Page 107 - 2021年第52卷第7期

Study on optimal water distribution of canal system based on
dynamic change characteristics of water conveyance losses

LIAO Xiangcheng，HU Tiesong
（State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan 430072，China）

Abstract： Optimal water distribution of canal system is an important water-saving management measure to
reduce the leakage loss and improve the water use efficiency of the canal system. However，the current cal⁃
culation method of leakage loss of the optimized water distribution model is difficult to reflect the dynamic
change characteristics of the soil permeability of the canal bed over time， resulting in more or less artifi⁃
cial water distribution. In view of this，this paper introduces the concept of pre-effect water content of ca⁃
nal-bed soil to describe the dynamic change of soil moisture in canal bed in the process of water transmis⁃
sion，and then puts forward a new dynamic calculation method for water leakage loss of canal bed. On this
basis，an optimal water distribution model with no aftereffect is established. The case study on the optimal
water distribution for summer irrigation in 2012 of general main canal system of Hetao Irrigation District
shows that： compared with the traditional optimal water distribution mode based on Kostiakov formula， the
new model accelerates the water distribution process in the initial stage of water distribution， makes the
soil in the canal bed reach the moist state as soon as possible，shortens the duration of soil free seepage，
and delays the water distribution process at the end of water distribution. Without increasing the total
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amount of water diverted from the general main canal，15.6 million m of water loss is reduced and the wa⁃
ter use efficiency of the canal is increased by 1% . The discovery of this law has important guiding value
for scientific and rational water distribution and centralized and unified operation of irrigation canal system.
Keywords： canal seepage loss； antecedent influenced water content； dynamic calculation model； optimal
water distribution of canal system
（责任编辑：韩 昆）

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A two-dimensional flow-ice-sediment coupled model for rivers Ⅱ：
validation and application

1，2 2 1
PAN Jiajia ，SHEN Hung Tao ，GUO Xinlei
（1. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin，
China Institute of Water Resources and Hydropower Research，Beijing 100038，China；
2. Department of Civil and Environmental Engineering，Clarkson University，Potsdam，NY 13699-5710.）

Abstract： Wintertime surface ice runs cause threats to the safety of dikes and structures in the northern
rivers. It is of great importance to investigate ice gouging and abrasion on streambanks for engineering pur⁃
poses. Based on the depth-averaged two-dimensional river ice model， this paper proposes a flow-ice-sedi⁃
ment coupled model including a two-dimensional flow and sand module， ice dynamic module， and river⁃
bank erosion module. The flow and sand module utilizes the streamlined upwind Petrov-Galerkin finite ele⁃
ment scheme based on the unstructured mesh. The ice module uses the smoothed parcel hydrodynamics
method. The riverbank erosion module utilizes two repose angles to adjust the equilibrium bank slope above
and below the water surface. These three modules are coupled through flow，ice，sediment，and bed geome⁃
try information exchange and feedback at the given time step. The main novelty is the combination of the
sediment theory and the river ice theory in the coupled model. It is applicable to flow，ice，and sediment
modeling in both ice-free and ice-affected rivers for all seasons. The new model is validated by the experi⁃
mental bank erosion and collapse in the dam-break flow. It is then applied to simulate bed evolutions with
and without ice cover in natural rivers， and riverbank erosion and collapses in ice jam formation and re⁃
lease. Simulated results show that the surface ice runs interact with the flow and sediment transport，caus⁃
ing significant riverbank erosion and retreat. The model works well in reproducing ice-affected flow fluctua⁃
tions， sediment transport， riverbank collapses， and bed changes. It provides a useful tool for ice-flooding
prevention and riverbank protection in northern rivers.
Keywords：ice movement；riverbank erosion；flow-ice-sediment coupling；repose angle；northern rivers
（责任编辑：李福田）

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