Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015

Based on the measured discharge,sediment load,and cross-sectional data from 1986 to 2015 for the lower Yellow River,changes in the morphological parameters(width,depth,and cross-sectional geomorphic coefficient)of the main channel are analyzed in this paper.The results show that before the operation of the Xiaolangdi Reservoir(XLDR)from 1986 to 1999,the main channel shrunk continually,with decreasing width and depth.The rate of reduction in its width decreased along the river whereas that of depth increased in the downstream direction.Because the rate of decrease in the width of the main channel was greater than that in channel depth,the cross-sectional geomorphic coefficient decreased in the sub-reach above Gaocun.By contrast,for the sub-reach below Gaocun,the rate of decrease in channel width was smaller than that in channel depth,and the cross-sectional geomorphic coefficient increased.Once the XLDR had begun operation,the main channel eroded continually,and both its width and depth increased from 2000 to 2015.The rate of increase in channel width decreased in the longitudinal direction,and the depth of the main channel in all sub-reaches increased by more than 2 m.Because the rate of increase in the depth of the main channel was clearly larger than that of its width,the cross-sectional geomorphic coefficient decreased in all sub-reaches.The cross-sectional geometry of the main-channel of the lower Yellow River exhibited different adjustment patterns before and after the XLDR began operation.Before its operation,the main channel mainly narrowed in the transverse direction and silted in the vertical direction in the sub-reach above Aishan;in the sub-reach below Aishan,it primarily silted in the vertical direction.After the XLDR began operation,the main channel adjusted by widening in the transverse direction and deepening in the vertical direction in the sub-reach above Aishan;in the sub-reach below it,the main channel adjusted mainly by deepening in the vertical direction.Compared with the rates of decrease in the width and depth of the main channel during the siltation period,the rate of increase in channel width during the scouring period was clearly smaller while the rate of increase in channel depth was larger.After continual siltation and scouring from 1986 to 2015,the cross-sectional geometry of the main-channel changed from wide and shallow to relatively narrow and deep.The pattern of adjustment in the main channel was closely related to the water and sediment conditions.For the braided reach,the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with suspended sediment concentration(SSC)during the siltation period.By contrast,the cross-sectional geomorphic coefficient was positively correlated with discharge and negatively correlated with SSC during the scouring period.For the transitional and meandering reaches,the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with SSC.

Simulating cross-sectional geometry of the main channel in response to changes in water and sediment in Lower Yellow River

To understand the non-equilibrium morphological adjustment of a river in response to environmental changes,it is essential to(i)accurately identify how past conditions of water and sediment have impacted current morphological adjustment of the river,and(ii)establish a corresponding simulation for non-equilibrium conditions.Based on discharge and suspended sediment concentration(SSC)as well as 82 cross-sectional data items for the Huayuankou-Lijin reach of the Lower Yellow River in the period 1965-2015,the process of adjustment of the geometry of the main channel(area,width,depth,and geomorphic coefficient),and its responses to changes in discharge and SSC for different reaches are statistically analyzed.Following this,a delayed response model(DRM)of the geometry of the main channel subjected to variations in discharge and SSC is established using a multi-step analytical model,with the discharge and SSC as the main controlling factors.The results show that the area,width,and depth of the main channel decreased initially,then increased,decreased again,and finally increased again.These features of the geometry of the channel were positively correlated with the 4-year moving average discharge and negatively with the 4-year moving average SSC.The geomorphic coefficient for the Huayuankou-Sunkou reach exhibited a trend of decrease,whereas that of the Sunkou-Lijin reach decreased initially,then increased,decreased again,and finally increased again.Except for the Huayuankou-Gaocun reach in 1965-1999,the coefficient was negatively correlated with the 4-year moving average discharge and positively with SSC.The simulated values of the morphological parameters of the main channel for all sub-reaches obtained using the DRM agreed well with the measured values.This indicates that the DRM can be used to simulate the process of response of the cross-sectional geometry of the main channel to variations in the water and sediment.The results of the model show that the adjustment of the geometry of the main channel was affected by the discharge and the SSC at present(30%)as well as for the previous 7 years(70%).The proposed model offers insights into the mechanism whereby past water and sediment influence the current morphological adjustment of the river,and provides an effective method for predicting the magnitude and trend of the geometry of the main channel under different flow conditions.

