SURFACE IRRIGATION POTENTIAL ASSESSMENT OF GEBA-RAMIS CATCHEMENT, RAMIS SUB-BASIN

Abstract

Assessment of potential irrigable land and available water resources for surface irrigation is very important schedule for planning and decision making of their use. The overall goal or objective of the present study was initiated to assess the available water and land resources potential of river for surface irrigation in Geba-Ramis catchment for development of surface irrigation and to identify the potential irrigable lands with respect to the various irrigation suitability parameters such as slope, soil, LULC and water availability of the catchment then mapped each physical parameter with the use of ArcGIS10.4.1. The gross irrigation water requirement, crop water requirement and irrigation requirement of Maize, Onion and Potato were estimated as per decade with the use of CROPWAT8.0 model. Soil depth, soil drainage and soil texture of the study area were overlay to each other so as to obtain the overall soil suitability and slope suitability was come up from DEM of 30*30-pixel resolution through reclassifying according to FAO guidelines. The overall suitability for surface irrigation potential was done through weighted overlay analysis of the slope, soil, LULC and distance from the water supply with the aid of model builder in the ArcGIS10.4.1 without including other factors of irrigation development. Accordingly, the overall soil suitability was 66.8% ranging from moderately to marginally suitable for the development of surface irrigation and about 5% slope of the catchment was highly to marginally suitable. About 17.3% of LULC was non-suitable for the development of surface irrigation. Grossly about 1.8% (1765.544ha) of the catchment areas could be developed potentially in Geba-Ramis catchment with the available flow of the rivers. Other factors and methods for irrigation suitability such as soil chemical properties, socio-economic aspects, environmental hazards and assessment of ground water potential should be studied additionally in detail for further irrigation development and qualities, as well as enhancing sustainability over the study area.Key words: Irrigable land, Assessment, ArcGIS, Suitability, Surface irrigation potential