Groundwater Potential Evaluation of Upper Shiloh V Aleut Eastern Tigray, Northern Ethiopia
No Thumbnail Available
Date
2005-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Water resources potential evaluation of Upper suluh river basin which is located north of Addis
Ababa and south of the town of Adigrate town. The evaluation is done based on the analysis of
hydromorphometric meteorological, hydrogeological and river flow data. The has a total area
of443 km2 with a big difference of altitude ranging from 2100 m to 3100 m above'mean sea
level and is the sub basin of River Tekeze. It has both low land with flat to gentle slope and
rugged topography along its peripheral area with dominant sedimentary terrain. The low land
area of the basin is covered with alluvial and Enticho sand stone. NNW-SSE and NE-SW
structures dominate in the basin especially in the north and nOltheastern P8lt of the study area.
The analysis result of different hydrormphic parameters overlaps with the geology and
hydrogeology which indicates that the North -Eastern ,East-Central and limited part of west
central part of the ~he potential zone for ground water exploitation. From long term
mean monthly rainfall data annual precipitation of the basin is calculated as
72232 mm per annum. The actual and potential evapotranspiraation for the basin are 652.63
mm and 8083 mm respectively. Of the total rainfall, 20.1 million cubic meter (MCM) water
leave the basin in the form of surface runoff per annum and 1 L1 million cubic meter (MCM)
water infiltrate within the basin, which is the annual recharge of the .basin.The ground water
potential estimation of the considering 25%ofthe total area for areas 'having slope of>20% is
336.54 MCM. Based on the permeability of the rocks the is divided in to three hydrogeology
groups higher permeability (L76m/d), moderate to lower permeability (L76-0.09m/d) and very low
permeability group «0.09m/d). For ground water exploitation, the alluvial deposit and the
Enticho sand stone area are the best potential sites.
The hydrochemistry of the basin is also analyzed and categorized in to fresh water. Boreholes,
hand dug wells and common springs are Ca-Mg-HC03 water type but two borehole samples
show Na-HC03 water type assumed to have localized dolerite influence. Concerning water
quality, the basin has no any water sources having values of parameters above the permissible
limit for water supply, irrigation and industries. With respect to irrigation the quality of ground
water in the is excellent to good. Presently, there is no ground water pollution indicated from
agriculture, industry and towns.
Description
Keywords
Hydrology