The Punjab Irrigation System is one of the world's largest contiguous systems, with its entire network extending over nearly 31,000 km in length. The system faces numerous constraints that limit the canal operations and their respective design discharges. Shortage of irrigation water is a contest that normally occurs at canal tail-end users. The hydraulic performance of open canal networks is not easy to assess; therefore, it is impossible to feed the lateral offtakes with their design shares without changing designed or existing gate openings. To overcome these problems, a Hydrologic Engineering Center's River Analysis System (HEC-RAS) model has been developed to simulate the flow situation in the canal system. For this study, the Hakra Branch Canal System with a command area of 1.4 million hectares was selected. To recognize model performance, water levels at the head of the canal and tail discharge have been compared with field data. The simulated results show the best-fit match with field head water levels with coefficients of determination (R²) of 0.765 and 0.877 and tail discharges of the canal with R² = 0.707 and 0.945, for calibration and validation periods, respectively. The hydraulic simulation model is a useful tool for effective canal operation to determine the losses and find out the expected discharge for the tail-end users. It has been observed that the proportion of excess actual delivery of water to lateral offtakes results in inadequate water supply for the tail-end users. It is recommended that during the observation of the seasonally discharge table, the irrigation engineer should adjust a factor either in the HEC-RAS model or in the observed data. It is also recommended to develop an unsteady model for considering sediment transport.

中文翻译：

---

使用巴基斯坦 Hakra 支渠系统的 HEC-RAS 建模进行有效运营和监测的创新举措*

旁遮普灌溉系统是世界上最大的连续灌溉系统之一，其整个网络长达近 31,000 公里。该系统面临许多限制运河运营及其各自设计排放的约束。灌溉用水短缺是一种通常发生在运河尾端用户的较量。明渠网络的水力性能不易评估；因此，在不改变设计的或现有的闸门开口的情况下，不可能用它们的设计份额来供给侧向取水口。为了克服这些问题，水文工程中心的河流分析系统 (HEC-RAS) 模型已被开发来模拟运河系统中的流动情况。在这项研究中，选择了指挥面积为 140 万公顷的 Hakra 支渠系统。为了识别模型性能，将运河头部和尾部排放的水位与现场数据进行了比较。模拟结果显示与具有决定系数的田头水位的最佳匹配（R ² ) 为 0.765 和 0.877 以及运河的尾部排放，其中R ² = 0.707 和 0.945，分别用于校准和验证期。水力模拟模型是有效的渠道运营的有用工具，可以确定损失并找出尾端用户的预期流量。已经观察到，过量的实际供水与横向取水的比例导致尾端用户的供水不足。建议在观察季节性流量表时，灌溉工程师应在 HEC-RAS 模型或观测数据中调整一个因子。还建议开发一个考虑沉积物迁移的非稳态模型。