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1.
TEXTUAL RESEARCH ON THE MAIN SOURCE OF THE CHANGJIANG RIVER 总被引：2，自引：1，他引：1
The Chinese people began to research the main source of the Changjiang (Yangtze) River 2,400 years ago. Limited by the scientific level, they did not discover it.The Tuotuo River was determined as the main source of the Changjiang River in the 1970s. However, this was not correct, because when comparing the length of the Tuotuo River with the Dam River, the glacier length at the headwaters was added to the Tuotuo River, resulting in that the Tuotuo River is 1 km longer than the Dam River, keeping in mind that the glacier can not be regarded as part of the river.In the summer of 1986, we investigated the source of the Changjiang River, we accurately measured the length of both the Tuotuo and Dam rivers, we discovered that the Dam River was 353.1 km long, and the Tuotuo River was 346.3 km long, the Dam River thus being 6.8 km longer than the Tuotuo River. The discharge of the Dam River is 196.18 m3/ sec., 2.6 times as large as that of the Tuotuo River, that of the Tuotuo River is 75.10 m3/sec. The drainag 相似文献
2.
该文在查明区域水文地质条件、湖区地下水的类型、分布、埋藏条件、含水层及隔水层特征、岩性结构以及地下水的补给、径流、排泄条件的基础上,通过现场试验,确定了天然状态下湖区各含水层之间的水力联系、黄河侧渗补给量及湖区向小清河的排泄量,结合数值模拟,预测了湖区维持设计蓄水位21.5m时黄河的侧渗补给量、湖区向小清河的排泄量及湖区对周边地下水位的影响。结果表明,天然状态下,黄河侧渗补给量为748.23m~3/d,湖区向小清河排泄量大约为52.03m~3/d,黄河侧渗补给量远大于湖区向小清河的排泄量。数值模拟结果表明,湖区维持设计蓄水位21.5m时,不同水文年湖区接受的侧渗补给量均大于湖区的渗漏量,且对周围地下水位的影响不超过1.5m,因此,湖区维持设计蓄水位21.5m时可不考虑防渗措施。 相似文献
3.
基于DEM的流域水系分维计算与结果分析 总被引：7，自引：0，他引：7
利用ArcGIS8.3和ArcVIEW3.2中的水文分析模块,根据不同最小河流长度,提取晋江流域河网信息,采用传统的网格法计算提取的不同河网的分维,研究以最小河流长度所提取的不同河网密度与分维的关系,确定晋江流域分维,分析流域地貌的演变。 相似文献
4.
One of the most important factors controlling the morphology of the modern Huanghe(Yellow) River delta is consolidation settlement, which is impacted by fast deposition, high water content, and low density of seafloor sediment. Consolidation settlement of the Huanghe River subaqueous delta was studied based on field data, laboratory experiments on 12 drill holes, and the one-dimensional consolidation theory. Results show that vertical sediment characteristics varied greatly in the rapidly forming sedimentary bodies of the modern Huanghe River subaqueous delta. Sediments in the upper parts of drill holes were coarser than those in the deeper parts, and other physical and mechanical properties changed accordingly. On the basis of the one-dimensional consolidation theory and drilling depth, the final consolidation settlement of drill holes was between 0.6 m and 2.8 m, and the mean settlement of unit depth was at 1.5–3.5 cm/m. It takes about 15–20 years for the consolidation degree to reach 90% and the average sedimentation rate within the overlying 50 m strata was at 5 cm/a to 12 cm/a. This study helps to forecast the final consolidation settlement and settlement rate of the modern Huanghe River subaqueous delta, which provides key geotechnical information for marine engineers. 相似文献
5.
