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1.
在河口地区判别泥沙来自于哪一沙源,对于岸线规划和航道整治显得尤为重要。而在这一水域中,由于入汇的河流众多,这些河流所挟带的泥沙在径流,潮流、波浪等因素的作用下,各河流泥沙淤积范围和淤积数量难以确定。本文根据各流域来沙中各重矿物含量不同的原理,采用均方差最小的方法,推导了计算各河流在任一水域中泥沙沉积的比例,并以伶仃洋交椅沙附近水域的沉积泥沙中的各种重矿物含量、进入伶仃洋诸河流水流所挟带泥沙中的各重矿物含量为例,说明这一水域中各河流挟沙的比例。这一计算与目前已有的定性分析结论相一致。  相似文献   

2.
选取南四湖流域相关水信息资料,利用水文统计等方法,分析了南四湖主要入湖河流干支流、入湖河流与湖区的洪水遭遇频率。研究发现:河道支流发生5a一遇、10a一遇、20a一遇降雨时,遭遇到其干流相应洪水标准分别为4a一遇、7a一遇、10a一遇洪水;入湖河流发生5a、10a、20a一遇洪水时,与相应的上、下级湖湖水位同频率。  相似文献   

3.
鄱阳湖泥沙来源及湖盆近期沉积规律探讨   总被引:5,自引:0,他引:5  
熊道光 《海洋与湖沼》1990,21(4):374-385
本文依据汇入鄱阳湖的河流泥沙资料和湖区泥沙淤积调查研究的成果,对鄱阳湖泥沙来源及湖盆近期沉积规律进行了探讨。赣、抚、信、饶、修五河及其区间来水挟带的泥沙是鄱阳湖泥沙的主要来源。通过沙量平衡计算:多年平均入湖沙量2310.9万吨,平均出湖沙量1179.7万吨,平均淤积量1131.2万吨。若平铺在面积为4646.64km~2的湖盆上,淤积速率为1.6mm/a。淤积部位主要是五河入湖的扇形三角洲前缘。从沉积环境的演变观点看,今后湖盆泥沙淤积有逐渐加重的趋势。  相似文献   

4.
河口海岸环境变异和资源可持续利用   总被引:15,自引:2,他引:15  
河口海岸是地球四大圈层交汇,能流和物流的重要聚散地带,中国入海河流众多,河流挟带泥沙每年达20亿t,占全世界入海泥沙的10%,植被破坏,水土流失,人类对水资源的开以及跨流域调水都能影响流域来水来沙,地下水超采也可以使河口海岸沉降,这些都影响着河口海岸的环境,该区域经济发达,人口集中,开发程度高,导致严重的环境变异,资源破坏,对区域持续发展造重大影响,特别是我国流域高强度开发对河口和邻近海域有直接和深远的影响。因此,开展河口海岸环境变异的研究,为解决国家目标和海岸带资源可持续利用是非常重要的。  相似文献   

5.
以2006-2008年的南四湖4条入湖河流水质监测数据为基础,以溶解氧、高锰酸盐指数、5日生化需氧量和氨氮作为监测项目,采用综合水质标识指数评价法对南四湖入湖河流进行水质评价.结果表明,除泗河监测断面水质为Ⅲ类水体外,其他都属于Ⅳ、Ⅴ类水体,污染较为严重.本研究可为南四湖主要入湖河流的污染治理提供一定的科学依据.  相似文献   

6.
基于1958—2008年滦河入海径流通量、泥沙通量及流域降水数据,采用线性趋势法和Mann-Kendall检验法来分析滦河入海水沙通量变化规律,结果表明:1958—2008年间,滦河流域年入海水沙通量显著减少,入海径流通量与泥沙通量时序均存在显著突变转折,突变发生于1980年前后,突变点出现时间与强烈人类活动介入时间相吻合,滦河入海水沙变化与流域人类活动影响密切相关。  相似文献   

7.
太湖宜溧河流域洗衣粉排磷贡献率的研究   总被引:3,自引:0,他引:3  
太湖宜溧河流域内总磷发生量为3540.98t/a,进入太湖的总磷量为157.43t/a、流域内总磷的入湖率为4.45%。流域内洗衣粉排磷发生量为336.20t/a,洗衣粉排磷入湖量为27.71t/a,洗衣粉排磷量占入湖总磷量的比例为17.60%。因此,洗衣粉“禁磷”措施在全太湖流域的实施,可削减约17.6%的总入湖磷量,这对减轻太湖富营养化状况,缓解藻花的暴发,改善太湖水环境起到一定的作用。  相似文献   

