Dynamic-node-numbering concept in channel network model

The Al-Hassa Irrigation and Drainage Authority in The Kingdom of Saudi Arabia covers approximately 8,000 ha of cultivable land. To irrigate this project, a precast concrete open-channel system has been in operation since 1971. This open-channel network, which consists of 19 mains, 178 submains, and 1,641 laterals, has more than 1,800 valves and vertical gates to divert water in different reaches of the system. The water is distributed according to a predefined irrigation schedule. In order to decide gate operating policies, a computer package known as channel network model has been developed to simulate depth and discharge variation with time under unsteady-state condition. This paper introduces dynamicnode- numbering concept in channel network model by which the control devices can be completely closed and the original schematic diagram, node numbering, and corresponding data for the modified system are internally updated without altering the original data files. This paper also addresses other features of the model such as gate operation under low differential head, interactive capabilities of the model, and simulation of large-scale irrigation network.