Integrated hydogeological study using major ion hydrogeochemistry and environmentalrnisotope tools were employed to characterize groundwater dynamics in tributary streams ofrnMuger River Catchments in the north and Holota River Catchments in the south.rnHydrogeochemical study reveals that water types vary from early stage of geochemicalrnevolution (CaHCO3 type) to the highest level of geochemical evolution (NaHCO3) and fromrnlow TDS to high TDS and NaHCO3 type are observed only in the downstream part of HolotarnRiver catchment. In relation to stable isotopes, highly enriched groundwater from deep wellsrnwere also observed in the downstream part of Holota River catchment. Radon concentrationrnhas been observed in the main Holota River and low in tributary streams. However, Radonrnconcentration is low in main Muger River but high in its tributary streams that flow throughrnacidic rock units. The stable isotopes signature of the deep aquifer in Holota River catchmentrnillustrates that, the groundwater is recharged through long subsurface path relative to therndeep aquifers found in Tributary streams of Muger River catchment. Radon signature showsrnthat main Holota River is recharged from the groundwater at some segments whereas it is notrnthe case for Muger River. And finally, groundwater level map together with isotopicrnsignature show that groundwater divide shifts from surface water divide towards MugerrnRiver catchment and the groundwater flow converges towards Holota River flow direction.rnKey Words: Groundwater dynamics, Muger River, Holota River, Stable isotopes, Radon