Real-time flood forecasting of Huai River with flood diversion and retarding areas

A combination of the rainfall-runoff module of the Xin’anjiang model, the Muskingum routing method, the water stage simulating hydrologic method, the diffusion wave nonlinear water stage method, and the real-time error correction method is applied to the real-time flood forecasting and regulation of the Huai River with flood diversion and retarding areas. The Xin’anjiang model is used to forecast the flood discharge hydrograph of the upstream and tributary. The flood routing of the main channel and flood diversion areas is based on the Muskingum method. The water stage of the downstream boundary condition is calculated with the water stage simulating hydrologic method and the water stages of each cross section are calculated from downstream to upstream with the diffusion wave nonlinear water stage method. The input flood discharge hydrograph from the main channel to the flood diversion area is estimated with the fixed split ratio of the main channel discharge. The flood flow inside the flood retarding area is calculated as a reservoir with the water balance method. The faded-memory forgetting factor least square of error series is used as the real-time error correction method for forecasting discharge and water stage. As an example, the combined models were applied to flood forecasting and regulation of the upper reaches of the Huai River above Lutaizi during the 2007 flood season. The forecast achieves a high accuracy and the results show that the combined models provide a scientific way of flood forecasting and regulation for a complex watershed with flood diversion and retarding areas.     

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.     

马斯京根分段演算与水箱模型组合在区间洪水过程预报中的应用

介绍了马斯京根流量演算方法和水箱模型,提出了将马斯京根分段分步流量演算方法与水箱模型相结合进行区间洪水预报的方法,并将该方法应用于渭河林家村站、汉江安康水库站的洪水预报的研究中,实践证明该方法合理可行,可以推广应用到其它的区间洪水预报中。     

淮河鲁台子以上流域洪水预报模型研究

本文以淮河鲁台子以上流域为例,采用分布式概念性水文模型,对王家坝以上流域及阜阳、蒋家集、横排头淮干支流进行降雨径流与洪水过程研究,同时进行参数率定。采用马斯京根法、马斯京根水位模拟法和扩散波非线性水位法,对淮河干流王家坝至鲁台子区间具有行蓄洪区流域洪水进行预报。预报模型在2007年的大洪水预报调度中得到了检验,取得了较高的精度。     

河道洪水流量预测方法研究

及时准确地预报某区域内河道指定区段洪水流量及发生时间,对合理实施该区域的防洪预案、落实抗洪抢险措施、组织调度人员及防汛物资具有重要意义。目前河道洪水预报普遍采用马斯京根流量演算法及加里宁—米尔加科夫洪水演进法,两种方法的参数率定存在局限性,对应支流的河道分段处理也存在问题。本文依据最小二乘法,建立含有预测河段上游干流、支流水文站（或水位站）流量或水位预测模型,该模型不受其他水文参数的率定精度影响,直接利用以往洪水及当次洪水上游、下游站的观测资料建立回归预测模型,并通过递推方式完成当次洪水预测,表达形式简单直观、便于实际应用。利用该模型完成了嫩江干流齐齐哈尔水文站2013年洪水流量预测,经与实测成果比较,洪峰流量最大拟合误差小于5.2%,具有较好的计算精度。     

大流域洪水预报与洪水调度管理方法研究

采用水文学与水力学、确定与随机相结合的方法，研究大流域洪水预报与洪水调度管理。确定性模型采用降雨～径流模型的新安江模型和经验预报方案进行流域流量过程预报，一维非恒定流水力学方法进行河道流量与水位以及蓄滞洪预报。随机模型采用线性动态模型进行下断面水位实时预报，最小二乘递推模型进行误差实时校正。以长江支流修水流域为例，采用新安江模型、经验方案进行万家埠与柘林水库入库洪水预报作为水力学计算的上边界条件，采用一维非恒定流水力学方法进行河道洪水流量、水位计算以及分洪计算。该方法为流域的防洪减灾提供了科学的途径。     

