采用降水集中度、等级分析及小波相干等方法,探讨了江淮下游里下河腹部地区1957—2006 年间降水、水位的等级特征及两者关系。结果表明:①年降水量的集中期与集中度皆为减小趋势,两者在1980 年前后由同相位转为反相位相关。②汛期高等级降水的日数和贡献率皆以1980 年代最高。不同等级的降水日数皆为减少趋势,但高等级降水的贡献率在大洪涝年中异常偏高,表明降水强度加强。③低、高等级水位日数皆为减少趋势,但低、高等级水位的贡献率分别呈增加、减少趋势,而中等级水位的日数与贡献率都显著增加。较之降水日数,降水贡献率对水位等级变化更具决定性影响。④高等级降水与水位在日数上呈显著的同相位正相关,但低等级相反,而中等级为较弱正相关,且等级降水总量与相应水位贡献率的相位关系亦具类似特征。高、低等级降水与水位的贡献率皆为显著同相位正相关,但在中等级上,其相位特征较弱。

Methods of precipitation concentration period and precipitation concentration degree analysis, classification analysis and wavelet coherence analysis are applied to explore the variations and relationship between precipitation and water level from 1957 to 2006 in the inner Lixiahe region, an area located in the lower reaches of Jianghuai basin. Results show that decreasing trends can be detected both in precipitation concentration period and precipitation concentration degree for the annual precipitation, it experienced an in-phase to anti-phase switch in 1980. Maximum days and contribution rate of higher grades of precipitation appeared in 1980s. Decreasing trend can be observed in the days of lower, middle and higher precipitation grades. However, precipitation contribution rate tends to be significantly higher in flooding years implying an increasing in precipitation intensity. Decreasing trend can be observed for the lower and the higher grades of water level days, but that it turns out to be increasing and decreasing trend for the lower and higher grades of water level contribution rate respectively. However, a significant increasing tendency can be identified for the middle grades of water level days and contribution rate with an implication that there might be an enhanced accumulation impact of middle precipitation grade on water level, this could be resulted from the negative hydrological effect of enhanced human activities. Precipitation contribution rate has more important impact on water level change compared to the precipitation days. A positive correlation can be examined between higher precipitation grade and water level days, while negative and positive correlation can be detected between lower and middle grade days of precipitation and water level respectively, and a similar phase relation can be found in grade total precipitation and contribution rate of water level. Furthermore, higher, lower and middle grade total precipitation exhibits an in-phase, anti-phase and weak phase relation with the corresponding water level respectively.

随着平原感潮河网地区城市化快速发展,下垫面变化落后导致河道泄洪能力不足,河道洪水水位明显上涨,村镇内涝灾害日益频繁,已明显制约当地经济发展。在分析平原感潮河网地区村镇内涝影响因素基础上,以典型村镇为例,通过数值模拟方法分析该地区河道洪水对村镇内涝影响。结果显示50 a一遇与100 a一遇河道洪水分别导致村镇排涝水量减少25.17%,55.24%,排涝水量减少对村镇内部河流洪水过程的影响明显。降雨量增大加剧了排涝水量减少对村镇内涝淹没面积扩大的影响。河道洪水可导致村镇内涝淹没面积扩大22%,加剧了村镇内涝灾情。此研究成果可为该地区村镇内涝风险管理提供参考。

In plain tidal river network area, rapid urbanization with delayed corresponding changes of underlying surface have resulted in insufficient discharging capacity of river channels, together with uprising flood levels and more frequent waterlogging in villages and towns, severely impeding the local economic development. On the basis of expounding influential factors of waterlogging in villages and towns in plain tidal river network area, the impact of channel flood on waterlogging is quantified via numerical simulation with some typical villages and towns as case study. To simulate channel flood and inundation process in town precisely, both of the processes are simulated with hydrodynamic model. Results indicate that influenced by 50-year event flood and 100-year event flood, the discharge in town decreases by 25.17% and 55.24%, respectively, which evidently affects the river flood process in town. Moreover, the increase in return period of rainstorm intensifies the impact of discharge reduction on the expansion of inundated area. Extreme channel flood would expand the waterlogging area by approximately 22%, and would aggravate the waterlogging in villages and towns. The research findings provide reference for the waterlogging risk management for villages and towns in plain tidal river network areas.

