黄河黄丰水电站泥沙问题分析及防沙措施

黄丰水电站坝前有2条较大的支沟——盐沟和街子沟，支沟的泥沙对电站的威胁较大，通过对支沟水沙调查分析计算，确定了支沟入库水沙特性。通过模型试验和入库泥沙分析提出的水库泥沙调度运行方式及防排沙措施，解决了电站的主要泥沙问题。     

大通河天王沟水电站泥沙设计重点问题探讨

天王沟水库坝前水深和库容都较小,且入库沙量相对较多,库沙比仅为0.8,所以水库很快淤积平衡,库区泥沙问题较为严重。天王沟水电站工程泥沙问题主要是研究水库回水与上游铁城电站尾水合理衔接以及保持进水口前＂门前清＂,通过对入库水沙分析提出的水库泥沙调度运行方式及防排沙措施,基本解决了电站的主要工程泥沙问题。     

瀑布沟水库拦沙作用分析

本文分析大渡河流域泥沙来源及其分布，阐明瀑布沟水库拦沙作用及尽早兴建瀑布沟水电站是解决龚嘴和铜街子电站泥沙问题的行之有效措施。通过瀑布沟水库泥沙冲淤计算论证，水库的拦沙效果显著，在100年内，龚嘴入库输沙量将减少72.7%以上。     

瀑布沟水库拦沙作用分析

本文分析大渡河流域泥沙来源及其分布,阐明瀑布沟水库拦沙作用及尽早兴建瀑布沟水电站是解决龚嘴和铜街子电站泥沙向题的行之有效措施.通过瀑布沟水库泥沙冲淤计算论证,水库的拦沙效果显著,在100年内,龚嘴入库输沙量将减少72.7％以上.     

瀑布沟水库拦沙作用及其对下游电站的影响

瀑布沟水电站坝址基本控制了大渡河流域的主要产沙区.瀑布沟水库蓄水后,由于其库容大,将在很长时间内拦截入库的大部分悬移质泥沙和全部推移质泥沙,从而使下游梯级水电站的入库泥沙大量减少.对下游梯级水电站的影响主要表现在:减轻过机泥沙对水轮机的磨损;减轻水电站的引水防沙难度;水库汛期水位可适当抬高,从而增加电站的发电效益;减缓龚嘴水库库尾成昆铁路沙坪1号洞路段的回水抬高速度.     

韭园沟与秃尾河流域淤地坝坝内泥沙粒径分析

淤地坝是韭园沟与秃尾河流域重要的水土保持工程之一,淤地坝所处流域和工程结构的不同,淤积物的粒径大小存在差异。通过钻孔取样法采集了韭园沟流域21座淤地坝和秃尾河流域36座淤地坝淤积物样品623个,根据样品的颗分结果,分析得出韭园沟流域淤地坝坝内粗泥沙粒径主要为0.05 mm,秃尾河流域淤地坝坝内粗泥沙粒径主要分布于0.05~0.10 mm之间,说明淤地坝能有效拦截流域内的粗泥沙;两流域淤地坝均呈现库尾泥沙粒径总体大于坝前,库尾泥沙粒径的大小取决于入库泥沙粒径的大小,入库泥沙粒径越大,淤地坝对其分选效果越明显。     

三门峡水库淤积及潼关高程的滞后响应

研究了三门峡水库淤积和潼关高程随坝前水位和来水条件变化的响应规律，分析了库区河床演变的滞后现象。发现水库的累计淤积量和潼关高程，不仅受当年水沙条件和坝前水位的影响。而且通过前期边界条件，还受过去若干年内的水沙条件和坝前水位的影响。表现在潼关高程的升降变化较库区泥沙淤积滞后大约2年，库区累计淤积量与5年叠加坝前水位关系密切，潼关高程与6年叠加入库水量之间具有较好的相关关系，以及潼坫段比降与7年移动平均坝前水位之间的关系最好。     

