The Blue-Green Sponge Toolkit - For the city of Bengaluru

The rapid urbanization in many Indian cities, including Bengaluru, has led to various environmental complications such as dense urban development, landscape fragmentation, and increased impervious surfaces. The resulting loss of surface waterbodies to encroachment and reduced infiltration of rainwater run-off into the ground have made Bengaluru susceptible to flooding during the monsoon seasons. Although several initiatives have been launched to address this issue, they have primarily focused on improving the city's grey infrastructure, and the root cause of the problem remains unaddressed. 

However, incorporating nature-based solutions such as Low Impact Development (LID) and Green Infrastructure (GI) in Bengaluru presents an opportunity to mitigate the negative impacts of rapid urbanization. LID strategies such as bioswales, green roofs, bio-retention tanks, and other approaches can reduce flooding with minimal disturbance and make the city more resilient to future climate change phenomena. 

Despite existing studies and research papers on nature-based solutions, the application of such strategies in cities like Bengaluru is limited due to existing infrastructure and insufficient vacant land availability. Therefore, this study proposes a LID system with a toolkit to educate the general public about the significance and efficiency of various LID strategies and their relevance to the region to mitigate flooding. 

The study uses ArcGIS and Stormwater Management Model software to identify flood-prone regions in Bengaluru and applies LID strategies to find optimized solutions for various typologies of sites based on considerations such as efficiency and resource availability. The study aims to address the challenges of applying LID strategies in cities like Bengaluru with existing infrastructure and insufficient land availability. 

Addressing the negative impacts of rapid urbanization in Indian cities like Bengaluru requires a combination of grey infrastructure and nature-based solutions. Incorporating LID strategies can provide an effective and efficient approach to mitigating the environmental complications caused by urbanization. This study's proposed toolkit can be a valuable resource for educating the public and implementing LID strategies in flood-prone regions of the city