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泥沙问题是三峡工程建设与运行中的关键技术问题之一,只有妥善处理好泥沙问题,才能保证三峡工程长期有效使用,维持水库功能的全面发挥。本文首先结合实测水文、河道地形观测资料,对三峡水库运行近20年来的泥沙淤积特性及水库排沙比进行了较为全面的分析研究,并与已有研究成果进行了对比;其次,围绕防洪、航运以及坝前段的泥沙淤积等方面,进一步分析了水库淤积产生的影响。结果表明:三峡水库蓄水以来,在不考虑区间来沙的情况下,三峡水库共淤积泥沙20.484亿t,近似年均淤积1.102亿t,水库排沙比为23.6%,水库年均淤积量为原论证预测值的33%。其中,库区干流段累计淤积泥沙17.835亿m3(变动回水区冲刷0.694亿m3;常年回水区淤积18.529亿m3),淤积在水库防洪库容内的泥沙为1.648亿m3(干、支流分别淤积1.517亿m3和0.131亿m3),占水库防洪库容的0.74%,“十一五”攻关阶段研究得出的多年平均淤积量及排沙比较实测值均偏大,变动回水区冲淤则出现反向的... 相似文献
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金沙江下游4个梯级水电站总装机容量相当于两座三峡水库,是“西电东送”中部地区的源头工程,工程效益发挥对经济社会发展意义重大。2012年以来,向家坝、溪洛渡、乌东德和白鹤滩电站等陆续蓄水运行,层层拦截金沙江的泥沙,2013—2020年向家坝出库年输沙量均值下降至152万t,减幅超过99%。大量泥沙淤积在梯级水库内,同时向家坝以下河道发生长距离冲刷。本文以自金沙江下游工程筹建以来的观测资料为基础,针对梯级水库的泥沙淤积和坝下游河道冲刷规律开展研究,结果表明:金沙江下游四个梯级电站自建成运行至2020年底,累计淤积泥沙约5.98亿m3,其中溪洛渡库区淤积量占比达92.5%,2013-2020年溪洛渡和向家坝水库排沙比分别为2.64%和22.2%,其水库泥沙主要淤积在常年回水区的干流河道内,以死库容内淤积为主,侵占有效库容的比例小于1.3%。金沙江下游库区干流河道的峡谷特征明显,淤积多表现为主河槽的平铺式淤高。溪洛渡和向家坝库区淤积的泥沙沿程分选特征明显,越靠近坝前,中数粒径减小、细颗粒泥沙沙量百分数增加,极细颗粒泥沙会在库区一定范围内大量沉积。向家坝下游河床普遍冲刷,但... 相似文献
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广东省水库富营养化评价 总被引：13，自引：2，他引：11
广东省水库水环境质量调查评价结果表明：广东省水库水质总体较好,但不同程度地发生了富营养化;在汛期,被 评价的132座水库中中营养型水库111座,中富营养型水库12座,富营养化水库2座;非汛期,中营养型水库111座,中富 营养型水库11座,富营养化水库1座．造成水库富营养化的主要原因是面污染的日益加剧、城市污水排放量的激增、水土 流失造成水库泥沙淤积严重、水库蓄水量减少等．水库的富营养化影响了其使用功能．为恢复富营养水库的使用功能,其 对策主要是减少面污染物排放量、提高污水处理率、加强水土流失的治理、清除淤泥等． 相似文献
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泥沙淤积问题直接影响着三峡水库的使用寿命及综合效益的发挥,研究其入库水沙特性对于解决水库泥沙淤积问题具有重要意义。根据水文站实测数据,分析了三峡水库入库水沙输移特性及来源组成变化,重点研究了金沙江下游梯级水库运行后的三峡水库高洪水期入库水沙特性。结果表明:2003—2021年,三峡水库入库泥沙集中于汛期的高洪水期,2013年以后该现象更为显著,泥沙来源也由金沙江为主转变为嘉陵江为主。寸滩站洪峰流量高于50000 m3/s的高洪水期三峡入库沙量显著大于30000～50000 m3/s区间的高洪水期,三峡水库泥沙调度关键在于上游发生编号洪水期间。三峡水库上游沱江或嘉陵江等支流发生流域性大洪水时,易引起高洪水期入库水沙出现“小水大沙”的特点。金沙江下游梯级水库运行后,三峡水库高洪水期入库泥沙大幅减少,中小洪水调度期间泥沙淤积量也大幅减小。研究结果可为三峡水库的泥沙精细化调度和长期高效使用提供基础数据支撑。 相似文献
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近30年来鄱阳湖湖盆地形演变特征与原因探析 总被引：1，自引：1，他引：0
利用鄱阳湖1980、1998和2010年3期湖盆水下地形数据,结合出、入湖泥沙输移数据以及流域水土流失、水库建设等资料,较为系统地研究鄱阳湖近30年来湖盆冲淤的时空变化特征及其影响因素.研究表明,1980-1998年,松门山以南主湖体位置淤积现象明显,平均淤高0.82 m,该淤积主要是由这一阶段内流域水土流失加剧所引起的;1998-2010年,在大规模植树造林和水库建设等人类活动影响下,鄱阳湖淤积现象减缓.但是在入江水道上湖盆高程显著下降,平均下降速率高达30.75 cm/a,这与入江水道处持续采砂和水流冲刷等因素有关;近30年来,"五河"入湖的洲滩区域冲淤变化及趋势有所差异,修水、抚河及赣江三角洲呈现逐渐降低的趋势,饶河入湖漫滩总体上以淤积为主,且地形坡度趋于变缓.研究结果对鄱阳湖水资源合理开发、水利工程建设及航运管理等均具有一定的实践和参考价值. 相似文献
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为了研究洪泽湖水沙特性、变化趋势与冲淤时空分布规律,运用累积距平法、Mann-Kendall趋势与突变检验以及R/S分析法等方法,分析了洪泽湖19502016年的水沙特征;采用地理信息技术,基于1992年和2016年实测地形,对湖区泥沙冲淤空间分布进行了定量计算与分析.结果表明,入湖径流量无明显增加或减少的趋势,输沙量和含沙量呈明显减小趋势,1990年以后含沙量基本稳定在0.2 kg/m^3以下;淮河干流(包括池河)入湖水量和沙量约占入湖总量的89.6%,三河闸出湖水沙占总出湖量的60%.淮干入湖口和溧河洼为主要淤积区域,淤积量分别为2300×10^4和1900×10^4 m^3,平均淤积厚度分别为0.35和0.25 m;其他区域自然冲淤基本平衡.上游水库和河道闸坝的拦沙作用、农业种植结构变化和水土保持、大规模人工采砂等是入湖沙量减少的主要影响因素;湖区水动力特性是泥沙自然淤积主导因素,而湖区库容变化的主因则是人工采砂、围湖造田和围网养殖,且人类活动的影响远大于自然冲淤. 相似文献
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长江中游的泥沙淤积问题 总被引：8，自引：0，他引：8
长江上游年产泥沙5.12×108 t, 经宜昌输入中游, 长江中游干流及各支流年产沙约 0.80×108 t. 这两部分中约1.24×108 t沉积于中游河湖中, 4.68×108 t经大通输入下游, 沉淤于河道及长江三角洲或入海. 长江中游的泥沙, 总体是淤大于冲, 但是冲淤的地理分布、时间段分布和河床断面分布不均衡. 长江干流的宜昌-城陵矶段、九江-大通段冲大于淤或冲淤平衡. 淤积主要发生在长江干流以武汉为中心的螺山-武汉-黄石段以及洞庭湖区和鄱阳湖区. 即使在主要淤积江段, 也有局部时段和江段以冲刷为主. 主泓所在的河槽以冲刷为主, 而河道两侧或河道之间的洲滩, 则以淤为主, 形成高而平的漫滩, 往往被人为改造成圩垸. 荆江以北的江汉平原因有大堤从长江隔开, 只有汉水少量泥沙供应, 冲淤量很小, 再加上构造沉降的累计效应, 其地面高程绝大部分低于干流洲滩数米. 螺山-武汉-黄石段的淤积导致该段及以上江段洪水位抬高. 干流断面冲槽淤滩使长江中游河道的典型形态呈深河谷、高漫滩, 靠干堤保护堤内平原. 这种断面在洪水时成为在同等水量下, 水位不断抬高的原因. 高水位要高堤防来防堵, 这就增加了堤防压力、水头压力, 容易导致管涌、渗漏等险情. 堤外滩及洪水位与构造沉降的堤内平原间的高差不断增大. 三峡工程建成后, 水库拦沙及中游河道冲深, 可使同流量下水位大幅度降低, 但城陵矶-武汉段冲刷量很小, 不能解决该段及以下江段的泥沙淤积问题, 因此江汉平原因相对于洪水位地势过低而造成的洪涝灾害及相关环境问题, 仍将是中游长远的重大隐患. 相似文献
