PERFORMANCE EVALUATION OF FIELD WATER APPLICATION ON FURROW IRRIGATION AT WONJI SHOA SUGAR ESTATE, ETHIOPIA

Abstract

Furrow irrigation is dominantly used method of surface irrigation in the large sugar cane irrigation projects in Ethiopia. This research was conducted to evaluate the performance of furrow irrigation with SIRMOD software by two point method and evaluate current performance of furrow irrigation system, identify the performance gaps and recommend means of performance improvement at Wonji Shoa Irrigation Estate. Three fields were selected according to soil type, furrow length and workability for measurement with field code 15, 52,108 which had furrow length of 64 m, 48 m and 32 m which was practice in the sugar estate. Different performance indicators were used to evaluate performance of furrow irrigation they were application efficiency, storage efficiency, application uniformity and deep percolation ratio. The estimated and simulation result obtained from the average application efficiency of the three selected fields (15, 52, and 108) were 74.42%, 41.19% and 64.12% and 74.39%, 50.20% and 75.18% respectively. The storage efficiency values for three selected fields were 100% for estimation and 99.11%, 99.67% and 99.65% for simulation respectively. The estimation and simulation average distribution uniformity of the three selected fields were 91.86%,90.78% and 89.86% and 92.44%,91.38% and 93.26% respectively and the deep percolation ratio for estimated and simulation were 25.35%,58.81% and 35.88% and 25.35%, 49.48% and 24.5 respectively . From the selected fields, filed 15 and 108 had better application efficiency with furrow length 64 and 32 respectively than the filed 52 with furrow length 48 m and the field 52 had low application efficiency and high deep percolation ratio. The result obtained from sensitivity analysis; discharge, cutoff time and length of furrow were highly sensitive to application efficiency and deep percolation ratio, whereas the slope of furrow had no effect on performance indicator in this study. The amount of water applied during irrigation event were more than the irrigation water required which indicates that large amount of water was being wasted due to poor irrigation water management practice. From the result of this study, it can be concluded that there were over irrigation problems