The study aims at evaluating physical suitability (land and water resource) for surfacernirrigation development using GIS techniques. The Dedessa sub-basin was selected as arncase study for this thesis work. The Dedessa sub-basin located at the Southern part ofrnthe Abbay River Basin. The study area covers an area of about 1.96 M hectares.rnThe evaluation of land in terms of the suitability classes for surface irrigation was basedrnon the method as described in FAO guideline for land evaluation. The essence of landrnevaluation is to compare or match the requirement of each potential land use with therncharacteristics of each kind of land. (FAO, Land Evaluation for Development. Soilrnbulletin)rnA land unit is obtained by the overlaying of selected theme layers, which has uniquerninformation of land qualities for which the suitability is based on. The selected themernlayers for this study include soil types, with their corresponding physical and chemicalrncharacteristics that affect irrigation agriculture, land cover, and slope layer, which isrnderived from the Digital Elevation Model of the study area. As its being the mostrnlimiting factor for the realization of, especially for surface irrigation method, the slopernlayer was used as the base map for the overlaying analysis.rnThe suitable land identified categorized according to the different climatic zones alongrnthe Dedessa River in the sub-basin. They are mostly concentrated in the central andrnEastern part of the sub-basin along the Dedessa and Wama River valleys.rnThe 95, 90, 85, and 80 percentage time exceedence flow of the available surface waterrnin the respective climatic zones was estimated and the area that can be irrigated withrnthis flow was computed using the selected climatic station data and estimated ETo.