坝系建设关键技术探讨

通过对黄土高原不同区域典型小流域坝系调查统计分析，小流域沟道布坝密度为0．4-3座/km^2最为合理。坝系建设顺序以先下后上，先干后支，即先从沟口至沟掌打坝为优，单坝打坝间隔年限以F/S=40为最优。坝系中骨干坝与中小型淤地坝的配置比例以1：2～1：(4～6)为宜，坝系布局支毛沟以小型淤地坝为主，支沟以大中小型淤地坝为主，适当位置建设蓄水塘坝，在较大支沟沟口布设骨干坝，干沟以大中型淤地坝为主。合理布设骨干工程和中小型水库，有效控制洪水泥沙，快速淤地，发展水坝地，提高坝系综合效益。     

王茂沟流域坝系用洪用沙经验

打坝淤地是充分利用水沙资源、变荒沟为良田的有效措施,是黄土丘陵沟壑区建设基本农田的主要途径之一。王茂沟流域坝系就是一例。一、基本情况和治理过程王茂沟是韭园沟中游左岸的一条支沟。流域面积5.97平方公里,主沟长3.75公里,平均比降2.7％,沟壑密度4.31公里/平方公     

近年来三峡水库坝下游河道强烈冲刷机理分析

金沙江下游梯级电站相继建成蓄水运用以来,三峡水库坝下游河道出现了较强冲刷,同时坝下游冲刷逐渐向下游发展,城陵矶以下河段河床冲刷强度明显增大。根据实测水沙资料以及坝下游河道地形资料,初步分析了近年来坝下游河道强烈冲刷原因,一方面,由于金沙江下游梯级电站相继建成蓄水运用,三峡水库入库和出库泥沙进一步减少,导致坝下游含沙量大幅偏小。另一方面,坝下游汛期洪峰较大,洪水过程持续时间偏长,同时近年来长江中下游区间来水较大。加之城陵矶以下河道床沙组成较细,造成城陵矶以下河段发生大幅度冲刷。研究成果可为坝下游防洪、航运及河道治理研究提供参考。     

黄河无定河流域“2017.7.26”洪水泥沙来源辨析

2017年7月25—26日无定河流域降大到暴雨,支流大理河发生建站以来的最大洪水,无定河下游形成高含沙洪水。为深入认识“7.26”暴雨无定河流域产沙和输沙等情况,选择典型小流域进行了侵蚀调查和淤地坝拦沙观测,对城区淤积及河道冲刷进行了调查和测量,采用不同方法对坡面和沟谷产沙进行分析。结果表明,无定河“2017.7.26”暴雨分布集中,单站最大24 h降雨量近100年一遇,无定河白家川水文站洪峰流量为建站以来第二大值,相应最大含沙量873 kg/m3; 洪水期输沙量64.1%来自大理河流域; 以闷葫芦淤地坝拦沙分析为依据,推算“2017.7.26”暴雨期无定河流域侵蚀产沙量约为1.249亿t,其中70%~85%来自沟谷坡,在泥沙沿程输移过程中,淤地坝拦沙对减少河道输沙入黄起重要作用。     

黄土高原治沟骨干工程坝系建设中几个问题的商榷

结合黄土高原地区十几年来坝系建设的实际情况和各地的一些典型做法，针对治沟骨干工程坝系建设中遇到的几个问题，提出在坝系建设中应注意以小流域为单元、支毛沟为重点，最终达到冲淤平衡的规划思想，并对坝系规划的范围、流域面积的确定和工程水沙计算等进行了探讨。     

