长江中下游干流河道河岸抗冲性较差,水流冲刷力强,河床冲淤变化频繁,崩岸险情时有发生,河道治理对促进沿江地区经济社会的快速、健康、可持续发展具有重要意义.简要分析了近年来特别是三峡水库蓄水以来长江中下游水沙变化与河道演变特性,分析了中下游河道崩岸与护岸工程现状、现有护岸工程存在的主要问题,阐释了河道崩岸的影响因素与发生机理,揭示了不同类型护岸工程的破坏机理,简要介绍了河道岸坡稳定性评估方法及其应用,总结了长江中下游的崩岸治理与河道整治技术,最后通过典型实例介绍了崩岸治理与河道整治技术在长江中下游的应用与实践.

三峡水库蓄水后清水下泄,长江中游含沙量将长期处于严重不饱和状态,水流含沙量沿程恢复将会引起长江中游河道长距离冲刷.根据三峡水库蓄水以来实测资料,分析了长江中游河段河床粗化与月均含沙量恢复的特性.结果表明:三峡水库蓄水运用以来,宜昌-枝城河段床沙粗化明显,河床已基本以卵石为主;枝城-监利河段河床粗化较为明显;监利-螺山河段、螺山-汉口河段河床有一定程度粗化.三峡水库蓄水运用后,d<0.125 mm粒径沙量在长江中游沿程恢复缓慢且恢复程度远小于蓄水运用前,d>0.125 mm粒径沙量在宜昌-监利河段恢复速率较快,且在监利站附近该粒径含沙量基本恢复饱和.宜昌-监利河段月平均含沙量恢复达到最大值,监利-螺山河段月平均含沙量以减小为主,而螺山-汉口河段月平均含沙量变化不明显.研究成果为将来水库下游不平衡输沙的深入研究提供了参考.

溪洛渡、向家坝与三峡水库联合运用后,坝下游河道的水沙过程进一步调整变化,长江中下游河床将进入新一轮的冲淤变化过程.利用长江防洪实体动床模型试验研究了新水沙条件下,三峡工程建成后至2022年长江中游杨家脑至北碾子湾段河床变形冲淤变化趋势.利用定床模型试验,选取典型洪、枯水流量过程,分别在现状地形和向家坝、溪洛渡与三峡水库联合运用至2022年末地形条件下,预测杨家脑至北碾子湾河段的洪、枯水位和流量的变化情况,分析该河段河床冲淤调整过程对防洪形势和取水工程正常运用的影响,为荆江河道治理、防洪、供水、灌溉等提供技术支撑.

三峡工程运用以来,长江荆江河段水沙条件发生较大改变,河床冲淤变化剧烈.沙市河段地处上荆江中段,属弯曲分汉河型,多年来深泓左右摆动和分汉段主支汉易位频繁,是荆江河势变化频繁、防洪形势严峻的河段之一.利用多年来,特别是三峡工程蓄水后的原型实测资料,首先分析了河段控制水文站的水沙特性及太平口分流分沙变化,并进一步分析了三峡工程运用以来沙市河段的河道冲淤演变特点及演变趋势,在此基础上综合考虑河段的防洪、航运、取水等需求,探讨了沙市河段未来的综合治理思路.

The adjustment of riverbed cross-section in alluvial river not only affects the floodwater discharge,the ability of sediment transport,but also influences the dike and dam security and stability,the planning and using of land on the bank on both sides. It is of great significance to research the regularity and mechanism of channel crosssection in alluvial river. In this paper,the research achievements and progresses in the regularity of riverbed crosssection adjustment in alluvial river are summarized,and suggestions for further research are proposed as follows:( 1) The existing research methods should be improved. Empirical analysis based on measured data are convenient but limited,which is only adaptive to specific examples; whereas mathematical model can only simulate the adjustment of small river or artificial channel in laboratory,and needs to be improved for complex natural rivers;( 2) More attention should be paid to the merging of theoretical research and field data analysis,and understanding on the regularity and mechanism of channel cross-section should be enhanced;( 3) The application field of computing methods of riverbed cross-section adjustment should be extended.

