THE CHANGE OF THE GENERAL FORM AND THE TRANSPORT OF THE WATER， LOAD AND SALT ABOUT THE NORTH－BRANCH OF THE CHANGJIANG RIVER MOUTH

The general form of the north-branch of the Changjiang River mouth has changed much as a result of the change of the main stream lines of the Nantong reach of the Changjiang River and the influence of human activities since 1915. By the 1930s, the main stream lines of the Nantong reach of the Changjiang River has shifted to the Tongzhou Bar west channel. The north-branch at the Changjiang River mouth has become atrophic because of Tongzhou Bar east channel's deposition. After 1958, Toughal Bar and Jiangxin Bar were exploited. And in 1970, the north channel of Jiangxin Bar was blocked up. All these things make the water of the north-branch more difficult to pass through. It leads to the decline of the total discharge percentage of the north-branch. And it causes the rising tide to go back to the south-branch. However, since 1978, with the development of Tongzhou Bar east channel and its left bank being scoured, the water amount of the north-branch has been increasing. And the water,load and salt of going back to the south-branch has been becoming less.

Contribution of Mesoscale Eddies to the Subduction and Transport of North Pacific Eastern Subtropical Mode Water

This study investigates the contribution of mesoscale eddies to the subduction and transport of North Pacific Eastern Subtropical Mode Water(ESTMW)using the high-frequency output of an eddy-resolved ocean model spanning the period 1994–2010.Results show that the subduction induced by mesoscale eddies accounts for about 31%of the total subduction of ESTMW formation.The volume of ESTMW trapped by anticyclonic eddies is slightly larger than that trapped by cyclonic eddies.The ESTMW trapped by all eddies in May reaches up to about 2.8×1013m3,which is approximately 16%of the total ESTMW volume.The eddy-trapped ESTMW moves primarily westward,with its meridional integration at 18°–30°N reaching about 0.17Sv,which is approximately 18%of the total zonal ESTMW transport in this direction,at 140°W.This study highlights the important role of eddies in carrying ESTMW westward over the northeastern Pacific Ocean.

Transport of Water Vapor over North China during the Drought Period in Summer of 1980

The features of water vapor transport, such as temporal evolution, vertical structure and spatial pattern, over North China during the prolonged drought in the summer of 1980 have been analyzed through computation of water vapor flux based on the once daily ECMWF grid-point data at 12GMT. The results indicate that it is unlikely that the characteristics of the atmospheric mass divergence, ascending motion and stratification stability in North China were completely opposite to those in the Yangtze River Valley, where the heavy flood occurred in the summer of 1980. It is major differences that the strong ascending motion and significant water vapor convergence overlap fairly well each other in the vertical levels in the Yangtze River Valley, while the maximum ascending motion is accompanied by water vapor divergence or weak water vapor convergence in North China. This vertical structure in North China results in insufficient water vapor supply and, therefore, little condensation and precipitation in the middle and upper atmosphere were produced. Additionally, a mode of monthly-scale low frequency oscillation can be found in water vapor flux, which is in correspondence to the fluctuation period of rainfall.

Integrated water risk early warning framework of the semi-arid transitional zone based on the water environmental carrying capacity (WECC)

