西、北江三角洲网河区水面线变异初探

90年代以来，珠江流域西、北江遭遇“94·6”、“94·7”、“97·7”和“98·6”等4场大洪水，三角洲网河区腹地部分水道(以顺德市为例)出现洪水水位异常，部分河段洪(潮)水位异高愈演愈烈。为正确分析变异环境下的洪水水位，提供江河流域规划及防洪工程设计参考依据，采用多种技术手段重新分析了顺德网河水位相关关系、水文频率和各级频率洪潮水面线。认识到由于人类活动的影响，西、北江三角洲网河区的来水分配、河床形态、洪水过程和洪水水位都在短期内发生急剧变化，导致原来的水面线分析成果与频率标准不适应当前防洪规划和水利工程建设的需要，也使防洪形势日臻严峻。用人工神经网络方法重新分析了高度非线性的网河水位相关关系，以一系列水文学的新方法分析变异的水文频率，并以一维不恒定流方法重新计算设计洪潮水面线，界定各级频率。希望加强对变化环境下江河水位频率的分析研究，以便及时认识江河水文变化，提高水利规划、水利建设水平，采取正确的防洪对策。

On the Variation of Water Surface Profiles in Waterway Network Area of North River-West River Delta

Since the nineties of 20th century the North River and the West River have encountered with four big floods. In part of waterways in the hinterland of the delta has occurred extraordinary flood level with increasingly raising extraordary high flood (tidal)level in aome sections In order to offer a reference basis for river planning and flood control project design by analizing the flood level under variable conditions,many kinds of technical means are employed to analize the correlation of water level in waterways, hydrologic frequencies and water surface profiles under various frequencies in Shunde. It is realized that the distribution of water inflow,the nxrphology of river bed,the flood course and flood level have changed sharply in a short period,therefore, the original results of water surface profiles and frequency standard can not meet the needs of present flood control planning and water conservancy construction,thus leading to severer flood control situation. In this paper,artificia] nervous net-work is employed to analize the highly nonlinear correlation of water level of waterway network. Series of new methods are employed to analize the variable hydrologic frequencies and design flood and tidal water surface profiles are calculated through 1-dimensional non-steady flow method to define various frequencies.