Effectiveness of LIDs In Resilience Enhancement of an Urban Drainage System: A Case Study

Urban flooding is a severe issue for many cities in India and over the world as well. The main causes of the problem of urban flooding are urbanization and changing climate. Urbanization leads to increased city population, further increasing pressure on the drainage system. Climate change leads to increased intensity and frequency of rains. So, both in combination exacerbate the problem of urban flooding in the cities. The present study considers the problem of flooding in Gurugram City of Haryana in the NCR of India. The function and structural resilience-based evaluation has been carried out to analyze the effect of urbanization, climate change, and the reliability of existing drainage systems. Functional resilience is the resilience of a system corresponding to internal threats such as urbanization and climate change. In contrast, structural resilience is the resilience of a system corresponding to internal failures such as blockage of conduits, structural damage and pump failure. The resilience-based evaluation indicates urbanization has pronounced effects on drainage systems compared to climate change. In structural resilience-based evaluation, 23 vulnerable nodes in the drainage system have been identified. Low Impact Development (LID) techniques have been frequently used by urban planners these days to diminish the problem of urban flooding. LID techniques are the nature-based solution to infiltrate the runoff and reduce the effect of urbanization. In the present study, Green roof and Bioretention cells have been deployed in the suitable location of the study area to enhance the system's resilience. The results indicate that 10% deployment of LIDs enhances functional resilience by 21% and reduces the number of vulnerable nodes in structural resilience evaluation to 20. The case study could assist urban planners in carrying out the resilience evaluation of the drainage system at the planning stage to safeguard the system from inundation hazards.