Water risk early warning systems based on the water environmental carrying capacity(WECC)are powerful and effective tools to guarantee the sustainability of rivers.Existing work on the early warning of WECC has mainly concerned the comprehensive evaluation of the status quo and lacked a quantitative prejudgement and warning of future overload.In addition,existing quantitative methods for short-term early warning have rarely focused on the integrated change trends of the early warning indicators.Given the periodicity of the socioeconomic system,however,the water environmental system also follows a trend of cyclical fluctuations.Thus,it is meaningful to monitor and use this periodicity for the early warning of the WECC.In this study,we first adopted and improved the prosperity index method to develop an integrated water risk early warning framework.We also constructed a forecast model to qualitatively and quantitatively prejudge and warn about the development trends of the water environmental system.We selected the North Canal Basin(an essential connection among the Beijing-Tianjin-Hebei region)in China as a case study and predicted the WECC in 25 water environmental management units of the basin in 2018–2023.We found that the analysis of the prosperity index was helpful in predicting the WECC,to some extent.The result demonstrated that the early warning system provided reliable prediction(root mean square error of 0.0651 and mean absolute error of 0.1418),and the calculation results of the comprehensive early warning index(CEWI)conformed to the actual situation and related research in the river basin.From 2008 to 2023,the WECC of most water environmental management units in the basin had improved but with some spatial differences:the CEWI was generally poor in areas with many human disturbances,while it was relatively good in the upstream regions with higher forest and grass covers as well as in the downstream areas with larger water volume.Finally,through a sensitivity analysis of the indicators,we proposed specific management measures for the sustainability of the water environmental system in the North Canal Basin.Overall,the integrated water risk early warning framework could provide an appropriate method for the water environmental administration department to predict the WECC of the basin in the future.This framework could also assist in implementing corresponding management measures in advance,especially for the performance evaluation and the arrangement of key short-term tasks in the River Chief System in China.

Research on Expansive Soils Encountered in Middle Route Project of South-to-north Water Transfer Canal

The main canal of the Middle Route Project of South-to-North Water Transfer totals more than 1 240 km in length. In Henan Province and Hebei Province, there will be a section of more than 120 km passing through an expansive soils area. Expansive soils is a special kind of tenacious clay, which swells when meeting with water and shrinks when losing water. With complicated mechanical properties, it changes with the variation of water content. As a result, expansive soils become the key object of study on unsaturated soils mechanics for the project. From the status of study on unsaturated soils at home and abroad, this paper covers an analysis on stability analysis method of expansive soils slope, determination of expansive soils strength, rational design of canal slope ratio and support, and forecast of landslide for the Middle Route Project of South-to-North Water Transfer.

Variation in Summer Rainfall in North China during the Period 1956-2007 and Links with Atmospheric Circulation

Using gauge precipitation data and NCEP-NCAR reanalysis data, the interdecadal changes in summer precipitation during the period 1956-2007 in North China and the link with atmospheric circulation change over Eurasia are studied. Results show that precipitation amounts decreased by 16.2 mm per decade, which was attributable to a significant reduction in precipitation frequency. Contrary wave trains were found in the subtropical westerly jet （wave guide） over Eurasia for the wet and dry years of North China. When the wave trains had a ridge （trough） around the Korean Peninsula, conditions favored （disfavored） the westward and northward extension of the West Pacific subtropical high. The westward and northward extension of the West Pacific subtropical high is, and was, beneficial to rainfall in North China. The downstream propagation of Rossby waves was found to favor the maintenance of these wave trains. Sensible heating in the south of Lake Baikal and latent heating from the Korean Peninsula to the south of Japan increased during the period 1980-2007, as compared to that during 1957-1979. the wet period. These changes had positive influences on the maintenance of Anticyclonic-Cyclonic anomaly centers in the wave trains. Furthermore, northerly winds were prevalent in the lower troposphere during the dry period （1980-2007）. which prohibited the transportation of water vapor to North China from the seas and thereby led to a decrease in rainfall in North China. The weakening of the Indian Monsoon during the dry period might be one of reasons for the reduction in water vapor transportation.