通过分析杭州江北主城区涝灾成因和区域防御总体能力,优化城区排涝格局,提出城市包围方案,为开展新一轮城市防洪排涝规划和治理工程提供决策参考。基于区域已有的杭嘉湖区域水利综合规划、杭州市城市防洪减灾规划、杭州城西科创大走廊水利专项规划等推荐的水利防洪排涝工程基础上,采用一维河网非恒定流数学模型,建立杭嘉湖东部平原防洪水利计算模型,计算城市包围方案实施效果。研究结果表明,通过北控线建闸建泵并进行优化调度,杭州江北主城区既能满足排涝标准,主动防御,又能最大程度减轻对下游地区的防洪压力,兼顾流域防洪。该研究成果对确定城市防洪排涝方案具有借鉴意义。

On the basis of analyzing the causes of waterlogging and the overall regional defense capacity of Jiangbei urban district of Hangzhou City, we present urban encirclement schemes to optimize the drainage pattern in the hope of offering reference for the decision-making of flood control planning and regulation. At present in Hangzhou we already have a series of flood control and drainage projects including the comprehensive water resources planning for Hangzhou, Jiaxing, and Huzhou region (hereafter referred to as Hang-Jia-Hu region), the urban flood control and disaster reduction planning for Hangzhou City, the special planning of west Hangzhou Kechuang corridor, and others. Under such background, we established the one-dimensional unsteady flow mathematical model of flood control for the eastern plain of Hang-Jia-Hu region, and calculated the implementation effect and impacts of three urban encirclement schemes involving different arrangements of canals and control gates. Results show that by constructing sluices and pumps along the north control line and together with optimizing operation, the Jiangbei urban district of Hangzhou City could meet drainage standards and actively prevent from waterlogging on one hand, and reduce the flood control pressure on downstream areas to the greatest extent and take into account the flood control of the river basin on the other. The research finding is of referential value for the flood control and drainage of cities in the middle and upper reaches of the eastern Hang-Jia-Hu plain.

近年来太湖流域平原河网地区洪涝灾害频发,居民的人身及财产安全受到了严重危害。降雨是导致本区域洪水的主要因素,其中最具代表性的降雨类型为梅雨和台风暴雨,由于二者时程分布特性有较大差异,其致洪机理也有所不同。以探究降雨时程分布对洪水过程的影响为目的,以太湖流域武澄锡虞水利分区为研究对象,采用MIKE 11与MIKE 21构建一、二维耦合水动力模型,利用实况洪水过程对模型进行率定验证,采用该模型对研究区域进行不同设计工况的模拟,讨论了次雨量、降雨历时以及降雨时程分布变化对太湖流域平原河网地区洪水过程的影响。结果表明:降雨时程分布对平原河网河道洪水过程有显著影响,其中长历时降雨对雨峰位置的后移较为敏感,短历时暴雨则受到降雨时间变差系数变化的影响较大,而次雨量变化则对二者都有显著影响。

Flood and waterlogging disasters in plain river network region in recent years have brought about severe damage to people's lives and property safety. Rainfall is the key factor causing flood disasters in the region, of which the most typical ones are plum rain and typhoon rainstorm. The flood generating mechanism of plum rain and typhoon rainstorm varies because of different temporal distribution. In the aim of investigating the influence of rainfall's temporal variation on flood process, a 1D- and 2D-coupled hydrodynamic model of Wuchengxiyu hydraulic district of Taihu Lake drainage basin was built with MIKE 11 and MIKE 21. The model was calibrated and validated by several measured flood events. Numerical simulation of flood processes under different design conditions in the study area was conducted. The influences of magnitude, duration and temporal variation of rainfall on flood process were examined. Results suggest that the temporal distribution of rainfall has apparent influence on flood in plain river network. Rainfall of long duration is sensitive to the delay of rainfall peak, while rainfall of short duration is largely affected by the time variance coefficient. Meanwhile, rainfall amount has evident impact on both long-duration and short-duration rainfall.