黄河下游流域的文化界说——兼论华北平原在黄河文化中的历史地位

黄河下游流域与文化的界定,是黄河文化研究中的一个重大问题。论者将黄淮海平原的广阔区域都作为黄河下游流域的传统看法是不恰当的。淮河作为一条大河,自有其独立的流域范围,“夺淮入海”时期,黄河夺占淮河支流和主河道,主要系人为因素改道和维持所致,且多为河道游移、水系混乱的“地上河”,并未形成自己的“集水区”;在文化上,淮河文化是长江文化的亚文化,在春秋战国时期是长江楚文化的重要组成部分。故无论从流域还是文化上看,淮河流域都不能作为黄河下游流域看待。泰沂山西延伏脉以北的华北平原,是黄河天然形成的入海之地;在秦汉以前,是中华文明起源、三代文明奠基的重要区域之一,是春秋战国时代的文化重心,是实现秦汉“大一统”的经学繁荣基地和思想库。该地区在中华文明起源、形成及中华民族共同体奠基的重要历史时期作出了突出贡献,是奠定黄河文化为中华民族“根”与“魂”的核心区之一。华北平原及其文化就是黄河下游的流域与文化。

Characteristics of the Lower Yellow River channel shrinkage and its discriminant parameters

This paper analyzes the changing trends of the Lower Yellow River(LYR) transverse profile parameters and their aberrance points by the time series analysis method.Research results show that there has been a trend of changes in the LYR channel transverse profile parameters since the 1950s.The main river channel has a tendency of shrinkage year by year and the trend will be continued in the future.The main features of the LYR channel shrinkage are remarkable reductions of bankfull dis-charges and bankfull areas,corresponding decreases of bankfull widths,average bankfull water depths and maximal bankfull water depths,as well as increases of bankfull water levels and width-depth ratios accompanied.The discriminant parameters for threshold of the LYR main channel shrinkage were put forward.It indicates that the LYR main channel began to shrink in the 1970s and has entered into a serious phase of channel shrinkage since the 1990s.The incompatible index of discharged water-sediment processes of the Sanmenxia Reservoir was introduced,which revealed that there was a trend of increasing in the incompatibility between water flow and sediment load.Response relations between the LYR main channel shrinkage parameters and discharged water-sediment processes of the Sanmenxia Reservoir were founded,which indicate that the LYR main channel shrinkage can be mitigated and improved through the regulation of discharged water-sediment processes of the reservoir,especially through the regulation of water-sediment incompatible index.The LYR channel for water and sediment transportation can be restored and maintained.

持续冲刷期内黄河下游河床演变特点分析

基于2006年10月至2018年11月黄河下游12个典型断面观测数据,通过分析断面主槽平滩形态特征参数变化率及深泓线和主槽中心线的摆动强度,探讨了持续冲刷期内下游河床的调整变化过程及特点。结果表明:黄河下游断面形态调整表现出既有横向展宽又有冲深下切或淤高态势;河床平面摆动促进了断面主槽形态调整,河相系数变化率与深泓线和主槽中心线摆动强度均成正相关关系;来水来沙条件是主槽形态改变的主要驱动力,且可引起局部河段深泓线摆动强度增大。通过调整小浪底水库的运行模式及布设控导工程可进一步塑造并维持稳定的黄河下游中水河槽。

内蒙古黄河干流行业间水权转让效果及对经济社会的影响

为定量评价内蒙古黄河干流行业间水权转让对经济社会的影响,从水权转让对农业的影响以及对全部受让工业企业的用水情况、生产经营情况、年度收益情况、民生及经济的影响等方面进行分析。结果表明:2019—2021年,内蒙古黄河干流行业间水权转让拉动工业项目总投资5995.80亿元,实现新增就业122145人,地区生产总值447.09亿元,工业增加值2388.21亿元,税收194.70亿元,新增铺设道路面积1316.17万m^(2),新增绿化面积3099.5万m^(2),明显提升了农业产值和农民收入,有助于解决地方民生问题,促进了沿黄地区生态保护和经济社会的协调发展。内蒙古黄河干流行业间水权转让缓解了沿黄工业企业水资源瓶颈制约,实现了农民增产、经济增效、生态修复的多赢,为黄河流域生态保护和高质量发展提供了有力支持。

黄河北干流水沙时空变化特征及协调性分析

为了解黄河北干流河段径流和输沙的时空变化规律及趋势,基于2002—2021年黄河北干流水沙数据,采用Mann-Kendall检验、突变点检验、小波分析、水沙关系协调性分析等方法,对黄河北干流河段的头道拐、龙门、潼关3个水文站2002—2021年的水沙时空变化特征进行了分析。结果表明:黄河北干流河段的输沙年内不均匀程度和集中度均大于径流,并且年内特征变化更加显著;各站径流集中期主要出现在9月,而输沙集中期主要在8月和9月;流域内水沙变化的显著突变年份多发生在2005年和2017年,可能与近年大型水利工程的调控影响相关;3个水文站水沙序列主要时间尺度对应的周期分别为13、10、9 a;黄河北干流的水沙不协调性在2008年之前主要表现为水少沙多,而在2008年之后则表现为水多沙少,其中头道拐的来沙系数始终小于0.009,一直处于水多沙少的状态。总体上,研究期内黄河北干流河段径流量在不断上升,而输沙量明显减少,且随着时间的推移水多沙少的趋势愈发显著。

