Research On Long Tan Dispatching Rule For The Safety Of Control Flood For The Downstream Of Xijiang Basin

Security of flood controling is an important factor for the steady development of city andmore and morehydrology researchers have brought attention to it.Xijiang River Basin has sufferedflood disastersdeeply.The problem was resulted from two aspects: firstly,there are few key useful reservoirs and the flood controling system is not perfect in this basin.secondly,many embankments has been built these years which lead to flood returning to main channel,aggravating the severity of flood problem.In view of this problem,the author of this paperanalysised the trait of changed flood under the influence of builtembankments,ameliorated the dispatching rules and improved the ability to defend flood in Xi Jiang main stream.The main research results are presented as follows:This paperanalyzed the engineering characteristics and runoff characteristics about Xi Jiang River Basin.In the former analysis,It higily introduced the construction of embankment and took some examples to demonstrate the influence of dike,which makes flood returning to main channel.In the later analysis,this papercalculated the frequency of flood encounter,helping to demonstrate the necessity and feasibility of getting superior dispatching rules.Trough comparing the advantages and disadvantages of hydraulics and hydrology methods,this paper confirmed that the 1-D hydrodynamic model was appliedto the calculation of returning flood better.After calibrating and verifying theparameter of Mike11 HD model,This papersimulated a large series of natural floods and got correspondingvolume returning floods data,which laid the foundation for the cauculation of design flood in new engineering environment.Based on the influence of flood returning to main channel,This paper analyzed the flood control capacity in the main stream of Xijiang River,and brought the problem in resisting the flood with the current dispatching rule.Furthermore,It increased judgment conditions in the rule of Long Tan based on the new design flood data,controlling the flood timely and improving the ability to defend flood significantly.However,as to the upper reaches flood.the rule didn't got obviously flood peak decrease.In consideration of the insufficient flood peak decrease to upstream flood in initial program,This paper took two methods to solve the problem.Firstly,It took Liu Zhou station as a new judgment condition in the solution to staggering flood peak.Secondly,It took Wu Xuan station as the control section of upstream flood.By comparing the results of flood peaking inWuzhou,It shows that the latter program satisfyed the operability in the actual dispatching and improvement of flood prevention capability.