INVESTIGATION OF LAND AND WATER RESOURCES POTENTIAL FOR SURFACE IRRIGATION (CASE STUDY: BERESA WATERSHED IN NORTH SHEWA, ETHIOPIA)

Abstract

Investigation of available land and water resources for irrigation is very important agenda for planning and decision making of their use.The present study was initiated with the objective of investigating the irrigable land and water resource potential of Beresa watershed for the development of surface irrigation and providing the geo-referenced data base regarding to irrigation suitability factors sepecifically slope,soil,LULC and water aviliability of the area.The suitability of slope, soil, LULC and water aviliability were investigated and geo-referenced each physical parameters using the aid of ArcGIS9.3.The gross irrigation water requirement,crop water water requirement and irrigation requirement of Wheat, Barely and Onion was estimated as per decade with the aid of CROPWAT8 model. Soil depth, soil drainage and soil texture of the study area were overlay to each other in GIS so as to obtain the overall soil suitability and slope was get hold of from DEM of 30*30 pixel resolution through reclassifying according to FAO guidelines. LULC of the study area was also done after importing the freely available satellite image of the area and classified in supervised classification type using the aid of ERDAS IMAGINE2014. The overall suitability was done through weighted overlay analysis of the slope, soil and LULC without including other factors of irrigation development. Accordingly, the overall soil suitability was 46.91% ranging from highly suitable to marginally suitable for the development of surface irrigation and about 4.06% to 48.33% slope of the watershed was highly suitable to marginally suitable. About 10.45% of LULC was non-suitable for the development of surface irrigation. Grossly 28.11%, of the catchment area could potentially be developed in Beresa with the available flow of the river. Other irrigation suitability factors such as soil chemical properties, socio-economic aspects, environmental hazards and ground water investigation should be studied additionally in detail for further irrigation development as well as enhancing sustainability over the study area.