Impact of future land use changes on flood risk and ecosystem service values (ESV) in a river basin

Land use change plays a critical role in altering hydrological processes and increasing flood risk, especially in ecologically sensitive regions like Kerala. This study investigates the impact of projected land use changes on flood inundation and ecosystem service values (ESV) in the Achankovil River Basin. Historical land use maps (2014–2024) were developed using supervised classification of Landsat imagery, and future scenarios were predicted using a Cellular Automata–Artificial Neural Network (CA-ANN) model. These projections were integrated into a hydrologic model (HEC-RAS) to simulate the flood depth and inundation extent. The results of the flood simulation were linked to an ESV framework to assess its economic implications. The findings of this study indicate a significant decline in forests and water bodies, along with an increase in built-up areas and agricultural land in the river basin. These land use transitions result in increasing the flooded area from 148.63 km2 in 2034–156.94 km2 in 2054. ESV dropped from USD 334.22 million in 2014 to USD 161.97 million in 2054, driven largely by loss of regulating services. The study highlights the link between land use changes and flood risk and emphasizes the need for conservation-oriented land use planning to safeguard ecosystem functions.