Floods encountered by a reservoir project during operation and management period are mainly determined by the volume of rainstorm and the previous flood volume of the river. For small watersheds, the latter plays a minor role which can be ignored. For large and medium watersheds, the latter has a greater impact and thus should be paid attention to. Based on the total probability formula the concept of quantificational characterizing this influence of flood frequency distribution of the annual maximum time period flood volume whose condition is previous flood volume is proposed, and the calculation formula is given. Two calculation methods for the manage-flood based on previous flood volume are established, i.e., the direct method and the indirect method. The paper divides the previous flood volume of the river into two states: less water and more water. The direct method is based on the measured flood data, and the conditional distribution of less water and more water is deduced by the principle of single variable frequency calculation principle. The direct method is simple and practical, but it requires more data. In the indirect method, the Copula function is first used to describe the two dimensional joint distribution of the maximum period flood volume of annual (such as annual maximum seven days flood volume) and the previous flood volume of the river. The key of this method is the choice of Copula function. By analyzing the correlation charts of the maximum period flood volume of annual and the previous flood volume of the river, the Clayton–Copula function is selected to deduce the conditional distribution. The indirect method can be used in lack of data, but the shortcoming is that the appropriate Copula function should be selected, and the calculation is more complicated. Finally, the proposed direct method and indirect method were applied to the calculation of channel flood in Zagunao River. The results showed that the overall benefit of the reservoir was higher than that of the original operation that fixed the limits water level of reservoir in flood period.

以成都市中心城区某内涝频发区为研究区域,应用MIKE URBAN模型研究设计暴雨雨型对城市内涝的影响.通过模拟不同重现期和雨型的设计暴雨条件下城市排水管网的节点溢流情况,并对溢流总量、易涝雨水井溢流时间变化情况和管网溢流空间分布变化情况进行对比分析.结果表明:重现期大于20年,设计暴雨雨峰系数越小,排水管网溢流总量越大;设计暴雨雨峰系数越小,易涝雨水井处溢流程度越严重,其影响程度随重现期增大而减小;设计暴雨雨峰系数越大,管网溢流点数量越多,相应的内涝灾害等级越高,内涝积水影响的空间范围越大.本文在揭示暴雨雨型与城市排水管网溢流规律的同时,验证了四川省水文手册中成都市中心城区设计暴雨雨型的合理性,对城市排水防涝工作具有一定指导意义.

The lack of flood measurement data due to complex and changeable landform brings about many incon-veniences to hydro-project construction in southwest China. According to data of design flood peak discharge (Qp) and collecting area(F) at 66 hydrologic stations in 11 basins in the southwest region of China,the relationship be-tween Qpand F is researched by statistical analysis. Results show the Qp-F relationships in the Jialing River basin, Tuojiang River basin, Fujiang River basin, Minjiang River basin and Lancang River basin follow linear relation-ship;while in the Dadu River basin,Qingyi River basin and Yalong River basin,the Qp-F relationships match well with exponential relationship;and in the Jinsha River basin,Nujiang River basin and Yarlung Zangpo River basin the relationships conform well to power function. The research results offer reference for obtaining the Qp-F relation-ships in ungauged river basins.

结合成都市西河流域的具体情况,构建包括水量、水质等6大方面17个指标的河流健康评价指标体系,并运用层次分析法计算各项指标的权重,采用灰色聚类分析与模糊综合评判法对比分析研究流域的健康状况.结果表明:两种评价方法都适用于西河流域,西河综合健康状态都为“很健康”,但各有2个分项指标未到达最佳状态,需着重考察.

针对日益突出的城市内涝问题,为了减少内涝灾害的发生、达到防洪排涝的目的,以成都市某小区为例,基于对小区排水管网的概化处理,雨量分配利用芝加哥雨型,应用MIKE URBAN软件模拟小区排水管网在不同降雨强度下承压运行情况及管点溢流情况,并通过设置小型调蓄池和扩增管径两种途径改善城市内涝状况.结果表明:改造后管网设计重现期由2年一遇提高到10年一遇,管段承压状况得到明显改善.在遭遇10年一遇降雨时,管道峰值流量明显降低,典型管道削峰率达62.5％,管网过水能力大幅度增加.在今后排水系统改造中,应当使城市管网与雨水调蓄池等海绵措施相结合,实现削减峰值雨量,从源头上防止内涝的发生.该模型具有建模简单、运算精确的特点,对城市防洪排涝相关研究有较好的借鉴意义.

Engineering potential destruction risk caused by flood can be presented by the frequency of annual highest stages in front of engineering (Hm).A quantificational relational expression among annual highest stages,flood peak discharge (x) and flood volume (y) is established based on the condition that flood hydrograph was generalized into a triangle.And then,based on the stochastic simulation method,the annual highest stages (Hm) N are calculated according to the flood prevention standard.Therewith,the combinations of flood peak discharge and flood volume are analyzed by satisfying the standard.Results have shown that calculation was above the flood prevention standard on the condition of the combination that flood peak discharge and flood volume have the same frequency.In addition,the variation of engineering's characters of flood prevention have impact on Hm.

According to the study on flood hydrograph, the new concept of specific flood hydrograph and its connotation were pro-posed. Meanwhile, the external and essential implication of engineering flood prevention standard were expounded. And then the re-lationship that was the new concept of external frequency of flood hydrograph between specific flood hydrograph and flood preven-tion standard was drawn. The specific flood hydrograph of three types of transformation and its calculation method were elaborated. The advantages and disadvantages of the common multiple method and the common frequency method of specific flood hydrograph were pointed out. A brief introduction about the basic idea of new calculation method of specific flood hydrograph was given.

Bivariate return periods of floods,with peak flood discharge x and flood volume y as variables,are important to calculation and evaluation of flood control in hydraulic engineering.For a flood event,calculation of its return periods much depends on its components and how to match the demands.This paper discusses and calculates four types of return periods using the Copula function theories-univariate return period N1,OR-event return period N2,AND-event return period N3,and matching retum period N4 -focusing on the demonstration of N4.And the four return periods are compared in a case study of the Mabian hydrological station of the Mabian River,a branch of the Minjiang River.The results show that for a given set (x0,y0) of the bivariate variables,the values of these periods are quite different.When both x0 and y0 are large or small,they follow a decreasing order of N3＞ N4＞ N1＞ N2;when x0 is large and y0 is small or y0 large and x0 small,N4 could become possibly much larger than N3 or even smaller than N1.Thus,attention should be paid to the special properties of the Copula functions and we recommend the use of bivariate matching values N4 in flood control calculations.