East-bank canal water delivery performance evaluation: case study of Finchaa Sugar Estate, Ethiopia

ABSTRACT

In this study, the operational and design performance of the main canal (MC) was assessed to determine the carrying capacity of water delivery during peak irrigation requirement using selected performance indicators. The performance indicators used were water delivery ratio, relative changes in water level (RCWL) and canal design capacity ratio. The study was carried by collecting data comprising flow discharges and canal water level at selected locations in the MC conveyance system. The climate data and the crop growth parameters were used to determine the peak irrigation requirement (Q_R). The peak of irrigation requirement estimated for the entire commands of the East-bank canal was 5.68 m³s⁻¹ during February. The results revealed that the designed flow discharge of the canal was sufficient to meet the present irrigation demands of the estate. However, the actual water delivery performance of the canal was lower as it was below 70.5% at downstream. RCWL estimated at the tail reach of the canal was 23.3% indicating a substantial reduction of canal flow depth at downstream. Lastly, it was concluded that the entire water conveyance system of the canal needs to be modified for improvements.

KEYWORDS:

• East-bank
• Conveyance system
• Canal design capacity
• Water delivery performance
• Flow discharge

Acknowledgments

The authors are thankful to the Finchaa sugar estate irrigation department supervisors for their thankful collaboration during the data collection: Mr Basazin Mamo, Mr Ketema Tsega, and Mr Moges Ademe.