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Strategies for managing reservoir sedimentation 总被引：2，自引：1，他引：1
Zhao-yin WANG Chunhong HU Prof. State Key Lab of Hydroscience Engineering Tsinghua University Beijing China. Prof. Secretary General of International Research Training Center on Erosion Sedimentation Beijing China Vice President of China Institute of Water Resources Hydropower Research No. A- Fuxing Rd Beijing China. 《国际泥沙研究》2009,24(4):369-384
Sediment deposition in reservoirs has caused the loss of 66% of the reservoir capacity in China. The main sedimentation control strategies are： 1） storing the clear water and releasing the turbid water; 2） releasing turbidity currents; 3） Draw-down flushing and empty flushing; and 4） dredging, The paper summarizes these strategies with examples. Sediment transport in many Chinese rivers occurs mostly during the 2-4 month flood season, that is, 80-90% of the annual sediment load is transported with 50-60% of the annual runoff. By storing the clear water after the flood season and releasing the turbid water during the flood season, less sediment deposits in the reservoir while the reservoir is still able to store enough water for power generation in the low flow season. The Three Gorges and Sanmenxia reservoirs apply this strategy and control sedimentation effectively. Turbidity currents have become the main sedimentation control strategy for the Xiaolangdi Reservoir. Empty flushing involves reservoir draw-down to temporarily establish riverine flow along the impound reach, flushing the eroded sediment through the outlets. Case studies with the Hengshan Reservoir and Zhuwo Reservoir are presented. Jet dredgers have been used to agitate the reservoir deposit so that the deposit is released from the reservoir with currents. The sediment releasing efficiency is 30-100% for storing the clear and releasing the turbid; 6-40 % for turbidity current; and 2,400-5,500% for empty flushing. Empty flushing causes high ecological stress on the ecosystem to the downstream reaches. Storing the clear and releasing the turbid is the best strategy to control reservoir sedimentation while achieving hydro-power benefit and maintain ecological stability. 相似文献
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M. Ali Kokpinar A. Burcu Altan-Sakarya S. Yurdagul Kumcu Mustafa Gogus 《水文科学杂志》2013,58(12):2189-2203
AbstractAnalyses of data from reservoir surveys and sediment rating curves are compared to predict sediment yield in three large reservoir watershed areas in Turkey. Sediment yield data were derived from reservoir sedimentation rates and suspended sediment measurements at gauging stations. The survey data were analysed to provide the volume estimates of sediment, the time-averaged sediment deposition rates, the long-term average annual loss rates in the reservoir storage capacity, and the long-term sediment yield of the corresponding watershed areas. Four regression methods, including linear and nonlinear cases, were applied to rating curves obtained from gauging stations. Application of the efficiency test to a power function form of a rating curve with nonlinear regression yielded the highest efficiency values. Based on the analysis of the sediment rating curves, sediment load fluxes were calculated by using average daily discharge data at each gauging station. Comparison of these two sediment yield values for each reservoir showed that the sediment yields from the suspended sediment measurements, SYGS, are 0.99 to 3.54 times less than those obtained from the reservoir surveys, SYRS. The results from the reservoir surveys indicate that all three reservoirs investigated have lost significant storage capacity due to high sedimentation rates. 相似文献
