平原感潮地区雨型潮型组合对除涝规模的影响

Study on rainfall-tide-combinations impacting on the drainage scales in a plain tidal area

以上海某感潮圩区水系除涝规模计算为例,采用水量平衡法和河网水动力数学模型法,研究了平原感潮地区的雨型潮型组合对圩区除涝规模的影响,并对涉及除涝标准的暴雨历时取值、涝水排除程度确定、起调水位与预降可能性、河道分期实施状况、用地性质变化、水面率控制等影响因素进行了分析。结果表明:在约100 km^2区域内,采用水量平衡法和河网水动力数学模型法计算的河道水力要素和除涝设施规模均可满足工程精度要求;对确定的除涝规模,不同雨型潮型组合情况下,内河最高水位和高水位持续时间不同,"麦莎"雨型潮型组合情况下内河最高水位较高,而"63年"雨型潮型组合情况下高水位持续时间较长,后期河道水位也较高;平原感潮圩区除涝标准的确定涉及设计暴雨重现期、设计暴雨历时、涝水排除时间、涝水排除程度、设计潮位与过程等因素,尤其是雨型潮型组合对除涝规模影响较大。

Based on the water budget method and a river-network numerical model,the drainage effects of the rainfall-tidecombinations were analyzed through the scenario of a certain tidal polder in Shanghai.Factors involving the drainage criteria,such as the value of rainstorm duration,the determination of drainage degree,the possibility of starting regulation level and pre-reducing water level,the short and long-term implementation of river regulation,the land usage transition and the controlling of the water surface ratio,were analyzed.The results indicate that in the study area of 100 km^2,the river hydraulic factors and the scales of the drainage facilities calculated by both the water budge method and the numerical model fulfill the engineering accuracy.For a certain drainage scale,the peak water levels and their durations vary under the different rainfall-tide-combinations.The peak water level is relatively large under the＂Matsa＂case,yet the duration of the high-water-level stage is longer and the water level is higher in the later stage under the ＂63-year＂ case.The technical standards of drainage in a plain tidal polder are related to the design rainstorm recurrence interval,the design rainstorm duration,the drainage time,the degree of the drainage,the design tidal level and tidal process.In addition,the rainfalltide-combinations can highly affect the scale of drainage ability.