渭河下游泥沙淤积及其影响

三门峡水库的设计，由于对泥沙问题认识不足，使潼关高程从建库前的３２３．４０ｍ迅速抬升到３２８．００ｍ，造成库区严重淤积，二期改建时期，潼关高程有所下降，全年控制运用以来，潼关高程有升有降，但以抬升为主要趋势，特别是９０年代以来，潼关高程居高不下，造成渭河下游河床普遍抬高、河势恶化、过洪能力锐减、防洪标准大大降低等诸多问题，针对以上问题，本通过建库以来水泥沙资料统计，对渭河下游泥沙淤积的原因及其     

防汛档案资料管理的对策和建议

渭南市位于陕西省关中东部，地处三门峡库区，境内有黄河、渭河、洛河及较大支流27条。三门峡库区涉及全市8个县（市、区）的47万人，177万亩土地。自1960年9月三门峡水库枢纽工程建成运用以来，由于泥沙大量淤积，潼关高程比建库前抬高5m，目前全市库区共淤积泥沙约47亿t。造成黄河小北干流和渭洛河下游河床抬高，泄洪能力降低，洪涝灾害加剧，特别是南山支流几乎年年决口成灾，小水大灾频繁发生，防汛形势十分严峻，洪水灾害已成为全市的心腹之患。     

降低潼关高程可行性分析

在对三门峡建库以前的历史资料分析和总结前人结论的基础上指出,造成渭河下游防洪形势严峻的主要原因是潼关高程的不断抬高。近两千年的历史资料证明,潼关断面附近河床年淤积厚度只有0.008 m。对三门峡建库以来资料分析证明,水库的高水位运用是造成潼关高程抬升的主要原因,水库的不同运用方式与潼关高程的变化有直接关系。综合分析认为,降低潼关高程是有可能的,在不明显降低三门峡水库综合运用效率的前提下,通过合理调度可以将潼关高程从现在的328 m至少降低2 m以上,这样可以使渭河下游堤防的防洪标准得到一定程度的恢复。本文还根据调查分析提出了降低潼关高程的几项具体建议。     

渭河下游来水来沙及冲淤情况分析

<正>1渭河下游的基本情况渭河下游河段是指从渭河咸阳陇海铁路桥(渭淤37断面)至入黄口的渭河河段,其河长208km,比降较小,水流较缓,河道泥沙淤积严重,属三门峡库区的重要组成部分。三门峡水库建库前,渭河下游是一条天然的河流,河道两岸未建堤防和河道工程。三门峡水库建成运用后,渭河下游由于泥沙的严重淤积,主槽过洪能力迅速降低,两岸先后修建了堤防和河道     

我省三门峡库区泥沙灾害不容忽视

三门峡库区包括黄河小北干流韩城龙门至潼关长132.5公里,北洛河蒲城状头至入渭口长 131.7公里,渭河咸阳铁桥至入黄口长208公里。涉及陕西关中东部3个地市、14个县区的近200万人口和200万亩耕地。三门峡水库建成运用以来,在为黄河下游防洪、防凌、发电等方面发挥巨大效益的同时,却给陕西岸区造成了一系列严重灾害。黄河潼关高程持续抬高,库区各河道泥沙淤积迅猛发展。尤其是近十几年来,在水库长期高蓄水运用等因素的影响下,潼关河床高程最大抬升值已达到5.2米.且居高不下。渭洛河下游和黄河小北干流泥沙淤积随之迅猛增加,已达到45亿吨。为建库以来潼关以上淤积最大值,并有继续淤积增加趋势。 伴随泥沙淤积和潼关高程抬升,库区河势进一步恶化,灾害逐年发展,发灾频次和成灾损失近年来明显增多、增大。防汛安全形势日趋严峻。     

