受下游水位顶托下的太湖流域西苕溪中下游水位预报研究

A study on forecast of mid-lower stream water level of Xitiaoxi River in Taihu Lake Basin under downstream stream backwater effect

西苕溪位于太湖流域中上游地区,由于其中下游河床比降较小,且受太湖水位顶托以及东苕溪导流干扰,经常发生洪涝淹没灾害,造成了严重的社会经济损失,长期以来该河流洪水预报工作显得尤为重要,但由于河流中下游水位流量关系复杂,该区域以水位预报为核心的洪水预报始终是其难点之一。文中探讨了研究区受下游洪水顶托影响下的洪水预报方法,采用20世纪80年代以来的12场较大洪水资料,建立了西苕溪流域下游水位混合回归预报模型,并利用后期的8场洪水加以验证分析。实例验证表明,对于西苕溪这类水文规律复杂的流域,系统的混合回归模型具有简单方便、模拟精度高等特点。

Xitiaoxi River is located in the area of the mid-upper stream of Taihu Lake Basin with a less riverbed gradient. Under the backwater effect of Taihu Lake water level and the interference of the water diversion of Dongtiaoxi River, flood and water-logging disasters frequently occur there with serious damages to the society. The study on flood forecast of the fiver is obvious to be significant for a long time, however, the flood forecast of the fiver with the core of the water level forecast for the area is one of the problems all along due to the complicated relationship between the water level and discharge of the mid-lower stream of the fiver. The method of the flood forecast under the downstream backwater effect of flood for the studying area is discussed herein; in which the mixed regression model for the downstream water level of Xitiaoxi River is established based on the data of 12 larger flood events since the 1980s, and then is verified by the later 8 flood events. The verification from actual case shows that the mixed regression model has the advantages such as simplicity, convenience and high accurate simulation for the river catchment with complicated hydrological law similar to Xitiaoxi River Catchment.