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1.
Daily river inflow time series are highly valuable for water resources and water environment management of large lakes. However, the availability of continuous inflow data for large lakes is still relatively limited, especially for large lakes situated within humid plain regions with tens or even hundreds of tributaries. In this study, we choose the fifth largest freshwater Lake Chaohu in China as our study area to introduce a new approach to reconstruct historical daily inflows at ungauged subcatchments of large lakes. This approach makes use of water level, lake surface rainfall, evaporation from the lake, and catchment rainfall observations. Rainfall–runoff relationship at a reference catchment was analysed to select rainfall input and estimate run‐off coefficient firstly, and the run‐off coefficient was then transferred to ungauged subcatchments to initially estimate daily inflows. Run‐off coefficient was scaled to adjust daily inflows at ungauged subcatchments according to water balance of the lake. This approach was evaluated using sparsely measured inflows at eight subcatchments of Lake Chaohu and compared with the commonly used drainage area ratio method. Results suggest that the inflow time series reconstructed from this approach consistent well to corresponding observations, with mean R2 and Nash–Sutcliffe efficiency values of 0.69 and 0.6, respectively. This approach outperforms drainage area ratio method in terms of mean R2 and Nash–Sutcliffe efficiency values. Accuracy of this approach holds well when the number of water‐level station being used decreased from four to one.  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.
青藏高原大部分湖泊近年来持续扩张,湖泊水位和水量明显增加.冰川消融是流域水量平衡和水循环的重要影响因素,直接导致湖泊水量变化.由于缺乏大范围的冰川质量平衡观测结果,青藏高原冰川消融对湖泊水量变化的影响仍存在较大争议.本文选择青藏高原内流区的色林错流域区(水系编号5Z2)作为研究对象,利用SRTM DEM和TanDEM-X双站InSAR数据,精确估算该流域三个主要冰川区(普若岗日、格拉丹东和西念青唐古拉)2000—2012年的冰川质量平衡,依次为:-0.020±0.030、-0.128±0.049、-0.143±0.032m·w.e.·a-1.并据此采用面积加权法准确推估出5Z2流域的冰川质量变化为:-0.166±0.021Gt·a-1.综合ICESat和Cryosat-2卫星测高数据,计算该流域2003—2012年湖泊水量变化速率(3.006±0.202Gt·a-1),并定量评估冰川质量变化对5Z2流域湖泊水量增加的贡献为:5.52%±1.07%,因此在青藏高原色林错流域区,冰川消融不是导致21世纪初期湖泊水位上升的主要因素.  相似文献   

4.
Environmental isotopes (δ18O, δD and 3H) were used to understand the hydrodynamics of Lake Naini in the State of Uttar Pradesh, India. The data was correlated with the in situ physico‐chemical parameters, namely temperature, electrical conductivity and dissolved oxygen. The analysis of the data shows that Lake Naini is a warm monomictic lake [i.e. in a year, the lake is stratified during the summer months (March/April to October/November) and well mixed during the remaining months]. The presence of a centrally submerged ridge inhibits the mixing of deeper waters of the lake's two sub‐basins, and they exhibit differential behaviour. The rates of change of isotopic composition of hypolimnion and epilimnion waters of the lake indicate that the water retention time of the lake is very short, and the two have independent inflow components. A few groundwater inflow points to the lake are inferred along the existing fractures, fault planes and dykes. In addition to poor vertical mixing of the lake due to the temperature‐induced seasonal stratification, the lake also shows poor horizontal mixing at certain locations of the lake. The lake–groundwater system appears to be a flow‐through type. Also, a tritium and water‐balance model was developed to estimate the water retention time of well‐mixed and hydrologically steady state lakes. The model assumes a piston flow of groundwater contributing to the lake. The developed model was verified for (a) Finger Lakes, New York; (b) Lake Neusiedlersee, Austria; and (c) Blue Lake, Australia based on literature data. The predicted water retention times of the lakes were close to those reported or calculated from the hydrological parameters given in the references. On application of this model to Lake Naini, a water retention time of ～2 years and age of groundwater contributing to the lake ～14 years is obtained. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

