Why a Map of Hydrographic Basins for This Area?

One of the objectives of the Joint Research Unit, HydroSciences Montpellier, is to study the impact of climate variations on water resources in West and Central Africa. One method employed to reach this objective was to model the rainfall/runoff relationship on a select set of watersheds. Physical characteristics such as rainfall, soil, and evaporation rates were collected at the basin level. Only gauging stations with a minimum of 20 years of recorded observations were considered for the project.

The author selected 385 sites with at least 20 years of data and delineated each corresponding watershed. This map represents one stage in the modeling process. The author first created this watershed delineation model using the hydrologic toolsets in ArcGIS and U.S. Geological Survey terrain numerical model GTOPO30. The hydrographic system information from the Digital Chart of the World enabled the refinement of the watershed delineation in the first stage. With hydrologic publications from the Institute for Research and Development (IRD), validation, correction, and further refinement of areas where the data was not effective were possible.

The new publishing features in ArcMap improved the final product, and the Designjet 500ps obtained by HydroSciences Montpellier gave a professional finish to this long project.

This map would not exist without the dedicated efforts of the engineers and researchers at IRD to collect, evaluate, and understand the chronological data.