Transient Flow Simulation in Irrigation Channels

This document shows a Transient Flow Simulation Model (SFT) in a main irrigation channel, this hydraulic model allows us to know the water levels, the flow and the time opportunity in channels for a correct operation strategy. SFT helps the channel operator in the irrigation district to get the correct control actions and to make water use more efficient. SFT is based on the conservative Saint Venant equations solved by a discrete solution with the Preissmann scheme. The non-linear terms in the momentum equations were solved by using the Newton-Raphson methodology and the convergence was tested under the Lax equivalence theorem with satisfactory results. This simulation model has a graphical user interface (GUI) in MATLAB®, which allows to load the geometry and hydraulic data. Also, we can indicate in the delivery points the type of lateral discharge structure. Those structures could be orifices, sluice or an AMIL gate, a discharge law or you can also calculate an in-line reservoir. The transient module is capable to work in an interactive way with a gate control algorithm for the level and the flow control attending different demanding conditions. Finally, the water profile, area, and flow variations along the channel, the gates movements and real lateral discharge flow are calculated. It is possible to get the graphics results in real time calculation or to save it and generate the graphics with the module called “Results”. In this work, SFT is applied to a Mexican main irrigation channel which has five sluice gates, six in-line reservoirs and three lateral outflows.