MIKE SHE software was used to estimate recharge into the aquifers of Ogun and Oshun Basins. Abeokuta within the Ogun Basin and Oshogbo in the Oshun Basin are subdivided vertically into two components: atmosphere, and unsaturated zone. The atmosphere zone comprises of rainfall and potential evapotranspiration, while the unsaturated zones, comprises of the Basement Complex and Sedimentary rock. Daily records from two rainfall stations, Oshogbo station (2008–2011) and Abeokuta station (2010–2014) water years were obtained for simulation of groundwater recharge processes using MIKE SHE model. The simulation results showed that daily groundwater recharge is influenced by rainfall and ranges from 0 mm∙day–1 in January when there was an insufficient rainfall in the two stations to 10.89 mm∙day–1 in Abeokuta and 29.85 mm∙day–1 in Oshogbo in the month of August when the soils had attained field capacity. The study found out that there are more daily groundwater recharge in Oshun basin compared to that of Ogun basin. This was alluded to more rain-fall and less evapotranspiration recorded at Oshun basin as compared to Ogun basin coupled with the sedimentary soil which allows more movement of water into the aquifer of the basin. It is recommended MIKE SHE model should be used to estimate recharge in other basins in Nigeria and Africa for quick and effective daily recharge calculations to permit better and scientific decision making in these areas.

The paper characterises the method of estimating the size of the areas supplying radon to radon groundwater intakes. It is presented on the example of the intakes of radon groundwaters and radon acidulous waters of Lądek Zdrój, Świeradów Zdrój and Kowary. The results of appropriate calculations prove that the volume of rocks supplying radon to the groundwaters of particular intakes oscillates from over ten to several hundred thousand cubic metres. Considering the depth of the zone where radon saturation of these waters takes place, the area supplying this gas to particular intakes varies from several hundred to several thousand square metres. The largest areas of radon-222 supply are characteristic of the most discharge springs, while the smallest ones belong to the springs of low discharge, especially the intakes of groundwater mixture, where only one component supplies large quantities of radon-222. The recharge areas of groundwaters in which