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1.
The paper presents a new approach to calculating the erosion and deposition values of floodplain lake basins, the erosion–deposition index (EDI). The EDI is a sum of the basin geometry indices (BGIs), which can be calculated for a separate cross section of the lake. The distribution of processes within the basin was investigated in two selected floodplain lakes with the use of BGIs. Field research was carried out in the Bug River valley from 1 November 2006 to 31 October 2011. The highest erosion was observed in the lakes located close to the parent river. Deposition processes were observed in lakes with high inflow of groundwater. The results showed that EDI values of 48 out of the 71 floodplain lakes ranged from ?0.2 to 0.2. Spatial distribution of erosion and deposition processes within the lake basins resulted from a velocity of water inflowing or flowing through the basin. This was observed especially in contrafluent–confluent lake. Inflow of rivers water via upstream crevasse occurred later than via downstream one, but energy of flowing water was higher, which favoured erosion of this part of the lake basin. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

2.
王容  刘元波  王若男  刘永伟 《湖泊科学》2023,35(3):1057-1071
GLEAM(Global Land Evapotranspiration Amsterdam Model)和MOD16(MODIS Global Evapotranspiration Project)全球蒸散发产品已经得到了广泛的检验和应用,但由于观测资料缺乏,尚缺少对高原地区的检验。本文以青藏高原然乌湖流域、羊卓雍错流域、纳木错流域、色林错流域和塔若错流域为检验区域,利用流域水量平衡法,采用相关系数、相对误差、均方根误差和Kling-Gupta系数,对这两种蒸散产品开展了精度验证与评价。结果表明:GLEAM蒸散发产品在然乌湖、色林错和塔若错流域整体存在低估现象,在羊卓雍错和纳木错流域存在轻微高估现象,而MOD 16产品仅在色林错流域有轻微低估现象,在其他湖泊流域均表现为高估;GLEAM和MOD16蒸散发产品在5个湖泊流域年降水量较少的年份均存在高估的现象,在湿润年份则为低估;GLEAM产品在然乌湖流域、羊卓雍错流域和色林错流域的验证结果相对较好,而MOD16产品在纳木错流域和塔若错流域的验证精度相对较高;总体而言,在年尺度和多年平均尺度下,GLEAM蒸散发产品在青藏高原中东南湖泊流域...  相似文献   

3.
Kaftar Lake is a high‐altitude fresh water lake located in High Zagros, south of Iran. Despite the high annual evaporation to precipitation ratio in the area, lake water electrical conductivity is usually lower than 1000 µS/cm, this may be due to high seepage from the floor of the lake. Therefore, the hypothesis of possible underground connections between Namdan Basin, where the lake is located, and the surrounding basins with lower elevation (Aspas and Dehbid Basins) was investigated. Hydrogeology, hydrochemistry, and stable isotopes data of the lake and surrounding basins along with the lake water balance study were applied to test the hypothesis. Results indicate that Kaftar Lake has no connection with Aspas Basin in south, but it is hydraulically connected to Dehbid Basin. In Dehbid Basin, “Ghasr_e_Yaghoob spring” (average discharge ?1200 L/s) emerges from a small outcrop (about 0.8 km2) of Daryan limestone Formation, where this outcrop is much smaller than the required recharge area for such average discharge rate. The study shows that this spring is recharged by Kaftar Lake and Namdan Basin aquifer, through Daryan Formation of Gandboee Syncline located to the northern part of the lake.  相似文献   

4.
The chemical and biological conditions of the Lake of Lucerne and of the lower basin of the Lake of Constance are discussed on the basis of observations on the phosphorus content in the course of the past ten years. The heavy load by suspended solids on two basins on the Lake of Lucerne caused a decrease of soluble P-compounds by adsorption. In two other basins of the same lake considerable phosphorus resolubilization from sediments is on the way since 1968. Phosphorus dynamics in the lower basin of Lake Constance is governed by wash-out and by resolubilization and sedimentation respectively. We recommend to adopt a minimum lower limit of 4 to 6 mg O2/l at any point and at any time in the water body of a lake as a specific criterion for defining the final aim of lake protection or lake restauration measures. With the fulfillment of this requirement, satisfactory conditions for all utilizations of a lake ecosystem will exist.  相似文献   