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Xiaoya Tang Sichen Tong Guoxian Huang Guangxiang Xu Xinghua Li Kun Lei Shiming Yao 《国际泥沙研究》2021,36(2):177-189
Construction of large dams is attractive because of their great benefits in flood control,hydropower generation,water resources utilization,navigation improvement,etc.However,dam construction may bring some negative impacts on sediment transport and channel dynamics adjustments.Due to the effects of recent water and soil conservation projects,sediment retention in the newly constructed large upstream reservoirs,and other factors,the sedimentation in the Three Gorges Reservoir(TGR)is quite different from the amount previously predicted in the demonstration stage.Consequently,based on the measured data,characteristics of sedimentation and the related channel deformation in the TGR were analyzed.The results imply that sediment transport tended to be reduced after the Three Gorges Project(TGP).Sedimentation slowed dramatically after 2013 and indicated obvious seasonal characteristics.Due to the rising water level in the TGR in the flood season,the yearly sediment export ratio(Eratio)was prone to decrease.The water level near the dam site should be reasonably regulated according to the flow discharge to improve the sediment delivery capacity and reduce sedimentation in the TGR,and to try to avoid situations where the flood retention time is close to 444 h.The depositional belt was discontinuous in the TGR and was mainly distributed in the broad reaches,and only slight erosion or deposition occurred in the gorge reaches.Sedimentation in the broad and gorge reaches accounted for 93.8% and 6.2% of the total sedimentation,respectively.The estuarine reach located in the fluctuating backwater area experienced alternate erosion-deposition,with a slight accumulative deposition in the curved reach.Sedimentation mainly occurred in the perennial backwater area.The insight gained in this study can be conducive to directly understanding of large reservoir sedimentation and mechanism of channel adjustment in the reservoir region in the main channel of large river. 相似文献
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The potential for using fallout (unsupported) Pb-210 (210Pb) measurements to estimate rates of overbank sediment deposition on the floodplains of lowland rivers is explored. A model which distinguishes the contribution from direct atmospheric fallout and the catchment-derived input associated with the deposition of suspended sediment has been developed to interpret the fallout Pb-210 inventories at floodplain sampling sites and to estimate average sediment accumulation rates over the past 100 years. The approach has been successfully used to estimate rates of overbank sedimentation on the floodplains of the Rivers Culm and Exe in Devon, U.K. A detailed investigation of the pattern of longer-term sedimentation rates within a small reach of the floodplain of the River Culm indicated a range of deposition rates between 0.07 and 0.59 g cm−2 a−1, which was in close agreement with estimates of current sedimentation rates obtained using sedimentation traps. 相似文献
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TaWei SOONG 《国际泥沙研究》1999,(2)
