Performance Evaluation of Woybo Irrigation Scheme: Wolaita Zone, Southern Ethiopia

Performance evaluation of irrigation scheme is vital for realizing the present status and identifying the area for improvement. The study was conducted in Woybo irrigation scheme which is located in Boloso Sore district, Wolaita zone, Southern Ethiopia. This study was aimed to evaluate the performance of Woybo irrigation scheme with internal performance indicators. A total of nine demonstrating farmers' fields were selected from three canal reaches (head, middle, and tail) through purposive sampling. Primary and secondary data were collected, recorded, and analyzed. To measure the water applied to each experimental field, Parshall flume was installed, and soil samples were taken to determine soil texture, field capacity, permanent wilting point, and soil moisture content before and after each irrigation event at regular soil depth intervals. The results revealed that the mean conveyance efficiency was 60.85% and the application efficiency was 48.53%. Water distribution uniformity, deep percolation, and storage efficiencies were 84.56%, 51.47%, and 85.22%, respectively. However, the overall irrigation efficiency was found to be 29.53%, which was poorly performed due to inadequate water application, ineffective field water management, and low efficiency in water delivery systems. The main factors contributing to the poor water delivery performance included failures in water regulating gates, leakages, and siltation of canals. To address these problems, recommendations are made such as improvements in water application techniques should be implemented, through proper irrigation scheduling, water conservation practices, surge irrigation techniques, and providing extension support, training, and experience sharing. Additionally, maintenance and lining of earthen canals are necessary, along with the replacement and repair of leakages and broken water regulating and controlling structures. These measures can help to upgrade water delivery efficiency and improve the overall performance of the irrigation scheme.