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1.
为探究极端降雨对南方红壤区流域水沙的影响,本文基于江西省鄱阳湖水系赣江上游濂江流域1984—2020年逐日降雨量、径流量和输沙量数据,使用95百分位法计算极端降雨,并采用最小事件间隔时间法分割降雨事件,综合应用Pettitt检验和线性回归方法对水沙突变、影响因子进行定量分析。结果表明:(1)发生极端降雨事件的时期是流域泥沙输出的关键时期,极端降雨对输沙量的贡献率达85.58%～87.79%,而对径流量的贡献为38.33%～43.42%。(2)在极端降雨情景下,年径流量从1984—1995年的209.21×106 m3下降到1996—2020年的165.23×106 m3,而年输沙量从1984—1995年的3.65×104 t增加到1996—2020年的12.8×104 t,相比于1984—1995年,1996—2020年的极端降雨所产生的径流量和输沙量占比有缩小趋势,分别表现为从43.42%到38.33%和从87.79%到85.58%。(3)极端降雨情景下... 相似文献
2.
黄土高原大理河流域水沙耦合模型应用研究 总被引：1，自引：1，他引：0
水沙模型是定量描述水沙关系及水沙规律的重要工具，现阶段国内外对于水沙模型的研究大都为基于某个典型流域的经验统计模型或基于流域大量基础资料的物理模型，极大限制了其使用范围及模拟精度.本文建立了结构与参数均具有物理意义的流域水沙耦合物理概念模型，其优点是物理概念清楚，模拟精度高，实用性强，易于深入研究泥沙基本规律.该模型将概念性水文模型和泥沙模型耦合，提出水流挟沙能力和土壤抗侵蚀能力概念，用对数曲线近似描述流域土壤抗侵蚀能力的空间变异性，在拜格诺河道水流悬移质泥沙公式基础上建立概念性沟蚀产沙公式，参照水流汇集相似性建立泥沙汇集演算公式.选取黄河中游大理河流域4个不同流域尺度的实际流域对模型进行应用检验，模拟结果表明，该模型的水流泥沙两部分均有很高的模拟精度，可以很好地模拟黄河中游地区不同流域尺度和年际尺度上的洪水过程和泥沙产生及输移过程，充分证明了该模型结构、参数和计算方法的合理性，可用于定量分析流域内各项水保措施的减水减沙效益及水沙关系变化趋势，对该模型的推广应用可做进一步分析研究. 相似文献
3.
鄱阳湖湖口、外洲、梅港三站水沙变化及趋势分析(1955-2001年) 总被引：5，自引：1，他引：5
对鄱阳湖流域三个主要控制站湖口、外洲和梅港多年(1955-2001年)水沙数据进行了统计分析,利用滑动平均法,Spearman秩次相关检验、线性回归检验方法对三个测站的水沙变化趋势进行了分析检验,结果表明,鄱阳湖泥沙出湖集中于长江大汛前的2-6月,在长江7-9月大汛期间,会出现长江泥沙倒灌鄱阳湖的情况．湖口站近期(1990-2001年)径流量和输沙量变幅都非常大,同上世纪80年代相比,年均径流量增加255．3×10~8 m~3．年均减少沙量0．29×10~8 t；外洲站近期的输沙量明显减少,沙量分别为70年代前、70年代、80年代的49．6%、48．7%和52．3%；梅港站径流量略微增加沙量无明显变化趋势．从入湖径流来看,赣江和信江占52．4%,入湖泥沙量占了76．0%以上．从赣江和信江水沙总体变化趋势来看,赣江径流量变化趋势不明显,而输沙量具有明显减少的趋势；信江径流量增加趋势明显,输沙量基本无明显趋势．鄱阳湖流域水沙变化主要受人类活动的影响．土地利用方式的改变和流域水利工程设施的修建极大地影响了流域水沙特征及其变化趋势． 相似文献
4.
