Hydrogeochemistry of Ziway-Shala Area, Main Ethiopia Rift

Temere, Engdasew (2013) Hydrogeochemistry of Ziway-Shala Area, Main Ethiopia Rift. Masters thesis, Addis Ababa University.

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Abstract

Ground water is the main source for domestic, agriculture and industries used in ZiwayShala Lake area .The study area is found in the main rift valley, in rift floor which include the four main lakes Ziway, Langano, Shala and Abijata. The climate condition of the area is characterized by alternating wet and dry seasons. In the area there water quality problems. The main objective the study is to investigate hydrogeochemistry of the ZiwayShala Lake area system using water chemistry (chemical composition). The water samples for analysis of major anions and cations are 56 water samples of boreholes, hand dugs, springs, Lake Waters and River waters. Of which 31 water samples are newly analyzed and the rest are secondary data from water work design and supervision enterprise and zonal office of water and energy in the study area. Prior to using the water chemistry results for the intended application, charge balance evaluation is done and those with an error greater than 10 were not used. The water types of most ground water in the area is Na- HCO3 specially found in Ziway area but a few samples shows water types of Na- Ca- HCO3 in Meki area and NaHCO3- Cl in Shala and Abijata area which is similar water type with the Lakes which indicates surface water – ground water interaction. The Na-HCO3 and Na-HCO3-Cl water types are common in the study area. The major drinking water quality problems in the area are TDS and fluorides in which the values exceed the WHO standards. This water quality problem is high towards Shala which have high fluoride, chlorides and TDS value which follow ground water flow. The water type in the area is fresh, Brackish and saline based on TDS classification. In the area there is water quality problem for irrigation purpose. In terms of SAR the surface waters (Rivers) are highly preferable for irrigation than ground water .The surface water quality shows variation seasonally. They have high TDS and major ions concentration in dry season than wet season. The agricultural activities in the area are not alarming on water quality problems but the floriculture activities have some impact on Lake Ziway, even if the change in chemistry of the lake at present due to floriculture is not significant.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	water quality, ground water, Surface water, hydrogeochemistry, rift floor
Subjects:	Q Science > Q Science (General) Q Science > QD Chemistry Q Science > QE Geology
Divisions:	Africana
Depositing User:	Selom Ghislain
Date Deposited:	28 Jun 2018 13:34
Last Modified:	28 Jun 2018 13:34
URI:	http://thesisbank.jhia.ac.ke/id/eprint/6164

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