Geographic Information System based suitability analysis for potentials and challenges of small-scale irrigation in Lake Tana sub-basin, Ethiopia

Abstract

ABSTRACT In assessing the challenges and opportunities of small-scale irrigation in a watershed, comprehensive assessment of all governing factors are important to get optimized, reliable and timely information on the area. This study was conducted in Abagerima watershed, Lake Tana sub-basin, Ethiopia. The aim of the study was to assess the level of suitability and potential of the watershed for small-scale irrigation using an integrated approach by Remote Sensing (RS), Geographic Information System (GIS), land and socio-economic survey. Land assessment was performed based on the Food and Agricultural Organization land evaluation techniques employing multi-criteria decision rule technique that integrates major determinant factors to practice irrigation at the smallholder level. Determinant factors including, slope, land use, soil type, water availability and accessibility were considered. For each factor, raster based spatial data were produced. The relative landscape suitability of the watershed was characterized as highly suitable, moderately suitable, marginally suitable and unsuitable. A cumulative suitability rank was determined using ArcGIS 10.2 software. Finally, a suitability map was produced. The result shows that about 20% of the watershed could be used for irrigation. However, only 2% of the watershed was irrigated during this research was conducted. This implies that about 18% of the watershed that could potentially be irrigated was not yet exploited and need to be further developed. The major challenges that hinder irrigation development in the watershed were land degradation, land fragmentation and lack of appropriate technology for water resource utilization and exploitation. Hence, it has to be recommended that water utilization efficiency should be improved through the creation of awareness, particularly on the introduction and use of better water conveyance and application technologies.