This paper assesses the aquifer characteristics and productivity nature of different rocks and se... more This paper assesses the aquifer characteristics and productivity nature of different rocks and sediments using geological and hydrogeological methods in Ellala catchment (296.5km 2) 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 m 2 /day with a mean value of 32.58 m 2 /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 m 2 /day with a mean value of 163.41 m 2 /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 m 2 /day with a mean value of 142.71 m 2 /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.
This paper assesses the aquifer characteristics and productivity nature of different rocks and se... more This paper assesses the aquifer characteristics and productivity nature of different rocks and sediments using geological and hydrogeological methods in Ellala catchment (296.5km 2) 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 m 2 /day with a mean value of 32.58 m 2 /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 m 2 /day with a mean value of 163.41 m 2 /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 m 2 /day with a mean value of 142.71 m 2 /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.
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