8.
小海是位于海南岛东海岸的一个典型湖。通过对小海湖的水文调查研究,较系统地掌握了湖潮汐、潮流、余流、盐度和泥沙的特征。湖水深虽小,但在口门一带的盐度分布及表、底层流流速、流向的差别却较大,存在类似入海河口的缓混合及纵向环流的现象。  相似文献   

9.
利用耦合北斗和GPS双定位系统的拉格朗日随体法水质点追踪仪,在2018年9月至2019年10月期间开展了总数为18次的洪泽湖和巢湖主要河流河水入湖后表层、中层和底层水体运移同步追踪观测,研究了两个湖泊河水入湖后的运移轨迹和速度特征。结果表明:淮河主河道河水入洪泽湖后流向南北两侧;徐洪河河口处水体表层流速在洪泽湖5条河道出入湖口处为最大;巢湖双桥河河口处水体流速受巢湖闸运行影响强烈,各层流速在7条入湖河流中最大。洪泽湖、巢湖入湖水体流速由表层至底层逐渐降低,洪泽湖各层水体流速大于巢湖。洪泽湖河口处表层水体8次测量平均流速为6.11cm/s;巢湖为5.51cm/s;二者中层流速分别为5.32和3.85cm/s;底层则分别为4.96和3.67cm/s。  相似文献   

10.
东平湖是黄河下游地区最大的蓄洪湖泊,大汶河是其唯一入湖河流。对东平湖33个表层沉积物样品进行粒度分析,探讨了东平湖表层沉积物粒度组成及空间分布特征。研究结果表明,受物质来源和流域降雨量变化影响,东平湖表层沉积物粒度各组分及分布特征具有明显的空间差异性。东平湖表层沉积物粒度组分以粉砂为主,平均含量达79.71%;黏土次之,占16.76%;砂含量最少,仅占3.51%。平均粒径、砂、黏土分别呈舌状自东南向西北方向延伸,粒度分异作用明显。东平湖现代表层沉积物主要来自大汶河搬运与一定比重的湖岸侵蚀崩塌产物,表层沉积物来源的确定有待于今后进一步结合物源示踪分析来准确判定。该研究对于深入认识东平湖地区水动力条件及物质输入状况、入湖污染物的迁移扩散规律等均具有重要意义。  相似文献   

11.
洞庭湖地区水系水动力耦合数值模型   总被引:2,自引:0,他引:2       下载免费PDF全文
针对洞庭湖地区复杂水系和复杂水情下的实际水流运动特征,建立了完全基于水力学方法的洞庭湖地区水系的一、二维耦合的全局水动力学模型,实现了不同水体数值模拟的自动有机衔接。模型包括湖泊、河网水系两部分。对长江干流荆江段、湘资沅澧四水、三口分流河道,运用能够反映河道主槽和边滩不同行洪特征的扩展一维水量模型进行模拟;对于洞庭湖湖区部分,采用二维非结构的有限体积法建立水动力模型;应用重叠投影法实现模型的耦合。模型具有动边界的自动处理,河道分区计算,分洪、溃堤过程实时模拟等功能。剖分的网格较为细致地刻画了湖区的地形,使模型能够模拟"高水湖相、低水河相"的湖流特征。运用1996年7月的实际洪水过程,进行了模型的验证,较为准确地模拟了实际水流特征。  相似文献   

