Assessing Water Availability for Development in Africa using GRACE Satellites

Access to water is a critical issue in Sub-Saharan Africa. The objective of our work was to assess spatiotemporal variability in water storage using GRACE satellites in the major aquifers and potential for development. Results show that Total Water Storage (TWS) variability tracked by GRACE satellites is dominated by interannual variability in most aquifer systems driven by dry and wet climate cycles, such as El Nino Southern Oscillation, Indian Ocean Dipole, Pacific Decadal Oscillation and others. Climate cycles result in systems being subjected to droughts or floods, which is challenging for water resources management. Linear trends in TWS were limited to west Africa attributed to land use change and north Africa linked to water use. Variability in storage of some reservoirs and groundwater hydrographs is similar to storage variability from GRACE satellites. Examples of approaches toward sustainable management of water resources include storage of excess flood water for use during droughts in surface reservoirs, conjunctive use of surface water and groundwater, and managed aquifer recharge. Understanding the linkages between climate cycles and water storage should help optimize water management within this framework.