泥石流沟危险度定量评价研究——以白龙江陇南两河口镇至桔柑乡段为例

泥石流的危险度是认识、防控泥石流的重要因素,针对反映泥石流危险度的特征函数进行分析,运用量纲分析方法,建立了基于泥石流势能的单沟危险度计算模型。同时考虑到防治工程的减危效果,增加了拦砂坝和排导槽对泥石流的拦挡排疏功能来修正模型,并以白龙江陇南两河口镇至桔柑乡段138条泥石流沟为例来验证模型的有效性,得到了研究区域单沟泥石流危险度值。结果表明:修正模型能计算增加防治工程后单沟泥石流的危险度,具有较好的实用性;沿白龙江流域的泥石流沟中,极高危险区占研究区范围的17.39%,高度危险区占研究区范围的21.74%,且危险区大多集中于白龙江北岸,计算值与野外实际情况基本吻合;然而由于防治工程减危值受历史条件的影响,对于极高危险区的泥石流沟,应及时做好防范。     

小浪底水库拦沙初期泥沙输移及河床变形研究

应用物理模型试验对小浪底水库运行初期的泥沙输移和河床变形进行了一系列的研究预测,结果表明水库运用初期基本上为异重流排沙;库区干流淤积形态为三角洲且不断向下游推进;支流淤积主要是干流倒灌的结果,在沟口可形成拦门沙;库水位大幅下降,干流河床将产生溯源冲刷和沿程冲刷,支流淤积面随之下降。水库投入运用以来的实测资料分析表明,尽管预报试验所采用的水沙条件与水库运用以来的实际情况不尽相同,但两者在输沙流态、淤积形态及变化趋势方面基本一致,从而证明了模型试验得出的结论是符合实际的。     

小流域沙棘植物柔性坝系累积水保效应原型试验

在典型砒砂岩地区内蒙古准格尔旗东一支沟小流域开展了沙棘植物柔性坝系累积水保效应原型试验。结果表明:沟道柔性坝系普遍发生了淤积,柔性坝系与下游刚性谷坊配套使用可天然分选沟道泥沙—拦粗淤细,将粗沙过滤在沟道里,细沙淤积在下游刚性谷坊中,拦沙效果非常明显;柔性坝系对沟道土壤水分具有较强的调节作用,可减缓沟道土壤水分蒸发,增大土壤入渗,达到拦沙保水的目的;柔性坝系发达的根系可显著的改善沟道土壤的理化性质和肥力,提高土壤的蓄水保土功能。本试验研究可为在砒砂岩地区推广沙棘植物柔性坝这一生物工程技术提供理论依据。     

Simulation Modeling of Runoff,Groundwater Flow and Sediment Transport into Kastoria Lake,Greece

Kastoria Lake is located in northwestern Greece. The whole basin of the lake is about 253 km². For the computation of the surface water volume inflowing into the lake from the main streams of the sub-basins located around Kastoria Lake, a rainfall-runoff sub-model is used. A quasi-three-dimensional simulation model of the Kastoria basin aquifer is also realized, in order to estimate the groundwater contribution to the volumetric budget of the lake and the whole basin as well. For the computation of sediment load inflowing into the lake from the main streams of the sub-basins, the rainfall-runoff sub-model is combinedwith a soil erosion sub-model and a sediment transport sub-model for streams. A GIS was developed in the hydrologic basin with all data needed for parameter identification and model application. The data base was enriched by a series of on site measurements of water discharge made in all main streams for one whole hydrologic year. By means of the resulting mathematical sediment model, those sub-basins, which deliver most sediment load to the lake, are identified. On the basis of this identification, a series of control measures, for the reduction of sediment inflowing into the lake, at certain places of the above mentioned sub-basins is proposed.     

Human impacts on suspended sediment and turbidity in the River Murray,South Eastern Australia: Multiple lines of evidence

