Potential effects of Land Use Land Cover Change on streamflow over the Sokoto Rima River Basin

This research investigated the effects of Land Use Land Cover Change (LULCC) over the Sokoto Rima River Basin (SRRB) using a setup of Weather Research and Forecasting (WRF) atmospheric model to generate the parameters to force WRF hydrological (WRF-Hydro) model which comprises of a parent domain at 12km horizontal resolution with an updated MODIS Land Use (LU) data and the nested domain at 4km resolution which focuses on the SRRB. The calibration of the model was done by modifying the infiltration and the Manning's roughness parameters. WRF-Hydro model was used to run simulations with the control LU and five different LU scenarios generated for Urban (Ur), Grassland (Gr), Savanna (Sa), Forest (Fr) and Barren (Ba). For the period analysed, simulation with Gr scenario increased streamflow in all the forecast points, while the Sa decreases it. A strong correlation was noted between the input precipitation and streamflow for all LU scenarios, and a significant Specific Discharge to Rainfall (SDR) for Ur, Fr and Ba scenarios. There was an increase in streamflow in the dry period due to afforestation and a decrease due to deforestation. Areas where grasslands were converted into savanna showed a little increase in evapotranspiration ET. There was more ET for the Sa scenario than the Gr scenario in the wet period, while there was more ET in the dry period for Gr scenario than it is for the Sa scenario. The study has shown that ET is a major factor to changes in streamflow due to LU changes over the basin. The sensitivity of the model to LULCC is reasonable, but more research is recommended to compare results with different hydrological model popularly used for LULCC impact studies.