小型水库超标准洪水溃坝模拟及风险分析

我国小型水库数目众多，承担着防洪、灌溉、供水等重要作用。为减少水库遇超标准洪水溃坝后下游风险区的生命财产损失，以南王水库为研究对象，考虑水库遇超标准洪水下瞬时溃坝与渐进式溃坝两种溃坝形式，采用DB-IWHR溃坝模型模拟溃口流量过程，利用MIKE软件构建一二维耦合模型模拟洪水演进情况并进行风险分析。结果表明，下游淹没情况符合溃坝洪水演进的一般规律，模型可较好模拟超标准洪水引起大坝溃决的溃口流量与洪水演进过程，可为小型水库超标准洪水溃坝应急预案提供参考。     

亭下水库溃坝洪水分析

为更好地预测亭下水库溃坝可能的影响,建立了二维溃坝洪水演进数学模型,计算了溃坝洪水流量过程,模拟不同工况下溃坝洪水的传播演进过程。通过分析溃坝洪水淹没范围内最大水深、最高水位、最大流速的等值线分布规律以及代表点、代表断面的洪水特性,得出溃坝洪水对水库下游区域的影响程度。分析结果表明:亭下水库一旦溃坝,溃坝洪水将严重威胁下游人民生命财产的安全。研究成果满足溃坝洪水分析要求,采用的技术路线与方法能够应用于其他水库的溃坝洪水分析。     

River2D模型在溃坝洪水演进数值模拟中的应用

River2D模型能模拟溃坝洪水在水库下游地区的演进过程.为模拟水库溃坝洪水演进,以江西省大余县油罗口水库为例,利用River2D模型模拟大坝溃决后洪水在下游的演进,预测洪水淹没范围、水深及流速等洪水风险信息.     

茜坑水库溃坝洪水数值模拟研究

研究应用M IKE21模块建立茜坑水库溃坝洪水演进数学模型,模拟洪水演进过程。从最不利因素考虑,确定坝址处溃坝最大流量、洪水下游演进过程和下游淹没水深,为制定水库大坝安全管理应急预案提供技术支撑。     

A水库溃坝对B水库大坝安全的影响研究

采用Preissmann四点加权隐式差分格式对一维明渠非恒定流方程进行离散,建立了A水库溃坝洪水计算模型.通过对A水库溃坝洪水的分析与计算,以其溃坝下泄流量过程作为下游B水库入库洪水过程,对B水库进行洪水调节计算,结果显示在A水库发生溃坝后,洪水演进至下游B水库坝址,不会导致B水库大坝发生溃坝.     

毛滩河水库溃坝洪水分析及对策研究

分析了水库溃坝洪水特点、分析内容;其后围绕毛滩河水库详细论述了突发性洪水溃坝影响因素、形式,并开展溃坝洪水及其演进计算,明确了水库溃坝洪水的危害;最后探讨了毛滩河水库溃坝调度应急管理工作,以期可供类型项目参考。     

A水库溃坝对B水库大坝安全的影响研究

采用Preissmann四点加权隐式差分格式对一维明渠非恒定流方程进行离散，建立了A水库溃坝洪水计算模型。通过对A水库溃坝洪水的分柝与计算，以其溃坝下泄流量过程作为下游B水库入库洪水过程，对B水库进行洪水调节计算，结果显示在A水库发生溃坝后，洪水演进至下游B水库坝址，不会导致B水库大坝发生溃坝。     

多支流多水库溃坝洪水计算

湖北大畈核电厂址上游已建及规划中的中型水库共有7座，众水库之间的关系较为复杂，如发生溃坝后洪水波不但沿河道演进还继续在富水水库库区内演进，危害严重。采用溃坝水力学和河道水力学公式对溃坝后的洪水波进行演进计算，并与影响厂址防洪安全性的洪水事件进行组合，分析了溃坝对厂址处的影响，为工程可行性研究阶段提供设计依据。     

水库群溃坝洪水计算

湖北大畈核电厂址上游已建及规划的中型水库共有7座,众水库之间的关系较为复杂.溃坝后,洪水波不但沿河道演进,还继续在富水水库库区内演进,较为特殊.采用溃坝水力学和河道水力学公式,对这些水库溃坝后的洪水波进行了演进计算,并与影响厂址防洪安全的洪水事件进行组合,分析了溃坝对厂址处的水位影响,为工程可研阶段提供设计依据.     

