Groundwater Potential And Recharge Zone Mapping Using Gis And Remote Sensing Techniques: A Case Study Of Melka Kunture Watershed In The Upper Awash River Basin In Ethiopia

Abstract

Groundwater Is The Most Valuable Natural Resources For Mankind For Drinking, Industrialization And Irrigation In Present Day, But The Availability Is Reduced Gradually Due To Over Exploitation And Lack Of Management. However, Identifying The Groundwater Potential Zones In Certain Areas Of Ethiopia Is Still Challenging In Terms Of Time And Cost For Resolving Water Scarcity Problems And The Management System Of Groundwater. The Broad Aim Of This Study Was To Map Groundwater Potential And Recharge Zone Using Integrated Approach Of Geographical Information System (Gis) And Remote Sensing (Rs) Technologies With Analytic Hierarchy Process In The Melka Kunture Watershed Of Upper Awash River Basin In Oromia Reginal State, Ethiopia. Eight Parameters (Lithology, Geomorphology, Slope, Lineament Density, Land Cover, Rainfall, Drainage Density, And Soil) That Affect Groundwater Potential And Recharge Were Identified First Based Three Theoretical Selection Criteria Setting Which Derived Using Saaty?�?S Analytic Hierarchy Process (Ahp) Approach Are Considered In This Study. The Thematic Layers Of Lithology, Geomorphology, Slope, Lineament Density, Land Use/Cover, Rainfall, Drainage Density, And Soil Were Prepared And Used For Groundwater Potential And Recharge Zone Map Development By Assigning Weights To Each Thematic Layer And Features. The Weights Of Each Thematic Layer Were Assigned (Weighted), Normalized And Ranked Based On Their Suitability, Characteristic And Relationship With The Potentiality To Groundwater And Recharge Zone Occurrences And Movements By Ahp Method Through Pairwise Comparison Matrix (Pcm). Accordingly, The Result Groundwater Potential Zone Of The Study Highly Influenced By Lithology (37%) And Geomorphology (22%) Whereas Rainfall (33%) And Lineament Density (23%) Highly Influence Groundwater Recharge Potential Zone Of The Study Area When Compared With Other Factors. Finally, The Reclassified Thematic Maps Were Integrated By A Weighted Sum Overlay Analysis (Woa) Tool To Develop Groundwater Potential And Recharge Potential Zones Map. The Result Showed That The Study Area Can Be Categorized Into Four Different Groundwater Potential Zones: Areas Of High Groundwater Potential Are Estimated To Cover 1105.60 Km2 (25.70% Of The Study Area), Moderate Potential 2308.00 Km2 (53.73%), Low Potential 880.0 Km2 (20.49%), And Very Low Potential 47.80 Km2 (1.10%). It Was Also Found That The Study Area Can Be Categorized Into Three Different Groundwater Recharge Potential Zones: Areas Of High Groundwater Recharge Are Estimated To Cover 250.20 Km2 (5.80% Of The Study Area), Moderate Recharge 3647.90 Km2 (84.00%), And Low Recharge 443.50 Km2 (10.20%). Hence, The Study Areas Has More Suitability For Groundwater Potential And Recharge Zone As Compared To Its Total Areal Coverage. The Groundwater Potential Zone Map Was Validated Using The Existing Water Source Inventory Point (Pumping Wells Yield) And So Most Wells Yield Are Observed In High And Moderate Gw Potential Zone In Central And North East Part Of The Study Area Respectively. This Indicated A Good Prediction Accuracy Of 88%. As Indicated On Groundwater Contour Map, The Groundwater Flow Direction Of The Study Area Is From Highland (Recharge Areas) To Where Groundwater Potential (Discharge Areas) Found At Central Part Of The Study Around Becho Plain And The Main Awash River, Topographically. Thus, Potential Zones Identified And Delineated In The Melka Kunture Watershed Of Upper Awash River Basin By The Gis And Rs Based Multicriteria Decision Analysis Technique Are Reliable.