Using Vegetation Indices from MODIS to Estimate Evapotranspiration for the Godomey Well Field in Benin, West Africa

The Godomey well field supplies groundwater for Cotonou, the largest city in Benin, West Africa. Due to the proximity of the wells to the Atlantic Ocean (5 km north of the ocean) and to Lake Nokoue, a shallow lake with high levels of chloride, the wells are threatened by saltwater intrusion. Ongoing efforts aim to characterize this groundwater system to provide management and sustainability information. As part of this effort, this study will utilize remotely sensed Moderate Resolution Imaging Spectroradiometer (MODIS) products to estimate evapotranspiration and improve boundary conditions of an existing groundwater model for the study area. Initial efforts demonstrate that weather data from various ground based stations in Benin, and from the Global Land Data Assimilation System (GLDAS) can be used in conjunction with MODIS products to better constrain estimates of recharge and discharge for the model. Remote sensing and regional scale hydroclimatic modeling provides a unique opportunity for improving hydrologic budgets in developing communities that are data limited.