潼关高程对渭河河床演变的影响

本文根据渭河下游河段自三门峡水库建库42年以来的大断面地形变化以及泥沙淤积资料，运用河床演变分析法，分析了潼关高程对渭河淤积演变的影响。分析发现，潼关高程的大幅度抬升和下降引起溯源发展的淤积和冲刷的行波，行波传播速度大约每年10km，传播过程中幅度逐步减弱。通过相关分析，发现潼关高程抬升是引起渭河下游特别是临潼以下河段淤积的主要原因，咸阳及其以上河段的淤积与潼关高程基本无关，渭河上游来水量对冲刷减淤起了很大作用，来沙系数影响略小。本文进一步建立了一种淤积平衡模型，用以模拟渭河下游淤积过程。模拟结果表明，模型能正确地模拟淤积过程，潼关高程抬升引起的渭河下游淤积有一个平衡淤积量。如果潼关高程维持在一定水平不变，渭河下游的淤积就会逐渐趋近于这个平衡淤积量，大约30年左右就会接近这个平衡。目前渭河下游累积淤积量已经接近潼关高程328.5m的平衡淤积量。如果潼关高程保持不变，渭河下游将随着来水量的波动而发生小幅度的冲刷和淤积，不会发生累积性的大幅度淤积。     

渭河流域综合治理迫在眉睫

渭河下游地处三门峡库区，泥沙淤积严重，主要原因是潼关高程抬高，防洪工程标准低等，造成小水大灾，泄洪能力不断降低，渭河南岸支流入渭困难，经常决口泛滥。为确保三门峡库区的防洪安全，渭河流域的综合治理已迫在眉睫，应采取以下措施解决问题：１对黄河全河水量进行统一调度；２改善三门峡水库运用，控制潼关高程；３加快投资，加速渭河下游治理；４加强领导，克服麻痹思想，增强水患意识。     

潼关高程变化及其对渭河下游的影响分析

采用实测资料分析三门峡建库以来潼关高程变化与渭河下游泥沙淤积的关系表明:2002年汛后原型试验以来潼关高程有所下降,2015年汛后为327.63 m,仍然偏高;潼关高程升降变化与渭河下游泥沙冲淤关系密切,由潼关高程抬升引起滩槽纵剖面调整造成的淤积约占渭河下游1971-2003年淤积的78.3%,是渭河下游严重淤积的最主要影响因素和根源;2003-2015年潼关高程与渭河下游累计淤积体相关性减弱明显,但渭河下游泥沙淤积量随着潼关高程的抬升或降低而增大或减少的规律仍然明显存在;渭河下游大量淤积逐步抬升演变成为地上"悬河",从根本上改变了渭河下游的防洪排涝形势,灾害损失巨大,严重影响着区域经济社会的稳定发展。建议采取综合措施将潼关高程控制在325.60~325.69 m以下,以减少渭河下游泥沙淤积,改善河道行洪条件,降低沿岸区域洪水灾害风险,为区域发展提供安全环境。     

渭河下游河道整治工程建设与实践

陕西省渭河下游自成阳铁路桥至潼关河口,全长208公里,是受三门峡水库回水影响的特殊河道。经30年治理,渭河下游防洪体系中的河道整治已初具规模,有效地发挥了定槽、固滩、保堤的显著效益。整治概况与效果三门峡建库后,引起渭河下游河床淤积抬高,比降迅速变缓,主流摆动频繁,崩滩塌岸加剧。为减轻三门峡水库的不利影响,保护沿河群众利益和防洪安全,从1964年开始进行渭河下游河道整治。截止     

潼关高程变化及其对渭河下游淤积的影响

三门峡水库1960年投入运用之后，经过两次改建和三次运用方式的调整，不仅发挥了较大的防洪、防凌效益，也为多沙河流上修建水库长期保持兴利库容创造了丰富的经验。但水库运用也给库区造成了一系列问题。作者对水库运用以来潼关高程变化和渭河下游冲淤演变进行了分析，认为建库初期蓄水、滞洪运用是渭河下游产生严重淤积的根本原因，1991年以来渭河下游的淤积主要受水沙条件影响，潼关高程的居高不下使问题更加严重。     

基于准三维理论的混流式水轮机转轮设计方法的研究

基于S1和S2两类相对流面理论,建立了混流式水轮机转轮内部流动的准三维计算与叶片设计的模型.利用周向平均处理方法,从三维欧拉方程导出子午面上的流函数运动方程,并利用周向平均的1个S2m流面和1组S1流面的迭代计算得到所设计的叶片.采用Galerkin加权余量法,建立了S2m、 S1流面方程的有限元方程,采用松驰法进行迭代计算;得到满足给定负荷分布及厚度分布的转轮,为转轮设计提供了一种新的有效的计算模型和方法.     

