The link between surface and groundwater variations over East Africa using GRACE and Altimetry data H31F-1185 1383054 A decreasing signal in water storage is evident over the East African region (Uganda, Kenya, and Tanzania) from the GRACE global water storage trends map. A number of regional lakes and rivers portray a declining trend which implies that the water table is falling. There has not been a regional assessment of the changes in groundwater, a major source of fresh water for the East Africa community. This study estimates groundwater variations from GRACE satellite measurements. Modeled land surface parameters (soil moisture, surface water and snow water equivalent) from GLDAS are separated from GRACE to estimate variations in groundwater. A contour map of the water table elevation is derived using groundwater level data from available in-situ monitoring wells and a DEM. The map provides a better understanding of the groundwater flow directions and interactions with surface water. By comparing changes in groundwater and lake level data from altimetry, causal relationships between observed surface and groundwater variations are derived. Results from this study are important in guiding water resources management in the region.
Jamiat Nanteza1, John T Reager1, Alexandra S Richey1, Huidong Liu1, James S Famiglietti1, Matthew Rodell2 1. Earth System Sciences, University of California Irvine, Irvine, CA, USA; 2. Hydrological Sciences Branch, NASA Goddard Space Flight Center, Washington,, WA, USA