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1.
Along the north bank of the Xuxi River, the sand-intercalated-muddy gravel layer from -3.7 - -5.8 m in the borehole 7508 at the East Dam and the middle, coarse and fine sand layer with a thickness of 4.5 m at the lower part of the borehole 8179 between the East Dam and the West Dam indicate that a large natural river was here before the Kingdom of Wu excavated the Xuxi Canal. The existence of Neolithic sites such as Xuecheng, Chaoduntou and Xiajiadang along the Xuxi River and the silt layer with dozens of meters archived under the earth＇s surface within a range of 1 km along both banks are the even more important evidences for the existence of the ancient Zhongjiang River. The floodgate of the East Dam nowadays makes against the communication between the Shuiyangjiang River and the Taihu Lake. The authors suggest the canal between Wuhu and Taihu Lake should be excavated as soon as possible, namely, the navigation channel from Wuhu through Guchenghu Lake, Xuxi River, East Dam, Liyang, Yixing to Taihu Lake should be further widen and the deposits composed of slope wash on the watershed between Shuiyangjiang River and Taihu Lake should be dredged away. Then, the channel journey can be shortened, the boats in ship transportation on the Yangtze River can be shunted to ensure the security of shipping, the resources of sand and gravel in the old river channel can be exploited and the dike of the Yangtze River can be reinforced. So, the problems of irrigation, flood diversion, pollution abatement and drainage of flooded fields in the lower Yangtze River will be resolved. Then, the above methods can impel the sustainable development of the Xuxi River and Taihu Lake area. 相似文献
2.
对江苏胥溪河成因及其开发利用的新探讨 总被引：1，自引：0，他引：1
胥溪河东坝北岸7508钻孔柱状剖面中-3.7~-5.8 m深处2 m厚的砂夹泥砾土层和东坝至下坝间的8179号孔下部存在4.5 m厚的中、粗、细粒砂层表明,在春秋吴国开凿胥溪运河之前,该处就存在规模较大的天然河流;胥溪河沿岸薛城遗址、朝墩头遗址和下家宕新石器时代遗址的存在,以及胥溪河两岸1 km范围内地表数米之下厚达数十米的淤泥层更是古中江在胥溪河一带存在的重要证据。目前胥溪河东坝所建的船闸不利于水阳江和太湖水系的沟通,也不利于发挥胥溪河流域灌溉和航运的应有作用。若能及早开发芜 (湖) -太 (湖) 运河,即进一步拓宽芜湖→固城湖→胥溪河→东坝→溧阳→宜兴→太湖的水运航道,清除水阳江和太湖水系之间由坡积物构成的分水岭岗地堆积物,不仅可缩短长江入太湖的水上航线,还可分流长江航运船只、保证安全通航率、开发古河道砂砾石资源、稳固长江堤防,解决长江下游灌溉、分洪、排涝和冲污等一系列现实问题,推动胥溪河流域经济可持续发展。 相似文献
3.
《The Professional geographer》2013,65(2):175-189
In-stream gravel mining, massive bridge piers, and channelization have all contributed to the geomorphic instability of the Lower Salt River channel in Arizona. Dam closure, changing dam operating rules, and the frequent modification of the channel bed have decreased our ability to predict the Salt River hydrology. Engineering practice has adapted to this situation and to a public that is increasingly intolerant of service disruptions by constructing larger bridges and extending levees. Building these larger structures may be counterproductive; future construction should not constrict the channel and should re-establish a braided river to decrease the energy available to the system. 相似文献
4.
5.
Martin Roberge 《The Professional geographer》2002,54(2):175-189
In‐stream gravel mining, massive bridge piers, and channelization have all contributed to the geomorphic instability of the Lower Salt River channel in Arizona. Dam closure, changing dam operating rules, and the frequent modification of the channel bed have decreased our ability to predict the Salt River hydrology. Engineering practice has adapted to this situation and to a public that is increasingly intolerant of service disruptions by constructing larger bridges and extending levees. Building these larger structures may be counterproductive; future construction should not constrict the channel and should re‐establish a braided river to decrease the energy available to the system. 相似文献
6.