流域因素与人类活动对黄河下游河道输沙功能的影响 总被引：6，自引：0，他引：6
从泥沙收支平衡的概念出发定义了河道的输沙功能, 提出了河道输沙功能的定量指标, 研究了流域自然因子和人类活动对黄河下游河道输沙功能的影响. 这种影响可以用不同水沙来源区的降水量、进入黄河下游的大于0.05 mm粗泥沙占来沙量百分比、黄河上游水库对汛期清水基流的调节程度(以兰州站汛期径流量占全年百分比表示)、高含沙水流频率、流域内水土保持措施实施面积等来定量表达. 运用多元回归分析方法, 建立了黄河下游河道输沙功能指标与上述7个因子之间的多元回归方程. 表明不同水沙来源区降水量的减少对下游河道输沙功能的影响是不同的. 河口镇以上清水区和龙门至三门峡之间年降水量减少, 将导致下游河道输沙功能指标降低; 河口镇至龙门间降水减少, 将导致下游河道输沙功能指标增高. 来沙的组成强烈地影响下游河道输沙功能指标, 进入黄河下游的大于0.05 mm粗泥沙占来沙量百分比越大, 则河道输沙功能指标越低. 因此, 小浪底水库拦截粗泥沙、排出细泥沙, 将有利于提高下游河道输沙功能指标. 兰州站汛期径流量占全年百分比越低, 下游河道输沙功能指标越低, 说明黄河上游水库大量拦截汛期清水基流, 是下游河道输沙功能降低的原因之一. 相似文献
5.
坡面植被恢复对沟道侵蚀产沙的影响 总被引：5，自引：0，他引：5
根据黄土高原不同地理空间林、草分布的宏观格局, 从主要产沙区的环境背景分析了黄河中游宏观坡、沟治理关系, 及自然、人类活动因子在侵蚀产沙中的权重. 根据目前黄土高原小流域的综合治理现状和水土保持坡、沟措施配置方案, 探讨了植被恢复对沟道侵蚀产沙的影响及植被减沙的效益. 黄河中游多沙粗沙区产沙模数与自然和人类活动的侵蚀环境背景的综合影响密切相关, 暴雨、垦殖率、林木覆盖率是影响多沙粗沙区产沙模数的主要因子. 退耕还林、草, 减少垦殖率、增加林草植被是抑制多沙粗沙区侵蚀的关键. 小流域治理必须坚持坡、沟兼治、生物与工程措施相结合的治理方针. 工程措施在坡面植被恢复初期具有重要作用, 杨家沟的典型案例表明植被恢复可以使沟道侵蚀产沙减少75%以上. 相似文献
6.
塔克拉玛干沙漠风沙运动若干特征观测研究 总被引：17，自引：0，他引：17
以塔克拉玛干沙漠公路沿线为研究区, 选取复合沙垄、新月形沙丘和平沙地三种典型风沙地貌为床面, 通过实地观测与分析, 研究了塔克拉玛干沙漠风沙流结构及其输沙强度等风沙运动特征. 横向沙丘链、纵向沙垄及平沙地上风沙流输沙量的对数与高度之间表现为线性关系, 即风沙流输沙量百分数随高度增加呈指数函数递减, 10 cm高度内输沙量占观测高度(40 cm)内总输沙量的80% ~ 95%, 20 cm高度内输沙量占总沙量98%以上. 不同地貌类型和地貌部位, 输沙率差异甚大. 并根据对风沙地貌成因、形态类型与分布特征的调查分析, 将复合横向沙丘链-冲积平原与高大复合纵向沙垄-垄间低地两种塔克拉玛干沙漠典型地貌组合的风沙流运动划分为若干状态特征带, 由工程设施所处地形与地貌部位, 可定性判断风沙危害类型与强度, 进而确定防治方案和措施. 相似文献
7.
采用水沙模型对流域水沙过程进行计算是目前分析和研究黄土地区水土流失、水沙锐减等问题的有效途径由于降雨的时段均化和缺测、漏测、误测等问题,导致水沙模型的重要输入项和动力因子——降雨资料存在误差,进而影响水流和泥沙过程模拟精度因此,本研究将降雨动态系统响应曲线的误差修正方法与概念性水沙模拟模型相结合以提高水沙过程模拟精度此方法将水沙模型的水流模拟部分看作响应系统,通过修正水沙模型的重要输入项——面平均雨量,利用修正之后的面平均雨量系列,通过模型重新计算以提高模型对产汇流和产汇沙过程的模拟精度通过理想案例验证该方法可行性后,选择黄土地区曹坪流域进行检验,结果表明修正后的水流和泥沙过程模拟精度均有显著提高,平均提高幅度分别为17.56%和15.86%. 相似文献
8.
