一、二维耦合数学模型在感潮河网洪水风险图编制中的应用

为了解决感潮河网径流、潮汐交汇，动力复杂，溃决洪水难以用经验公式准确概化的问题，建立直接以溃口为耦合断面的河网一维、保护区二维侧向耦合模型，将感潮河网与保护区一体化，避免环境因素及经验参数的不确定性带来的溃口流量估算误差。典型算例和中顺大围溃决洪水情景模拟表明：洪水自溃口集中喷射出后分散流向围内，流态受围内下垫面影响显著，溃口水位、流量随外江潮位涨落而起伏变化，由溃口流量过程线计算所得溃口水量与根据淹没区各单元的面积和水深计算的围内总水量一致。模拟成果直接反映下垫面、水头差、潮位涨落，及溃口流态对溃决洪水的综合影响，反映出本耦合模型计算溃口流量及对溃决洪水模拟的合理性、可信性，具有较好的应用前景。

Application of a 1-D and 2-D Coupled Mathematical Modelin the Mapping of Tidal River Flood Risk

As the dynamics of tidal river network is complex with runoff and tide confluence, breach discharge in tidal river network is too complex to be estimated by empirical formula accurately.In view of this, a hydrodynamic model coupling 1-D model of river network and 2-D model of reserve area is developed with the breach as the lateral linkage.The model integrates the tidal river network and the reserve area, hence avoiding the deviation of breach discharge caused by the uncertainty of environmental factors and empirical parameters.Simulation results of typical example and embankment-break flood scene show that 1) the jet-flow of breach disperses into the reserve area, and the flow pattern is affected by the underlying surface significantly;2) water level and discharge of the breach change with tide fluctuation, and the calculated total water amount according to breach discharge agrees with that from flooded areadepth.The simulation results reflect the combined influence of underlying surface, water head, tide level and flow pattern on breach flood.The proposed model is rational and reliable in calculating breach discharge and simulating embankment-break flood.