The modern Yellow River delta is formed near the estuary of the Yellow River with the characteristics of short formation time, efficient sedimentation rate and loose structure which make sediments prone to be compacted and consolidate under the geostatic stress and overburden stress. It is one of the key areas with land subsidence disasters in China, bringing a series of safety hazards to production and living. Based on the data of massive surface cores and ten drill holes ranging from 12 to 40 m obtained from the northern modern Yellow River subaqueous delta, the inversion method suitable for the calculation of consolidation settlement characteristics of the modern Yellow River subaqueous delta is discussed, and the consolidation settlement characteristics of the delta sediments are inversed and predicted in this paper. The actual void ratio of the delta sediments at the depth from 3 to 15 m shows a significant power function relationship with the depth, while the void ratio of the sediments below 15 m changes little with depth. The pre-consolidation settlement(from deposition to sampling) of the delta sediments is between 0.91 and 1.96 m, while the consolidation settlement of unit depth is between 9.6 and 14.0 cm m~(-1). The post-consolidation settlement(from sampling to stable) of the subaqueous delta sediments is between 0.65 and 1.56 m in the later stage, and the consolidation settlement of unit depth is between 7.6 and 13.1 cm m~(-1) under the overburden stress. The delta sediments with a buried depth of 3 to 7 m contribute the most to the possible consolidation settlement in the later stage. 相似文献
6.
On the northern fringe of Mt. Huangshan, many river terraces are developed at the junction between mountains and plains. The river terraces are most typical in the Jingxian Basin, Anhui Province, where the Qingyijiang River, one of the longest tributaries of the lower Yangtze River, developed three staircase terraces. The topmost terrace (i.e., the T3 terrace) tread is 38 - 39 m above river level, and the top of the gravels is generally covered by 3 - 10.9 m of red clay deposits. Systematic magnetostratigraphy and electron spin resonance dating are used to research the timing of the establishment of the Qingyijiang River. The main results show that the topmost terrace developed no later than 900 kyr ago and that the appearance of the Qingyijiang River occurred correspondingly at least before 900 kyr ago on the northern fringe of Mt. Huangshan. In view of the almost synchronous age, the establishment of the Qingyijiang River was seemingly a response to the Mid-Pleistocene Revolution when the 100 kyr cycle commenced, and the Kunlun-Huanghe movement during the early-middle Pleistocene transition. In addition, the establishment of the Qingyijiang River possibly reflected the birth of the modern Yangtze River to some degree. Therefore the timing of the formation of the Yangtze River is restricted to no later than 900 kyr ago based on the appearance of the Qingyijiang River 相似文献
7.
为探究济南市玉符河人工补源对趵突泉泉域的影响,在系统分析泉域水文地质条件的基础上,采用地下水数值模拟软件GMS10.0建立了2012—2014年覆盖趵突泉泉域的地下水流数值模型,通过模型对玉符河补源实施后地下水的径流方向、影响面积以及对泉水位和西郊水源地水位的提升作用进行评估。结果表明:玉符河补源在实际渗漏量为10.52×10~4m~3/d的情况下,玉符河补源水首先沿着炒米店地堑由南向北流,然后再向东、西方向径流。补源后第177 d,补源影响范围基本抵达四大泉群,玉符河补源的最大影响范围为485.79 km~2。玉符河补源对趵突泉、黑虎泉的最大影响水位为0.06 m和0.04 m;对济南西郊水源地的水位起到明显的提升作用,最大值达到0.57m。西郊水位的抬升可以缓解地下水开采对趵突泉水位的影响,减小保泉的压力,也为将来济南百姓重新喝上优质地下水奠定了基础。 相似文献
8.