鄱阳湖与长江之间存在着复杂的相互作用关系,决定着江湖水沙交换,对整个区域的水资源、防洪、航运、生态环境等均具有重要影响。本文基于能量的观点,在从新的角度解释鄱阳湖和长江相互作用原理的基础上,构建了江湖相互作用的表征指标—能差Fe,对20世纪50年代以来江湖作用关系变化进行了研究。结果表明,自20世纪50年代以来,Fe值整体呈现增加趋势,说明长江作用减弱,鄱阳湖作用不断增强。三峡水库蓄水运用对江湖关系产生了重要影响,进一步削弱了长江作用。从年内变化来看,由于三峡水库的调节,枯水期长江作用略有增强,汛末长江作用减弱较大。江湖作用一定程度上影响着湖区旱涝灾害的产生,当五河来流较大且长江顶托作用明显时,易发生洪涝;当五河来流较小但又对长江有明显的补水作用时,易发生旱情,三峡水库蓄水使湖区9-10月更易发生干旱。 相似文献
7.
青弋江上游泾县段阶地砾石层砾组结构及其沉积环境研究 总被引：1，自引：1，他引：0
通过对青弋江上游泾县段阶地砾石层进行砾组分析,讨论阶地砾石层的沉积环境及其对青弋江发育的启示。结果表明：① 砾径以中砾和粗砾为主,砾石沉积时水动力条件较强,流速基本为2 m/s左右,最大可达到3.5 m/s,特别是T3砾石层形成时期;② 砾向在T3和T2砾石层形成时期分别为南南西（SSW）和南西西（SWW）方向,古流向变化不大,呈自南而北的基本流向;③ 砾态以次圆和圆为主,其总含量超过70%,较高的磨圆度暗示砾石经历了较远距离的搬运;④ 砾性主要有石英砂岩、砂岩、脉石英和石英岩,其总含量达到90%以上,且砾石物源区变化不显著;⑤ T2砾石层和T1砾石层是典型的河流沉积,而T3砾石层可能是河流沉积和泥石流沉积叠加作用的产物,并且T3砾石层的沉积特征对于分析古青弋江的发育有一定的启示作用。 相似文献
8.
三峡大坝下游水位变化与河道形态调整关系研究 总被引：8，自引：2，他引：6
三峡水库蓄水利用已有13年,对坝下游洪、枯水位和河道形态调整的影响已初步显现,通过对1955-2016年长江中游水位、河道地形等资料的分析,结果表明：① 坝下游各水文站同流量枯水位下降、洪水位变化不大,最低水位上升,最高水位下降趋势;② 2002年10月-2015年10月枯水河槽冲刷量占平滩河槽冲刷量的95.5%,冲淤分布由蓄水前“冲槽淤滩”转为“滩槽均冲”,不同蓄水阶段存在差异;③ 河槽冲刷过程中,上荆江及以上河段枯水位下降趋势趋缓,下荆江及以下河段下降速率增加,应采取防控措施遏制河道水位下降趋势;④ 枯水河槽冲刷是长江中下游航道水深提升的基础,枯水位降幅小于深槽下切深度,在河道和航道整治工程综合作用下航道尺度提升,提前5年实现了2020年航道尺度规划目标;⑤ 平滩水位以上河槽形态调整不大,在河床粗化、岸滩植被、人类活动等综合作用下河道综合阻力增加,出现了中洪水流量—高水位现象,应引起足够重视。三峡水库汛期调蓄作用可有效提升中下游洪水防御能力,但不排除遭遇支流洪水叠加效应,中下游洪水压力仍然较大。 相似文献
9.
Seasonal variations of sediment discharge from the Yangtze River before and after impoundment of the Three Gorges Dam 总被引：14，自引：0，他引：14
Over the past decades, > 50,000 dams and reforestation on the Yangtze River (Changjiang) have had little impact on water discharge but have drastically altered annual and particularly seasonal sediment discharge. Before impoundment of the Three Gorges Dam (TGD) in June 2003, annual sediment discharge had decreased by 60%, and the hysteresis of seasonal rating curves in the upper reaches at Yichang station had shifted from clockwise to counterclockwise. In addition, the river channel in middle-lower reaches had changed from depositional to erosional in 2002.During the four years (2003–2006) after TGD impoundment, ~ 60% of sediment entering the Three Gorges Reservoir was trapped, primarily during the high-discharge months (June–September). Although periodic sediment deposition continues downstream of the TGD, during most months substantial erosion has occurred, supplying ~ 70 million tons per year (Mt/y) of channel-derived sediment to the lower reaches of the river. If sand extraction (~ 40 Mt/y) is taken into consideration, the river channel loses a total of 110 Mt/y. During the extreme drought year 2006, sediment discharge in the upper reaches drastically decreased to 9 Mt (only 2% of its 1950–1960s level) because of decreased water discharge and TGD trapping. In addition, Dongting Lake in the middle reaches, for the first time, changed from trapping net sediment from the mainstem to supplying 14 Mt net sediment to the mainstem. Severe channel erosion and drastic sediment decline have put considerable pressure on the Yangtze coastal areas and East China Sea. 相似文献
10.
