Mitigation of Urban Flooding using Blue-Green Infrastructure: A Case of Dehradun City, India

Abstract

Increasing frequency and intensity of floods caused lives of 6.7 million people between 1920-2020. Rapid urbanization and climate change are the two leading causes of urban flooding. During the past several years, India has seen an increase in the number of urban flooding catastrophes. The city of Dehradun in Uttarakhand, India situated in a valley in the Himalayan foothills, suffers from the contradictory problems of urban flooding due to increase in the builtup area and water supply gaps. The aim of the study is to mitigate urban flooding through blue-green infrastructure development. The study uses Geographic Information System (GIS) and remote sensing to understand Land Use Land Cover (LULC) change in the period 1995-2020 and to estimate the surface run-off generation of this period using the weighted co-efficient and Soil Conservation Service Curve Number (SCS-CN) methods. The result reveals that with the blue-green infrastructure, rainwater harvesting potential can be increased to 82.03 MLD and groundwater recharge would increase to 2.66 MLD. With this, the rainwaer harvesting potential becomes equivalent to 37% of the water supply for the design period of 2031.