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Critical depth of water is an important hydraulic parameter in open channel hydraulics, which is a key sign of distinguishing the flow state of water in open channel. The traditional methods for calculating critical water depth of open channel with trapezoidal section include the trial-and-error method, the approximate solution and the iteration method, which own shortcomings of large amount of calculation and rough accuracy. For this reason, the method of Accelerating Genetic Algorithm based on real coding (RAGA) was adopted in this paper to solve this problem. The Simulated Annealing algorithm (SA) was used to improve the convergence rate during the late of evolution of RAGA. Practicality and accuracy of RAGA were tested through calculating critical water depth of open channel with trapezoidal section in practice. The results of case showed that operating speed of RAGA was faster than SGA, its accuracy was higher than traditional methods, which demonstrates that the RAGA is a suitable method for calculating critical water depth with trapezoidal section.

Changzhou Hydro-junction spans two islands and three rivers. The navigation lock is arranged in the right bank of Wai jiang river. The horizontal and reverse flow velocity of the outlet portal on the navigation lock is always the main issues of the hydraulic research on navigation lock, due to the influence of the complicated flow condition. After several measures are carried out, including the conveyance conduit applied in the head of downstream guiding dike, the spurs applied the outside of the dike and optimal operation of the lock gate. The researches show that the horizontal and reverse flow velocity of the outlet portal is effectively controlled. The effectiveness is favorable through the auto-navigate ship model test. The results of this research can be served for similar projects reference.

According to mathematical statistic's mathematic expectation theory, the stochastic dynamic programming method based on the expected benefit is established for the reservoir power plant. The model's objective function, solution ideas and process are introduced in detail. The calculation results of example indicate that the expected benefit of the power plant increases by 16.4% more than the design benefit, 34.5% more than the actual benefit. The effect of this method is very remarkable, and it can provide reference for the built reservoirs.

Allowing for catchment hydrological effect due to spatial variability of precipitation and underlying topography, the catchment is divided into a number of basic units of concentration flow within only one channel link by the method of natural divide. The basic unit of concentration flow is regarded as a V-shaped structure, and a distributed watershed concentration flow model is built on a series of V-shaped units of catchment. In the model, geomophologic instantaneous nit hydrograph based on area-time curve methodology is used to simulate overlanflow concentration, and Musking mothodology is used to simulate river flood routing. The model is applied in Xingfeng river basin and the result is reasonable.

Urban flood control layout, based on which urban flood control engineering projects are constructed, will be synthetically evaluated taking into consideration the social, political, economic, environmental and technical factors involved in different levels. Furthermore, a hierarchical structure model for urban flood control layout is presented in this paper. Then a grey-AHP model is proposed based on the analytic hierarchical process (AHP) and the Grey system theory, by which the layout of multiple-objective programming problem can be simplified into a single-objective problem system. Results from an example demonstrate the feasibility of the proposed method, which can be widely used in engineering practice of water resources systems.