Land Suitability Assessment For Surface Irrigation Potential Along The Gibe River Sub-Basin Of Jimma Zone, Ethiopia

Abstract

Land Suitability Mapping Methods And Gis Have Been Used To Support Analysis Potential Surface Irrigation Evaluation In The Study Areas; However, Its Application And Practices Are Limited In The Areas Due To Some Factors Such As Infiltration Rate, Availability Of Water Hold Ing Capacity And Characteristics Of Rivers Data Did Not Gained In The Study Area. Therefore, The Aim Of This Study Was To Identify Potential Sites For Surface Irrigation By Selecting The Major Limiting Factors. To Select The Potentially Suitable Sites For Surface Irrigation, Gis Based Multi-Criteria Analysis (Mca) Was Adopted. Eight Limiting Factors Were Considered To Decide For The Weight; Namely, Topography (Slope), Land Use/Cover, River Proximity And Soil Data (Texture, Depth, Drainage, Ph And Cation Exchange Capacity) By An Analytic Hier Archy Process (Ahp) From Multi-Criteria Analysis. The Results Show That Slope Is The Most Important Factor Since All Its Values Are Less Than One, Followed By Land Use/Land Cover Which Only Has A Value Lower Than One. With Respect To Slope Suitability, 57.4% Of The Total Area Was Cultivated Land And It Was Highly Suitable And 2.8% Grazing Land Was Moderately Suitable. Marginally Suitable Classes, Which Are Shrub And Bush Land In The Area, Were 9.5And 30.2% Of The Study Area And They Are Not Suitable For Surfaces Irrigation. The Domi Nant Drainage Status Was The Well-Conditioned Class Of 78% And It Was Highly Suitable. The Soil Texture Results Revealed That 90.3% Of The Study Area With Soil Texture Of Clay, Silt Clay Loam And Silt Loam Was Highly Suitable. The Soils In The Study Area That Was In Ph Range Of4.5-5.5, Thus Moderately Suitable Class, Were More Than Half (54.8%). 58 .4 % Of The Com Mand Area Was Close To The Water Source And Thus Highly Suitable For Surface Irrigation. Generally, The Results Showed That 0.8, 9.4, 2.3, And 87.5% Of The Study Area Are Highly Suitable, Moderately Suitable, Marginally Suitable And Not Suitable For Surface Irrigation, Respectively. Thus, The Application Of Gis-Based Mca Provided An Effective Methodology To Solve A Complex Decisional Problem In Potential Surface Irrigation Site Selection In The Study Area.