黄河干流甘肃段旅游产业与生态环境协调发展时空分异研究

基于黄河干流甘肃段旅游产业与生态环境相关数据建立评价指标体系,采用熵值法与耦合协调度模型探究旅游产业与生态环境指数的时空分异特征和耦合协调水平。结果表明:旅游产业与生态环境指数在空间演化上表现为整体水平不高,在时间演变上呈现差异化显著特征;旅游产业与生态环境综合发展评价指数在时空演变上属较低层次耦合度等级;旅游产业和生态环境耦合协调度在时间演变上呈两极分化趋势,在空间演变上是分布失衡状态。为推动旅游产业高质量发展和生态环境高水平保护的协同一体化,必须强化顶层设计,大力发展生态旅游和低碳旅游,基于区域差异精准化施策。

黄河下游游荡性河段主流线调整与水沙关系研究

通过对多年河势资料的统计整理，分析了主流线的调整规律。研究表明，主流线弯曲系数与汛期水量和洪水径流量成反比，与汛期平均含沙量关系不大，但与年径流量也有关；主流线弦高与汛期水量之间无明显增减关系，对于长河段平均意义而言，弦高基本稳定在1000～1500m之间，而弦长与汛期径流量有明显的正比关系；近年来，主流线弯曲系数增加，同时河湾个数增多，但两者之间并非简单的线性关系；主流线长度随汛期水量增加而减小，且其递减率与汛期水量成线性统计关系。

黄河干流上游梯级水量实时调度自优化模拟模型研究

本文以黄河干流上游梯级为例 ,根据实时调度中用水计划和径流预报的时段滚动修正特点 ,研究了自优化模拟技术在水量实时调度中的应用 ,建立了黄河干流上游梯级水量实时调度自优化模拟模型 ,给出了求解方法 ,并进行了算例分析。该模型简单、灵活 ,有一定的实用性。

黄河下游高含沙洪水冲淤特性及其调控对策初探

基于黄河下游实测资料,对高含沙洪水对下游各河段河槽淤积的影响进行了分析,认为来自河口镇至龙门区间的高含沙洪水是造成下游高村以上河段河槽淤积的主要原因,高村以下河段的汛期河槽淤积物甚至全部来自高含沙洪水.降低含沙量、增大流量和提高细沙比例至70%～80%以上均可显著减轻高含沙洪水对河槽的淤积,而这可通过调控水库排沙比来实现.进一步分析了水库排沙比与出库泥沙的含沙量与细沙比例的关系,建议小浪底水库对高含沙洪水的调控要控制其排沙比在50%.在河龙间粗泥沙集中来源区,由于其来水很少、来沙很多,可利用该区＂沙随水来＂的特点使河龙间洪水就地利用,以减少黄河高含沙洪水产生几率和入黄泥沙量.

基于流域系统科学的黄河下游河道系统治理研究

黄河下游河道治理是一项复杂的系统工程。系统回顾和总结了欧美等发达国家河流治理的发展历程与经验启示,深刻诠释了河流系统治理的必然性和必要性。在此基础上,结合黄河水沙变化、区域社会经济发展情势以及重大国家战略,分析了黄河下游河道治理研究的现状与局限性,明确了新时代河道滩槽协同、上-中-下-河口联动、行洪输沙-社会经济-生态环境协调治理的战略需求,进而阐述了流域系统科学及其在黄河下游河道滩槽协同治理中的应用价值。

黄河下游主槽恢复目标研究

维持黄河下游主槽断面良好的形态和大小对保障河道的排洪输沙功能至关重要,而平滩流量是一个能够综合反映主槽形态和大小的指示性因子。本文利用实测水文数据,分析了非漫滩情况下流量-流速关系,认为在非漫滩情况下,尽管平滩流量越大,洪水输沙效率越高,但当平滩流量大于5000-5500m^3/s后,其单位水量的输沙能力增加甚微;而且,从与未来洪水相适应角度,下游平滩流量也不宜大于5000m^3/s,否则将降低其输沙效率。文章还分析了不同平滩流量对排泄设防大洪水的影响,认为平滩流量达4000m^3/s以上才可基本满足防御大洪水的要求,应作为平滩流量下限。基于此,文章建议将＂平滩流量4000-5000m^3/s作为黄河下游健康主槽的标准。进一步分析了下游汛期水量与主槽的响应关系,认为小浪底水库拦沙期结束前下游平滩流量恢复目标宜为4000m^3/s左右。

