Simulation Of The Limiting Technology About Diffusion And Flow For Sudden Water Pollution Accidents In The South-to-north Water Diversion Project

To solve the problem of water shortages in northern China, the South-to-NorthWater Diversion Project was started constructing in2002. In the project,openchannel sections of Midline Engineering consist of lots of control-buildings andcross-buildings, East-Line Engineering is covered densely of river network,especially in Jiangsu section, so the risks of unexpected water pollution accidents isconsiderable. Therefore, how to ensure the security of water has become an urgentproblem. Reasonably and effective emergency processing scheme can control therange of pollution as much as possible, deal with pollution water as soon as possible,to maintain the supply of water to the north. So the limiting technology aboutdiffusion and flow for sudden water pollution accidents has been simulated anddiscussed.In this paper, the channel model is built by the actual data of demonstrationproject, and its verification is based on the measured operating parameters. Takeninto account the limitation of the water flow characteristics, two emergencyresponse schemes to be adopted when sudden water pollution incidents occurred inMidline Engineering channels: the first scheme is to layout hanging adsorptionmatrix to remove and adsorb the contaminant; the second scheme is to use softdiversion dam to lead contaminant group to retreat drains so it can retreat back. Byusing soluble water pollution as an example, this paper simulate the local flow fieldand concentration distribution of different plans which designed by changing thearrangement of adsorption matrix and the position and angle of the diversion dam toanalyze their effects and conclude the basic principles of layout programs. Finally,determine whether the screened scheme can play a role for other types of waterpollution accidents.In East-Line Engineering, channels are not only water channels, but alsoimportant waterways, so there are many possible sources of contamination, andunexpected water pollution incidents are more complex and diverse. Combined withthe special circumstances of the East-Line Engineering, the emergency plan thatwater supply in different quality can be used. This paper use canal section betweenJiangdu West Gate and Shaobo Gate in East-Line demonstration Engineering as theresearch object, analyze it's possible operating conditions in the actual operation,match it's different water transfer schemes and simulate the diffusion of pollutantsunder different water transfer schemes to determine the most unfavorable conditions.Then depending on the contaminated water quality, this article make the dual watersupply plan more exhaustive through detailed the water retreat project. At the same time, this paper simulate the water retreating process of different water retreatsolutions according to the designed water supplying condition of channel, anddetermine the minimum time of water retreating.