Climatic and anthropogenic impacts on the flow regime of the Nakambe River in Burkina Faso

The annual hydrological regime of the Nakambe River shows substantial changes during the period 1955 to 1998 with a shift occurring around 1970. From 1970 to the mid 1990s, despite a reduction in rainfall and an increase in the number of dams, runoff increased, including maximum daily discharges, and a delay of several weeks in the timing of peak flows occurred. To assess the impact of land-use change on soil water holding capacity (WHC) during this period we compare the results of two monthly hydrological models using several different rainfall, potential evapotranspiration (PE) and WHC data sets. Soil WHC values are modified over time using historical maps of land use, and compared with a constant value for WHC over time. There is a moderate improvement in flow simulation using the varying values of soil WHC.