5.
Himalayan basins have considerable snow‐ and glacier‐covered areas, which are an important source of water, particularly during summer season. In the Himalayan region, in general, the glacier melt season is considered to be from May to October. Changes in hydrological characteristics of the runoff over the melt season can be understood by studying the variation in time to peak and time lag between melt generation and its emergence as runoff. In the present study, the runoff‐delaying characteristics of Gangotri Glacier, one of the largest glaciers in the Indian Himalayas, have been studied. For this purpose, hourly discharge and temperature data were collected near the snout of the glacier (4000 m) for three ablation seasons (2004–2006). The diurnal variations in discharge and temperature provided useful information on water storage and runoff characteristics of the glacier. In the early stages of the ablation period, poor drainage network and stronger storage characteristics of the glaciers due to the presence of seasonal snow cover resulted in a much delayed response of melt water, providing a higher time lag and time to peak as compared to the peak melt season. A comparison of runoff‐delaying parameters with the discharge ratio clearly indicated that changes in time lag and time to peak are inversely correlated with variations in discharge. Impact of such meltwater storage and delaying characteristics of glaciers on hydropower projects being planned/developed on glacier‐fed streams in India has been discussed. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

6.
We analysed contributions to run‐off using hourly stream water samples from seven individual melt‐induced run‐off events (plus one rainfall event) during 2011, 2012 and 2013 in two nested glacierized catchments in the Eastern Italian Alps. Electrical conductivity and stable isotopes of water were used for mixing analysis and two‐component and three‐component hydrograph separation. High‐elevation snowmelt, glacier melt and autumn groundwater were identified as major end‐members. Discharge and tracers in the stream followed the diurnal variations of air temperature but markedly reacted to rainfall inputs. Hysteresis patterns between discharge and electrical conductivity during the melt‐induced run‐off events revealed contrasting loop directions at the two monitored stream sections. Snowmelt contribution to run‐off was highest in June and July (up to 33%), whereas the maximum contribution of glacier melt was reached in August (up to 65%). The maximum groundwater and rainfall contributions were 62% and 11%, respectively. Run‐off events were generally characterized by decreasing snowmelt and increasing glacier melt fractions from the beginning to the end of the summer 2012, while run‐off events in 2013 showed less variable snowmelt and lower glacier melt contributions than in 2012. The results provided essential insights into the complex dynamics of melt‐induced run‐off events and may be of further use in the context of water resource management in alpine catchments. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

7.
Baojin Qiao  Liping Zhu 《水文研究》2017,31(15):2752-2763
Most lakes of the Tibetan Plateau were experiencing quick expansion in recent decades; a detailed study on the changes in lakes of different supply types will help to understand the cause of the changes by analysing area change of 34 lakes and water level change of eight lakes in the north‐western Tibetan Plateau. All lakes are classified into three types: non‐glacier‐fed lakes, upstream lakes and glacier‐fed lakes. The glacier‐fed lakes are separated into glacier‐fed_P1 (quick expansion region) and glacier‐fed_P2 (slow expansion region). Combining the changes in precipitation, temperature and evaporation, less precipitation may be the main reason for lake shrinkage from 1976 to 1996 and quickly increasing precipitation led to the lakes' expansion from 1996 to 2000. However, after 2000, upstream lakes remained in a stable state with slight variation, non‐glacier‐fed lakes and glacier‐fed_P2 lakes exhibited a slightly increasing rate with high precipitation and high evaporation, and glacier‐fed_P1 lakes still expanded quickly. On the basis of the assumption of same precipitation and evaporation, glacial meltwater may make an important contribution (>52%) to the increase in water storage of Bangdag Co and Meima Co. The results suggest that glacial meltwater augments the increased rate of glacier‐fed_P2 lakes and plays a much more important role in the expansion of glacier‐fed_P1 lakes compared to other lakes.  相似文献   

