The impact of land use and land cover change on groundwater recharge in Guna Tana watershed

ABSTRACT Rapid industrialization, climate change, urbanization, agriculture, and land use change have increased global water demand, making sustainable groundwater recharge (GWR) and management a critical concern. This study examines the dominance of land use in controlling GWR in the Guna Tana Watershed (GTW) using the WetSpass-M, addressing gaps in understanding the effects of land use/ land cover (LULC) change on recharge dynamics. The major findings were as follows: (1) The built-up area in the GTW expanded markedly from 0.05 km2 in 1991 to 8.08 km2 in 2021, significantly influencing recharge. (2) In 1991, land use was dominated by agriculture (78.82%), followed by grassland (6.96%) and shrubland (5.92%), with notable LULC change identified using ENVI 5.3. (3) AET accounted for the majority of water loss in the watershed in all land use scenarios (43.7, 43.8, and 44.3%), followed by runoff (24.3, 24.2, and 25.2%) in 1991, 2007, and 2021, respectively. (4) The corresponding average annual GWR declined from 351 mm/year in 1991 to 349 mm/year in 2007 and 344 mm/year in 2021, indicating a gradual reduction associated with LULC changes. This study improves GWR estimation through enhanced spatial and temporal resolution and demonstrates the influence of land use on GWR in the GTW.