清林径水库溃坝水流在深圳城区的演进数值模拟

溃坝洪水数值模拟对城区溃坝的风险分析、溃坝后果评价对防洪决策具有重要意义。为了研究城区溃坝洪水的演进过程,运用了VOF法追踪自由表面,以N-S方程为基础,建立了三维溃坝紊流洪水演进数学模型。结合清林径水库在逐渐溃溃坝模式下的下游城区洪水演进过程,分析了溃坝水流的水深和流速的沿程分布情况,为城区溃坝风险分析和溃坝后果评价提供了关键水情信息。     

时变条件下高堆石坝施工度汛协商演化模型

高堆石坝填筑施工过程以其挡水和过水的特点被广泛应用于施工度汛中。施工洪水和大坝的填筑进度直接影响中后期导流方案的选择，同时也影响施工度汛中不同利益干系人的行为决策，而方案的决策结果也影响着下一阶段的填筑高程及进度安排。本文通过高堆石坝度汛坝体挡水高程与施工洪水随机性描述了施工度汛的时变风险，结合决策者风险偏好及利益导向，引入施工方与业主方在不同度汛方案下的效益函数，运用微分对策理论建立时变条件下的高堆石坝施工度汛协商演化模型，确定其最优协商解及演化路径。实例计算结果验证该演化模型与实际工程结果符合良好，对高堆石坝度汛风险决策效率的提高具有借鉴意义。     

考虑分级防洪目标的梯级水库汛控水位调度模型及应用

围绕中小洪水减压、大洪水保安和特大洪水降损等防洪目标，构建了面向分级防洪目标的梯级水库汛控水位优化调度模型，针对不同频率设计洪水，基于“模拟-优化”框架，采用仿生进化算法对调度模型进行了高效求解，并利用熵权法对调度方案进行了多目标评价，比选了梯级水库汛控水位方案。以金沙江中下游6个梯级水库和三峡水库组成的梯级水库为研究对象，研究结果表明：相比原汛限水位方案，在不降低原防洪标准的前提下，选定的方案可使梯级水库水位抬高0.36～6.22 m,发电量增加6.28亿～19.26亿kW·h,增幅为1.18%～4.27%,经济效益显著，可为梯级水库汛控水位的规划设计提供技术支撑。     

土石坝漫顶溃决过程数值模拟研究

针对水动力条件变化复杂、水土耦合作用强烈的土石坝溃决过程,结合水库调洪演算、清水冲刷以及溃口冲刷侵蚀机理,在Breach模型基础上建立了土石坝漫顶溃口流量过程计算物理模型。结果表明:模型对JP水库大坝溃决过程的模拟,很好地再现了溃决洪水流量过程线、溃口展宽和下切过程,验证了模型的合理性和应用潜力。     

基于Vega Prime的流场三维动态可视化研究

基于数学模型的洪水演进计算输出结果通常表达为数值表示的水位流速场,为了探寻洪水演进的规律,借助可视化的手段将数据进行了基于图像图形的直观表达;同时以虚拟现实平台软件Vega Prime为基础,分析了实现流场动态可视化的技术框架、实现方法,并通过实例对该方法进行了验证。结果表明,该方法能较好地实现流场的可视化表现,可用于超大流量天然河道洪水演进模拟。     

HEC-RAS模型在二维溃坝洪水研究中的应用

为准确模拟大坝失事后溃坝洪水的下游演进,运用HEC-RAS二维水动力学模型,修正面板坝溃口发展曲线,设计两种闸门开度的小井沟面板坝漫顶溃坝工况,模拟水库泄洪影响下溃坝洪水的下游演进并生成相应的洪水风险图、最大流速分布图、滞留时间图。研究结果展现了溃坝洪水在中下游平原丘陵地区的泛滥情况、洪水风险的分布差异以及水库泄洪对溃坝洪水的影响。分析得出不同闸门开度下溃坝洪水在中下游平原丘陵地区的淹没水深和范围差异明显,最大流速和洪水滞留时间区别不大, 说明水库全力泄洪能有效降低溃坝洪水对下游人员聚居的平原地区的危害。研究成果对后续的人员疏散和损失估计具有重要参考意义。     

Analysis of changes in flood regime using a distributed hydrological model: a case study in the Second Songhua River basin,China

