Estimation of groundwater recharge in Southern Ghana

The rainfall infiltration breakthrough (RIB) model has been applied to estimate groundwater recharge over parts of the saprolite aquifer unit in Southern Ghana.This method relies on rainfall and groundwater level data monitored simultaneously over a period, and properties of the aquifer material.The water table fluctuations (WTF) technique was applied independently to validate the results of RIB technique.Both methods were executed based on specific yield (Sy) values in the range of 1%-5%.The results suggest a wide range of variations in groundwater recharge rates over the terrain.Groundwater recharge rates fall in the range of 0.58%-21.36% of annual precipitation based on the RIB.The results indicate that the lag period between rainfall and eventual groundwater recharge ranges between 0 and 9 months, depending on the thickness and content of the unsaturated zone.Estimates of groundwater recharge suggest variably good fortunes for groundwater.