复杂河道实时洪水预报的半自适应模型研究

具有行蓄洪区的复杂河道的洪水演算是洪水预报中的一难点。对于复杂河道如何在水文学方法中考虑分洪、蓄洪并提高实时洪水预报的精度是一个重要的问题。为解决这一难题，在提出基于马斯京根流量演算河道洪水实时预报的半自适应滤波模型的基础上，对该模型在具有行蓄洪区的复杂河道中的应用问题进行了深入的研究，提出了蓄洪区的计算与预报方法，使得半适应滤模型可以用于复杂河道行蓄洪的调度和实时洪水预报。     

Optimal Operation of Multi-reservoir Systems Considering Time-lags of Flood Routing

Operations of multi-reservoir systems are nonlinear and high-dimensional problems, which are difficult to find the optimal or near-optimal solution owing to the heavy computation burden. This study focuses on flood control operation of multi-reservoir systems considering time-lags caused by Muskingum flood routing of river channels. An optimal model is established to jointly minimize the flood peak on the downstream flood control station for the multi-reservoir systems. A hybrid algorithm, Progressive Optimality Algorithm and Successive Approximation (POA-SA), is improved to solve the multi-reservoir operation model by modifying the POA. The POA-SA uses the DPSA to reduce the spatial dimensionality due to the multiple reservoirs, and adopts an improved POA to alleviate the temporal dimensionality caused by the time-lags of the Muskingum flood routing. Linear programming is then implemented to verify the solution of the POA-SA method with a linear approximation of the discharge capacity curve. The multi-reservoir systems of China’s Xijiang River is selected for a case study. Results show that the flood peak of Wuzhou station can be averagely decreased by 6730 m³/s (12.8 %) for the 100-year return period floods, indicating that the proposed method is efficient to operate the multi-reservoir systems and resolve the time-lags issues.     

A System Approach to Real-time Hydrologic Forecast in Watersheds

Abstract

In non-structural measurement of flood control, hydrologic forecasting plays a very important role. Owing to time-variance, non-linearity, and uncertainty of hydrological processes, realtime forecasting has become an efficient approach. The paper addresses an important practical problem: improving short-term hydrological forecasting based on real-time updating in the operation model. A simple nonlinear model with a variable gain parameter (VGPM) is developed. A separated calibration approach for updating parameters used in the runoff generation process and the response function in the flow routing is proposed. State space equations associated with updating model parameters in a real time scheme were developed. The VGPM approach is verified for three types of representative watersheds. The performances of different updating schemes in rainfall-runoff modeling and real-time forecasting were tested. The results indicate that significant improvement in the efficiency of hydrological modeling can be obtained from the VGPM approach, relative to simple linear models (SLM). For the watersheds with a time-variant characteristic, moreover, significant improvement in the hydrologic forecasting efficiency can be obtained by adaptive schemes. The efficiency of real-time modeling by the self-adaptive Kalman Filtering algorithm was found to be very close to that of the Recursive Least-Square method.     

基于马斯京根法的嫩江江桥-大赉段洪水演算

针对嫩江江桥-大赉河段洪水演进不平衡问题,首先分析了1998年前后江桥和大赉两个水文站的径流变化规律;然后引入河道洪水演进损失系数,建立了基于分段马斯京根方法的江桥-大赉河段的洪水演算模型;最后利用1998年后洪水资料,采用粒子群优化算法率定了河道洪水演进参数和洪水演进损失系数,并分析了参数和损失系数的合理性。结果表明,由于受1998年大洪水的冲刷以及河道两岸冲毁的影响,嫩江江桥-大赉段河道洪水传播速度加快,同时在演进过程中洪水向河道外满溢,导致上下游水量不平衡。     

考虑水文模型参数时变的水库水位多预见期实时预报——以水布垭水库为例

精准可靠的坝前水位预测可支撑水库的调度决策,保障流域防洪安全。传统水库水位实时预报方法均基于降雨径流稳态假定,在变化环境下精度不高。为此,本研究提出了一种整合水文模型参数时变和实时校正的水库水位多预见期实时预报方法：识别变化环境下水文模型参数的时变过程,构建时变参数与自然、社会经济因子的函数关系;基于时变参数函数式构建预报调度集成模型,以预见期内多个时刻预报水位与观测水位的吻合程度为目标函数率定水文模型的参数;采用基于反向拟合算法的实时校正技术进行误差校正,输出不同预见期的水库水位预报。以水布垭水库流域为研究对象,结果表明,较传统水库水位预报方法,论文提出的方法在率定期和检验期的平均绝对值误差分别下降了0.050和0.040 m,可为防洪减灾提供高精度、长预见期的水库水位预测。     