The heavy mineral compositions of the sediments in core D04 with a length of 20.2 m from the muddy area outside the Oujiang Estuary along the coast of Zhejiang-Fujian Provinces have been analyzed. Core D04 can be divided into three units: DU1(0–7.4 m), DU2(7.4–11.4 m) and DU3(11.4–20.2 m). The results showed that the heavy minerals are authigenic pyrite(65.6%)– hornblende(16.0%) – epidote(4.6%) assemblages. The core sediments are mainly composed of clayey silt, which belongs to the clinoform deposit formed since 5.8 kyr, indicating a weak hydrodynamic environment. The deposition rates changed in the trend of high-low-high upward. Quantitative analysis shows that the core sediments were mainly from the suspended sediments of the Changjiang(Yangtze) River, accounting for 79.2%, with only 10.0% from Oujiang, and 10.8% from other provenance. The Oujiang-derived sediments were gradually increased from the bottom unit DU3(3.1%) to the top unit DU1(17.8%), but the Changjiang-derived sediments were gradually decreased. The source changes are closely related to the development of Yangtze River Delta and Wenzhou Bay, climate changes and human activities. During the period of 2.1–3.7 kyr, the sediment supply was greatly reduced due to the poor reclamation capacity of the river basins, resulting in a low deposition rate. Since 2 kyr, the enhancement of human activities in the Yangtze River Basin and the Oujiang River Basin led to more soils to be eroded and transported to the study area. Due to the short distance of the site of core D04 from the Oujiang River mouth, the study area received more Oujiang-derived sediments when upper unit(DU1) deposited than the lower units(DU2 and DU3). 相似文献
9.
10.
CHENG Jie ZHANG Xujiao TIAN Mingzhong YU Wenyang and YU Jiangkuan China University of Geosciences Beijing China TANG Dexiang Institute of Process Engineering Chinese Academy of Sciences Beijing China YUE Jianwei Institute of Geographic Sciences Natural Resources Research Chinese Academy of Sciences Beijing China 《山地科学学报》2005,2(3):193-201
Introduction The Tibetan Plateau, located in west China, was uplifted during the Cenozoic and became the most youthful plateau in the world. Some researches have also shown that it started to develop into the cryosphere in the beginning of the Middle Pleistocene and became one of the three global cryospheres (two other cryospheres being the Artic and the Antarctic) (SHI et al. 1996). Because of the cryosphere development in the Tibetan Plateau, many periglacial and permafrost geomorpholog… 相似文献
11.
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12.
黄河流域作为中国东部平原的生态屏障,研讨其植被覆盖的时空变化有助于生态环境治理。本文利用GEE平台,基于Landsat数据通过像元二分模型反演了1990—2020年黄河流域植被覆盖度（FVC）,并通过Theil-Sen Median趋势分析和 Mann-Kendall检验方法剖析FVC的时空变化趋势,挖掘出FVC趋势变化与海拔、坡度、坡向等地形因子之间的响应关系。结果表明：① 黄河流域FVC整体呈现西北低东南高的空间分布趋势,其中低等FVC占整个流域面积的45%,主要集中于西北部干旱半干旱地区;② 流域中部植被覆盖改善明显,占整个流域的57.07%,西北部和东南部退化程度相对较高;③ 植被覆盖受地形效应影响较为显著,在坡度大于40°及高程（-31~637 m）时高等级FVC占比较高,坡度8~18°及高程1852~2414 m范围内植被改善效果相对较好。结果可以为黄河流域生态环境保护及高质量发展提供科学支撑。 相似文献
13.
西藏一江两河地区人口分布与地形要素关系分析 总被引：2，自引：0，他引：2
地形条件是影响区域人口分布的最基本的因素之一,本文基于1 km×1 km人口空间分布公里网格数据定量分析一江两河地区人口分布基本特征及其与高程、坡度、坡向、地形起伏度等地形要素之间的关系,有助于揭示西藏高原人口分布现状的本质、理解人口空间分布结构特征,对于今后宜居地选址、改善农牧民人居环境、制定区域经济发展政策,促进区域内人口、资源与环境可持续发展具有重要意义。研究结果表明：① 一江两河地区90%的区域人口密度不足10人/km2,80%的人口分布在不足5%的土地上,人口分布比较集中。当前一江两河地区有2个主要的人口集中区,分别是拉萨市城关区和日喀则地区日喀则市,拉萨市城关区尤其显著。② 一江两河地区人口沿河分布,80.46%的人口居住在距离河流10 km以内区域,人口总数、人口密度与距河流距离呈明显的指数关系,距离河流2 km以内的区域人口密度高于50人/km2;③ 近99%的人口分布在海拔4500 m以下,当高程超过3800 m时,人口密度随海拔升高呈下降趋势;④ 近70%的人口分布在坡度小于15°的区域,而且随着坡度越大,人口密度越小,人口分布受坡向的影响不明显;⑤ 地形起伏度对人口分布的影响显著,近85%的人口分布在地形起伏度小于800 m的区域,人口密度与地形起伏度之间为倒指数关系。 相似文献
14.
