Exploring Hydrological and Environmental Transformations by Tank Structures in Odisha Using Sentinel-2 Data

This study investigates the environmental and hydrological impacts of groundwater recharge structures constructed under the Green Climate Fund (GCF) project between 2018 and 2024 in drought-prone regions of Odisha, India. The research focuses on ten districts—Kalahandi, Keonjhar, Nabarangpur, Rayagada, Sambalpur, Subarnapur, Boudh, and Balangir—characterized by water scarcity and deteriorating vegetation health. Multi-temporal Sentinel-2 satellite imagery was analyzed using indices such as MNDWI, NDII, NDMI, PWI, WBI, and WRI to assess changes in vegetation cover, soil moisture, and water body extent before (2018) and after (2024) the interventions. The results demonstrate significant environmental improvements in districts with targeted water conservation efforts. Kalahandi achieved a notable reduction in low moisture content (95.93–63.30%) and a sharp increase in water-saturated vegetation (1.84–69.91%), reflecting successful recharge structures. Keonjhar showed improvements in vegetation cover (11.82–48.15%) and high-water content (1.06–10.29%), while Boudh exhibited exceptional growth, with water bodies increasing from 13.37–67.65% and high vegetation rising from 18.99–72.78%. Balangir’s severe drought areas decreased from 45.22–19.37%, showcasing the effectiveness of localized water management. Rayagada recorded modest increases in water bodies (19.48–22.43%) but a decline in heavy vegetation (16.53–4.71%). Sambalpur demonstrated substantial progress in moisture retention, with high moisture content rising from 1.11–46.77%. These findings highlight the critical role of afforestation, sustainable agriculture, and targeted water conservation in improving ecological conditions. However, districts impacted by industrial activities require focused interventions to achieve balanced and sustainable environmental development.