Physical modeling tests were performed to study the fluvial process in Shishou reach of Yangtze River in the purpose of predicting the river regime tendency and proposing river regime control plans for the changes at different stages of Three Gorges Project(TGP).The results reveal that until the end of 2022,apart from some local changes,the overall river regime of Shishou reach will generally remain the same as that at the present,which presents a braided pattern with the left branch of Xinsheng shoal,a newly developed shoal,as the dominant and with the left channel in the left branch as the main channel.The preliminary plan of river regulation projects include bank protection works,either reinforcements or new constructions to be carried out at vulnerable spots along the river bank which are close to the thalweg or heading to the main flow.Additionally, to maintain the present regime or prevent it from deteriorating,bank protection projects will be constructed at some local sandbars or beaches based on the tendency of river regime adjustment.

Based on the existing research results of river pattern in the downstream of Three Gorges and Danjiangkou reservoirs,the formations of different river patterns are summarized and analyzed,including incoming flow and sediment condition,boundary condition of river channels and gradient ratio.It is concluded that after completion of Danjiangkou Reservoir,the river channel of middle Hanjiang River changes into a stable braided or single channel and the bend bypassing and shore cutting occur in the lower reach;after operation of Three Gorges Reservoir,the changes of downstream river channel are smaller than lower reach of Hanjiang River.Furthermore,we point out the complexity of river pattern changes in downstream of Three Gorges Reservoir and the problems need to be studied.The research results provide reference for studying the mechanism of river pattern change in downstream of large-scale hydro project.

Due to the reservoir regulation of the Three Gorges Project(TGP),the water and sediment load flowing into the Jingjiang river reach downstream of,TGP have undergone significant changes both in the process and in the amount.Conspicuous erosion,which leads to river regime changes in some locations,has occurred in the Jingjiang river channel,consequently affecting the embankments,bank protection works along both sides,river regulation projects,and the stability of river bed at different levels in the long-run,and further affecting the flood control,navigation,ecology,environment and the integrated function of the river in these areas.In this paper,the movable bed model test of Changjiang River Flood Protection Model was adopted to study the changing process,the amount and distribution,of scouring and silting of the Jingjiang river course from Yangjianao to Haoxue at the initial operation stage of TGP.Based on this understanding,the tendency of river changes were predicted as well.The obtained research results may be taken as technical references for the planning and designing of river harnessing and river regime control projects in this river course.

The variation process,characteristics and trend of runoff and sediment load in the main stream of upper Yangtze River are analyzed based on more than 50 years′ hydrological data.The results show that there is no obvious variation trend in annual runoff of the main stream of upper Yangtze River,however,annual sediment load decreases on the whole;the transported sediment load in middle and lower reaches of the Yangtze River has decreased obviously since 2003 due to the sediment retaining of TGP reservoir and sediment load reduction from the upper Yangtze River.The annual flow and sediment distribution are characterized by concentrating in flood season from May to October,especially for sediment.For recent 50 years,the annual runoff of the upper reaches of Yangtze River varies in a main cycle of 12-years,and based on correlation analysis results,the annual runoff is positively correlated with annual sediment on the whole.The trend analysis shows that the runoff of upper reaches of the Yangtze River is relatively low at present,and after a few years the Yangtze River will turn into a wet period;with the construction of soil-water conservation works and the appearance of sediment retaining function of reservoirs in the upper reaches of Yangtze River,the sediment load in the middle and lower river reaches will remain in a low level during the reservoirs′ equilibrium period.

