Application of Open-Source Geospatial and Modeling Techniques for Flood Assessment and Management—A Case of Flood 2017, Rel River Catchment

Abstract

Floods are disasters; it cannot be prevented; however, their effects can be reduced or minimized using contemporary geospatial and modeling techniques. Floods are unpredictable, though it can be diagnosed and lessen the catastrophic consequences in flood residing areas. India’s more than 40 × 104 million sq. mt. (12% Geological area) lands are flood-prone, affecting the country’s productivity and essential properties. Therefore, flood assessment is a crucial need of the country for societal and economic growth. Remote Sensing (RS) and Geographic Information System (GIS) is an important part of geospatial techniques, help to analyze the flood-prone area; however, due to the coarse resolution of RS techniques, it can’t provide the flood inundation information up to sub-metric resolution. To overcome the limitation and apply the contemporary tools, hydrologic and hydrodynamic modeling is a blessing for the hydrologic community to analyze the flood and produce the various flood decision-making maps, i.e., flood arrival, flood velocity, flood inundation, water surface elevation, etc. The hydrologic model is utilized to simulate the runoff from the catchment, and the hydrodynamic model is utilized for flood assessment in 1D and 2D. The present case is the Rel River, which was affected by a flood in 2017. The hydrodynamic model simulates runoff under extreme flooding conditions to identify the flood catastrophe and vulnerability. It helps provide the boundary conditions of Rel River and tributaries for flood simulation at Dhanera city. The 2D HEC-RAS-based open-source hydrodynamic modeling is utilized for flood simulation in 2D. Overall, the paper shows the application of geospatial techniques for preparing various files for flood modeling. In contrast, the hydrologic and hydrodynamic model shows the utility of the contemporary method for flood assessment and management.