Estimation of the minimum amount of Seepage and Operational Losses in the Earthen Canals using Ant Colony Optimization Algorithms

Background and objectives: a significant portion of water is wasted during the conveyance and distribution process due to seepage and operational losses. To deal with the limitation of water resources, it is necessary to provide methods for reducing losses from canals. Therefore, the current study aimed to represent a method for estimating the minimum seepage and operational losses in earthen canals in order to improve water efficiency in agricultural water distribution systems using ant colony optimization algorithm.
Material and methods: In this research, the innovation and aim are to optimize seepage and operational losses in water distribution system using the ant colony optimization and the results of the algorithm are used to manage water resources, especially in agricultural water distribution systems. To achieve this goal, initially, basic information was collected from the Moghan plain canal and for the purpose of hydraulic flow simulation in the canal a simplified mathematical integrator-delay model was used. Then, in order to minimize seepage losses, a formula extracted from research history was applied. In addition, the seepage formula was calibrated and validated based on the measured seepage amount at each segment over the 23 km of the canal. Also, to optimize the purpose of this study, two single objectives, which they were minimizing seepage and water shortage delivered to each offtake in the main canal distribution process, respectively, were defined and adjusted in ant colony optimization algorithm model. Then, by linking the hydraulic simulator model, the estimation seepage formula and the Ant colony optimization model, it was possible to optimize the mentioned objective functions.
Results: According to the results, optimizing the first objective function, in order to minimize seepage losses caused the reduction of total seepage amount during the 23 Km of selected research area, from 0.199 Cubic meter per second (seepage in the present condition of the studied canal) to 0.187 Cubic meter per second. Therefore, the reduction in seepage losses for the first objective function was 6 percent. However, the application of the first objective function has led to an increase in the amount of operational losses from 39.91%, which is the amount of current operational losses in the canal, to 45.55%. In other words, the operational losses from the first objective function compared to the current operational losses, increased by 5.64%. Accordingly, the total reduction of losses in the first objective function compared to the current losses in the canal was 0.39 percent. By applying the second objective function, the results show a reduction in operational losses from 39.91% to 27.91%, which indicates a 12% reduction in operational losses compared to the current situation of this type of losses. Also, seepage losses have increased from 0.199 cubic meter per second to 0.2168 cubic meter per second, which indicates an 8.9% increase in seepage losses compared to the current situation. Overall, the total losses reduction in the second objective function compared to the current situation is equal to 3.1 percent.
Conclusion: single objective functions of seepage and operational losses reduction results showed that optimization with the purpose of reducing seepage losses did not lead to a significant reduction in total losses in irrigation canals. On the other hand, in order to reduce operational losses, Ant colony optimization algorithm model by choosing optimum water depths could reduce the amount of operational losses to a considerable amount. According to the results, it can be generally acknowledged that modernization, renovation and rehabilitation projects of irrigation networks with the target of reducing losses and improving water use efficiency, if more focused on improving the operating process, more reduction of losses would result in agricultural water distribution system.