Assessing potential land suitable for surface irrigation using groundwater in Ethiopia

Abstract

Although Ethiopia has abundant land for irrigation, only a fraction of its potential land is being utilized.This study evaluates suitability of lands for irrigation using groundwater in Ethiopia using GIS-basedMulti-Criteria Evaluation (MCE) techniques in order to enhance the country's agricultural industry.Key factors that significantly affect irrigation suitability evaluated in this study include physical landfeatures (land use, soil, and slope), climate (rainfall and evapotranspiration), and market access (proximity to roads and access to market). These factors were weighted using a pair-wise comparison matrix,then reclassified and overlaid to identify suitable areas for groundwater irrigation using a 1-km grid.Groundwater data from the British Geological Survey were used to estimate the groundwater potential,which indicates the corresponding irrigation potential for major crops. Results indicated that more than6 million ha of land are suitable for irrigation in Ethiopia. A large portion of the irrigable land is located inthe Abbay, Rift Valley, Omo Ghibe, and Awash River basins. These basins have access to shallowgroundwater (i.e., depth of groundwater less than 20 m from the surface) making it easier to extract. Thecomparison between available groundwater and total crop water requirements indicate that groundwater alone may not be sufficient to supply all suitable land. The study estimates that only 8% of thesuitable land can be irrigated with the available shallow groundwater. However, groundwater is a viableoption for supplementing surface water resources for irrigation in several basins in the country