Objective: Water is a critical resource for agricultural development and national food security, particularly in arid and semi-arid regions. Due to increasing water demand and limited availability, equitable and efficient water distribution in irrigation networks has become a major management challenge. Performance evaluation of irrigation canals is essential for optimal water management and improving the performance. To hydraulically model and quantitatively evaluate the performance of the Shuaibiyah irrigation canal, with emphasis on efficiency, adequacy, and equity in water delivery and distribution.
Method: An unsteady-flow hydraulic model was developed in HEC-RAS for the main canal, incorporating nine water-level control structures and fifteen offtakes. After calibration and validation using field data, the model simulated baseline conditions and eight operational scenarios with positive and negative inflow variations. Performance indicators—efficiency, adequacy, and equity—were computed at local and regional scales and classified using standard criteria.
Results: Local assessments showed that efficiency remained within the “good” range for all offtakes across all scenarios, with a network-wide average of 0.998, indicating very high conveyance performance. However, adequacy for some downstream offtakes declined to the “fair” range under certain scenarios, reflecting supply shortfalls despite high efficiency. Equity analysis revealed marked structural imbalance: baseline equity values were 0.005 (upstream), 0.197 (middle), and 0.285 (downstream), demonstrating significant preferential allocation to upstream users.
Conclusions: Although the Shuaibiyah irrigation canal exhibits excellent technical efficiency, it faces pronounced structural inequity that disadvantages middle and especially downstream regions. Achieving sustainable and balanced performance requires revising water allocation strategies and improving operational management to enhance equity throughout the system.