Abstract

This study proposes and tests a new approach to detect and analyze changes in flood regime using a distributed hydrological model (EasyDHM), using the Second Songhua River basin, China, as a case study. Model calibration and parameter sensitivity were used to represent flood regimes in a 60-year series (1954–2013), with three different flood regime periods identified. The changes in flood regime were estimated by model parameters, flood result residuals and the overall process in the hydrological model in the three periods. The results show that human activities significantly impacted flood regimes, with significant flood regime change largely attributed to increases in water storage in multiple small reservoirs. Flood volume was reduced significantly between the periods in all three watersheds. The parameters also changed in variety between the periods. The study highlights the importance of incorporating data on small-reservoir constructions in flood control systems.     

Optimal Design of Check Dams in Mountainous Watersheds for Flood Mitigation

One of the measures for flood control is to construct a series of small barriers, known also as check dams, on tributaries of watershed stream network. Check dams are generally used in mountainous areas in order to control sediment transport and attenuate flood peak. In this paper, a simulation-based optimization model is developed to determine size, shape and the number of check dams for flood mitigation. HEC-HMS model is used to simulate watershed rainfall-runoff process considering various check dam designs. The model is coupled with a multi-objective evolutionary algorithm, called non-dominated sorting differential evolution (NSDE), to find the trade-off solutions considering three objective functions: 1) minimizing the investment cost, 2) minimizing the flood peak discharge and 3) maximizing the time to peak discharge. The proposed model is applied to a mountainous watershed in Iran and (near) optimal strategies, including the suitable number of check dams in each sub-watershed, and optimal dam size (e.g. optimal height, bottom width and side angles) in each sub-watershed are obtained. The results show that cost-effective designs can decrease peak discharge up to 53%, 54 and 54% corresponding to 2-yr, 5-yr and 10-yr flood return period scenarios, respectively. In addition, the check dams can also increase the time to peak for up to 88%, 81 and 77%, corresponding to 2-yr, 5-yr and 10-yr flood scenarios, respectively.     

考虑大孔隙下渗的HBV模型及其在山洪预报中的应用

小流域山洪预报一直是水文学研究的热点和难点问题之一。考虑到土壤大孔隙在径流形成过程中的重要作用,采用变动面积法为HBV模型增添大孔隙模块,并以黄泥庄小流域为研究区,使用改进后的HBV模型模拟分析了2010-2015年间6次洪水事件。结果表明:改进后的HBV模型在黄泥庄流域洪水模拟中模拟效果较好,预报精度均在乙级以上,可用于模拟类似小流域短历时高强度的洪水,从而为淮河流域上游山区的防汛决策提供重要参考。     

Improving Urban Drainage Systems Resiliency Against Unexpected Blockages: A Probabilistic Approach

Considering the increase of flood hazards in many large cities, the rehabilitation of hydro-urban infrastructures is an important concern for the municipal authorities. A probabilistic approach based on Monte Carlo Simulation (MCS) is presented in this study to improve the resiliency of urban drainage systems when they are subject to unexpected structural blockages. The approach is integrated with SWMM simulation model and an evolutionary search algorithm to find the best set of rehabilitation measures under a significant number of blockage scenarios. Experimental results on the west zone of main drainage system in Tehran city indicate that proposed approach outperforms the conventional hydraulic-based methodology in terms of cost effectiveness and functionality. Results also show that adding the redundancy to the system by bypass lines in bottlenecks is considerably more efficient for flood mitigation and the increase of system resiliency under blockage incidents rather than using conventional methods such as detention ponds and enlargement of the channel sizes.     

Rainfall-runoff simulation and flood forecasting for Huaihe Basin

The main purpose of this study was to forecast the inflow to Hongze Lake using the Xin＇anjiang rainfall-runoff model. The upper area of Hongze Lake in the Huaihe Basin was divided into 23 sub-basins, including the surface of Hongze Lake. The influence of reservoirs and gates on flood forecasting was considered in a practical and simple way. With a one-day time step, the linear and non-linear Muskingum method was used for channel flood routing, and the least-square regression model was used for real-time correction in flood forecasting. Representative historical data were collected for the model calibration. The hydrological model parameters for each sub-basin were calibrated individually, so the parameters of the Xin＇anjiang model were different for different sub-basins. This flood forecasting system was used in the real-time simulation of the large flood in 2005 and the results are satisfactory when compared with measured data from the flood.