近70年来荆江三口分流持续减少,为分析各历史阶段三口分流变化的驱动因素,根据1955—2021年干支流水文、地形实测资料开展研究,并基于控制变量法识别各驱动因素贡献比例。结果表明:三口分流阶段性减少,且集中在5—11月。长江上游降雨减少导致的干流来流偏枯以及下荆江裁弯、葛洲坝拦沙造成的干流河道冲刷和三口口门淤积对三口分流减少促进作用明显,调弦口堵口对三口分流影响不大,三峡水库蓄水后干流河道与三口口门同步冲刷,三口分流变化不大。长江上游汛期降雨减少明显,对5—11月三口分流减少影响较大,且三口分流主要发生于汛期干流中洪水位时,导致在下荆江裁弯期干流河床大幅下切条件下5—11月分流显著减少;葛洲坝调度、三峡水库初期调度和试验性蓄水调度也集中于5—11月,使得5—11月三口分流量分别减小0.4×108、12.5×108和38.6×108m3。调弦口堵口对三口分流的增大作用远小于降雨的减小作用,贡献比例为负值;下荆江裁弯对三口分流减少的贡献比例达85%;水库运用期降雨对三口分流减少的贡献最大,贡献比例大于50%,葛洲坝调度几乎不... 相似文献
9.
三峡水库举世瞩目,是长江保护与治理的关键性枢纽工程,水库自2003年蓄水运行后库区水沙条件均发生了显著改变,对库区水生态环境产生了深远影响。本文系统综述了三峡水库蓄水运行后库区的水流动力特性和泥沙淤积特性,总结了蓄水后水库的新水沙运动情况;从水库蓄水运行后水质参数特征,营养物质、重金属和典型有毒有机污染物的赋存特征等方面,分析了三峡水库库区新水沙变化条件下的水环境响应特征;基于水库蓄水前后浮游植物、底栖动物等重点生物群落的现存量和群落特征变化规律,探索了三峡水库新水沙变化条件下库区的水生态响应特征;最后对未来三峡水库运行下的水生态环境效应研究提出展望,本文可为三峡水库水生态环境保护科学研究和管理提供新的认识和决策参考。 相似文献
10.
为针对性地提出洪湖流域水资源适应与应对气候变化和人类活动影响的措施,保护洪湖流域生态资源,促进其可持续发展,采取分布式水文模型SWAT定量辨识了1990s流域城镇快速发展以来气候变化和人类活动对洪湖流域地表径流的影响程度.结果表明:近20年来,人类活动是洪湖流域地表径流减少的主要原因,其影响量占径流减少量的63.72%,气候变化的影响占36.28%.但不同阶段人类活动与气候变化对流域径流影响的程度不同,1990s气候变化对流域径流的影响量高于人类活动,2000s气候变化对流域径流的影响量低于人类活动,近20年来的水土保持措施已经发挥了较好的径流调节和保水效益. 相似文献
11.
《国际泥沙研究》2023,38(5):653-661
Studying the characteristics of runoff and sediment processes and revealing the sources of sediment provide key guidance for the scientific formulation of relevant soil erosion protection measures and water conservancy development plans. In the current study, the flow and sediment data of five hydrological stations on the main stream of the Fu River Basin (FRB) from 2007 to 2018 were selected to identify flood events, explore the variation of sediment transport along the FRB, and clarify the sediment sources. The results found that the Jiangyou–Fujiangqiao section is the main source of sediment in the FRB during the flood season. The runoff volume and sediment load during flood events in the Jiangyou–Fujiangqiao section accounted for 35% and 145% respectively of that of Xiaoheba station. These results combined with the change of the sediment load before and after the 2008 Wenchuan Earthquake (May 12) show that the sediment in this section mainly comes from the Fu River tributary–the Tongkou River watershed. The calculation results for the sediment carrying capacity of the Fu River show that the main stream was in a state of erosion in theory. However, according to the calculation results for the interval sediment yield during flood events, the sediment load at the Xiaoheba station was smaller than that at the Shehong station upstream. The analysis indicates that this was not because of sediment deposition in the river channel, but because of sand mining in the river channel and sediment interception by water conservancy projects. If heavy rainfall occurs in the FRB, the sediment accumulated upstream will move downstream with the resulting flood, and the sediment yield in the FRB may further increase. These research conclusions can provide reference information for improving the prediction and management ability of soil and water loss in the FRB and scientific regulation of the Three Gorges Reservoir. 相似文献
12.