5.
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6.
The aim of this paper is to assess the relative importance of low flow indicators for the River Rhine and to identify their appropriate temporal lag and resolution. This is done in the context of low flow forecasting with lead times of 14 and 90 days. First, the Rhine basin is subdivided into seven sub‐basins. By considering the dominant processes in the sub‐basins, five low flow indicators were selected: precipitation, potential evapotranspiration, groundwater storage, snow storage and lake storage. Correlation analysis was then carried out to determine the relationship between observed low flows and preselected indicators with varying lags (days) and temporal resolutions (from 1 day to 7 months). The results show that the most important low flow indicators in the Alpine sub‐basins for forecasts with a lead time of 14 days are potential evapotranspiration with a large lag and temporal resolution, and lake levels with a small lag and temporal resolution. In the other sub‐basins groundwater levels with a small lag and temporal resolution are important in addition to potential evapotranspiration with a large lag and temporal resolution. The picture is slightly different for forecasts with a lead time of 90 days. The snow storage in the Alpine sub‐basins and the precipitation in the other sub‐basins also become relevant for low flows. Consequently, the most important low flow indicators in the Alpine sub‐basins for forecasts with a lead time of 90 days are potential evapotranspiration with a large lag and temporal resolution, lake levels with a small lag and temporal resolution and snow storage with a small lag and large temporal resolution. The resultant correlation maps provide appropriate lags and temporal resolutions for indicators to forecast low flows in the River Rhine with different lead times. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

7.
Hydrocarbon distribution in sediments from three lakes are related to the level of human activity in the respective drainage basins. Petroleum hydrocarbon contamination is found in surface sediments of a lake surrounded by a major city, compared to no detectable contamination in a lake located in a National Park.  相似文献   

8.
The character of organic carbon (OC) in lake waters is strongly dependent on the time water has spent in the landscape as well as in the lake itself due to continuous biogeochemical OC transformation processes. A common view is that upstream lakes might prolong the water retention in the landscape, resulting in an altered OC character downstream. We calculated the number of lakes upstream for 24,742 Swedish lakes in seven river basins spanning from 56º to 68º N. For each of these lakes, we used a lake volume to discharge comparison on a landscape scale to account for upstream water retention by lakes (Tn tot). We found a surprisingly weak relationship between the number of lakes upstream and Tn tot. Accordingly, we found that the coloured fraction of organic carbon was not related to lake landscape position but significantly related to Tn tot when we analysed lake water chemical data from 1,559 lakes in the studied river basins. Thus, we conclude that water renewal along the aquatic continuum by lateral water inputs offsets cumulative retention by lakes. Based on our findings, we suggest integrating Tn tot in studies that address lake landscape position in the boreal zone to better understand variations in the character of organic carbon across lake districts.  相似文献   

9.
Permafrost degradation associated with the expansion of thermokarst lakes is commonly interrupted by catastrophic drainage. Subsequently, in tundra areas, permafrost aggradation in drained basins leads to uneven topography characterized by raised centres and wet, depressed margins. The genesis of such topography has been investigated in Old Crow Flats (OCF), a glaciolacustrine plain in the continuous permafrost of northern Yukon. The thermokarst lakes of OCF have a mean depth of only 1.5 m because excess ice is dominantly found only in the uppermost 10 m of the ground. Surface conditions were measured in three drained thermokarst lake basins, including relief, snow conditions, ground temperatures, near‐surface ground ice, and sediment stratigraphy. Four nearby lakes provided information on wave base, shore recession patterns, and bathymetry before drainage: the bottoms of these lakes were not raised in the centre. An elevation difference of up to 2 m was recorded between drained basin margins and centres but was not associated with variations in ice‐wedge density or segregated ice content. Hence basin topography was not controlled by differences in volumetric ground‐ice content between margins and centres. We propose that transport of fine sediment away from eroding lake margins during lake development is the primary mechanism for the genesis of depressed margins and raised centres in drained basins of OCF. Over time, the transport results in the deposition of more and finer sediment in the central parts of lakes, where the lake bottom has subsided below wave base, than at the shallow margins, where resuspension by wave action occurs frequently. This difference in sediment volume is revealed in the topography after drainage, when permafrost aggrades in the lake‐bottom sediment and underlying talik. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

