urban areas. Water sensitive urban design (WSUD) provides a variety of benefits in stormwater quantity management, ranging from stormwater harvesting to flood mitigation. Currently, however, developed areas lack any system that can improve the management of existing stormwater harvesting facilities to increase stormwater storage capacity without enlarging the stormwater drainage system. This study modelled a new method, Site Real-Time Adaptive Control (SRAC), that combined existing stormwater harvesting infrastructure at both regional and site levels with the existing stormwater drainage system (SWDS) through a cloud computing platform to increase stormwater storage capacity and reduce runoff water to the surface. The research found that: (1) the SRAC can manage runoff water dynamically and reduce flood inundation. The proposed impact factor Mt could help designers to measure the recovery capacity between two continuous rainfall events; (2) the SRAC model could postpone the peak flow in the trunk drainage system by 8-10 min; (3) the SRAC model could remove most of the excess water during very frequent rainfall events, decreasing over 98 % excess flow in design events 1h1EY (14,650 m3) and 2h1EY (11,272 m3); (4) the SRAC model showed a 36-50 % reduction in total outfall volume in the 1 h rainfall events, a 42-50 % reduction in the 2 h rainfall events; (5) the SRAC model could increase the capacity of downstream water treatment plants and save 43 % of the stormwater trunk drainage demand.