Studying the impact of rainfall and LULC changes in the reservoir water level of the Hatia dam, Ranchi, India

ABSTRACT This study analyses rainfall pattern and land use land cover (LULC) changes and their impact on the water level of the Hatia dam, a crucial water source for Ranchi city in Jharkhand, India. High-resolution daily-gridded rainfall and temperature data from 1991 to 2023 were collected from IMD Pune and analyzed using Mann–Kendall and Sen's slope estimator. The results showed a significant decline in annual, monsoon, post-monsoon, and winter rainfall, while pre-monsoon rainfall increased. LULC changes were assessed using Google Earth Engine at 5-year intervals, revealing notable shifts in waterbodies, built-up areas, forests, barren land, and agriculture before and after the monsoon. The analysis shows that during the pre-monsoon season, the waterbody decreased from 8.68 to 4.94%, while the built-up area increased from 2.71 to 11.08%. Similar trends were observed during the post-monsoon season, with the waterbody decreasing from 10.06 to 7.3% and the built-up area increasing from 2.74 to 11.27%. It is observed from the rainfall analysis that the annual rainfall is decreasing from 1,561 to 703 mm and the reservoir surface area has decreased from 126.31 to 37.44 ha. The findings highlight the need for sustainable water management strategies.