Abstract
This paper assesses the aquifer characteristics and productivity nature of different rocks and sediments using geological and hydrogeological methods in Ellala catchment (296.5km2) in Tigray, northern Ethiopia. The catchment consists of limestone (29.91%), intercalation of limestone-shale-marl (27.90%), dolerite dykes and sills (21.85%) and recent sediments (20.33%). Compared to rocks, the sediment due to lack of both extensive areal coverage and thickness, its water-bearing capability is almost negligible. Aquifers developed in the different rocks are mainly due to secondary processes such as weathering, fracturing and karstification. The degree of variations in the groundwater productivity is mainly linked with the variations in the effect of these processes in the respective rock. Hydrodynamic analyses of the aquifers reveal that in the limestone aquifer hydraulic conductivity is ranging from 0.046 to 4.65 m/day with a mean value of 1.44 m/day and transmissivity is ranging from 2.38 to 93.02 m2/day with a mean value of 32.58 m2/day; in the intercalated limestone-shale-marl aquifer hydraulic conductivity is ranging from 0.87 to 70.13 m/day with a mean value of 10.11 m/day and transmissivity is ranging from 17.88 to 645.7 m2/day with a mean value of 163.41 m2/day; and in the dolerite aquifer hydraulic conductivity is ranging from 1.67 to 108.86 m/day with a mean value of 59.32 m/day and transmissivity is ranging from 57.63 to 307 m2/day with a mean value of 142.71 m2/day. Based on these determined transmissivity values of different aquifers and geomorphological setup of the catchment, the potentiality degree of the aquifers of the catchment range from moderate to negligible. The negligible potentiality aquifer is found covering steep slopes and topographically high areas, whereas aquifers that have moderate to weak degree of potentiality are found occupying flat to rugged topography of the catchment.Keywords: Groundwater, Aquifer, Ellala catchment, Hydraulic conductivity, Transmissivity, Ethiopia.
Highlights
Groundwater potential in Ethiopia is low compared to surface water resources
In order to define the characteristics of aquifer, such as hydraulic conductivity, transmissivity etc, aquifer tests should be conducted in open holes and wells
Based on Şen (1995) classification scheme, which takes into account the transmissivity values, the potentiality aquifers of the catchment is ranging from moderate to weak; dolerite aquifer is moderate; intercalated limestone-shale-marl aquifer is from moderate to low; and, limestone aquifer is from moderate to weak
Summary
Groundwater potential in Ethiopia is low compared to surface water resources. But, the total exploitable groundwater potential is high. Aquifer characterization takes into account how the different geological formations get a water-bearing nature; how the arrangement. Volume 7(2):203-221, 2015 of these water-bearing geological formations with adjacent impervious layer looks like and the potentiality nature of the aquifer (Şen, 1995; Nedaw, 2003). This characterization is very essential, when dealing with problems of groundwater flow and groundwater resource evaluation. Ellala is one such catchment is in Tigray region that has experienced this intervention This resulted in drilling a number of shallow wells in rural parts of the catchment.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