In-depth studies of water and sediment fluxes from rivers into the sea are very important for understanding the interactions between land and sea. This paper is concerned with identifying the changes in the time series of water and sediment fluxes from Feiyun River in Zhejiang Province, China. Inter- and intraannual variability in the water discharge and sediment load of the Feiyun River into the sea are analyzed using the observed data of runoff (1956–2008) and sediment (1957–2008) at Xuekou Station, which is in the main channel. The results show that there is a good peak–valley correlation between the water discharge and sediment load, and there are obvious seasonal variations, with a 65.7% water discharge and 89.2% sediment load during the flooding periods. Water discharge is mainly controlled by natural rainfall, but the construction of the upstream reservoirs in 1997 increased the discharge amount in the dry season and decreased the amount in the flooding season. Sediment loads were reduced after a huge flood in 1990 and construction of upstream reservoirs, while the latter also decreased the sediment load during the typhoon flooding period. Furthermore, the correlation between water discharge and sediment load is also affected by the flood and reservoir construction. There are some differences in the regression equations of sediment load and water discharge for 1957–1989, 1991–1996, and 1997–2008. 相似文献
13.
Spatiotemporal variations of suspended sediment transport in the upstream and midstream of the Yarlung Tsangpo River (the upper Brahmaputra), China 总被引：4，自引：0，他引：4 
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下载免费PDF全文 Xiaonan Shi Fan Zhang Xixi Lu Zhaoyin Wang Tongliang Gong Guanxing Wang Hongbo Zhang 《地球表面变化过程与地形》2018,43(2):432-443
The Yarlung Tsangpo River, which flows from west to east across the southern part of the Tibetan Plateau, is the longest river on the plateau and an important center for human habitation in Tibet. Suspended sediment in the river can be used as an important proxy for evaluating regional soil erosion and ecological and environmental conditions. However, sediment transport in the river is rarely reported due to data scarcity. Results from this study based on a daily dataset of 3 years from four main stream gauging stations confirmed the existence of great spatiotemporal variability in suspended sediment transport in the Yarlung Tsangpo River, under interactions of monsoon climate and topographical variability. Temporally, sediment transport or deposition mainly occurred during the summer months from July to September, accounting for 79% to 93% of annual gross sediment load. This coincided with the rainy season from June to August that accounted for 51% to 80% of annual gross precipitation and the flood period from July to September that accounted for approximately 60% of annual gross discharge. The highest specific sediment yield of 177.6 t/km2/yr occurred in the upper midstream with the highest erosion intensity. The lower midstream was dominated by deposition, trapping approximately 40% of total sediment input from its upstream area. Sediment load transported to the midstream terminus was 10.43 Mt/yr with a basin average specific sediment yield of 54 t/km2/yr. Comparison with other plateau‐originated rivers like the upper Yellow River, the upper Yangtze River, the upper Indus River, and the Mekong River indicated that sediment contribution from the studied area was very low. The results provided fundamental information for future studies on soil and water conservation and for the river basin management. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
14.
《水文科学杂志》2013,58(4):777-792
Abstract Based on data from five hydrometric stations, Pingshan station on the Jinshajiang River, Gaochang station on the Minjiang River, Wulong station on the Wujiang River, Wusheng station on the Jialingjiang River and Yichang station on the Yangtze River, a study has been made of the temporal variation in grain size of suspended sediment load in the upper Yangtze River. The results show that in the past 40 years, the grain size of the suspended sediment load in the main stem and major tributaries of the upper Yangtze River has had a decreasing trend, that can be explained by the effect of reservoir construction and implementation of soil conservation measures. The reservoirs in the upper Yangtze River Basin, all used for water storage for hydro-electric generation and/or irrigation, have trapped coarse sediment from the drainage area above the dam and, thus, the sediment released now is much finer than before the construction of the reservoirs. The downstream channels are all gravel-bedded or even in bedrock, with little fine sediment, and thus, the released flow can hardly get a supply of fine sediment through eroding the bed. Then, after the downstream adjustment, the grain size of suspended sediment is still fine. Large-scale soil conservation measures have significantly reduced sediment yield in some major sediment source areas. The relatively coarse sediment is trapped and, thus, the sediment delivered to the river becomes finer. 相似文献
15.