10.
Glacier recessions caused by climate change may uncover pro‐glacial lakes that form important sedimentation basins regulating the downstream sediment delivery. The impact of modern pro‐glacial lakes on fluvial sediment transport from three different Norwegian glaciers: Nigardsbreen, Engabreen and Tunsbergdalsbreen, and their long‐term development has been studied. All of these lakes developed in modern times in overdeepened bedrock basins. The recession of Nigardsbreen uncovered a 1.8 km long and on average 15 m deep pro‐glacial lake basin during 1937 to 1968. Since then the glacier front has been situated entirely on land, and the sediment input and output of the lake has been measured. The suspended sediment transport into and out of the lake averaged 11 730 t yr?1 and 2340 t yr?1 respectively. Thus, 20% remained in suspension at the outlet. The measured mean annual bedload supplied to the lake was 11 800 t yr?1, giving a total transport of 23 530 t yr?1 which corresponds to a specific sediment yield of 561 t km?2 yr?1. A 1.9 km long and up to 90 m deep pro‐glacial lake basin downstream from Engabreen glacier was uncovered during 1890 to 1944. The average suspended sediment load delivered from the glacier during the years 1970–1981 amounted to 12 375 t yr?1and the transport out of the lake was 2021 t yr?1, giving an average of 16% remaining in suspension. The mean annual bedload was 8000 t yr?1, thus the total transport was 20 375 t yr?1, giving a specific sediment yield of 566 t km?2 yr?1. For Tunsbergdalsbreen glacier, measurements in the early 1970s indicated that the suspended sediment transport was on average 44 000 t yr?1. From 1987 to 1993 the recession of the glacier uncovered a small pro‐glacial lake, 0.3 km long and around 9 m deep. Downstream from this, the suspended sediment load measured in 2009 was 28 000 t yr?1, indicating that as much as 64% remained in suspension. Flow velocity, grain size of sediment, and morphology of the lake are important factors controlling the sedimentation rate in the pro‐glacial lakes. A survey of the sub‐glacial morphology of Tunsbergdalsbreen revealed that there are several overdeepened basins beneath the glacier. The largest is 4 km long and 100 m deep. When the glacier melts back they will become lakes and act as sedimentation basins. Despite an expected increase in sediment yield from the glacier, little sediment will pass these lakes and downstream sediment delivery will be reduced markedly. Beneath Nigardsbreen there was only a small depression that may form a lake and the sediment delivery will not be significantly affected. © 2014 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.  相似文献   

11.
深入认识大型湖泊在不同风速、风向和水位下三维风生流结构特征对于湖泊污染控制、生态恢复及资源的开发利用具有重要意义.本文在构建笛卡尔坐标系下洪泽湖三维水动力模型的基础上,利用2次全湖30个点位流场监测数据验证了模型精度.基于1975-2020年长系列风场观测数据,确定了洪泽湖典型风速风向.在此基础上,模拟了16种不同风向,13种不同风速和20种不同水位工况条件下洪泽湖三维风生流结构.结果表明：水动力模型可以较好地刻画洪泽湖三维湖流变化特征.洪泽湖风生流结构随风向变化呈现出较大空间差异.风生流流速随着风速的升高呈加速上升趋势,其中表层水体流速上升幅度远高于其他水层.在2.4 m/s东风驱动下,溧河洼、成子湖和南部湖区垂向平均流速随着水位上升呈先升高后降低的趋势,3个湖区分别在12.7、12.4和12.2 m水位下流速达到最大值.  相似文献   

12.
In the present study, the mean annual sediment inflow into Vistonis Lake (Thrace, northeastern Greece) was calculated. The sediment quantity originates mainly from the basins of Kossynthos, Kompsatos and Travos (Aspropotamos) Rivers. The whole basin area (mountainous part) contributing to the lake amounts to about 845 km2. The above mean annual sediment quantity was compared with the mean annual sediment accumulation in the lake. The latter quantity was estimated from the mean annual decrease of the lake water volume for a period of 22 years, which was determined by means of older and newer topographic maps (isobath contours). For the calculation of the mean annual sediment yield at the outlets of the three above mentioned basins, a mathematical model consisting of three submodels was used: a rainfall-runoff submodel, a soil erosion submodel and a sediment transport submodel for streams. The comparison of the computational results by means of the mathematical model with the estimation results by means of the topographic maps is satisfactory and encouraging.  相似文献   

13.
Since the Meso-Cenozoic, controlled by paleoclimate, a series of fresh to brackish water basins and salt to semi-salt water basins were developed in wet climatic zones and in dry climate zones in China, respectively[1]. The geological and geochemical char…  相似文献   

14.
The recent rapid expansion of inland lakes on the Tibetan Plateau (TP) are a good indicator of the consequences of climate change. Quantifying the hydrological cycle of the lake basin is fundamentally important to understand the causes of lake growth. However, the hydrological processes of the TP interior are very complex and difficult to investigate because of the lack of observations. This is especially true for estimating the lake changes when run‐off inflows are affected by small lakes located in the flow routes within drainage areas. We used an integrated hydrological model, in combination with glacier melt and lake retention models, to analyse the run‐off inflows to Lake Siling Co, the largest endorheic lake in Tibet. It includes four subdrainage basins: Zhajiazangbu, Zhagenzangbu, Alizangbu, and Boquzangbu. Lake Siling Co was characterized by considerable increases during warm season from 1981 to 2012, due to the increased run‐off from Zhajiazangbu accounting for about 51–62% of the total run‐off inflows. Moreover, the dramatic increases exhibited during cold seasons were related to the increased retention water released from the small lakes within Zhagenzangbu and Alizangbu. Of the studied subdrainage basins, Boquzangbu contributed the least during both warm and cold seasons. On average, the annual amount of evaporation from lakes within the drainage area was about 2 times greater than that of glacier melt run‐off. Our results suggest that the retention effects of lakes on river inflows should receive more attention, because understanding these effects is potentially crucial to improved understanding of lake variations in the TP.  相似文献   

