The absolute geographical location of the Gidabo river catchment is between 6.090and 6.600N latitude and38.00and 38.380 E longitude with an area and perimeter of 3,342.37 square kilometers and 305.25 kilometers respectively. rnGidabo river catchment and its surroundings are totally covered with generally moderate to highly fractured and weathered igmberite, basalt, trachayte ryolite. The area is affected by farmer and later volcanism and tectonics. rnGround water potential of study area relatively good rain fall throughout a year and the people are largely dependent on a rain fed agricultural system. In the study area the utilization of ground water for irrigation purpose is not common. But, there is small scale irrigation using several intermittent and perennial rivers that drain ground water. rnThe majority of productive aquifers are characterized by their high degree of weathering and intense fracturing. Fractured weathered volcanic rocks; Ignimbrite and basalt are the major potential rock units for storage and movement of ground water. In addition, the intergranular pore spaces of vesicular basalt and alluvium also have significant role in occurrence of ground water. The main recharge for ground water of the area is precipitation, although surface water and Perennial River and streams are also act as local recharges. rnThe surface and shallow groundwater systems are characterized by high iron concentrations. The source is believed to be the red soils that cover the study area. rnHigh fluoride concentration in the study area is recognized by its relatively higher concentration in the rift floor boreholes than the escarpment and the highland boreholes; in addition fluoride affects, such as teeth motility is recognized in the rift floor inhabitants than the highland ones.