GIS–AHP screening of dam and barrage sites in the Nagavali–Vamsadhara basin, India

The Srikakulam district in eastern India frequently experiences water stress due to rainfall variability, inadequate storage facilities, and increasing agricultural and domestic demand. This study aims to identify regionally suitable sites for dams and barrages along the Nagavali and Vamsadhara rivers to support integrated water resources planning in a data-limited semi-arid basin. Remote sensing and Geographic Information System (GIS) techniques were integrated with the Analytical Hierarchy Process (AHP) to assess regional suitability. Sixteen thematic layers derived from Landsat imagery, ASTER DEM, published geological maps, and long-term rainfall data were used to represent topographic, geological, geomorphological, land surface, and hydrological factors. Criteria weights were assigned through expert-based pairwise comparison and validated using consistency ratios. A composite suitability map was produced using a weighted overlay approach. The results classify zones of high, moderate, and low suitability for water-harvesting structures. Validation against the spatial distribution of existing dams and barrages showed strong agreement, confirming the reliability of the proposed screening framework. This research report offers a generalisable and economical GIS–AHP procedure of preliminary screening of potential dam and barrage locations in the data-deficient semi-arid basins, and can be applied in other hydro-climatic environments.