Alteration of groundwater recharge areas due to land use/cover change in Kathmandu Valley, Nepal

Abstract

Study regionKathmandu Valley, Nepal. Study focusThe focus of this study is to project future LULC, delineate potential recharge areas, and evaluate encroachment in recharge areas due to future changes in LULC. New hydrological insights for this regionThe consequences of urbanization in Kathmandu Valley (KV) have been observed in various forms such as change in runoff, groundwater recharge, water scarcity, and others. To sustainably utilize groundwater resources by ensuring adequate supply/recharge to groundwater system, land use/cover (LULC) management is required. A set of models and tools such as the Conversion of Land Use and its Effects at Small regional extent (CLUE-S) model for future LULC projection; geographic information system (GIS) for spatial data management and analysis; analytical hierarchy process (AHP) to estimate appropriate weights for different layers that influence groundwater recharge; and in-situ field test and analysis for infiltration rate were used to achieve the objectives. Results showed that built-up area in the KV watershed is projected to change by +21.4%, agricultural land by -20.5%, and forest areas by -0.9%. between 2020 and 2050. In terms of recharge area, 6% of open land is projected to convert into impervious area every decade. The projected changes are expected to have implications in terms of depletion in groundwater levels and subsequent consequences in urban water environment, including base flows in rivers.