Systematic comparison of 1D and 2D hydrodynamic models for the assessment of hydropeaking alterations

Numerical hydrodynamic models enable the simulation of hydraulic conditions under various scenarios and are thus suitable tools for hydropeaking related assessments. However, the choice of the necessary model complexity and the consequences of modelling choices are not trivial and only few guidelines exist. In this study, we systematically evaluate numerical one-dimensional (1D) and two-dimensional (2D) hydrodynamic models with varying spatial resolution regarding their suitability as input for hydropeaking-sensitive, ecologically relevant hydraulic parameters (ERHPs), and their computational efficiency. The considered ERHPs include the vertical dewatering velocity, the wetted area variation between base and peak flow and the bed shear stress as a proxy for macroinvertebrate drift. Furthermore, we quantified the habitat suitability of brown trout for different life stages. The evaluation is conducted for three channel planforms with morphological characteristics representative for regulated Alpine Rivers, ranging from alternating bars to a braiding river morphology. For the prediction of habitat suitability and bed shear stress, a 1D model appears to be always insufficient, and a highly resolved 2D model is suggested. Reducing the spatial resolution of 2D models leads to computational efficiency similar to 1D, while providing more accurate results. Thus, our results suggest, that while a highly resolved 1D model is sufficient for accurate predictions of the dewatering velocity and wetted area in the less complex alternating bar morphology, a 2D model is recommended for more complex wandering or braiding morphologies. This study can serve as guideline for researchers and practitioners in the selection and setup of hydrodynamic models for hydropeaking.     

The impact of river regulation on the lotic macroinvertebrate communities of the lower rhǒne,France

Channelization and the construction of 12 dams on the Lower Rhǒne during the last 30 years increased the morphological and biological effects of 19th century embanking along the river. These trends were demonstrated on the main channel, i.e. the central axis of the alluvial floodplain, by the synchronic study of the benthic macrofauna of six lowhead hydroelectric impoundments. The variability of the most significant taxa was investigated by an ANOVA, and the data-samples matrix was processed with a Principal Components Analysis in order to analyse the communities organization and their significance. The benthic macroinvertebrate communities of the channel include some lentic potamic species topographically related with this kind of river (metapotamon), as well as eurytopic and pollution-tolerant species. Thus, the Lower Rhǒne has become a slow potamic river, in the same way as other large mid-European rivers. Flow velocity appears to be the most important structural factor in a large regulated river. The homogeneity of the macroinvertebrate communities and the absence of longitudinal typology show that, in a very intensely regulated river, the River Continuum Concept is too theoretical, and the disturbing effects of dams on longitudinal changes and species response to regulation must be taken into account.     

Dissolved organic carbon dynamics in the upper rhone: The influence of side-arms?

Dissolved organic carbon (DOC) dynamics were investigated over a two year period in the Upper Rhǒne River to examine the role of side-arms in providing DOC to the main channel in relation to discharge fluctuations, especially floods. Concentrations of DOC are shown to remain low in space and in time (average 1.5 mg ^?1) and to be more related to global hydrological events (precipitation) than to any local flushing for backwaters during floods. The results do not support the general assumption that side-arms are the providers of DOC to the main channel.     

洪水与风暴潮共同作用下的溃堤洪水一维、二维耦合模型及应用

为了解决复杂条件下河道洪水漫堤、溃堤和潮水倒灌的问题,建立了在洪水和风暴潮共同作用下的天然河道漫溃堤洪水在防洪保护区的一二维水动力耦合模型。在兼顾计算效率和精度的基础上,分区剖分网格,设置合理的网格面积;根据植被和地物的不同,分区设置糙率;通过宽顶堰的方式将河道一维模型和防洪保护区二维模型进行侧向耦合;采用基于侵蚀的渐变溃破坏方式模拟河道溃堤过程,实现了河道上游发生洪水和下游遭遇外海风暴潮的复杂情况下精细化模拟。实例研究表明,所建模型可灵活处理复杂多变的水力条件,模拟结果合理可靠,可为防汛部门制定决策提供有力的科学依据。     

