evaluating Surface Water irrigation Potential of gumara-Maksegnit catchment using Spatial Modeling, north-east lake tana Basin, ethiopia

Abstract

Despite large potential for surface irrigation development, only few percentages of suitable area have been utilized in Ethiopia. This study evaluated the physical land suitability of surface water irrigation for small-scale irrigation development (<200 ha) in the study area. The potential was examined by considering various interacting physical factors, such as river proximity, nature of soil type, land use/cover, and slope gradient factors with a spatial modelling-based multi-criteria evaluation (MCE). The relative importance of each factors in an overall suitability process were determined based on relevant literatures and expert’s estimation to produce the resultant suitability maps of the study area. The results of this study indicated that nearly 2254 ha (6%) of the study area were classified as suitable for surface water irrigation. The findings also revealed that about the largest percentage, i.e., 21737ha (58%) of the study area were classified as moderately suitable. This was largely due to physical limitations such as existing topography and spatial proximity in surface water source. On the other hand, irrigation activities practiced in the study area are largely characterized by traditional water diversion structures, which are often traditional, prone to water wastage and less efficient schemes of lower productivity and poor market linkage. Therefore, the irrigation potential in the study area can only be met by increasing dry season flows (following watershed management in the upstream), increasing water use efficiency thereby decreasing water use wastage, and provision of adequate extension service for small scale irrigation scheme holders.