Assessment Of Land Suitability For Surface Irrigation Using Gis And Weap Model In Sibilu Watershed (Upper Abbay Basin In Ethiopia)

Abstract

Assessing Potential Land And Water Availability For Irrigation Is An Important Factor To Extent Of Irrigated Agriculture In An Area And Improving Food Security By Increasing Agricultural Production. This Study Assessed Irrigation Potential For Surface Irrigation In Sibilu Watershed By Considering The Irrigation Suitability Factors Such As Slope, Soil Type, Texture, Depth, Drainage, Proximity To River, And Land Use And Land Cover By Using ArcGis10.8.1.The Suitability Of Each Parameter Was Analyzed Individually And Then The Weighted Overlay Analysis Was To Get The Overall Suitable Land. The Results Showed That36.2 %( 23019.4ha) Highly Suitable, 51.6 %( 32828ha) Moderately Suitable, 11.6 %(7351.2ha) Of The Land Was Marginally Suitable For Surface Irrigation And 0.7 %( 428.4ha)Of The Land Was Not Suitable For Surface Irrigation. The Crop Water Requirement Of Five Commonly Grown Crops Was Identified By The Cropwat8.0 Model Using Climate Data. Irrigation Water Requirements For Dominant Crops Which Include Wheat, Barley, Bean, Pepper And Potato Was Calculated And Founded As Were 265.5, 297.2, 254.9, 300.6 And324.5mm Respectively. The Stream Flow Was Assessed With The Weap Model. The Model Calibration And Validation Using Observed Stream Flow. The Result Showed That Model Performance Evaluation Statistics Coefficient Added Determination, Nash-Sutcliffe Model Efficiency, And Percent Bias For Calibration Were 0.77, 0.71, And 17.02 And For Validation0.74, 0.7, And 9.41 Respectively. This Shows That A Good Agreement Between The Simulated And Observed Values. The Assessment Of Available Stream Flow, The Total Net Irrigation Water Demand For All Selected Crops With Identified Land Potential For Surface Irrigation Were The Land Suitable And The Available Water In The Study Area Was Found 63199.4 Ha And88mm3 Of The Total Suitable Land In The Study Area. The Annual Water Demand And Supply Of The Catchment Including Losses Reuse And Demand Side Management Shows Increment At November, December, January, April And May, Of Supply Requirement For Irrigation.