AHP GIS-aided flood hazard mapping and surface runoff estimation in Gurugram, India

The present study is aimed to perform flood susceptibility mapping in the rapidly developing Gurugram district of India. Major flood-triggering factors, namely, slope, elevation, land use land cover, precipitation, drainage density, and soil texture, were selected, and their relative weights were assessed using the Analytical Hierarchy Process method through an expert survey. The highest weightage was attributed to precipitation (34%), while the least (7%) was assigned to elevation and soil texture each. Flood hazard maps were developed using overlay analysis in the Geographic Information System (GIS) environment to provide a quantitative assessment of flood vulnerability covering the time periods of 1985–1994, 1995–2004, 2005–2014, 2015–2019, and 2020–2021. A surface runoff estimation was done using the GIS-aided Natural Resource Conservation Service-Curve Number method for the past thirty-seven years (1985–2021) to explore how land use alterations have impacted surface runoff. The results from flood hazard maps and surface runoff estimation together revealed that the northern part of the district is the most likely to experience flooding. This was in concurrence with the locations that were inundated in the recent past. To the best of our knowledge, no current studies have used these two approaches together to detect flood-prone areas. The developed methodology can be easily employed in regions with limited data for urban drainage planning and undertaking disaster management measures by prioritising areas depending on the likelihood of flood occurrence. The inclusion of more flood-triggering factors and encouraging micro-level studies can be done as part of future research.