IINTRODUCTIONLanddevelopmentandlandusepatternsinthewatershedcaninduceincreasedsedimentloadsinriversandstreams.AGREATIllstudy(1982)illustratedthatsedimentyieldsfromagriculturallandcouldbeseveralfoldsmorethanothertypeoflandusesanderosionsources.ThesamestudyalsodemonstratedthatfinesedimentsweretheheaviestportionoftotalsoillossesfromeachtypeoflandusesinthetwelvehydrologicareasitinvestigatedintheUMRS.Thesamecouldbetrueforotheruplandareasalso.Howeverfinesediments,formthewashloadofthestream… 相似文献
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Temporal variations of reservoir sediment sources in a small mountainous catchment in Korea 总被引：1，自引：0，他引：1
An understanding of the temporal variation in reservoir sedimentation and identification of the main sources of sediment are necessary for the maintenance of sustainable reservoirs. For this purpose, field measurements, sampling, and fingerprinting of reservoir sediment were undertaken from July 2005 to November 2007. Source fingerprinting of reservoir sediment was conducted using cesium‐137 (137Cs). The relative contributions of gully bank and forest road, and forest floor material to reservoir sediment were calculated using a mixing model. Bank and forest road material, estimated to make up about 96% of the reservoir sediment, was the dominant source. Enormous reservoir sedimentation, which amounted to about 60% of the total reservoir sedimentation during the observation period, occurred during a heavy rainstorm with an 80‐year recurrence time. To maintain the sustainability of the reservoir in this study, therefore, temporal and spatial preparation strategies for heavy rainstorms and bank and forest road erosion should be considered. However, spatial information on sediment sources from 137Cs fingerprinting is limited. To better identify the sediment sources spatially and temporally, further studies applying soil erosion models and more detailed field studies are needed. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Large dam construction for irrigation, hydropower, water supply, and flood control in tropical to sub-tropical areas increased markedly after 1950. Many of the dams built during this period have filled with sediment and no longer perform to their original design specifications; in many cases, forecast dam life was greatly overestimated. This study investigates the useful life of Burdekin Falls Dam (BFD), northeastern Australia and compares the findings with other tropical reservoirs. Using two independent methods it is estimated that between 61 and 65 million m3 of sediment has been deposited in the reservoir over the 24 years of operation through 2011. This sediment volume equates to an average of 0.15% of capacity lost per year since construction was completed. If current sediment loads/climate regimes persist, reservoir capacity will be reduced by 50% after 345 years. However, the useful life of the BFD reduces to just 276 years when drawdown data are considered; these data show reservoir use would be affected once 40% of storage was filled with sediment, with a 60% drawdown return period of 1 in 15 years. When compared to similar large tropical to sub-tropical reservoirs, the BFD has a slightly longer reservoir useful life than dams in India and a much longer half-life than for both similar-sized and larger dams in China, Brazil, and Iran. Properties of the BFD that promote a longer useful life include a lower trap efficiency, relatively low annual sediment load delivered to the reservoir, limited sediment deposition behind the dam wall (and uniform distribution of deposited sediment), and the export of highly turbid annual floodwaters before settling and deposition of any remaining sediment within the reservoir. 相似文献