European settlement has led to increased loads of fine suspended sediment (SS) entering the River Murray, Australia's largest, and arguably, most important river. The River Murray's anthropogenic sediment history can be divided into four periods with varying source areas, sediment loads, and seasonal patterns. The Aboriginal period (before 1840) was characterized by clear water at summer low‐flows in the River Murray and its southern tributaries, with more sediment coming from the northern catchment than the southern, and the Darling River being turbid at all flows. There is little evidence that Aboriginal burning resulted in any measurable increase in SS. SS loads peaked in the 1870s and 1880s (the gold and gully period, 1850–1930) as valley floors were incised by gullies (mostly in northern tributaries), and gold sluicing flushed huge amounts of sludge into southern tributaries. Sedimentation in wetlands and on floodplains increased by 2–10 times in this period, and the biota in wetlands switched from clear water to turbid water communities. In the hiatus period (1930–1960) sediment supply from gullies and gold mining waned and low flow SS concentrations returned to low levels. Dam construction through the 1960s and 1970s (the regulation period, 1960 on) disconnected the River Murray from catchment derived sediment. Despite this, SS levels increased again: now largely derived from instream sources including bank erosion from long duration summer irrigation flows, the spread of bottom‐feeding carp (Cyprinus carpio), and wave erosion from boats. Erosion switched from winter to summer dominated. Significant investment in securing water for the environment in the Murray‐Darling Basin could be complemented by addressing in‐channel sediment sources in the River Murray itself to reduce turbidity. Overall, European era SS concentrations remain relatively low with small sediment delivery to the ocean (0.1 Mt per annum), despite high catchment erosion rates. This is due to poor sediment delivery efficiency through the low‐gradient landscape.     

A knowledge gap analysis on multi-scale predictive ability for agriculturally derived sediments under South African conditions.

Agriculture has been implicated as a major source of sediments in South Africa. The aim of the knowledge gap analysis was to understand the production and delivery components of agriculturally derived sediments under South African conditions and to assess the predictive ability to address the fate of these sediments from field to catchment scales. An overview is given of important erosion processes and erosion modelling applied in South Africa at the field and catchment scale. A limitation of the sediment models is that gully erosion is not simulated; therefore, the models should be complemented with gully erosion predictions if gullies are an important sediment source. Field-scale models inadequately predict sediment production localised at hydrologically sensitive areas as a result of saturation excess flow and/or throughflow. The discussion on erosion modelling reveals that more complex models have had limited application in South Africa because they require large and detailed data sets, and may have parameters that are difficult to measure or to estimate. A modelling framework is discussed which allows linking of sediment models requiring readily available data, gully erosion models/maps and the use of other techniques to assess the fate of agriculturally derived sediments from field to catchment scale.     

三峡水库和下游河道泥沙模拟与调控技术研究

三峡工程泥沙问题是贯穿三峡工程论证、设计、施工、运行中的关键技术问题之一,针对三峡水库蓄水运用以来出现的新情况、新问题和新需求,开展了三峡水库和下游河道泥沙模拟与调控技术研究,取得了如下主要成果:揭示了三峡水库泥沙絮凝规律、清水冲刷条件下推移质输沙及河床二次粗化机理、坝下游典型滩群演变与水库水沙过程调节的响应关系;提升了水库和坝下游河道泥沙数学模型技术,大幅提高了模拟精度;建立了三峡入库泥沙预测模式,提出了三峡入库新水沙系列;揭示了长江与洞庭湖、长江与鄱阳湖江湖分汇关系调整机理及变化趋势;研发了透水坝头和台阶式坝头两种新型航道整治结构技术;提出了三峡水库泥沙调控与多目标优化调度方案,优化了"蓄清排浑"运用方式,拓展了三峡工程综合效益,为三峡工程高效安全运行提供了技术支撑。     

黄河粗泥沙界限与中游多沙粗沙区区域研究

本文首先讨论了黄河粗泥沙界限的确定方法，认为以下游淤积物中占多数的观点来确定黄河粗泥沙粒径界限较好，经分析淤积物中0．025mm以上的泥沙占多数，0．05mm以上的泥沙近半数；然后讨论了中游多沙粗沙区区域界定的两种方法，认为指标法能够直观反映出多沙粗沙区的位置I最后甩0．OSmm和0．025mm两种界限分析了多沙粗沙区面积，分别为8．15万km^2和6．99万km^2．两者位置和面积比较接近，但在治理方略上有一定差异．前者强调治沟治基岩，后者强调沟坡兼治。