Application of a GIS based multi-criteria evaluation technique in land suitability assessment for surface irrigation :

Abstract

The importance attached to agriculture in Uganda is enormous providing livelihood to more than 70% of the population and great contributor to GDR. Over reliance on: rainfall is undermining this importance, irrigation practice is still very low hampered by high initial investment costs, limited knowledge on the irrigation best practices, methods and suitability. This research focused on evaluation of land suitability for surface irrigation system. The main objective of this study was to develop a land suitability map of surface irrigation of Tororo District Malaba sub-catchment by developing spatial database of physical land resource, determining hydrological sequence and land suitability for surface irrigation and lastly, modeling surface irrigation suitability using MCE tools in ArcGIS. From the assessment, Tororo terrain is generally flat with black aid grey clay loam and reddish brown sandy clay loam soils. The favored classes of are highly suitably and moderately suitable represented by 6.34% and 61.47% respectively of the total district area. With minimal soil water and agronomic amendments; third class represented by 29.77% can be transformed to the favored class. The combined not suitable class represent 2.42% are attributed to by hills, out growths and marked distance from water sources like streams and rivers; other water sourcing method like ground water abstraction can be employed. A vast proportion of the district land is. suitable for surface irrigation, first priority in terms of suitability for investment is Nagongera, Kitewa, Paya, Sop-Sop, Merikit, Nabuyoga and Iyolwa respectively; a big proportion of the land is covered with either highly suitable or moderately suitable for irrigation in relation to criterion used in this research. This research was structured into five main chapters; chapter one presented the background outlining the need for land evaluation for irrigation using GIS tools, statement of the problem, objectives, justification and scope of the study. Chapter two took critical look at what Other authors did and theories which have been used in relation to the subject of the study. The content of this chapter reviews discussions on land evaluation, Its assessment and potential analysis. Chapter three described a multi criterion land suitability study of Tororo District so as to map the suitable. locations for surface irrigation. A number of constrains and criterion with positive influence of cultivation of maize were identified and evaluated. Chapter four presented results and discussions regarding suitability and evaluation for surface irrigation system. Appendices and references are presented in chapter five.