UNDERSTANDING WETLAND DYNAMICS BEFORE, DURING, AND POST-DROUGHT: A REMOTE INVESTIGATION OF THE SUDD WETLAND, SOUTH SUDAN

Management of complex watersheds, especially those with vital wetland resources that support vulnerable populations, becomes increasingly important under changing global conditions and shifting priorities. Obtaining consistent, reliable, and economical data to support management plans and protect some of the world’s most valuable wetlands is an ongoing challenge. This study assesses the ability of remote sensing to provide valuable insights into wetland hydrology before, during, and after major drought events using the Sudd Wetland, South Sudan, as a case study. By taking advantage of online geospatial databases and analysis software, we combine Moderate Resolution Imaging Spectroradiometer (MODIS) multispectral imagery, Gravity Recovery and Climate Experiment (GRACE) equivalent water thickness data, along with evapotranspiration, precipitation, and soil moisture datasets to construct a time series of wetland hydrology from April 2003 to March 2017. Together, these datasets provide valuable information on how this wetland functions under normal, drought, and drought recovery conditions. Despite the lack of in situ hydrologic investigative techniques, this study reveals distinct patterns of wetland behavior that can be used in planning and management of regional water resources. The Sudd’s total water storage recovered more slowly post-drought than its surface wetland extent, indicating the wetland is more vulnerable to severe droughts than could otherwise be expected. The single year drought (water year 2009) included in this study period required three annual cycles for total wet season recovery, despite surface wetland extent appearing to recover within a single water year. These findings suggest severe or long-term droughts could compound, detrimentally impacting local and regional aquifer resources long after a single drought event has passed.