8.
全球变化下青藏高原湖泊在地表水循环中的作用   总被引：2，自引：2，他引：0  
青藏高原是地球上最重要的高海拔地区之一,对全球变化具有敏感响应.青藏高原作为"亚洲水塔",其地表水资源及其变化对高原本身及周边地区的经济社会发展具有重要的影响.然而,在气候变暖的情况下,构成高原地表水资源的各个组分,如冰川、湖泊、河流、降水等水体的相变及其转化却鲜为人知.湖泊是青藏高原地表水体相变和水循环的关键环节.湖泊面积、水位和水量对西风和印度季风的降水变化非常敏感,但湖泊面积和水量变化在不同区域和时段的响应也不尽相同.湖泊水温对气候变暖具有明显响应,湖泊水温和水下温跃层深度的变化能够对水—气的热量交换具有明显影响,从而影响了区域蒸发和降水等水循环过程.由于湖泊水量增加,高原中部色林错地区湖泊盐度自1970s以来普遍下降.根据60多个湖泊实地监测建立的遥感反演模型研究发现,2000—2019年湖泊透明度普遍升高.对不同补给类型的大湖水量平衡监测发现,影响湖泊变化的气象和水文要素具有较大差异.在目前的暖湿气候条件下,青藏高原的湖泊将会持续扩张.为了深入认识湖泊变化在青藏高原区域水循环和气候变化中的作用,需要全面了解湖泊水量赋存及连续的时间序列变化,需要深入了解湖泊理化参数变化及对湖泊大气之间热量交换的影响,需要更多来自大湖流域的综合连续观测数据.  相似文献   

9.
王欣  丁永建  张勇 《湖泊科学》2019,31(3):609-620
冰川融水通过热量、水、物质传输对山地冰冻圈冰湖水文效应产生影响,引起广泛关注.本文从山地冰冻圈冰湖的水量、物理化学性质、生物等方面系统总结冰川融水对冰湖水文效应的影响.冰川融水被冰湖滞留能在一定程度上延缓区域冰川水资源的亏损,但也直接导致了潜在危险性冰湖数量和危险程度增大.冰川融水对冰湖物理性质的影响主要表现在降低湖水温度、影响透明度/浊度、改变湖水密度、造成湖水热力分层现象等方面,对冰湖化学性质的影响主要表现在增加湖水中的氮素、溶解有机物、持久性有机污染物、各类离子和重金属等,进而影响冰湖生物的分布、组成、结构和功能.深入系统地开展冰川融水及其变化对冰湖水文效应研究,对冰川水文与水资源、山地冰冻圈生态环境研究具有重要意义.  相似文献   

10.
Rapid water level rise due to climate change has the potential to remobilize loose sediments along shorelines and increase the turbidity of nearshore waters, thereby impacting water quality and aquatic ecosystem health. Siling Lake is one of the largest and most rapidly expanding lakes on the Tibetan Plateau. Between 2000 and 2017, this lake experienced an increase in water level of about 8 m and a doubling in water turbidity. Here, using this lake as a study site, we used a wave model and high-resolution remote sensing of turbidity (Landsat-8) to assess the potential connection between water-level rise, enhanced wind-driven sediment resuspension and water turbidity. Our analysis revealed that strong bottom shear stresses triggered by wind-generated waves over newly flooded areas were related to an increase in water turbidity. The spatial variability of Siling Lake turbidity showed a strong dependence on local wind characteristics and fetch. Two factors combined to drive the increase in turbidity: (1) high wave energy leading to high bottom shear stresses, and (2) flooding of unvegetated shallow areas. Using a new relationship between wave energy and turbidity developed here, we expect the increase in turbidity of Siling Lake to taper off in the near future due to the steep landscape surrounding the lake that will prevent further flooding. Our results imply that rising water levels along the coast are not only expected to influence terrestrial ecosystems but could also change water quality. The methodology presented herein could be applied to other shorelines affected by a rapid increase in water level. © 2020 John Wiley & Sons, Ltd.  相似文献   