A Modified Muskingum Flow Routing Model for Flood Wave Propagation during River Ice Thawing-Breakup Period

During the period of river ice thawing and breakup process (termed as “ice cover thawing-breakup”), vast amount of water stored in ice-covered river reach will be released comparing to that under open flow condition. The flow routing process during river ice thawing-breakup period will be different from that under open flow condition, since water stored in and channel from ice thawing-breakup process and flow routing process are very complicated. If the flow routing process during river ice thawing-breakup period can be predicted, it will very important for flood protection in the downstream river reach. In present study, water released from ice cover thawing process is considered as the lateral inflow to the channel flow during propagation process of flood wave from upstream to downstream. A model for the flood routing process during river ice thawing-breakup period has been developed based on the Muskingum hydrologic method. Using the modified Muskingum model, the routed outflow hydrograph has been determined along the Baotou Reach of the Yellow River during river ice thawing-breakup period. Results showed that the simulated hydrographs using developed model agree well with those of field measurements.

     

基于集合预报的淮河流域洪水预报研究

建立基于集合预报的淮河具有行蓄洪区流域洪水预报及早期预警模型。在洪水预报中引入数值天气预报以延长洪水预报的预见期。集合预报采用多模式和多分析集合预报技术,考虑初始场的不确定性和模式的不确定性,避免“单一”确定性数值天气预报结果易存在的预报误区。THORPEX 项目支撑的THORPEXInteractiveGrand GlobalEnsemble（TIGGE ）集合预报目的是建立全球交互式预报系统。本文以淮河流域为试验流域,以TIGGE 集合预报（加拿大气象中心（简称CMC,集合成员数为15个）、 欧洲中期天气预报中心（简称ECMWF,集合成员数为51个）、 英国气象局（简称UKMO ,集合成员数为24个）、 美国国家环境预测中心（简称NCEP,集合成员数为15个））驱动构建的水文与水力学相结合的具有行蓄洪区流域洪水预报模型以达延长洪水预报的预见期,新安江模型用于降雨径流计算、一维水动力学模型用于河道洪水演算,实现洪水预报及早期预警。为了进行比较,同时采用地面雨量计观测降水驱动构建的洪水预报模型,对2007和2008年淮河汛期洪水进行检验。结果表明,基于TIGGE 集合预报驱动的洪水预报预见期延长了72~120h ,证明了TIGGE 集合预报可以应用于洪水预报及早期预警。     

Application of New Hybrid Optimization Technique for Parameter Estimation of New Improved Version of Muskingum Model

The Muskingum method is one of the most utilized lumped flood routing model in which calibration of its parameters provides an active area of research in water resources engineering. Although various techniques and versions of Muskingum model have been presented to estimate the parameters of different versions of Muskingum model, more rigorous approaches and models are still required to improve the computational precision of calibration process. In this study, a new hybrid technique was proposed for Muskingum parameter estimation which combines the Modified Honey Bee Mating Optimization (MHBMO) and Generalized Reduced Gradient (GRG) algorithms. According to the conducted literature-review on the improvement of Muskingum flood routing models, a new six-parameter Muskingum model was proposed. The hybrid technique was successfully applied for parameter estimation of this new version of Muskingum model for three case studies selected from literature. The obtained results were compared with those of other methods using several common performance evaluation criteria. The new hybrid method with the new proposed Muskingum model perform the best among all the considered approaches based on most of utilized criteria. The new Muskingum model significantly reduces the SSQ value for the double-peak case study. Finally, the achieved results demonstrate that not only the hybrid MHBMO-GRG algorithm overcomes the shortcomings of both phenomenon-mimicking and mathematical optimization techniques, but also the presented Muskingum model is appeared to be the most reliable version of Muskingum model comparing with other considered models in this research.     