黄河三角洲是中国唯一一块保存最完整、最典型、最年轻的湿地生态系统,由于其地理位置优越、自然资源丰富等特点,在国际上备受关注。该文在已有资料分析、现场地质调查、遥感数据分析的基础上,构建了黄河三角洲湿地资源地质环境评价指标体系,采用定量与定性相结合的方法,将黄河三角洲湿地地质环境质量分为5个等级(优、良、一般、较差和差),研究结果表明,该地区19个县(市、区)中湿地地质环境资源质量为良的有8个,质量一般的为11个,总体处于健康-疾病的临界状态。并基于以上研究成果,针对性地提出了黄河三角洲湿地资源保护对策。 相似文献
15.
车志伟 《广东海洋大学学报》2007,27(6):89-92
河流入海口及感潮河段是陆海相互作用藕合带，受径流和潮汐的共同作用，具有独特的海洋环境。三亚河位于三亚湾的东侧，是注入三亚湾的最大河流，其流程28．8km，集雨面积337．02km^2，河床平均坡降6．09‰，总落差459．21m，三亚河属潮汐河流，平均每日纳潮量达490万立方米，年径流量为179亿立方米，现实际日纳潮量为253立方米、年径流量为92亿立方米。近年来，国内学者已对三亚湾海域开展了若干研究，如中国科学院南海海洋研究所何雪琴、南京大学海岸与海岛开发教育部重点实验室毛龙江等都先后报道过三亚湾的研究结果，但对三亚河口及感潮段悬浮物分布的研究目前尚未见报道。本文通过分析监测结果，研究了三亚河入海口及感潮河段悬浮物分布特征和潮汐对其影响。 相似文献
16.
Oasis System and Its Reasonable Development in Sangong River Watershed in North of the Tianshan Mountains, Xinjiang, China 总被引：1，自引：0，他引：1
LEI Jun LUO Geping ZHANG Xiaolei LU Qi 《中国地理科学(英文版)》2006,16(3):236-242
An oasis is a kind of medium-sized or small-sized non-zonal landscape coming into being in the dry climate and supported by natural rivers in deserts, which is characterized by the comparatively high primary pro- ductivity and has the mesophytic plants or xero-mesophytic plants as the dominant vegetation (Jia, 1996). The oasis system, first of all, is a subsystem within the macro system of “mountain-oasis-desert” in the arid region. It is also a complex system where the natural and artificia… 相似文献
17.
Estimation of ecological water requirements based on habitat response to water level in Huanghe River Delta, China 总被引：3，自引：0，他引：3
Baoshan Cui Yanyan Hua Chongfang Wang Xiaolin Liao Xuejie Tan Wendong Tao 《中国地理科学(英文版)》2010,20(4):318-329
In recent years,wetland ecological water requirements (EWRs) have been estimated by using hydrological and functional approaches,but those approaches have not yet been integrated for a whole ecosystem.This paper presents a new method for calculating wetland EWRs,which is based on the response of habitats to water level,and determines water level threshold through the functional integrity of habitats.Results show that in the Huanghe (Yellow) River Delta water levels between 5.0 m and 5.5 m are required to maintain the functional integrity of the wetland at a value higher than 0.7.One of the dominant plants in the delta,Phragmites australis,tolerates water level fluctuation of about ± 0.25 m without the change in wetland functional integrity.The minimum,optimum and maximum EWRs for the Huanghe River Delta are 9.42×106 m3,15.56×106 m3 and 24.12×106 m3 with water levels of 5.0 m,5.2 m and 5.5 m,corresponding to functional integrity indices of 0.70,0.84 and 0.72,respectively.A wetland restoration program has been performed,which aims to meet these EWRs in attempt to recover from losses of up to 98% in the delta's former wetland area. 相似文献
18.
