Evaluating The Impact Of Urban Expansion On Groundwater Recharge Potential: A GIS-Based Hydrological Assessment

Abstract

The urban growth is a major cause of changes in the natural land cover affecting the hydrologies of the area and decreasing the groundwater recharge. This research uses Geographic Information Systems (GIS) and hydrological modeling to assess the effects of high rates of urbanization in recharge areas in a mid-sized urban area. A weighted overlay analysis was done to combine remote sensing data, land use/ land cover (LULC) classification, soil, slope, and rainfall distribution to outline recharge potential zones. The results show that there has been a significant loss of very suitable sites of recharge where almost 30-40 percent of the natural infiltration areas have been covered with hard surfaces as a result of urban sprawl. Subsequently, there is a preponderance of medium and low recharge zones which indicate lowground water sustainability. The paper has established the applicability of GIS-based techniques in the determination of the vulnerable recharge zones of aquifers and effective urban planning. There are, however, shortcomings such as dependence on secondary data, absence of field testing of infiltration rates, and not considering temporal variability. In-situ hydrological measurements, long-term monitoring, and combination with climate change scenarios should be implemented in future work in order to enhance the quality of recharge evaluations.