Gis Based Multicreatrea Analysis For Identification Of Suitable Irrigable Land In Gilgel Abay River, Lake Tana Sub Basin, Amhara Region

Abstract

The Study Aimed At GIS Based Multicritrea Analysis Of Land For Suitable Irrigation In Gilgel Abay, Tana Sub Basin, Ethiopia Which Used To Identify Suitable Irrigable Land And To Estimate Crop Water Requirement And Schedule Of Maize And Tomato In Bahir Dar And Dangila. The Analysis Of Land Considers Land Use, Soil Type, Slope, Drainage Density, Soil Depth, Proximity (Distance), Rainfall And Temperature As Factors To Identify And Prioritize Its Suitability For Irrigation. Lack Of Detailed Study That Showed The Potential Of Irrigable Land In Gilgel Abay Did Not Trigger Private Investors In The Area Of Irrigation, Poor Know How Of Irrigation Significance By The Communities, Reduces The Initiation Local Administrators For Irrigation And In General Reduced Management And Practice Of Tradition Irrigation(Dillip, R. Khairnar, M, Etal 2015).The Main Factors Considered To Identify Potentially Suitable Irrigable Land Were The Soil Type, Land Use, Slope, Drainage Density, Soil Depth, Proximity (Distance), Rainfall And Temperature With Their Weight 41%, 25%, 14%, 9%, 5%, 3%, 2%, & 1 % Respectively. The Map Of Parameters Was Prepared And Reclassified Using Arcgis 10.3 And Erdas Imagine 2014 Software. Weighted Overly Used To Produce Suitable Irrigable Map Using Spatial Analyst Of Arcgis Software Very High, High, Moderate, Low And Very Low Suitability Orders With 14%, 38%, 36%, 10 %, And 2% Area Coverage Of The Study Area Accordingly. The Large Parts Of The Study Area Have A Potential Of Cultivation For Irrigation Purpose With 52 % Of Very High And High Classes Of Suitability. Cwr And Schedule In Highly Suitable Irrigable Land For Maize, And Tomato Was Analyzed Using Cropwat8 Window Tool In Bahir Dar & Dangila For Vertisol Soil Types. Cwr Of Maize In Bahir Dar Estimated 482.2 Millimeter Of Water Per Decade And 176.9 Millimeter Of Water Per Decade In Dangila. This Variation Is Due To Higher Temperature, Wind Speed And Solar Radiation, Dry Humidity And Low Rainfall In Bahir Dar. Similarly, Cwr Of Tomato In Bahir Dar (180.7 Mm/Dec) Is Higher Than Dangila (176.9 Mm/Dec). The Result Indicates That Maize Requires Higher Amount Of Water Than Tomato Due To Crop Characteristics, Kc And Growth Period Variations. The Water Discharge (Flow) Varies In Different For Maize And Tomato In Bahir Dar As Well As In Dangila. 8.5 L/S/Ha Water As Flow Required For Maize In Bahir Dar Which Is Larger In Dangila With 7.14 L/S/Ha. Similarly, Tomato Needs 4.24 L/S Ha And 3.91 L/S Ha In Bahir Dar And Dangila Respectively. This Variation Comes As The Result Of Climatic Variation In Bahir Dar And Dangila, Difference In Kc And Characteristics Of Maize And Tomato.