Fluvial Flood Risk in Contemporary Settlements: A Case of Vadodara City in the Vishwamitri Watershed

• Published in: Engineering proceedings Vol. 56; no. 1; p. 70
• Main Author: Nishchay Kumar
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.11.2023
• Subjects: environmental degradation; fluvial flood; HEC-RAS; LULC change; Vishwamitri watershed
• ISSN: 2673-4591
• DOI: 10.3390/ASEC2023-15270

Settlements situated downstream of hills and dams are invariably at risk of floods. Constant land use/land cover changes in the Vishwamitri Watershed and long-term climate variability have made Vadodara City more susceptible to river flooding in recent times. In the past, the local government authorities have only tried to solve this issue within the administrative boundary of the Vadodara City. This study demonstrates the importance of watershed scale investigation over administrative scale. The study presents a review of the current flooding and environmental degradation challenges that are affecting the Vishwamitri Watershed. For the analysis, the entire watershed was classified into two parts: (1) the upper watershed and (2) city limits. The data-deficient upper watershed was studied with the aid of site visits and secondary sources. The floodplain within the city limits was simulated for the 2005 peak discharge event (805 cumec) using Hydrological Engineering Centre—River Analysis System (HEC-RAS, 5.0.7.) software and HEC-GeoRAS (10.2.) (a set of procedures, tools, and utilities for processing geospatial data in ArcGIS using a graphical user interface). The simulated water surface elevation from HEC-RAS was validated with the in situ data available within the city limits. The generated floodplain extent map was used for conducting a primary flood impact survey and analysing the inundation-affected zones. Various aspects of the flood plain, like land use, land cover, built form, affected demography, river system, natural environment and habitat, were analysed during this survey. For the mitigation of floods and other maladies associated with the watershed, this probing calls for the restoration of the river ecosystem back to its original state to the maximum possible extent. Nature-based solutions were found to be the remedy for most of the issues pertaining to the floodplain. The study can potentially help concerned stakeholders of any flood-prone urban settlement to envision the issue of flooding with the whole river system and watershed in mind. This will discourage the usual approach of interventions limited to administrative boundaries.