“23·7”华北极端强降水特征和水汽条件研究

利用地面气象站降水资料和ERA5再分析资料,对2023年7月29日—8月1日华北极端强降水的特征和水汽条件进行研究。结果表明,“23·7”华北极端强降水具有降水时间长、累计降水量大的特征,表现出显著极端性。降水主要位于太行山和燕山山前,最大降水带与山脉走向基本一致。极端强降水期间存在显著的环流异常,偏北的副热带高空急流、异常偏北的西太平洋副热带高压是导致此次极端强降水的关键环流;北上的台风“杜苏芮”残余环流、台风“卡努”和低空急流等是此次极端强降水的主要影响天气系统。此次极端强降水的水汽条件存在显著的阶段性特征,7月29日08时—31日08时主要降水区域低层辐合、高层辐散和上升运动较强,低层气旋式风场发展深厚,水汽由台风“杜苏芮”残余环流近距离输送及“卡努”接力输送,并以前者为主,京津冀地区整层水汽处于净流入状态,最大水汽净流入速度达1.5×10^(8)kg/s;7月31日08时—8月1日08时上升运动、对流层低层辐合和高层辐散均显著减弱,低层气旋式风场厚度收缩,“杜苏芮”残余环流消亡,仅由台风“卡努”远距离输送水汽,京津冀地区整层水汽处于净流出状态,最大水汽净流出速度为5×10^(7)kg/s。太行山和燕山地形的阻挡作用使得水汽辐合中心长时间滞留,同时其摩擦作用可能有利于山前上升运动增强,为本次极端强降水提供了有利条件。

干旱和局部渗水对膨胀土渠堤稳定性影响研究

为探究膨胀土渠堤表面风干、地下水位升高和侧坡渗水等因素对其稳定性的影响,防控由此引发的现场灾害,开展了填方渠坡室内模型试验,研究了南水北调渠堤膨胀土含水量波动对渠坡变形和裂缝发育规律的影响,分析了边坡变形值、裂缝长度宽度与含水率、时间和渗水位置的关系,揭示了膨胀土含水量波动的致灾过程和时空发育规律。试验结果表明:(1)旱季坡面水分蒸发导致渠坡表层200 mm深度内首先产生垂直坡表面的“V”形簇状纵向裂缝,后逐渐水平发育,坡面最大沉降值为4 mm, 15 d后沉降趋于稳定;(2)雨季渠堤下部地基水位抬升使渠堤底部膨胀土发生显著膨胀,渠堤整体抬升3.32 mm;(3)在渠堤侧坡渗水中心点附近土体含水量上升8%以上,坝堤内自由水沿纵横向不均匀扩散而引起土体各向不均匀膨胀变形,并在右坡坡脚处产生长400 mm、宽14 mm的宽大裂缝;(4)基于膨胀系数的地基变形计算公式可以较好地预测渠坡浸水后各位置的变形量,有助于依据土体含水量判别各点的变形状态,为渠堤稳定性分析提供参考。

平陆运河水资源论证

平陆运河采用多级省水船闸节水技术,控制断面马道枢纽船闸布置三级省水池,航运用水量可节省60%以上。考虑货运量发展周期及船舶过闸效率等因素,近期需从郁江引调水约24 m 3 s。根据水资源论证分析,平陆运河在与引郁入钦调水工程相结合的基础上,以不影响现状贵港枢纽最小下泄流量保证率为前提,通过调整百色水库发电调度,结合西津、邕宁等水库统一调度,可保障平陆运河近期航运用水需求。

平陆运河工程建设关键问题研究与思考

平陆运河是西部陆海新通道的骨干工程,是新中国首个连通江海的运河工程。平陆运河建设规模巨大、综合效益明显、工程技术复杂,存在高效省水船闸、长寿命混凝土、智慧运河等关键技术难题。建设“优质工程、绿色工程、廉洁工程”,及时总结平陆运河的创新成果和实践经验,可以为我国未来建设运河工程提供借鉴。

基于水化学的南水北调中线干渠水与地下水水力联系指标识别

从一般水化学角度研究了南水北调中线源头地表水、干渠水及其周边地下水的差异。结果发现,钠离子在地下水与干渠水和源头地表水中的浓度差异最为明显,其次是总溶解固体(TDS)浓度,其他主要离子以及pH差异均不明显,说明钠离子浓度可作为识别南水北调中线干渠水及其周边地下水水力联系的备选指标。利用聚类分析和水化学类型的相似性,剔除了与干渠水可能存在水力联系的地下水样钠离子浓度,初步确定南水北调中线沿线与干渠水没有水力联系的地下水钠离子浓度大于9.8 mg/L,且该数值是干渠水钠离子浓度的1.6倍以上。因此,可将钠离子浓度及其参考范围用于快速判断南水北调干渠周边地下水与干渠水是否存在水力联系。

