Blue space resilient urban planning to enhance severely distressed thermal environment

Water resilience is a vital aspect of current smart city planning. Maintaining the quality and volume of urban blue spaces can benefit local ecology, environment, and social well-being. The application of geospatial techniques provides an opportunity to achieve such goals in a spatially and temporally effective manner. While researchers often highlight city-level environmental problems, location-based solutions are insufficient, particularly for the rapidly sprawling Asian cities—the current work aimed to examine the water-resilient urban planning scopes for an Indian tropical megacity. The work assessed a major environmental hazard, i.e., urban heat island, which appeared to cover 9.6 %–17.4 % of the area of the city region during the summer months. The importance of blue spaces in mitigating heat islands was quantified using data from nearly 150 waterbodies, including a river, a vast wetland, and multiple lakes and urban tanks. Linear and logarithmic models established how the cooling effect increases with larger water bodies. Blue space ranging between 1.8 km² and 2.3 km² was recommended as the smallest yet effective size for future recreational zones. Incorporating ambient wind patterns further aided in deciding the locations of blue wedges that can be key for heat island mitigation. Moreover, to substantially amplify the blue resource recharge rate in a cost-effective manner, a multi-parameter decision analysis was carried out. Overlay of five surface characteristics contributed to planning sites for surface infiltration systems. The entire framework of the work was built to achieve sustainable development goals.