Hydraulics And Water Quality Calcuation And Roughness Optimization Of Water Diversion And Flow Strengthen In Tidal River Networks

Based on Tiansha River water diversion flow strengthen project in Jiangmen ,the hydraulics and water quality characteristics in tidal rive networks have been simulated numerically. Zero-dimensional and one-dimensional hydraulic models have been applied. This paper presents the concept of roughness optimization. It provides theoretical reference for tide receiving and sewage flushing and improvement of water environment. It mainly contains:1. According to recorded tidal water level and rate information,the tidal type has been analyzed and tidal characteristic has been ascertained. This provides theoretical reference to the position of water diversion and drainage.2. In order to macroscopically decide the possibility of water diversion and the effect of water quality renewal,Zero-dimensional hydraulic and water quality model was built. This model was used to analyze the river networks' capability of water diversion and drainage. With this method,the feasibility of project can be decided preliminarily.3. One-dimensional hydrodynamic model is built,in which implicit difference format (Preismann discretization scheme) and 'three steps method ' of one-dimensional unsteady flow model is used,hydraulic calculation is done for water diversion and flow strengthen in tidal networks and the method is enhanced in which the precision is improved greatly.4. Optimization model of networks' roughness is established. In this model,objective function is the average scedasticity of relative error for water level and discharge. With the recorded water level and tidal data,the value of roughness is optimized. The optimization model is more reasonable. The efficiency and precision of calculation have been increased greatly.5. According to Tiansha River's water diversion and flow strengthen project that is determined by zero-dimensional model,the plan of tidal river networks is successfully calculated.