Irrigation Water Quality Index and GIS Approach based Groundwater Quality Assessment and Evaluation for Irrigation Purpose in Ganta Afshum Selected Kebeles, Northern Ethiopia

Abstract

Author Grmay Kassa Brhane Department of Earth Science, College of Natural and Computational Sciences, Adigrat University, Adigrat, Ethiopia Email: grmaykassa@yahoo.com, gk2011.mcs@gmail.com, grmayks@hotmail.com Abstract The research has conducted over a total areal coverage of about 38.94km 2 which covers all the well fields which are serving the irrigating land and supporting the food security at house hold level. The area is located in the Ganfa Afishum Wereda which includes two kebeles in the Eastern Tigrai, Northern Ethiopia. This paper assesses the groundwater quality and evaluates its quality for irrigation purpose with GIS technology and Irrigation Water Quality Index approach and compare with irrigation water quality standards. The status of the groundwater in the area varies widely depending up on the human activities. A total of 22 (13, 4, 4 and 1 from Bore hole, shallow wells, 4 handug well and reservoirs respectively), Depth integrated groundwater samples were collected by purpose sampling technique. These samples were analyzed for their Physicochemical components. The groundwater was evaluated by nine chemical parameters (EC, SAR, Na + , Ci , NO3 -2 , pH,TDS, SSP, HCO3 and IWQI) and five water quality parameters (EC, SAR, Na + , Ci , and HCO3 ) were utilized to calculate the irrigation water quality index. The groundwater is suitable for irrigation purpose with respect to pH, EC, Na + , Ci , NO3 -2 , SSP and SAR but, with TDS and HCO3 , the groundwater needs slight water treatment for quality adjustment. The ionic concentration and the chemical parameters, generally is high near the town in all side of the area but, it is also significant in highly cultivated agricultural fields where point and non sources. The groundwater in the area is classified as moderate restriction (90.1%) and high restriction (8.9%). The groundwater is suitable generally with some moderate restrictions. The objectionable groundwater is restricted around the town with main of contaminants domestic and factories wastes.