The study area, the Kulfo River basin, is located 500 km south of AddisrnAbaba. It is bounded on the basis of the surface divide of the Kulfo River. Thernarea is composed of part of the rift floor and part of the western escarpment. Morernthan 85% of the area is underlain by Oligocene basalt and the lowland areas byrnalluvium and Quaternary basalt.rnUsing thrE;!e meteorological stations, the weighted mean annual rainfall ofrn1232 mm was computed by using the Thiessen Polygon method. ThernThornthwaite method was applied to calculate the potential and actualrnevapotranspiration of the area, which are 971 mm and 940 mm, respectively.rnFrom the above data, the surplus water was obtained, which is 291 mm. Thernmean annual runoff depth of the Kulfo river is 361 mm which is less than therncalculated surplus water. The reason might be that there is an inflow ofrngroundwater from an adjacent basin.rnConcerning the aquifer characterstics of the different rock units, thernalluvium is more productive than the other rock units. One representative well fromrnAWn was taken to calcualte the hydraulic parameters of this unit.rnUsing the discharge data from Arbaminch Springs, the general hydrologicalrnconditions of the springs were computed. This includes the computation of thernrecession constants and the recession curve for the springs. The hydraulic volumernwhich feeds the springs instant by instant were also computed. The study of thernchemistry of the springs was based on data from WSSA's Arbaminch water supplyrnproject. This study confirms that the quality of the water is suitable for drinking andrnagricultural purposes according to international standards. However, the presencernof E. coli bacteria indicates that the water needs to be chlorinated on a regularrnbasis.