《国际泥沙研究》2020,35(4):365-376
The Yom River is one of the four major sediment sources to the Chao Phraya River in Thailand. Human activities and changes in climate over the past six decades may have affected the discharge and sediment load to some extent. In the current study, the river discharge and sediment characteristics in the mainstream of the Yom River were investigated using the field observation data from 2011 to 2013 and the historical river flow and sediment data from 1954 to 2014 at six hydrological stations operated by the Royal Irrigation Department of Thailand (RID). The non-parametric Mann-Kendall test and double mass curve were used to analyze the sediment dynamics and temporal changes in the discharge of the Yom River. The results revealed that the sediment was mainly transported in suspension, and the bed-to-suspended sediment loads ratio varied between 0 and 0.05. The daily suspended sediment load (SSL) in the upper and middle basins had a strong correlation with the daily discharge and could be represented by power equations with coefficients of determination higher than 0.8. The daily suspended sediment load in the lower basin did not directly depend on the corresponding discharge because of the reduction in river slope and water diversion by irrigation projects. It also appeared that the river discharges and sediment loads were mainly influenced by climate variation (floods and droughts). Moreover, the average sediment transport of the upper, middle, and lower reaches were 0.57, 0.71, and 0.35 million t/y, respectively. The sediment load in the lower basin decreased more than 50% as a result of changes in the river gradient (from mountainous to floodplain areas). The results from sediment analysis also indicated that the construction of the Mae Yom Barrage, the longest diversion dam in Thailand, and land-use changes did not significantly affect the sediment load along the Yom River. 相似文献
16.
Sedimentation of overbank floods in the confined complex channel–floodplain system of the Lower Yellow River,China 下载免费PDF全文
下载免费PDF全文 The channel boundary conditions along the Lower Yellow River (LYR) have been altered significantly since the 1950s with the continual reinforcement and construction of both main and secondary dykes and river training works. To evaluate how the confined complex channel–floodplain system of the LYR responds to floods, this study presents a detailed investigation of the relationship between the tempo‐spatial distribution of sedimentation/erosion and overbank floods occurred in the LYR. For large overbank floods, we found that when the sediment transport coefficient (ratio of sediment concentration of flow to flow discharge) is less than 0.034, the bankfull channel is subject to significant erosion, whereas the main and secondary floodplains both accumulate sediment. The amount of sediment deposited on the main and secondary floodplains is closely related to the ratio of peak discharge to bankfull discharge, volume of water flowing over the floodplains, and sediment concentration of overbank flow, whereas the degree of erosion in the bankfull channel is related to the amount of sediment deposited on the main and secondary floodplains, water volume, and sediment load in flood season. The significant increase in erosion in the bankfull channel is due to the construction of the main and secondary dykes and river training works, which are largely in a wide and narrow alternated pattern along the LYR such that the water flowing over wider floodplains returns to the channel downstream after it drops sediment. For small overbank floods, the bankfull channel is subject to erosion when the sediment transport coefficient is less than 0.028, whereas the amount of sediment deposited on the secondary floodplain is associated closely with the sediment concentration of flow. Over the entire length of the LYR, the situation of erosion in the bankfull channel and sediment deposition on the main and secondary floodplains occurred mainly in the upper reach of the LYR, in which a channel wandering in planform has been well developed. 相似文献
17.
Sediment storage in the reach of the middle Yellow River located in the Fenwei Graben,China 总被引：1，自引：0，他引：1
Jiongxin Xu 《水文研究》2013,27(18):2623-2636
Fenwei Graben is a famous sediment sink. The Longmen‐Sanmexia sediment sink of middle Yellow River is located in the middle part. Using the sediment budget based on annual data from the period 1920–2006 and flood‐event data from 154 flood events from the period 1950–1985, the variations in sediment storage, release and transport have been analysed. Data from different methods and sources indicate that, during an 1800‐year period, the variation of sedimentation rate in this sink has undergone a cycle from increase to decline; the cause for this can be found in the changes in the manner and intensity of human activities. Over 87 years, sediment storage in this sink can be separated into four stages which showed different trends, depending on changing human activities, such as reservoir construction, soil and water conservation and water diversion. Stepwise multiple regression shows that the runoff and sediment yield from three major source areas have differing influences on sediment storage in the sink. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
18.