南水北调中线总干渠污染物降解及自净能力研究

自净过程是影响河湖水体水质变化的重要因素,污染物降解系数是决定水体自净能力的关键参数。定量分析长距离输水过程中渠道本身的自净作用,对于认识总干渠水质变化过程,区分其他外源因素对水质变化的影响都有着重要意义。以高锰酸盐指数和氨氮为研究对象,采用室内实验模拟的方法测定了南水北调中线输水总干渠典型断面的污染物降解系数,并将模拟的自净衰减过程与水质实际变化过程进行对比。结果显示:①总干渠污染物降解系数k相对天然河流处于较低水平,陶岔断面k_(COD_(Mn))为0.055 d^(-1),k_(NH_(3)-N)为0.003 d^(-1),郑湾断面k_(COD_(Mn))为0.049 d^(-1),k_(NH_(3)-N)为0.003 d^(-1),大安舍断面k_(COD_(Mn))为0.032 d^(-1),k_(NH_(3)-N)为0.009 d^(-1);考虑到高锰酸盐指数实际组分复杂,渠道降解系数较模拟结果可能更低。②模拟的自净衰减过程受温度、流速的影响较大,不同条件下总干渠高锰酸盐指数将从1.8 mg/L下降至0.228~1.042 mg/L,氨氮浓度将从0.034 mg/L下降至0.026~0.030 mg/L。由于存在藻源性、大气沉降和坡面径流等外源输入增量,总干渠沿程实测高锰酸盐指数介于1.8~2.4 mg/L之间(2019年),基本维持稳定;氨氮浓度介于0.029~0.096 mg/L之间(2019年),有升高趋势。理想条件下,自净作用最大能够消减高锰酸盐指数增量的81.81%,消减氨氮增量的30.37%。研究成果可为深入认识南水北调中线总干渠输水过程中水质沿程变化提供参考。

试论近代“黄运交汇”对流经区域的影响

1855年,黄河自河南兰考铜瓦厢改道,流经华北平原地区,在山东阳谷张秋镇与运河交汇,黄运交汇对华北平原地区社会经济文化史的发展产生了重要影响。其影响以新中国成立为界限,前期由于黄河经常决口漫流,造成田亩房屋淹没,居民迁徙,截断运河交通运输等灾难性危害。新中国成立后,党和国家实施多种措施,利用黄运水文资源,变害为利,促进了流经地区社会经济文化的进步与发展。

基于全过程输水损失的灌区渠系优化配水模型构建——以长岗灌区为例

为发挥灌区用水调度决策潜能,以黑龙江省长岗灌区为研究区,提出一种基于全过程输水损失的灌区渠系优化配水多目标模型,该模型充分考虑灌区骨干渠系内不同渠段、渠道之间的水量平衡和各级渠道的输水能力,兼顾渠系输水损失、配水及时性与公平性多目标的协同,优化决策配水流量与输水历时。此外,利用随机森林模型预测未来气候变化情境下灌区的供需水量,基于此,计算未来气候模式下的渠系输水损失并获得长岗灌区渠系优化配水方案。结果表明:同一生育阶段内上级渠道不同渠段的输配水损失水量占上级渠道输配水损失总量的比例差异性显著,任一生育阶段内上级渠道靠近渠首的第一个渠段的输配水损失水量占比最大(返青期、抽穗开花期和乳熟期均为20.71%、分蘖期为21.21%、拔节孕穗期为25.43%);通过渠系优化配水模型得到长岗灌区作物全生育期渠系输配水总量为230.51万m^(3),总配水历时为494.32 h,输水损失总量为8.66万m^(3),与灌区采用经验系数法计算的输配水损失水量相比,输水损失减少24.89%,显著提高输配水效率。该模型有助于提供科学、合理的渠系配水方案,为综合提升灌区水资源管理能力和精细化管理水平提供决策支持。

