Water allocation in multi-purpose and multi-year reservoir using ant colony optimization

This study aimed to develop Multi-Year Reservoir Operation Model (MYROM) to optimize water allocation in multi-purpose and multi-year reservoir. MYROM relied on Ant Colony Optimization (ACO) method to address non-linear optimization challenges associated with multiple objectives. In addition, water availability in the reservoir was assessed, which was an analysis of constraints in minimizing water shortages at study location. The weighted priority for each type of water use was then obtained from a model that followed ACO method. This priority weighting was carried out to provide an assessment regarding decisions related to water management, particularly in determining the sequence of use for various purposes, such as irrigation, domestic and industrial water supply, or hydroelectric power generation. The model used was tested at Wonorejo multi-purpose Reservoir in East Java, Indonesia using historical water availability and use from 2003 to 2021. The simulation results showed that MYROM succeeded in allocating water through the minimization of shortages by proposing parameters α = 1, β = 2, and ρ = 0.4, with the number of ants (m) = 100 in the water demand variable. In addition, the water demand variable was in the form of hydropower, irrigation needs, and raw water needs with a period of 10 days for the next 5 years. Based on these results, the use of MYROM with specified parameter values could serve as a practical approach to improve the planning of reservoir water allocation operations. In addition, this showed that the performance of future water allocation planning model depended on predicted water availability data.