Optimizing water allocation across canal networks based on channel hydrodynamics: Modelling and application

Abstract

【Objective】 The mismatch between water distribution time and water flow rate is an issue in distributing water across canal network systems. This paper proposes an optimal method to allocate water across canal networks in irrigation districts. 【Method】 The method was based on channel hydrodynamics. The objective of the optimization was to maximize flow water distribution and expedite water allocation. The constraints included channel discharge capacity, water distribution rate and sequence, water balance, bifurcation diversion processes, and channel transmission losses. The optimal water distribution was obtained by solving the one-dimensional hydraulic model for each channel. The model was applied to irrigation districts with four-level of channels. Aligning with water distribution practices in the irrigation districts and for facilitating gate regulation management, the model adopted a top-down irrigation approach. 【Result】 The optimal method coordinated the timing and flow of water distribution in the main canal, branched canals, lateral canals and field canals well, achieving a well-balanced water distribution in each irrigation event. Compared to traditional water distribution, the proposed method improved the start and end timing of water distribution in each level of the canals; the results were more aligned with the real water supply process. Water flow rate and volume in the canals at the end-level can meet the water demand. 【Conclusion】 The channel hydraulic-based optimization method we proposed for water distribution can accurately allocate the water over the irrigation area and improve the efficiency of water distribution management.

Keywords

• canal system
• water distribution
• simulation
• irrigated region