Investigation the Effect of Using Variable Values for the Parameters of the Linear Muskingum Method Using the Particle Swarm Algorithm (PSO)

Flood routing is a technique to determine the flood hydrograph at a point of downstream where is of great importance and flood-induced risks can cause irreparable damages. Routing methods can be classified into two categories: hydraulic routing and hydrologic routing. Hydrologic methods are less accurate than hydraulic methods but they are widely used for engineering of rivers due to simplicity and being acceptable. Muskingum is a simple, widely used hydrologic method in the flood routing. In present study, accuracy of the linear Muskingum method has been evaluated using the Particle Swarm Optimization (PSO) algorithm in a Karun River reach bounded to the Mollasani hydrometric station and Ahwaz station upstream and downstream of the river, respectively. The results suggest that if three distinct values rather than constant values are used for X, K, ?? parameters in the Muskingum method, the accuracy of computed outflow will be increased particularly in the peak section of hydrograph so that the Mean Relative Error (MRE) of the peak hydrograph section was 2.44% when constants were. However, in the case of using three different values for these parameters, the error value reached 0.89%.     

空间嵌套式流域水文模型的初步研究——以三峡水库入库洪水预报为例

三峡水库的防洪调度是多任务和多目标的,既需要掌握整个长江上游的水、雨和工情,也不能忽视三峡区间洪水信息。本论文以三峡水库入库洪水预报为例,依据入库洪水特性,在整个长江上游和三峡区间分别构建了大小两种尺度网格单元的分布式水文模型,并与一维和二维非恒定流的库区水动力学模型相结合,初步实现了这两种尺度水文模型的空间嵌套,以此探讨适合于大型流域数字水文模拟的空间嵌套式流域水文模型结构与构建方法。研究初步表明,嵌套模式构建的流域水文模拟方法,能够解决大流域水文模拟中多尺度之间的衔接问题。     

MSKLOSS河道洪水演算模型参数敏感性分析

模型参数的敏感性分析是洪水预报的基础性工作。以中国洪水预报系统为平台,采用局部分析法,对MSKLOSS河道洪水演算模型参数进行敏感性分析,以提高洪水预报的精度。为提高MSKLOSS河道洪水演算模型的应用效率,考虑模型适用性、模拟分析方便性,选取海河南系河道下垫面接近现状条件的滹沱河黄壁庄-北中山、南运河岳城-蔡小庄"96·8"和大清河东茨村-新盖房"12·7"三场洪水资料对模型参数进行分析。分析表明:河道分段数、初始下渗率、下渗曲线指数和湿周等参数的敏感性较高,稳定下渗率的敏感性在洪水量级较小时相对较高,在参数优选和实时作业预报时需注意其初始范围的设定。     

基于区间入流预报的右江河道洪水演进

广西右江如果发生大洪水,将对郁江和南宁市的防洪产生严重威胁,因此右江洪水演进分析对南宁市的防洪具有重要意义。选出百色水文站洪峰流量依次增大的5场洪水,用右江百色-田东河段区间内的小流域作为代表性流域率定新安江模型参数,对区间入流洪水进行了预报。根据预报结果采用经参数试错法率定后的马斯京根模型对5场洪水进行了演进,计算了田东水文站断面的流量。结果表明:计算结果与实测流量相对误差较小,相关性系数较大,说明试错法对于马斯京根模型参数求解精度较高。     

小浪底水库2002年调水调沙下游河道洪水演进跟踪模拟计算

本文采用黄河下游河道洪水演进数学模型，开展了2002年汛期小浪底水库调水调沙下游河道洪水演进与河床冲淤演变时实跟踪计算，计算结果与调水调沙后整编的实测资料对比分析发现，该模型能够较准确复演天然河道的水沙演进与河床冲淤演变过程．可以在黄河下游河道洪水演进及河床冲淤演变预测中应用。     

HEC-HMS水文模型在大渡河流域的应用研究

HEC-HMS模型是一个具有半物理机制的半分布式降雨径流模拟模型,在洪水分析和洪水预报中具有广泛的应用。以大渡河流域上游为例,结合流域实测水文气象资料,构建了流域的HEC-HMS模型,基于Morris筛选法确定了模型敏感性参数为CN、初损、滞时以及峰值系数。通过大渡河上游的7场洪水过程对该模型进行了率定验证,结果表明纳什效率系数均在0. 72~0. 88之间,洪峰流量相对误差均小于14. 4%。分析表明该模型在大渡河流域洪水模拟中有较好的适用性。