灌漑・排水システム工学

Evaluation of Overhead Irrigation System Performance at Finchaa, East- Bank Sugar Estate, Ethiopia

Abstract

Terefe Y and Singh P

The study was done to assess the overhead irrigation system performance of dragline sprinklers at Finchaa, Eastbank sugar estate irrigation scheme using water distribution uniformity indicators, sprinkler discharge efficiency and variation of system discharge and operating pressure. The measurements of sprinklers water distribution uniformity were made for overlapped sprinklers at recommended spacing of 18 m × 18 m at head, middle and tail end of lateral lines for selected field at different locations of the command area. The estimated values of uniformity coefficients (CUc) and distribution uniformity (DU) along the laterals from head to tail ends varied from 71.8 to 82.8% and 66.6 to 74.3% respectively. The water distribution uniformity decreased from head end to the tail end of the lateral lines and was not satisfactory at middle and tail ends of the laterals. The sprinklers discharge and pressure along the lateral line from head end to tail end varied from 6.1 to 14.3% and 9.4 to 24.1% respectively. The values were higher for field having longer laterals (360 m to 410 m) as compared to the fields having shorter laterals (260 m to 295 m). The sprinkler discharge efficiencies varied from 87.08 to 92% and the values were slightly lower than the proposed ranges. The sprinkler spray losses were higher due to high evaporation during the test.