Assessment of Ground Water Potential Zones in Megech River Catchment in North Gondar, Ethiopia

Abstract

This study focused on the assessment of groundwater potential zones in Megech River Catchment. The area is found in the North Gondar Zone of the Amhara Regional State in the Northern portion of Lake Tana sub basin. The current water supply system of the Gondar city was designed to have two water sources that are Angereb reservoirs and boreholes. These sources all together cover only 47% of the water requirement of the city. This indicates that the water supply coverage of the city is very low which is due to low capacity of exciting system. So it is important to assess the Ground water potential condition for the area.The metrological data, geological data and hydrogeological data’s have had an input for the determination of groundwater potential for this area. To get the average rainfall over the area arithmetic method has been used. Other meteorological data such as temperature, relative humidity, sunshine hour, wind speed have been organized in a way suitable for analysis. They have been put into penman modified method for calculation of potential evapotranspiration (PET). The actual evapotranspiration (AET) which uses rainfall and PET as an input is calculated by Thornthwaite and mather soilwater balance model. The annual average recharge of catchment has been estimated by water balance method. The collected data on geological map, land use land cover map, lineaments map, drainage map, and slope map combined with Hydro-geological data analysis have been integrated using GIS 10.3 and related software to make rational interpretations that meets the objectives of the research. The catchment receives the mean annual rainfall of 1123 mm; the actual evapotranspiration is 890.32 mm; the mean annual surface runoff that leaves the catchment is 109 million cubic meter of water and the amount of annual recharge is 133 million cubic meter. The groundwater potential zone map shows that the downstream of the river near Lake Tana has high potential zone because of high infiltration rates by agricultural land use.