Dam site suitability analysis using geo-spatial technique and AHP: a case of flood mitigation measures at Lower Tapi Basin

Dams throughout the Surat district are a key solution for mitigating flood events, enhancing surface water budgets, and creating groundwater recharge locations. The success of this initiative is largely pivotal to finding the finest dam location in the area. Recent improvements in remote sensing (RS), geographic information systems (GIS), and decision-making processes have provided useful tools for mapping Dam Sites Suitability Model (DSSM). Rainfall, stream order, geomorphology, geology, LULC, soil, distance to road, elevation, slope, and major fault fracture are among the ten thematic layers examined in the DSSM's preparation. The most prominent factors affecting the Dam Site Location Map (DSLM) were rainfall and stream order. The analytical hierarchy process (AHP) technique is one of the Multi-Criteria Decision Making (MCDM) technique which was used to establish the weights of the thematic map layers. The overlayed map visualizes five classes of suitability, from very high to very low suitability regions. On the basis of a suitability map for the constructing dams in Surat, three suitable dam locations with high and very high suitability were identified. The study provides decision-makers with a useful and very inexpensive tool for identifying the areas with high restrictions (low appropriate site) and concentrating on area with fewer restrictions for a more apposite location for the construction of dams. In terms of percentage, 15.03% of Surat lies in the range of very low suitability, and 14.33% lies in the low suitability area. A maximum of 29.51% of the area lies in the moderately suitable region of the Surat district. 27.19% for the highly suitable area of Surat city, and 13.94% of the area for very high suitability area. So this gives us approximately 40% of the area are more suitable to construct the dam in the region. A novel approach of integrating GIS and MCDM techniques in determining the suitable dam site location for the study area has been carried out effectively.