黄河中下游泥沙通量变化规律

根据黄河中下游多个主要水文控制站50多年的实测资料,利用水文学、泥沙运动力学、河床演变学和经验统计相结合的分析方法,分析黄河中下游泥沙通量的变化规律。结果表明,黄河中下游泥沙通量递减的同时泥沙粒径变细,人为因素影响巨大;中下游泥沙通量变化具有阶段性、季节性和自相关性。黄河下游河道泥沙冲刷与淤积均具有上段变化大、下段变化小的特点,这是由河道下游上宽下窄、上陡下缓特征决定的;下游河道输沙能力影响因子中,河道水量尤其是汛期水量起主要作用。

黄河下游中常洪水调控指标

从塑槽径流条件、水流动床阻力、河道整治、滩区及防洪等方面,论证了未来黄河下游主槽目标过流能力采用4 000m3/s左右的合理性,提出了黄河下游发生明显淤滩刷槽的临界流量。同时,根据不同量级洪水河道的冲淤特点,提出了小浪底水库控制下游流量、含沙量指标。即在目标主槽过流能力条件下,控制漫滩洪水流量不低于6 000m3/s,含沙量不大于250-300kg/m3;小漫滩洪水和非漫滩洪水,尽量按流量2 300-4 000m3/s、含沙量20-50kg/m3的水沙搭配控制,避免出现4 000-6 000m3/s8、00-2 300m3/s两个量级的洪水过程。

黄河下游平滩流量不同确定方法的比较

平滩流量是主槽过流能力的一个重要指标,准确估算各断面平滩流量大小是黄河下游水沙调控的一项内容。本文首先阐述了平滩流量的概念,并结合黄河下游不同年代的实测横断面形态特征,给出了确定主槽范围及平滩高程的原则。接着评述了国内外已有确定平滩流量的方法,并分析了断面平滩流量四种确定方法各自的优缺点及适用范围。最后以下游花园口断面为例,给出了四种计算方法所得平滩流量的结果及其差别。通过比较认为,本文提出的采用一维水动力学模型确定平滩流量的方法所得结果较为合理。

河床横向摆动计算方法及其在黄河下游游荡段的应用

深泓摆动、主槽摆动等河床横向变形过程容易引起游荡段河床形态的剧烈调整,从而对河道防洪及滩区土地利用等产生重大影响,因此提出河床横向摆动的定量计算方法并用于黄河下游游荡段,对深入研究该河段的河床演变规律具有重要意义。提出利用遥感影像资料、实测断面地形资料以及河段平均的方法来定量计算河床横向摆动宽度及强度,并通过1986—2016年黄河下游游荡段实测资料加以检验。结果表明:小浪底水库运用后,游荡段深泓及主槽摆动的宽度和强度均显著降低,深泓及主槽摆动宽度分别由1986—1999年的234、410m/a减小到1999—2016年的119、185m/a,分别减小49%、55%;来水来沙条件是影响深泓及主槽摆动强度的主要因素,年均水流冲刷强度则是影响摆动强度的关键水沙因子;深泓及主槽摆动是河床横向摆动的不同表现方式,但二者存在本质上的差异,通常大尺度的主槽摆动会引起深泓摆动,但深泓摆动不一定会引起主槽摆动。

试论干旱区流域开发中人口、资源、环境和经济发展的协调

本文讨论了干旱区流域开发中的人口承载力、人口超载和移民问题；资源开发和人类活动的强度及其环境问题。认为要解决和预防这些问题，必须协调人口、资源、环境和经济发展（PRED）。在对PRED协调的必要性，可能性，理论基础和一般模式，有关措施作了初步分析之后，以宁夏黄河干流流域开发为例，讨论了干旱区流域开发中PRED的协调问题。

黄河下游滩槽冲淤演变与水沙过程的响应关系

采用实测资料分析的方法,研究了黄河下游滩槽冲淤演变对水沙过程的响应关系。研究结果表明:1986年后,进入黄河下游的水沙明显减少,导致下游河道滩槽皆淤。2000年后,由于小浪底水库蓄水拦沙运用,下游全程持续冲刷。黄河下游滩槽冲淤演变与水沙过程存在响应关系:主槽冲淤量随水量参数、水量分配参数的增大而减小;随沙量参数、沙量分配参数的增大而增大;滩地冲淤量随水量参数、沙量参数、水量分配参数和沙量分配参数的增大而增大。

长江中下游干流水功能区评价指标构成及内涵

目前我国水功能区达标评价指标主要是COD、氨氮双指标,双指标难以客观评价水功能区水环境质量是否满足设定的水体用途以及水功能区管理需求。在系统分析水功能评价指标体系的基础上,结合长江中下游干流水环境特点以及不同水功能区用途,从水量、水质、水生态3个方面,针对性地提出了不同水功能区的评价指标,为开展水功能区达标评价与考核提供技术支撑。