Evaluation of Groundwater Quality and Suitability for Drinking and Irrigation Purposes Using Hydrochemical Approach: The Case of Raya Valley, Northern Ethiopia

Gebrerufael Hailu Kahsay,Tesfamichael Gebreyohannes,Fethanegest Woldemariyam Tesema,Tesfa-Alem Gebreegziabher Emabye

doi:10.4314/mejs.v11i1.5

Gebrerufael Hailu Kahsay, Tesfamichael Gebreyohannes + Show 2 more

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https://doi.org/10.4314/mejs.v11i1.5

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Journal: Momona Ethiopian Journal of Science	Publication Date: May 30, 2019
Citations: 2	License type: cc-by

Affiliation: Mekelle University

Abstract

Groundwater is a vital source of water for domestic and agricultural activities in Raya valley due to non-perennial flow of surface water.Thus the present study aims to evaluate the groundwater quality and assess its suitability for drinking and irrigation purposes. A total of 137 groundwater samples were examined for various physico-chemical parameters to evaluate the quality and suitability of groundwater for the intended purposes. Piper-Hill diagram was adapted to infer hydro-geochemical facies and water types. The suitability of groundwater for drinking purpose was evaluated by comparing the analytical results of different water quality parameters to the Ethiopian standard as well as World Health Organization Standards (WHO, 2006). Salinity, sodicity and related parameters were considered to evaluate the suitability of the groundwater for irrigation use. The dominant water types are magnesium bicarbonate and sodium-calcium bicarbonate.The hydrochemistry of the groundwater changes from Mg-Ca-HCO 3 dominance at the foot of volcanic hills to Ca-Mg-Na-HCO 3 and Ca-Na-Mg-HCO 3 at the valley floor. On the basis of total hardness, 46 % of the water samples in Raya valley fall in the very hard water class whereas, based on TDS values 95% of the water samples are found to be permissible for drinking. With the exception of three constituents (Mg 2+ , Ca 2+ and K + ), all other analyzed constituents in groundwater are within the established standards of Ethiopia. Water suitability for irrigation indicates that the groundwater fall in the range of good to permissible, however, higher salinity, magnesium hazard and low permeability index restricted its suitability in southeastern parts of the study area. Keywords: Water quality; SAR; Irrigation and drinking suitability; Raya Valley; Ethiopia

Highlights

Water naturally contains several different dissolved inorganic constituents
Composition of the water in the area is mainly controlled by the chemical weathering of silicate minerals which are the major constituents of the basaltic rocks making up the Raya valley
The dominant water types identified from the hydrochemistry analysis of the groundwater samples in Raya valley are Mg-HCO3 and Ca-Na-HCO3 type

Summary

Introduction

Water naturally contains several different dissolved inorganic constituents. Magnesium, sodium and potassium (cations); and chloride, sulphate, carbonate, and bicarbonate (anions) constitute about 90% of the total dissolved solids (TDS) in water (Fetter, 2001). Strontium (cations); nitrate, phosphate, and fluoride (anions). Water quality is a consequence of the natural physical and chemical state of the Momona Ethiopian Journal of Science (MEJS), V11(1):70-89,2019 ©CNCS, Mekelle University, ISSN:2220-184X. E (MEJS) Volume 11(1):70-89,2019 water as well as any alterations that may have occurred as a consequence of anthropogenic activities (Venkateswaran et al, 2011). Analysis of water chemistry is used to describe the physical, chemical and biological characteristics of the water in respect to its suitability for particular purpose. Water chemistry data can be used to infer flow directions, identify sources of recharge to groundwater and estimate amount of recharge (Anderson and Woessner, 1992)

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