11.
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   

12.
Streamflow response in Boreal Plains catchments depends on hydrological connectivity between forested uplands, lakes, and peatlands, and their hydrogeomorphic setting. Expected future drying of the Boreal Plains ecozone is expected to reduce hydrological connectivity of landscape units. To better understand run‐off generation during dry periods, we determined whether peatland and groundwater connectivity can dampen expected future water deficits in forests and lakes. We studied Pine Fen Creek catchment in the Boreal Plains ecozone of central Saskatchewan, Canada, which has a large, valley‐bottom, terminally positioned peatland, two lakes, and forested uplands. A shorter intensive study permitted a more detailed partitioning of water inputs and outputs within the catchment during the low flow period, and an assessment of a 10‐year data set provided insight into the function of the peatland over a range of climate conditions. Using a water balance approach, we learned that two key processes regulate flow of Pine Fen Creek. The cumulative impact of landscape unit hydrological connectivity and the peatland's hydrological functional state were needed to understand catchment response. There was evidence of a run‐off threshold which, when crossed, changed the peatland's hydrological function from transmission to run‐off generation. Results also suggest the peatland should behave more often as a transmitter of groundwater than as a generator of run‐off under a drier climate future, owing to a reduced water supply.  相似文献   

13.
Lasafam  Iturrizaga 《Island Arc》2005,14(4):389-399
Abstract   Since the mid-nineteenth century, devastating glacier lake outbursts have occurred in the Karambar Valley. The exact source areas of these floods are to date unknown. The present study uses geomorphologic field evidence and interviews of local inhabitants to reconstruct nine potential glacier dams in the Karambar Valley within a horizontal distance of only 40 km. The article focuses on the geomorphologic reconstruction of the highest glacier dams, the Chateboi and Saklei Shuyinj Glaciers. Their lake basins were connected in former times resulting in a complex interfingering of lake sediments, lake terraces and glacial deposits. The outbursts of these lakes could have triggered the drainage of one of the lower ice-dammed lakes (Sokther Rabot, Chillinji, Warghut or Karambar) and therefore initiated an outburst cascade in the upper Karambar Valley. Successive glacier dams are wide spread in the Karakoram, and cascading lakes might have also played a role in other lake outburst scenarios. In the Karambar Valley, even today the Chateboi Glacier blocks the Karambar River over a distance of 4 km and represents a permanent hazard for the villages located downstream.  相似文献   

14.
Glaciers are significant freshwater storage systems in western China and contribute substantially to the summertime run‐off of many large rivers in the Tibetan Plateau. Under the scenario of climate change, discussions of glacier variability and melting contributions in alpine basins are important for understanding the run‐off composition and ensuring that water resources are adequately managed and protected in the downstream areas. Based on the multisource spatial data and long‐term ground observation of climatic and hydrologic data, using the remote sensing interpretation, degree‐day model, and ice volume method, we presented a comprehensive study of the glacier changes in number, area, and termini and their impacts on summertime run‐off and water resource in the Tuotuo River basin, located in the source region of the Yangtze River. The results indicated that climate change, especially rising temperature, accelerated the glacier melting and consequently led to hydrological change. From 1969 to 2009, the glacier retreat showed an absolutely dominant tendency with 13 reduced glaciers and lost glacier area of 45.05 km2, accompanied by limited growing glaciers in the study area. Meanwhile, it indicated that annual glacial run‐off was averagely 0.38 × 108 m3, accounting for 4.96% of the total summertime run‐off, followed by the supply from precipitation and snowmelt. The reliability of this magnitude was assessed by the classic volume method, which also showed that the water resources from glacier melting in the Tuotuo River basin increased by approximate 17.11 × 108 m3, accounting for about 3.77% of the total run‐off over the whole period of 1969–2009. Findings from this study will serve as a reference for future research about glacier hydrology in regions where observational data are deficient. Also, it can help the planning of future water management strategies in the source region of the Yangtze River.  相似文献   

