Evaluating actual Evapotranspiration using SEBAL model, in the omo kuraz irrigation site, Ethiopia.

The purpose of this study was to assess actual water use for different land uses particularly for agricultural crops is considered as one of the major factors for water resource planning and irrigation water management. However, actual water use of a sugar cane is mainly determined by its actual evapotranspiration (ETa). In order to analyze the distribution of evapotranspiration over the treatment area, the SEBAL (surface energy balance algorithm) model was used to evaluate the evapotranspiration (ET) rate for sugar cane at the lower reach of the omo river basin. Surface energy balance algorithm input like NDVI, and also along with actual field data (irrigation delivery schedule, root depth of crop in each stage, soil moisture before and after irrigation and water diverted to the field) in recent time, with the accomplishment of new satellite application, evapotranspiration can be calculated from remotely sensed land surface temperature using various land surface energy balance algorithms. In put parameter like: Land surface temperature, TOA albedo and emissivity was calculated from land sat 8 image using ENVI software. Meteorology data was collected from the farm site meteorology station. This especial method apply the collection of meteorological observation with data extracted from remote sensing to calculate evapotranspiration and other energy exchange at earth surface. The result shows that SEBAL (ETa) varies between 5 mm day-1 and 6mm day-1 in the study area. As a result, the researcher made the following recommendations: in the large scale irrigation farm remote sensing approach is very important to asses actual (ET) but there is some limitation in cause of potential (ET) estimation so other researcher should work on this again.