The Jianli river reach is located in the lower part of Jingjiang river reach which is one of the 14 key reaches in the middle and lower reaches of Changjiang River.By analyzing the 1950-2006 prototype data of Jianli Station in Jianli river reach,a representative hydrological station,some conclusions indicate as follows: The annual runoff and sediment load of Jianli river reach all changed irregularly and periodically,and were divided into two phases clearly by late 1980s.In 2006,the annual runoff and sediment load of Jianli river were the lowest in the past years.The distribution of runoff and sediment load in one year was uneven,mainly concentrated in flood season from May to October,especially for sediment load.The runoff and sediment load had direct correlation on the whole,that is,the more the runoff,the more the sediment load.Besides the incoming water and sediment from the upstream river reach,the cut-off works in lower Jingjiang river reach,the variation of the silt-carrying flow division through three branches in Jingjiang River,and the construction of large-scale water conservancy projects,such as TGP,are all the main influencing factors of water and sediment load variation in Jianli river reach.

Hydrological time series usually in time domain have multiple time scales structures and localization features.In this paper,the wavelet multiple time scales analysis method was used to analyze annual runoff time series from 1882 to 2006 of Yichang Hydrological Station.Research results show that the annual runoff time series of Yichang Hydrological Station has obvious annual change features,and mainly has change cycles of 30-40 yr,10-20 yr and below 10 yr.The first change cycle is 14 yr,the second cycle is 7 yr.Runoff trend analysis shows that the annual runoff will be in a relative dry period in about 3 years since 2006,and then,a relative wet period.

To analyze temperature rise influence by power plant thermal effluent,a 2-D hydrodynamic and thermal diffusional mathematical model was established based on previous work and with river regime-fitted computational meshes.Sensitivity analyses of parameters and coefficients in the thermal diffusion equation qualitatively show that this mathematical model can simulate the temperature rise influence.Application results also show that,the model has basically the same temperature-rise envelope in comparison with the physical model,and the simulation error of 1℃ envelope area between two models is within 8%.

Jianli river reach is the key river reach of lower Jingjiang river(the middle reach of Changjiang River).In this paper,the characteristics of water and sediment load of Jianli river reach was summarized preliminaryly.By analyzing the 1950~2006 prototype data of representative hydrological station-Jianli station in Jianli river reach,results and conclusions would come to as follows.The annual runoff and sediment load of Jianli river reach all changed irregularly and periodically,and have a little large amplitude of variation.In 2006,the annual runoff and sediment load of Jianli river are the lowest in the past years.The distribution of runoff and sediment load in one year is uneven,mainly concentrated in flood season from May to October.The runoff and sediment load have direct correlation on the whole,that is,the more the runoff,the more the sediment load.While since 2000,the annual runoff and sediment load have no correlation,and the annual sediment load showed an obvious decreasing tendency.Besides the incoming water and sediment from the upstreem river reach,the cut-off works in lower Jingjiang river reach,the variation of the flow division through three branches in Jingjiang river,the construction of large-scale water conservancy projects,such as TGP,the jacking action by the outflow of Dongting lake,are all the main influencing factors of water and sediment load variation in Jianli river reach.

Meshless mathematical modeling is based on variation principle,using power function to fit the real resolution,and therefore what kind of a power function is considered as to be very important.Meshless method is a kind of modeling method without any grid,only with discrete nodes information,and regarded as to be a hopeful.An algorithm of nodes arrangement in complicated plane area is presented.The point-in-region query is a key problem when arranging the nodes.A very simple point-in-region query algorithm is presented.Examples are also given to show the availability of the algorithm.An auto-generation program with FORTRAN language environment is organized.

随着现代工程技术手段的不断发展,近一百多年来人类对河流进行了大规模的开发利用,兴建了一大批各种各样的水利工程。这些水利工程一方面给社会带来了巨大的经济效益和社会利益,另一方面也极大地破坏了人类赖以生存的自然资源和生态环境。因此,如何兴利弊害,充分发挥水利工程为人类造福的优势,减免其对环境的不利影响,是广大水利工作者必须考虑的问题。水利工程对环境的影响可以分为有利影响和不利影响,其不利影响主要表现在对自然环境和社会环境的影响方面,这些影响可以通过修建补偿措施工程来加以缓解或消除。