15.
Bulk runoff and meteorological data suggest the occurrence of two meltwater outburst events at Finsterwalderbreen, Svalbard, during the 1995 and 1999 melt seasons. Increased bulk meltwater concentrations of Cl? during the outbursts indicate the release of snowmelt from storage. Bulk meltwater hydrochemical data and suspended sediment concentrations suggest that this snowmelt accessed a chemical weathering environment characterized by high rock:water ratios and long rock–water contact times. This is consistent with a subglacial origin. The trigger for both the 1995 and 1999 outbursts is believed to be high rates of surface meltwater production and the oversupply of meltwater to areas of the glacier bed that were at the pressure melting point, but which were unconnected to the main subglacial drainage network. An increase in subglacial water pressure to above the overburden pressure lead to the forcing of a hydrological connection between the expanding subglacial reservoir and the ice‐marginal channelized system. The purging of ice blocks from the glacier during the outbursts may indicate the breach of an ice dam during connection. Although subglacial meltwater issued continually from the glacier terminus via a subglacial upwelling during both melt seasons, field observations showed outburst meltwaters were released solely via an ice‐marginal channel. It is possible that outburst events are a seasonal phenomenon at this glacier and reflect the periodic drainage of meltwaters from the same subglacial reservoir from year to year. However, the location of this reservoir is uncertain. A 100 m high bedrock ridge traverses the glacier 6·5 km from its terminus. The overdeepened area up‐glacier from this is the most probable site for subglacial meltwater accumulation. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

16.
The Manso Glacier (~41°S, 72°W), in the northern Patagonian Andes of Argentina, is a regenerated glacier that, like many other glaciers in the region and elsewhere, has been showing a significant retreat. Glacial melt water feeds the Manso Superior River, which, before crossing the Andes to reach a Pacific outfall, flows through the Mascardi (a deep, oligotrophic and monomictic lake) and significantly smaller Hess and Steffen lakes. Harmonic analysis of Mascardi's lake level series suggests that the El Niño‐Southern Oscillation signal has been strong during the 1985–1995 decade but has grown weaker during the initial decade of the 21st century. Hydrological trend analyses applied in data recorded in the uppermost reaches show a monthly and annual decreasing trend in the Manso Superior River discharge series and Mascardi's lake level, which are connected with both, decreasing melt water discharge and (austral) wintertime atmospheric precipitation. Downstream, the decreasing signal initially looses statistical significance and then, when flowing through Steffen Lake, reverses the lake level trend that becomes significantly positive. This suggests that, on its way to the Pacific Ocean, the Manso River receives abundant Andean snow melt water and atmospheric precipitation, which are sufficient to obliterate the negative trend recorded in the uppermost reaches. The reason for this local phenomenon is that the Manso is an antecedent river (aka superposed stream), and hence, the valley crossing the Andes allows the incursion of Pacific humidity that modifies the hydrological regime several hundred kilometres inland. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

17.
The sedimentology of proglacial Silt Lake was assessed by lake sediment coring and monitoring of lacustrine processes during a late‐summer period of high glacier melt to characterize sediment delivery from the heavily glacierized catchment and investigate the sediment trapping dynamics of this upland lake. A complete varve chronology was established for a distal basin of the lake which was exposed by Lillooet Glacier retreat between 1947 and 1962. The varve record showed decreasing sedimentation rates in the basin while the glacier retreated, and as the lake became free of ice contact in the early 1970s. Although recession has continued over recent decades, and glacier proximity to the lake has, therefore, continued decreasing, lacustrine sedimentation rates are now accelerating due to changing basin morphometry caused by delta progradation. Over shorter time scales, lake sedimentation patterns respond to changing runoff conditions, including late‐summer glacier melt intensity, intra‐annual flooding events, diumal runoff fluctuations, and within‐lake turbidity currents. Turbidity currents included quasi‐regular flows during high diurnal discharges and an episodic flushing of temporarily stored sediment from the sandur or delta at a time of low stage. Suspended sediment yield to Silt Lake is estimated to exceed 103 Mg km?2 a?1, a magnitude that surpasses previous local and regional yield estimates for the glacierized headwaters of the Lillooet River valley. Since Silt Lake currently traps a significant prooportion of that upland sediment supply, and the trapping efficiency of the basin has been variable at decadal time scales, the formation and continued development of Lilt Lake has likely had a significant influence on downstream sediment delivery. Lacustrine sediment‐based proxies of long‐term hydroclimatic variability being developed in glacially distal settings should include provisions for dynamic sediment trapping effects in upstream water bodies that often form in the active proglacial environment. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