15.
ABSTRACT

Understanding of the effect of basin water resources utilization on lake nutrients is helpful to prevent lake eutrophication and facilitate sustainable water resources management. In this study, a lake basin dualistic water cycle system is established to identify the environmental effect of lake water. Four water utilization indicators were chosen to build a driving relationship with the lake nutrients. Three different trophic lakes in Yunnan Province, China – Dianchi, Erhai and Fuxian – were selected to demonstrate the changes in basin water utilization, runoff, nutrient loads and water-use indicators for the period 2000–2015. In addition, the driving forces of water-use indicators to nutrients (total nitrogen and total phosphorus) were analysed by a general additive model. Finally, an optimized water utilization system for each lake basin is proposed. The research provides a practical tool for water resources and environmental management in lake basins.  相似文献   

16.
The current and future state of the Earth’s water resources under present-day trends in water use is discussed. The activity of international institutions in the organization of management of lake ecosystems and drainage basins was analyzed from the viewpoint of sustainable development. The work of International Committee on Lake Environment, International Joint Commission (USA and Canada), International Commission on Lake Constance Protection, Autonomous Bilateral Management of Lake Titicaca, Commission on Chad Lake Basin, and Fishery Organization of Lake Victoria. Recommendations are proposed for the organization of international management of water bodies and their drainage basins.  相似文献   

17.
Spatial variability of recent lacustrine sedimentary structures and sedimentation rates are examined for Green Lake, a morphologically complex lake basin of the southern Coast Mountains, British Columbia. A dense, 100 m grid sampling scheme was used for sediment coring within the 2 km2 lake basin. Deltaic, massive, weakly laminated, and varved sediment sequences are identified within the sediment record. Spatial patterns among these sedimentary deposits are related to within‐lake sediment transfer processes, morphometric controls, and the extent of post‐depositional mixing by bioturbation. Unconformities, turbidites, and cohesive slump failure deposits, observed within the contemporary varve sequences, could all be correlated with major flooding events in the catchment area and direct anthropogenic disturbances along the shoreline. There is an overall, non‐linear decrease in sedimentation rates with increasing distance from the lake inflows; however, this pattern is disrupted in deep water sites of intervening lake sub‐basins where locally higher accumulation rates are observed. Spatial sedimentation patterns are quantitatively described by an empirically‐derived model. Systematic variations in the model parameters are observed for different lake sub‐regions and are associated with changing sediment transfer dynamics between proximal and distal sub‐basin settings. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

18.
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19.
中国近海前新生代残留盆地初探   总被引：32，自引：18，他引：14  
中国近海沉积盆地按形成时代可以划分为新生代盆地和前新生代盆地。新生代陆相碎屑岩断陷盆地有良好的油气前景,而古生代还有广泛海相碳酸盐岩分布地区,只要它们经受中生代挤压,改造后还能保留下来,就具有巨大的油气潜力。初步分析中国近海的油气勘探资料及大地构造演化史表明,陆内断坳盆地下伏以古生代碳酸盐岩为主的残留盆地。而陆缘盆地并不是寻找古生代残留盆地的场所。但在台西南盆地,珠江口盆地潮汕坳陷发育海相中生代盆  相似文献   

20.
In the Great Lakes basin of North America, annual run‐off is dominated by snowmelt. This snowmelt‐induced run‐off plays an important role within the hydrologic cycle of the basin, influencing soil moisture availability and driving the seasonal cycle of spring and summer lake levels. Despite this, relatively little is understood about the patterns and trends of snow ablation event frequency and magnitude within the Great Lakes basin. This study uses a gridded dataset of Canadian and United States surface snow depth observations to develop a regional climatology of snow ablation events from 1960 to 2009. An ablation event is defined as an interdiurnal snow depth decrease within an individual grid cell. A clear seasonal cycle in ablation event frequency exists within the basin and peak ablation event probability is latitudinally dependent. Most of the basin experiences peak ablation frequency in March, while the northern and southern regions of the basin experience respective peaks in April and February. An investigation into the interannual frequency of ablation events reveals ablation events significantly decrease within the northeastern and northwestern Lake Superior drainage basins and significantly increase within the eastern Lake Huron and Georgian Bay drainage basins. In the eastern Lake Huron and Georgian Bay drainage basins, larger ablation events are occurring more frequently, and a larger impact to the hydrology can be expected. Trends in ablation events are attributed primarily to changes in snowfall and snow depth across the region.  相似文献   

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