长江上游卵石推移特性变化及驱动力分析 总被引：2，自引：1，他引：1
长江上游的水沙特性变化 ,直接关系到三峡工程的调度运行。朱沱站和寸滩站是长江上游与三峡水库的水沙主要控制站。本文分析了朱沱、寸滩站卵石推移特性的近期变化 ,发现寸滩站从 1981年起、朱沱站从 1991年起卵石推移特性发生了明显变化 ,主要体现在 :1)卵石推移量系统减小 :朱沱站 1992～ 2 0 0 1年卵石年均推移量比 1975～ 1991年减少了 4 6 9% ,寸滩站 1982～ 2 0 0 1年比 196 6～ 1981减少了 4 0 6 % ;2 )推移质粒径细化 ,中数粒径细化了约11mm ;3)流量 -输沙率关系发生明显变化 :朱沱站输沙率系数B减少 4 7 5 % ,寸滩站系数B减少 4 1 1% ;4 )输沙不平衡量增大 ,计算的磨损系数增大近 70 %。长江上游卵石推移特性变化的驱动力分析结果表明 :采取水土流失治理等措施是直接原因 ,水利工程拦沙和建筑材料开采等人类活动是主要影响因素。依据上述分析 ,本文指出 ,应当继续加强水土保持建设 ,尽快开展长江上游和支流泥沙运移和淤积情况及规律调研。并建议以可开采沙量为依据 ,严格控制采沙。 相似文献
11.
Xu Jiongxin 《Geomorphology》1996,17(4):351-359
Due to the changes in environmental factors during a river's historical development, underlying gravel layers are found in many large plain rivers. When the buried depth of this gravel layer is within the reach of down-cutting by clear water scour after reservoir construction, it may be exposed and exert a far-reaching influence on channel adjustment. In Hanjiang River, the longest tributary of the Yangtze River in China, down-cutting has been greatly reduced and even stopped, due to the total change of bed material composition. The exposure of a gravel layer results in a dramatic increase in the bed's hydraulic roughness, so the channel slope may increase after a decline during the period prior to the exposure of the gravel layer. Moreover, the exposed gravel layer increases the erosion resistance of bed material, making a lower relative erosion resistance of bank to bed material. Where the bank's erosional resistance is weak, this may lead to a tendency towards channel widening. 相似文献
12.
长江中游马口-田家镇河段40 年来河道演变 总被引：2，自引：0，他引：2
运用地理信息系统(GIS) 与数字高程模型(DEM) 分析了马口-田家镇河段1963 年、1972 年与2002 年河道地形数据, 较为系统地研究了该河段过去40 年冲淤时空变化。研究结 果认为, 1972 年与1963 相比冲刷量达到789.9 hm3, 冲刷面积为39.7×104 m2; 2002 年与1963 年相比冲刷量达到1196.5 hm3, 冲刷面积为59.4×104 m2; 2002 年与1972 年相比冲刷量 达到960 hm3, 冲刷面积为54.3×104 m2。由以上结果认为, 马口-田家镇河段近40 年来以冲刷为主; 河道冲淤变化以马口卡口与田家镇卡口等窄深河段最为剧烈, 宽浅河段与顺直河 段冲淤变化较为和缓, 冲淤变化幅度不大; 卡口上、下端以淤积过程为主, 而卡口顶冲水流的顶弯部位以冲刷过程为主。研究河段冲淤变化受上游来水来沙条件影响很大, 对未来三峡工程建成后, 三峡大坝下游来水来沙以及研究河段冲淤变化的影响研究提供借鉴。 相似文献
13.
Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler (ADCP) instrument, we analyzed shapes of river cross sections of the middle Yangtze River basin (mainly focusing on Makou and Tianjiazhen river reach). Hydrodynamic properties of river channels were also discussed. The research results indicate that nonlinear relationships can be identified between river-width/river-depth ratio (W/D ratio), sizes of cross section and mean flow velocity. Positive relations are detected between W/D ratio and mean flow velocity when W/D<1; and negative relations are observed when W/D>1. Adverse relationships can be obtained between W/D ratio and cross-section area. Geomorphologic and geologic survey indicates different components of river banks in the wider and narrower river reaches respectively. These may be the main driving factors causing unique hydrological properties of river channels in the middle Yangtze River basin. Narrower river cross sections tend to raise water level in the upstream river reach near narrower river channel, giving rise to backwater effects. River knots can cause serious backwater effects, which is harmful for flood mitigation. However river knots will also stabilize river channel and this will be beneficial for river channel management. The results of this paper may be helpful for flood mitigation and river channel management in the middle Yangtze River basin. 相似文献
14.
In this study, data measured from 1955-2016 were analysed to study the relationship between the water level and river channel geometry adjustment in the downstream of the Three Gorges Dam (TGD) after the impoundment of the dam. The results highlight the following facts: (1) for the same flow, the low water level decreased, flood water level changed little, lowest water level increased, and highest water level decreased at the hydrological stations in the downstream of the dam; (2) the distribution of erosion and deposition along the river channel changed from “erosion at channels and deposition at bankfulls” to “erosion at both channels and bankfulls;” the ratio of low-water channel erosion to bankfull channel erosion was 95.5% from October 2002 to October 2015, with variations between different impoundment stages; (3) the low water level decrease slowed down during the channel erosion in the Upper Jingjiang reach and reaches upstream but sped up in the Lower Jingjiang reach and reaches downstream; measures should be taken to prevent the decrease in the channel water level; (4) erosion was the basis for channel dimension upscaling in the middle reaches of the Yangtze River; the low water level decrease was smaller than the thalweg decline; both channel water depth and width increased under the combined effects of channel and waterway regulations; and (5) the geometry of the channels above bankfulls did not significantly change; however, the comprehensive channel resistance increased under the combined effects of riverbed coarsening, beach vegetation, and human activities; as a result, the flood water level increased markedly and moderate flood to high water level phenomena occurred, which should be considered. The Three Gorges Reservoir effectively enhances the flood defense capacity of the middle and lower reaches of the Yangtze River; however, the superposition effect of tributary floods cannot be ruled out. 相似文献
15.
近50年来长江与鄱阳湖水文相互作用的变化 总被引：13，自引：2，他引：11
通过分析1957-2008 年长江与鄱阳湖相互作用的基本特征及其与长江中游、鄱阳湖流域的径流量和气候变化的关系,并用2004-2006 年三峡水库蓄水、放水量的数据,定量地计算和比较了三峡水库运行和区域气候变化对长江与鄱阳湖相互作用的影响程度,得出如下主要结论：1)从年际、年代际尺度上来看,鄱阳湖流域的气候变化和五河入湖流量是鄱阳湖水位和水量变化的主要因素,同时也在很大程度上决定了长江与鄱阳湖相互作用关系及其强弱变化。2) 长江与鄱阳湖的相互作用强度是此消彼长的关系。从季节来看,鄱阳湖对长江的较强作用主要在4-6月,而长江对鄱阳湖的较强作用主要发生在7-9 月。3) 三峡水库运行并没有改变长江与鄱阳湖作用的基本特征,在多数季节三峡水库的影响不足以解释长江径流量变化的10%,但是水库在不同季节的蓄水或放水在一定程度上影响了江湖作用的季节变化和鄱阳湖流域的旱涝机率。4-6月的放水加强了长江作用,由于此时正值鄱阳湖流域的雨季,增强的长江作用在湿润气候的环境下可能增加初夏鄱阳湖流域发生洪涝的概率;7-9 月的少量蓄水则减弱长江对鄱阳湖的作用,降低了湖区洪涝的概率;而10 月份三峡水库的大量蓄水可能增加鄱阳湖流域的旱季干旱发生率。 相似文献
16.
基于前期研究工作成果和外部环境变化因素分析,探讨了青弋江发育原因及其与长江贯通的关系。研究表明：① 昆黄运动可能在长江中下游地区产生了区域构造响应,导致研究区断层被激活而发生了较大幅度的断块抬升运动,进而为青弋江发育提供了下切驱动力,驱动了青弋江发育;② 东亚夏季风在约1.3 Ma和约0.9 Ma发生的2次显著阶段性减弱事件,引起区域降水量显著增加,进而为青弋江发育提供了下切媒介和持续水流,控制了青弋江发育年代;③ 青弋江发育与长江贯通可能都是昆黄运动区域构造响应与东亚夏季风强度阶段性减弱共同作用的结果,并且长江贯通后所形成的新局部侵蚀基准面也可能促进了青弋江发育,因此青弋江发育年代在一定程度上能反映长江贯通年代。 相似文献
17.