18.
“十三五”时期,长江流域水环境质量改善明显,但湖泊水质和富营养化状况改善滞后.长江中游作为我国淡水湖泊集中分布区域之一,部分湖泊存在水环境质量恶化和富营养化加重问题.本文以长江中游区域国家开展监测的洪湖、斧头湖、梁子湖、大通湖、洞庭湖和鄱阳湖这6个典型湖泊为研究对象,科学评价其2016-2020年水质和富营养化时空变化特征及关键驱动因素,探讨其成因及治理对策.结果表明,“十三五”时期长江中游湖泊水质和富营养化程度存在较大差异,与2016年相比,2020年大通湖水质改善最为明显,梁子湖水质变差,总磷是影响长江中游湖泊水质类别的主要因子;洪湖富营养程度恶化最为严重,斧头湖次之,TLI(SD)对长江中游湖泊富营养化评价贡献最大.目前长江中游湖泊呈有机污染加重和叶绿素。浓度升高现象,洪湖、斧头湖和梁子湖主要与氮、磷营养盐浓度升高有关,而大通湖、洞庭湖和鄱阳湖受水文过程、流域纳污量和湖泊管理等非营养盐因素影响较大.总氮和总磷仍然是影响“十三五”时期长江中游湖泊水质和富营养化的最主要驱动力,且各湖泊总氮和总磷浓度变化均具有较强正相关性,建议开展河湖氮、磷标准衔接工作,提出河湖氮、磷标准限值或考核目...  相似文献   

19.
藏北色林错流域的水文特征   总被引：4，自引：0，他引：4  
本文报道了1997年降1998年夏季对藏北色林错等水体水文特征的考察情况,结果表明,色林错是一个大型深水湖泊,表层水温在下午4：30左右达到最高,清晨7：30左右时最低,浅水区域表层湖水在6月份的极端最高水温为21．2℃,极端最低水温为11．0℃,而日平均水温变幅仅5．6℃,其幅度大于在同一时段湖区内不同区域之间表层水温的变化,色林错湖水的pH值较高咪9．19－9．66;表层水的pH昼夜变化较小,仅0．15,最高值出现在凌晨,同时水体不同区域及深度的pH值基本一致,其溶解氧变化在4．62－5．12mg/L,而且不同深度水层之间的变幅较小,仅0．03－0．35mg/L;但其湖汊浆东如瑞溶解氧的昼认变幅为4．58－5．59mg/l;盐度的日变幅为1．60％－2．20％,考察表明,藏北水体的盐分有一个从河流到湖泊、以及由流水向静水富集的趋势;鱼类的分布与水体盐分的含量密切相关,即鱼类随着水体盐分的增加而消失,代之以嗜盐性卤虫的出现及大量繁衍。  相似文献   

20.
适宜生态水位作为反应湖泊水文情势的重要指标,是维持湖泊生态系统稳定的关键要素。已有研究大多集中于水文过程对生态系统影响,缺乏耦合考虑湖泊营养负荷的全季节生态水位阈值研究。本研究在刻画恢复天然水位情势的基础上,综合考虑了人类活动导致湖泊营养负荷的季节性波动以及冰封期的最小生态水位,构建了适用于季节性冰封湖泊全季节的适宜生态水位阈值获取的综合框架,确定了年内不同时期适宜生态水位阈值。结果表明,查干湖入湖口非冰封期的总氮(TN)浓度与平均水位均呈上升趋势,总磷(TP)浓度呈下降趋势;6月湖内TN和TP滞留量最高,分别达到1044.36和23.61 t;确定了查干湖全季节不同时期的适宜生态水位,冰封期(11月—次年4月)为129m,汛期(6—9月)为130.15～130.86 m,非汛期(5和10月)为130.08～130.57 m。研究结果可为季节性冰封湖泊的适宜生态水位研究提供方法支撑,也可为湖泊的水环境管理提供理论支撑。  相似文献   

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