12.
山东半岛南部近岸全新世泥质区表层沉积物   总被引:1,自引:0,他引:1  
泥质区沉积记录是全新世海洋环境演变的重要信息载体。中国近海沿岸发育着若干小型泥质沉积体,比较明确的有南海西部近海的泥质区,但尚未进行研究。通过对山东半岛南部近岸海域采集的浅地层剖面资料精细解释后发现,在该区近岸海域存在一个小型泥质沉积区,主要分布在青岛崂山头以北至乳山口附近的近岸海域,整体上平行海岸线呈条带状分布,由近岸向海逐渐变薄,等厚深度分布平行于岸线,沉积中心位于鳌山湾海域,沉积中心最厚可达22.5 m。AMS14C测年结果表明,该泥质区形成于全新世。本文利用在泥质区采集的表层沉积物的粒度、黏土矿物、碎屑矿物、地球化学元素等分析测试结果,对比研究区周边主要入海中小河流物质成分和黄河物质成分,探讨了山东半岛南部近岸海域泥质沉积区的沉积特征和物源情况。结果表明,该泥质区的形成是黄河与周边入海河流共同作用的结果。  相似文献   

13.
Tidal sand bars and tidal sand ridges are extensively developed in the macrotidal Gulf of Khambhat, offshore western India. The inner and outer regions of the gulf are characterised by the development distinct tidal sand bodies with discrete geometries and dimensions. The outer gulf ridges are long, narrow, curvilinear and several metres high (∼20 m). They are asymmetric in cross-section and migratory in nature, forming ‘ribbon’ like sand bodies separated by tidal channels. Active dunes on these ridges indicate the presence of sand and their orientation parallel to palaeo-shorelines supports a tidal origin. In contrast to the outer gulf tidal sand ridges, sand bars associated with macrotidal estuaries flanking the Gulf of Khambhat typically have an elongate to diamond shape and are only hundreds of metres in width and a few kilometres length. These tidal sand bars occur in the estuary mouths and within the tidally influenced fluvial reaches of the rivers flowing into the gulf. The height of these sand bars is in the range ∼1–3 m. Due to high tidal ranges and bi-directional flow the sand bars do not develop significant height and are formed between the mutually evasive ebb and flow channels. Their bi-directional foresets and the presence of abundant mud drapes associated with the dunes within in-channel sand bars indicate a tidal origin.The Gulf of Khambhat acquired the present configuration in the last few thousand years since the Pleistocene sea-level lowstand (last glacial maximum, ∼18 ka) when the entire continental shelf was subaerially exposed and rivers down-cut into the coastal plain. With increasing sea-level rise, the exposed shelf was drowned, flooding parts of the Modern western Indian peninsula, and large tidal sand ridges formed in the outer gulf. After the fall of sea-level at 2 ka the gulf acquired the Modern configuration with multiple estuaries on both coastlines, rivers supplied the embayment with sandy sediment, and tidal sand bars formed in the Modern estuaries.Quantitative data gathered from the Modern Gulf of Khambhat indicates that for the P50 case, a vertical drill hole will encounter tidal sand bodies (ridges and bars combined) of approximate dimensions 1700 m long, 470 m wide and 1.5 m high, with a spacing of 400 m. In subsurface hydrocarbon reservoirs, where data is sparse and only limited amount of core is available, this quantitative dataset can be useful to constrain subsurface geocellular models. Also, the overall geometry, distribution and aspect ratio of the tidal sand ridges and tidal sand bars can be used to identify ancient counterparts through seismic geomorphology or in core.  相似文献   

14.
The Quaternary history of the Amazon lowlands is characterized by deposition of sediments of Andean provenance and by the influences of changing sea levels. Areas well above the present water tables were not reached by Pleistocene high-water stages. These areas have been intensively weathered since the Tertiary, forming hard lateritic weathering horizons. These weathering horizons are best explained by the relatively constant, humid tropical climate throughout the Quaternary. In the western Amazonian Lowland, flood plains corresponding to the different Pleistocene sea-level heights were formed. During low sea level, erosion in the drainage areas increased and the water levels of the central Amazon River system were lowered. Valleys drowned and lakes formed in the lower reaches of rivers and creeks during high sea-level stages. These lakes (ria lakes) remained in the valleys with rivers having a low sediment load. Seismic profiling (3.5 kHz) in some of these lakes clearly showed deposits of the three last periods of Quaternary high sea-level stages.  相似文献   

15.
南黄海辐射沙洲中心沿岸晚更新世以来的沉积环境演变   总被引:5,自引:0,他引:5  
对南黄海辐射沙洲中心沿岸地区两个钻孔采用高密度、定量采样方法进行有孔虫和沉积分析。结果表明,该地区晚更新世晚期可能发育了古长江河道、河口、河流边滩或河漫滩以及泛滥平原乃至泛滥湖沼等陆相沉积环境。进入全新世,则先后依次出现了潮滩、河口、潮滩、潮流沙体和潮滩,及至最终成陆。  相似文献   

