From urban sprawl to aquifer strain: The hydrological consequences of Land Use/Land Cover Changes in the Mitidja plain, Algeria

This study investigates the effects of land use and land cover changes (LULCC) on groundwater recharge in the Mitidja plain, Algeria, from 1983 to 2023. By utilizing remote sensing data and a water balance approach in Google Earth Engine (GEE), the research analyzes the relationship between historical LULC changes and hydrological processes. Results reveal a 38.30 % increase in urban areas and a 28.04 % decrease in agricultural land, leading to a drastic reduction in groundwater recharge (40 %). The most severe deficits occurred between 2007 and 2015, with recharge values falling as low as −600 mm/year. The Soil Conservation Service Curve Number (SCS–CN) method demonstrated significant shifts in hydrological dynamics, as Curve Number (CN) values for Hydrologic Soil Group (HSG) B increased from 81 to 92, and for HSG C from 88 to 94, reflecting reduced soil infiltration and higher runoff. Despite this trend, the southern Mitidja characterized by lower urbanization maintained recharge rates of up to 200 mm/year. The Modified Mann-Kendall test showed an increase significant trend of +10,59 Mm 3 /year in recharge for woodland areas, while urban zones exhibited a weak, non-significant negative trend −1,25 Mm 3 /year. This study emphasizes the urgent need for sustainable land management practices to mitigate the adverse effects of LULCC on groundwater resources. It underscores the value of integrating remote sensing data into water management strategies for improving groundwater conservation and land use planning in semi-arid regions, offering critical insights for policymakers and stakeholders. • Urbanization caused a 38% rise in cities and a 28% loss of farmland, cutting Mitidja plain groundwater recharge by 40% in 40 years. • Between 2007 and 2015, severe groundwater recharge deficits reached - 600 mm/year, highlighting major land use change impacts. • SCS-CN method showed higher Curve Numbers in groups B and C, revealing reduced infiltration and more runoff from urban growth. • Forested green spaces showed positive groundwater recharge trends, while urban zones exhibited a non-significant negative trend. • Sustainable water strategies include boosting permeable surfaces, protecting vegetation, and validating models with isotopic data and field based techniques.