地铁盾构区间下穿南水北调干渠研究

为保证南水北调干渠安全及地铁自身安全,以郑州市轨道交通7号线一期工程漓江路站—刺绣路站区间为例,开展对其盾构区间下穿南水北调干渠隧道工程设计与研究。分别从盾构区间平纵断面、隧道加强措施等方面,结合以往设计经验进行优化设计,提出更合理的工程设计方案,通过数值模拟验算该穿越过程的可行性。

南运河冬季输水冰情及对策研究

南运河的冬季输水工作开展较少,冰期输水经验不足。2022—2023年度,南水北调东线北延输水为线路启用以来首次冬季输水。输水期间,在南运河段设立安陵、北陈屯2个观测站点,对冰期输水各个阶段的冰情特点进行观测,从而了解并掌握冰情的变化规律,并提出冰期输水对策,为今后的冰期输水工作提供参考。

On conservation and development of architecture and environment in the construction of large-scale national infrastructure——Exemplified by the Jiangsu Section of the Eastern Route South-to-North Water Diversion Project

The water-diverting route project’s characteristics,natural landscapes,and histories and humanism of the Jiangsu Section of the Eastern Route South-to-North Water Diversion Project were systemically analyzed through proposing and studying the canal culture routes,the water resources heritage corridors,the landscape and recreation corridors,and the town economic corridors.The station areas along the water-diverting route were scientifically zoned and graded through quantitative and qualitative synthetic methods.Both planning compendiums and construction controlling methods were proposed based on the project grades of points,lines,and areas.Conservation and development of architecture and environment in the large-scale national infrastructure construction were explored systemically.Theories and methods of developing harmonious water-supplying functions,ecological functions,landscape effects,and cultural effects of large-scale water resources were examined.

“通州堰”防洪工程体系下的北运河水资源调度研究

北运河是北京市重要的排水河道,近年来,随着两岸经济社会的发展、河道水利工程的兴建,北运河河道功能也在不断转变与丰富,北运河的水资源调度需满足多目标保障需要。为此,本文梳理了在“通州堰”防洪工程体系建设背景下,北运河水资源调度工作面临的新形势及研究开展情况,分析了现阶段存在的突出问题并针对性地提出了解决建议,可为优化北运河防洪及水资源调度工作提供参考。

清代运河漕运剥船建置述论

运河漕运剥船是专门用于剥挽漕粮的船只。元末明初是漕运剥船制度确立和发展的重要阶段,永乐朝以后北运河沿岸的剥船设置范围逐渐扩大。入清后,因运河水情、通航能力和航行方式不一,漕船每至河道淤浅之处受阻,清廷遂置体积较小、船底平缓、载重较轻的漕运剥船,分载越浅。相较于明代,清代漕运剥船设立的范围和规模更广,清廷在北运河段剥船的基础上,增设其他运河段剥船,以备遇浅起剥。晚清漕粮海运,沙船径直天津,然向来“沙船不入河,河船不放洋”,故北运河段的剥船设置依旧。清代漕运剥船的设立实现了漕粮运转的区域化和资源调配的细分化,体现了清代社会治理与自然环境的密切联系和相互作用。

试论明清漕粮由河运转向海运及其启示

中国古代南粮北运关系国计民生。自隋唐迄明清,运河一直为南北物资交流大动脉。明清定都北京,财赋仰给于东南。为解决国家军费与宫廷食用,每年沿运河从江南转输四百万石左右漕粮入供京师,故视漕运为天庾正供,军国大计。康熙曾把漕运、河工、盐政视为国家三大政,书于宫廷廊柱。但在明后期和清中期,由于黄河水患与漕运积弊影响,河运危机不断,并在统治集团内部两度引起继续沿用传统的河运还是因时制宜实行海运的论争,结果以转向海运而告终。探究明清时期漕粮由河运向海运的转变,对于研究明清社会经济,保护黄河流域生态具有一定现实意义。