r. naghaei

In order to delivery and distribution programs of water in irrigation network have been used the design and implementation of different structures. Lopac gate is one of the upstream control structures having some advantages such as, performing as overflow structure, easy automation, crossing sediments and floating bodies simultaneously. One of the effective tools to study control structures is mathematical model. Due to the unsteady nature of flow in irrigation canals, incorporation of mathematical model of control structure with hydrodynamic models, is necessary. In this research, the Various Hydraulic and Operation Conditions of Lopac Gate is introduced and mathematical model of Lopac gate is developed and linked with ICSS hydrodynamic model. The developed model is validated using physical model data. The maximum error obtained as 6%, which is acceptable for practical purposes. The model was tested on a canal of DEZ irrigation network in Iran under many different conditions. Results showed that, the model is performing well for tested applications and could be used in various studies of irrigation canals equipped with this structure.