Intragenomic variation of rDNA internal transcribed spacers in the endemic Baikal sponge Lubomirskia baikalensis (Pallas, 1776) (Spongillida,Lubomirskiidae): Implications for Porifera barcoding

Baikal endemic sponges are a species group for which species identification is difficult and the taxonomy is insufficiently developed. The rDNA ITS (internal transcribed spacers) are practical molecular markers for sponges. However, intragenomic polymorphism of the ITS spacers has recently been detected in many organisms including marine and freshwater sponges. We for the first time demonstrate intragenomic polymorphism of the ITS region in the sponge family Lubomirskiidae. We identified 27 new ITS1 and ITS2 haplotypes. The level of intragenomic polymorphism of the ITS1 and ITS2 regions in Lubomirskia baikalensis was 0.1–2.0%, which overlaps with the intraspecific polymorphism of L. baikalensis and to the interspecific polymorphism within Lubomirskiidae. Thus, the detected level of intragenomic polymorphism of Lubomirskiidae suggests species identification of Baikal sponges using ITS sequences would be difficult. The reasons for the lack of concerted evolution of the ITS spacers in Lubomirskiidae may be hybridization or insufficient divergence time. Our work contributes to the development of sponge barcoding markers.     

珠江河口水动力一维、二维联解的有限元计算方法

该文应用有限元联解方法计算珠江河网与河口的整个水动力。仿照四点隐式差分法在每个一维单元内部形成独立的单元方程组,改进RMA有限元软件包实现河网一维数值模拟。借鉴弹性力学年中通过固结杆件与块体的连接结点实现两构件组合计算的思路,设计了珠江河网一维、河口二维水动力联解的有限元法,通过单元矩阵的构建、合并与叠加,形成整体方程组,实现整体求解的连接模式,有效地解决了不同形态流场的模拟问题。应用研究表明:该方法合理,计算结果较理想。     

盐溶质及其离子品位空间变异性的Co—Kriging估计

根据土壤特性的空间变异性和大型灌区水盐监测需要，本文用多元地质统计学(MVG)的Co—Kriging(CK)方法，研究了引黄灌区内2种尺度条件下So2-4—Cl-型盐渍化土壤盐溶质及其主要离子品位的协同估计，用3种单变量和一组多变量预测主变量信息不足时的不同目标，结果表明：用野外易测的EC值可精确估计Cl-；用EC&Cl-组成的多变量可估计较难测定的K++Na+品位；由小尺度获得的CK模型可精确用于中尺度估计并对求解CK方程的有关技术作了探讨，有助于MVG理论在土壤—水科学领域的应用与开拓。     

A coupled 1-D and 2-D channel network mathematical model used for flow calculations in the middle reaches of the yangtze river

A coupled one-dimensional (1-D) and two-dimensional (2-D) channel network mathematical model is proposed for flow calculations at nodes in a channel network system in this article.For the 1-D model, the finite difference method is used to discretize the Saint-Venant equations in all channels of a looped network.The Alternating Direction Implicit (ADI) method is adopted for the 2-D model at the nodes.In the coupled model, the 1-D model provides a good approximation with small computational effort, while the 2-D model is applied for complex topography to achieve a high accuracy.An Artificial Neural Network (ANN) method is used for the data exchange and the connectivity between the 1-D and 2-D models.The coupled model is applied to the Jingjiang-Dongting Lake region, to simulate the tremendous looped channel network system, and the results are compared with field data.The good agreement shows that the coupled hydraulic model is more effective than the conventional 1-D model.     

三峡大坝175 m蓄水运行后猪儿碛河段水动力条件变化分析

三峡大坝175 m成库运行后将对变动回水区的水流特性产生重大影响,对其展开分析将为该河段的航道整治、通航规划、水沙规律研究提供重要理论支持。在长江上游水文局实测资料基础上,选择变动回水区中段猪儿碛河段作为典型代表河段,采用数值模拟与原形观测数据理论分析相结合的方法,借助Aquaveo.SMS软件建立平面水流二维数学模型,将年内各时段与有无回水影响的各种工况进行组合,分析探讨了回水作用对流场、流速横向分布、水动力轴线等水动力条件的影响。分析成果可为该河段的河流研究与航道治理提供依据,建立的数值模拟方法可为同类河段的数模研究提供参考。