REMOTE SENSING ENHANCED WATER BUDGET CALCULATIONS FOR THE SUDD AND BAHR EL GHAZAL BASINS

Abstract

This study aims at developing a methodology for continuous monitoring of the Sudd and Bahr el Ghazal wetland extent, evaporation losses and storage variations. Wetland extent map time series are produced based on a thorough calibration process of MODIS satellite images at small time increment. Four different satellite radar altimetry datasets are used to derive matching characteristic water levels. Both area and level time series are employed to obtain a terrain model that allows for continuous monitoring of storage variations. A set of Python codes have been developed and validated for automating the image processing, and water level extraction, as well as synchronization of both time series. Results indicated that the former studies over-estimated the extent of the Sudd wetlands areas, but Bahr el Ghazal area results agree with literature. Storage variations estimates confirm that both wetlands don’t act as a reservoir but more as a sink. Since flow records in the basin cease to exist, the developed workflow provides a reliable alternative tool for wetlands hydrologic monitoring.