The blocking or reversing effect of the downstream trunk river on its tributary lakes is an essential aspect of river-lake hydraulics. To measure how and the extent to which a trunk river can influence its tributary lakes, we made a case study in Changjiang River and one of its tributary lakes, Lake East Dongting (Lake ED) during a 35-year study period (1980–2014). Specifically, we investigated Lake ED’s discharge ability into Changjiang River using stage-discharge relationship curves, and hence the changes of the lake discharge ability under different hydrologic conditions of the Changjiang River. The results show that (1) the Changjiang River does exert a huge impact on the water regimes of Lake ED. And this impact varies seasonally. A variation of 3000 m3/s in Changjiang River’s runoff would change the lake water level by about 1.1 m in dry seasons, by 0.4 m in wet seasons, and by 0.6 m during severe summer floods. (2) Changes in the Changjiang River runoff triggered by the Three Gorges Dam since 2003 have led to dramatic water regime variations in Lake ED. Other factors, including reduction of lake inflow and the lake bed erosion, also exacerbated the water regime variations in Lake ED. 相似文献
18.
长江中下游河床沉积物分布特征 总被引：10，自引：0，他引：10
对长江中下游武汉至河口段304处河床沉积物样品进行了粒度测量与分析,通过各参数间的模拟、统计及对比,探讨了沉积物粒度、水动力因素及河床地貌三者间的关系。研究结果表明：本区河床沉积物以中、细砂为主,床底搬运十分微弱,河道相对稳定;从上至下沿程有明显的“粗-细-粗-细”粒径变化,主要反映河流动力地貌、动力沉积特征;粒径在河床的沿程分布总体为北粗南细,说明北岸侵蚀,南岸淤积的特点。研究同时也表明,颗粒因河型不同而迥异;颗粒偏态度-峭度在不同河型中表现各异,对区分顺直微弯分汊和鹅头形分汊河道尤为显著。 相似文献
19.
长期以来过江通道供需矛盾突出,高效利用现有通道并合理规划建设新通道设施、吸引两岸要素无障碍流动成为长江下游地区率先实现跨江发展、推进次区域合作的基本物质保障。基于此分析2000年以来长江下游地区公路过江通道建设对南北岸间交通的“时空压缩”效应,尝试探讨高等级公路网体系中过江通道通行利用空间特征。研究时段内过江通道建设实现由点到面扩张,从单一到多样化的跨江条件改善压缩区位差异对发展造成的不公平,跨江时间成本逐渐转变为自岸向两侧的由高到低梯度推移。沿岸地区就近选择过江通道,中远岸市县由高等级公路网引至特定通道方向,完整的过江通道是包含跨江桥隧和后方高等级连接公路的交通走廊。各通道因其在路网体系中的定位不同,通行利用存在差异,区域空间和基础设施建设的有限性要求建立“干线公路-跨江桥隧”多对多选择,提升既有通道通行能力并将连接道路建设向新通道方向倾斜,以分流通行压力并缩小区域内跨江成本差距。 相似文献
20.
现在的洪泽湖和淮河中游河道不断淤高,致使淮河中游洪涝不断。入洪泽湖后淮河水主要流入长江。而苏北北部地区需要水,因入海泥沙数量太少而致海岸侵蚀问题不能根本解决,那里需要淮河的泥沙。为改变这种不合理的格局。在洪泽湖北岸和浅水区开挖与洪泽湖分离的河道,连接完成远期工程的淮河入海水道和拓宽、挖深的淮沭河—北六塘河—新沂河水道,使淮河水沙只经过这两条水道到达黄海,改变淮河水沙不合理的资源分配。新水道路程短,比降大,使洪泽湖和淮河中游河道不再淤高,并将进一步使淮河中游水道刷深,减轻淮河中游洪涝灾害,并为洪泽湖湖底高程降低创造条件。通过分析现在淮河的输沙量、输沙模数,与历史时期和其他流域对比,认为连云港至射阳河口这段海岸将改变为北部稳定,南部缓慢进积,形成新的淮河三角洲,彻底解决苏北海岸侵蚀问题。 相似文献