Hydrological Impacts of the Changes in Simulated Rainfall Fields on Nakanbe Basin in Burkina Faso

Abstract

Changes in rainfall regime during the last five decades over the West African Sahel have significantly modified the hydrological regime of many rivers with a significant impact on water resources. In this study, the main hydrological processes on the Nakanbe watershed in Burkina Faso are described with two hydrological models: GR2M (lumped and monthly model) and ORCHIDEE (ORganising Carbon and Hydrology In Dynamic EcosystEms) (distributed and half hourly model). Both models were calibrated on the watershed from observed runoff data at Wayen outlet (area of 22,000 km 2 ) for the 1978-1999 period. The mean annual hydrological balance components on the watershed over this period are composed of about 4% of runoff, 10% of groundwater recharge and 86% of actual evapotranspiration for both models. An assessment of the hydrological impacts of the changes in rainfall regime simulated by five regional climate models shows some discrepancies. The hydrological simulations show that the hydrological impacts on the water balance of the watershed come mainly from the changes in rainfall field with regard to the frequency and the intensity of rain events. Compared to the decrease in frequency, it appears OPEN ACCESS Climate 2015, 3 443 that the decrease in the intensity of rain events is much more prejudicial to runoff and groundwater recharge.

Trend and variability in a new, reconstructed streamflow dataset for West and Central Africa, and climatic interactions, 1950–2005

“…Interestingly, while rainfall variability has been investigated at the continental scale in Africa, its effects on runoff regimes have mostly been investigated at catchment scales, using different statistical approaches and hydrological models (e.g. Ibrahim et al, 2015). This is mainly due to restricted data, and several factors (e.g.…”

Climate Change and Its Impacts on Water Resources in the Bandama Basin, Côte D’ivoire

“…The implementation of the model consists of the determination of the two parameters X1 and X2 during a calibration period and then a validation where the representativeness of the two parameters is evaluated (different with the calibration period) [35]). GR2M is calibrated and validated through the Nash efficiency criterion [37].…”

“…The GR2M model is widely used for hydrological modeling of river basins in Sub-Saharan Africa [29][30][31][32][33]35]. The GR2M model is a spatially lumped and a monthly time-step model developed by IRSTEA [36].…”

Assessing Nonstationary Spatial Patterns of Extreme Droughts from Long-Term High-Resolution Observational Dataset on a Semiarid Basin (Spain)

“…However, despite the decreasing trend of flow rates in the SRB between 1950 and 2010, the same decreasing pattern is not observed in precipitation, then the relationship in precipitation-flow is much more complicated. In some cases, the longer the dry spells, the greater the evapotranspiration rates from the upper soil layer [21], then the effect of lengthening dry spells is more noticeable on the water cycle. Regular daily high-resolution gridded rainfall dataset (named Spain02), for the time period 1950 to 2007, derived from a very dense network of 2756 quality-controlled stations [22], was considered for the analyses.…”