Jinqing Liu Ke Cao Ping Yin Fei Gao Xiaoying Chen Yong Zhang Yiyong Yu 《中国海洋大学学报(英文版)》2018,17(6):1352-1360
Clay mineral compositions of 199 offshore surface sediment samples collected from the Hangzhou Bay have been analyzed. The clay minerals in the sediments from the Hangzhou Bay are dominated by illite(58.7%, on average), followed by chlorite(20.3%), kaolinite(16.9%) and smectite(4.1%). Two provinces were classified by Q-mode cluster analysis. Class Ⅰ with relatively low amounts of illite and smectite is widely distributed in the Hangzhou Bay, especially concentrated in the top and mouth of the bay, and the northern and southern nearshore areas. Class Ⅱ with comparatively high amounts of illite and smectite is mainly concentrated in the central part of the bay with the water depth of 8–10 m. By comparing clay mineral compositions with the neighbouring regions, we can find that the sediments in the Hangzhou Bay are mainly influenced by the resuspension and repeated deposition of particles from the Yangtze River due to the strong dynamic environment. In particular, the clay fraction of Class Ⅰ is mainly supplied by the Yangtze River, while the sediments of Class Ⅱ are mixture of the clay minerals carried by the Yangtze River and Qiantang River. In general, the distributions of clay minerals in the northern bay are affected by Yangtze River runoff, coastal current and flood tide together, and in the southern they are mainly affected by the Qiantang River runoff and ebb tide. 相似文献
19.
钱步东 《中国地理科学(英文版)》1997,(3)
I.I~IOXENds(EINabs/SouthernOscillation)eventsaretheintensivesignalsofair-seainteractionintropicalarea.PlentyOfresultsfromdifferentresearchersshoWthattheENdssignalcanbedetectedoninterannualvallationsoflargescaleatmOSPhericcirculationandclimateregimeSovermostpartsoftheworld.SeveralkindsofrelationShipbetweenENdsandprecipitationoverChinahavebeenrevealedbydifferentreSearcherS,buttherearemanydifferencesamongthepublishedreSults.Itmayberesulted*fromthatdifferentreSearchersuseddifferentindic… 相似文献
20.
Xiaohong Ma Zongzhu Han Yong Zhang Shipu Bi Gang Hu Jinqing Liu Chengfen Xu 《中国海洋大学学报(英文版)》2018,17(6):1369-1381
To examine the composition and source variations of heavy minerals in the Fujian-Zhejiang mud belt(FZMB) over the past few hundred years, heavy minerals in 150 surficial sediment samples and two sediments cores collected from the southern FZMB were identified and analyzed. The results show that the mineral assemblage of hornblende-magnetite-epidote-chlorite is dominant in the study area. Based on the heavy mineral contents, the study area is divided into two mineral zones, namely a near-shore muddy sediment zone(zone Ⅰ) and an offshore mixed sediment zone(zone Ⅱ). The sediments from zone Ⅰ contains relatively abundant metallic minerals with proximal sediments from the Oujiang River and the Minjiang River as the primary component. The sediment from zone Ⅱ has relatively low content for minerals from the near-shore materials and is significantly affected by the Oujiang River sediments, and by the flaky minerals from the Yangtze River to a certain extent. The characteristics of heavy minerals in the cores may be affected by a variety of factors. Before the 20th century, under the influence of strong East Asian winter monsoon(EAWM), the sandy sediment in FZMB is significantly affected by the Oujiang River and the Yangtze River sediments, and relatively unaffected by near-shore terrigenous matter. In the 20th century, as the intensity of the Zhejiang-Fujian Coastal Current(ZFCC) decreased, the influence of the Minjiang coastal sand enhanced. Since the 1980s, as the collective effect of relatively weak EAWM and frequent storm surges and typhoons, the impact of the Minjiang River sediments on the FZMB sediments has increased considerably. 相似文献