INTEGRATING GROUND-BASED WELL OBSERVATIONS AND HYDROLOGIC REMOTE SENSING TO UNDERSTAND CHARACTERISTICS OF AQUIFER RECHARGE IN RURAL TANZANIA

Water is essential for life, but large areas of East Africa rely on aquifers of moderate quality to meet people’s water needs, especially during the dry season. Several studies have shown the importance of threshold rainfall events for recharging these aquifers, and inundation of depressions may be a critical mechanism for recharge during these events. Here, we analyze two wet and dry seasons of Sentinel-1 Synthetic Aperture Radar (SAR) imagery in addition to water level data from three wells in a rural area of the semi-arid Singida Region. While optical remote sensing data is widely utilized for flood hazard mapping, SAR data is ideal for detecting inundated areas, as data coverage spans both periods of day and night and all weather. Our preliminary comparison of variations in inundated area and groundwater levels demonstrates general increases of both during the 3-month wet season. Future analysis will focus on relating the timing of these changes and seeking to identify “recharge hotspots,” or areas where changes in inundation area may strongly predict recharge. If robust relationships emerge in this region of Tanzania, SAR data may prove useful to guide groundwater management in other regions where observations are scarce.