Mohammad Javad Monem

Because of water scarcity, improvement of water management has been gaining in importance. Agriculture is the largest water consumer, so improvement of irrigation networks is the priority. An automatic control system is one measure for achieving this goal. With the exception of automatic hydraulic structures, other automatic systems are new to Iranian irrigation networks, which make their selection a complicated task. In this paper, a dynamic system approach was used to investigate the interactions among automatic system components and the long‐term behaviour of irrigation networks. The conceptual model was developed and presented in a separate article. In this research, the quantified model is developed and verified for the Qazvin irrigation network (QIN). A data series of conveyance and distribution efficiency, and groundwater withdrawal, are used for verification using statistical indicators and extreme condition tests. The results show that the model simulates the system behaviour correctly. Sensitivity analysis shows that distribution and delivery management is the most effective parameter in irrigation network utility. Some improvement scenarios are tested. The results show that improving managerial structure has the greatest impact on network utility; in fact, other measures are not so useful, unless managerial structure is improved. © 2019 John Wiley & Sons, Ltd.

Pipe size of pressurized irrigation networks that usually have a branched layout had been optimized by assuming a predetermined layout. Few researches have considered simultaneous layout and pipe size optimization. In this study, a hybrid approach that is a combination of pipe size optimizer and layout optimizer is adapted for simultaneous layout and pipe size optimization. Once the solutions (specific layouts) are developed, a modified version of Labye’s iterative discontinuous method (LIDM) is applied to optimize pipe sizes. After the layout optimizer rearranges, the solutions and the process continues. Two versions of a new discrete particle swarm optimization (PSO) are used as tree layout optimizer, namely, original jumping PSO (JPSO) and tree growing JPSO (TG-JPSO). In the original JPSO, a loop model network is considered first, and a spanning tree is produced by using JPSO for eliminating certain branches. Tree growing JPSO without producing a loop model directly deals with branched layout. The proposed methods are applied on three benchmark examples. The results showed that using the proposed approach leads to better solutions with a very small number of function evaluation. However, compared with the existing nonhybrid approaches, the hybrid approach takes a longer CPU time to calculate objective function because of the application of LIDM for pipe sizes optimization.