16.
于升松 《海洋与湖沼》1996,27(2):125-131
根据1985-1987年来1989-1991年对青海湖及其水系的考查资料,研究其化学变化。结果表明,近30年来,青海湖及其入湖河流水系在萎缩过程中,水系总矿化度增加,逐渐咸化。除尕海水的Mg^2+;耳海水的K^+,SO^2-4,CO3^2-;人湖河流水的SO4^2-离子浓度减小外,青海湖、尕海及耳海本中Na^+,Cl^-,SO4^2-离子增加速率较大,Ca^2+,Mg^2+等离子增加速率较小。尕海  相似文献   

17.
西藏盐湖及其水系中的痕量金属   总被引:1,自引:1,他引:0  
于昇松 《海洋与湖沼》1992,23(4):407-414
于1978年采集了西藏高原26个盐湖、6条河流、10处泉水及3地盐湖区的大气降水的水样,以ZCP等离子光谱仪测定所采水样中Fe,Mn,Al,Cu,Pb,Zn,Ni,Cr等痕量金属含量,结果表明,1.盐湖水及河流、泉水和大气降水等水系中的痕量金属均高度富集,但以盐湖水的最大;盐湖水中各痕量金属富集程度不一,其顺序:Pb>Mn>Cr>Fe>Zn>Cu>Al>Ni。2.区域出露的岩性、气候、湖盆及水文等为盐湖水中富集痕量金属创造了有利条件。3.高痕量金属浓度的河流、泉水及大气降水是控制和影响盐湖水中痕量金属富集的主要的直接因素。4.盐湖水的矿化度、pH及水化学类型也影响着水中痕量金属的富集。  相似文献   

18.
The riverine mud that escapes retention in the estuaries and enters the Gulf of Papua appears to be transported southeastward, across depth contours, by the prevailing currents in a series of wind-driven events. The mud deposits to the southeast of the rivers, at the mid-shelf region within a depth range of 40–60 m. Mud transported farther eastward is carried down the continental rise. Coarser riverine sediment (silt and sand) is deposited closer inshore. On the outer shelf (depth >60 m) relict carbonate debris dominates. The area of mud has maximum rates of pelagic and benthic productivity in the gulf.  相似文献   

19.
Two well-defined deltaic sequences in the Bohai Sea and in the South Yellow Sea represent post-glacial accumulation of Yellow River-derived sediments. Another prominent depocenter on this epicontinental shelf, a pronounced clinoform in the North Yellow Sea, wraps around the northeastern and southeastern end of the Shandong Peninsula, extending into the South Yellow Sea. This Shandong mud wedge is 20 to 40 m thick and contains an estimated 300 km3 of sediment. Radiocarbon dating, shallow seismic profiles, and regional sea-level history suggest that the mud wedge formed when the rate of post-glacial sea-level rise slackened and the summer monsoon intensified, at about 11 ka. Geomorphic configuration and mineralogical data indicate that present-day sediment deposited on the Shandong mud wedge comes not only from the Yellow River but also from coastal erosion and local rivers. Basin-wide circulation in the North Yellow Sea may transport and redistribute fine sediments into and out of the mud wedge.  相似文献   

20.
辽东湾北部潮滩及浅海区泥沙运移趋势   总被引:1,自引:0,他引:1  
本文根据多断面昼夜水文、泥沙观测,潮滩重复水准测量并借助~(210)Pb测年,分析了辽东湾北部潮滩和浅海区潮流及泥沙的分布和变化。结果表明:本区泥沙以纵向搬运为特征。双台子河口及西部来水来沙是东部沙洲和浅滩发育的主导因素。汛季大潮期,泥沙落淤在河口及附近浅海且泥沙自西向东运移;小潮期,泥沙除纵向扩散外(向东),存在净向海搬运。调查期滩面淤积强度自西向东减弱。高、中浓度泥沙浑位置与盐度梯度区的上部界面相符,多出现在25—30km以内的岸段(水深10—13m),30km以外泥沙骤减,海水亦由黄棕色变为兰绿色。  相似文献   

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