Multi‐temporal scale changes of streamflow and sediment load in a loess hilly watershed of China 下载免费PDF全文
下载免费PDF全文 Global climate change and diverse human activities have resulted in distinct temporal–spatial variability of watershed hydrological regimes, especially in water‐limited areas. This study presented a comprehensive investigation of streamflow and sediment load changes on multi‐temporal scales (annual, flood season, monthly and daily scales) during 1952–2011 in the Yanhe watershed, Loess Plateau. The results indicated that the decreasing trend of precipitation and increasing trend of potential evapotranspiration and aridity index were not significant. Significant decreasing trends (p < 0.01) were detected for both the annual and flood season streamflow, sediment load, sediment concentration and sediment coefficient. The runoff coefficient exhibited a significantly negative trend (p < 0.01) on the flood season scale, whereas the decreasing trend on the annual scale was not significant. The streamflow and sediment load during July–August contributed 46.7% and 86.2% to the annual total, respectively. The maximum daily streamflow and sediment load had the median occurrence date of July 31, and they accounted for 9.7% and 29.2% of the annual total, respectively. All of these monthly and daily hydrological characteristics exhibited remarkable decreasing trends (p < 0.01). However, the contribution of the maximum daily streamflow to the annual total progressively decreased (?0.07% year?1), while that of maximum daily sediment load increased over the last 60 years (0.08% year?1). The transfer of sloping cropland for afforestation and construction of check‐dams represented the dominant causes of streamflow and sediment load reductions, which also made the sediment grain finer. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
19.
Sediment yield of the lower Tana River,Kenya, is insensitive to dam construction: sediment mobilization processes in a semi‐arid tropical river system 下载免费PDF全文
下载免费PDF全文 Naomi Geeraert Fred Ochieng Omengo Fredrick Tamooh Paolo Paron Steven Bouillon Gerard Govers 《地球表面变化过程与地形》2015,40(13):1827-1838
Dam construction in the 1960s to 1980s significantly modified sediment supply from the Kenyan uplands to the lower Tana River. To assess the effect on suspended sediment fluxes of the Tana River, we monitored the sediment load at high temporal resolution for 1 year and complemented our data with historical information. The relationship between sediment concentration and water discharge was complex: at the onset of the wet season, discharge peaks resulted in high sediment concentrations and counterclockwise hysteresis, while towards the end of the wet season, a sediment exhaustion effect led to low concentrations despite the high discharge. The total sediment flux at Garissa (c. 250 km downstream of the lowermost dam) between June 2012 and June 2013 was 8.8 Mt yr‐1. Comparison of current with historical fluxes indicated that dam construction had not greatly affected the annual sediment flux. We suggest that autogenic processes, namely river bed dynamics and bank erosion, mobilized large quantities of sediments stored in the alluvial plain downstream of the dams. Observations supporting the importance of autogenic processes included the absence of measurable activities of the fall‐out radionuclides 7Be and 137Cs in the suspended sediment, the rapid lateral migration of the river course, and the seasonal changes in river cross‐section. Given the large stock of sediment in the alluvial valley of the Tana River, it may take centuries before the effect of damming shows up as a quantitative reduction in the sediment flux at Garissa. Many models relate the sediment load of rivers to catchment characteristics, thereby implicitly assuming that alterations in the catchment induce changes in the sediment load. Our research confirms that the response of an alluvial river to external disturbances such as land use or climate change is often indirect or non‐existent as autogenic processes overwhelm the changes in the input signal. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
20.
Observation of the operation of the Sanmenxia Reservoir on the Yellow River has led to the conclusion that to preserve a certain effective storage volume for reservoirs built on heavily silt-laden rivers is feasible if the reservoir is operated according to the principle known as "storing the clear water and discharging the muddy flow". The relative stability of the bed elevation at the end of the backwater and the reservoir's erosion and deposition equilibrium depend on the compatibility of the pool level maintained in non-flood seasons with the conditions of flow and sediment load during flood seasons. Operating the reservoir to regulate the flood and sediment load during flood seasons can reduce the rate of aggradation in the Lower Yellow River. The basic condition for applying the operation mode of "storing the clear water and discharging the muddy flow" is that a sufficient amount of water should be used for discharging sediment during flood seasons. Under the condition of extremely low flow years, reservoir sedimentation cannot be avoided even if this operation mode is adopted. 相似文献