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1.
Glacial lake outburst flood (GLOF) is a powerful natural phenomenon that is very active in the Karakoram and Himalayas. This paper presents a case study from Gupis Tehsil in northern areas of Pakistan that is exposed to GLOFs from nine different glacial lakes in its upper catchment areas. Khukush Lake being the largest of all the glacial lakes has been studied and a flood attenuation model has been created for the whole Gupis Tehsil. This lake covers almost 2.2 km2 of surface area, and its calculated volume is 2.6 × 104 m3. In case of its outburst, the peak flow discharge is calculated to be 7,642 m3/s. The catchment area which contributes water and debris to the lake is 170 km2. This lake is dammed by a glacial moraine, which is not strong enough to sustain the pressure for a longer period of time. Other factors that are reducing the reliability of the dam are the secondary hazards which are in direct contact with the lake, and in case of their reactivation, they can put severe impacts on the dam. There are eight potential sites of the snow avalanche activity where debris along with snow may fall directly into the lake producing a strong wave. This strong wave of water will increase the pressure on the dam and ultimately will increase the probability for its outburst. The presense of water springs towards the downstream side of the natural dam also indicate the presence of hidden channels passing through the dam which may weaken the shear strength of the dam. Almost 24 villages settled along either sides of the Gupis River are critically studied for the expected flood from Khukush Lake. With few exceptions, almost 20–25 % area of all the villages will be affected from this flood.  相似文献   

2.
Coastal wetlands are hotspots for biodiversity and biological productivity, yet the hydrology and carbon cycling within these systems remains poorly understood due to their complex nature. By using a novel spatiotemporal approach, this study quantified groundwater discharge and the related inputs of acidity and CO2 along a continuum of a modified coastal acid sulphate soil (CASS) wetland, a coastal lake and an estuary under highly contrasting hydrological conditions. To increase the resolution of spatiotemporal data and advance upon previous methodologies, we relied on automated observations from four simultaneous time-series stations to develop multiple radon mass balance models to estimate groundwater discharge and related groundwater inputs of acidity and dissolved inorganic carbon (DIC), along with surface water to atmosphere CO2 fluxes. Spatial surveys indicated distinct acid hotspots with minimum surface water pH of 2.91 (dry conditions) and 2.67 (flood conditions) near a non-remediated (drained) CASS area. Under flood conditions, groundwater discharge accounted for ～14.5 % of surface water entering the lake. During the same period, acid discharge from the acid sulphate soil section of the continuum produced ～4.8 kg H2SO4?ha?1 day?1, a rate much higher than previous studies in similar systems. During baseflow conditions, the low pH water was rapidly buffered within the estuarine lake, with the pH increasing from 4.22 to 6.07 over a distance of ～250 m. The CO2 evasion rates within the CASS were extremely high, averaging 2163?±?125 mmol m?2 day?1 in the dry period and 4061?±?259 mmol m?2 day?1 under flood conditions. Groundwater input of DIC could only account for 0.4 % of this evasion in the dry conditions and ～5 % during the flood conditions. We demonstrated that by utilising a spatiotemporal (multiple time-series stations) approach, the study was able to isolate distinct zones of differing hydrology and biogeochemistry, whilst providing more reasonable groundwater acid input estimates and air–water CO2 flux estimates than some traditional sampling designs. This study highlights the notion that modified CASS wetlands can release large amounts of CO2 to the atmosphere because of high groundwater acid inputs and extremely low surface water pH.  相似文献   

3.
2013年西藏嘉黎县“7.5”冰湖溃决洪水成因及潜在危害   总被引：11，自引：3，他引：8  
冰湖溃决洪水（泥石流）是西藏自治区主要自然灾害之一. 2013年7月5日,西藏自治区嘉黎县忠玉乡发生“7.5”冰湖溃决洪水灾害事件,导致人员失踪,房屋被毁,桥梁、道路等基础设施遭到严重破坏,直接经济损失高达2.7亿元. 基于不同时间段地形图和遥感影像资料,利用地理信息技术,发现导致“7.5”洪灾的溃决冰湖为然则日阿错. 该冰湖溃决的直接诱因可能是雪崩和冰崩的共同作用,溃决前的强降水过程及气温的快速上升是其间接原因,而冰湖长期稳定的扩张导致水量聚集是其溃决并造成巨大灾害的基础. 然则日阿错溃决后形成2个冰湖,面积分别为0.25 km2和0.01 km2,再次发生溃决的概率极小. 这次溃决洪水和泥石流灾害事件阻塞了尼都藏布的罗琼沟及衣布沟,并形成2处面积分别为0.33 km2和0.13 km2堰塞湖,且存在溃决风险,在今后一段时间内应加强监测工作与排险工程实施.  相似文献   

4.
Glacial hazards relate to hazards associated with glaciers and glacial lakes in high mountain areas and their impacts downstream. The climatic change/variability in recent decades has made considerable impacts on the glacier life cycle in the Himalayan region. As a result, many big glaciers melted, forming a large number of glacial lakes. Due to an increase in the rate at which ice and snow melted, the accumulation of water in these lakes started increasing. Sudden discharge of large volumes of water with debris from these lakes potentially causes glacial lake outburst floods (GLOFs) in valleys downstream. Outbursts from glacier lakes have repeatedly caused the loss of human lives as well as severe damage to local infrastructure. Monitoring of the glacial lakes and extent of GLOF impact along the downstream can be made quickly and precisely using remote sensing technique. A number of hydroelectric projects in India are being planned in the Himalayan regions. It has become necessary for the project planners and designers to account for the GLOF also along with the design flood for deciding the spillway capacity of projects. The present study deals with the estimation of GLOF for a river basin located in the Garwhal Himalaya, India. IRS LISSIII data of the years 2004, 2006 and 2008 have been used for glacial lake mapping, and a total of 91 lakes have been found in the year 2008, and out of these, 45 lakes are having area more than 0.01?km2. All the lakes have been investigated for vulnerability for potential bursting, and it was found that no lake is vulnerable from GLOF point of view. The area of biggest lake is 0.193, 0.199 and 0.203?km2 in the years 2004, 2006 and 2008, respectively. Although no lake is potentially hazardous, GLOF study has been carried out for the biggest lake using MIKE 11 software. A flood of 100-year return period has been considered in addition to GLOF. The flood peak at catchment outlet comes out to be 993.74, 1,184.0 and 1,295.58 cumec due to GLOF; 3,274.74, 3,465.0 and 3,576.58 cumec due to GLOF; and 100-year return flood together considering breach width of 40, 60 and 80?m, respectively.  相似文献   

5.
关于长江中游洪灾问题的思考   总被引：2，自引：0，他引：2  
中国是一个水灾频发的国家 ,长江中游历来就是重灾区。 1998年的长江洪水是 1954年以来最大的一次全流域性洪水 ,高水位持续时间长 ,洪水量大 ,洪水遭遇情况恶劣是这次长江汛期的突出特点 ,由此造成的损失十分严重。导致长江中游洪灾的原因是众多的 ,其中气候异常是最直接的影响因素 ,但过度围湖垦殖与江湖关系失调亦是洪涝灾害日趋严重的一个重要原因。由于自然演变和人类活动的共同作用 ,长江中游河湖环境越来越不利于超额洪水的排泄。江汉湖群、洞庭湖和鄱阳湖面积缩小 ,容积减少 ,对河流水量的调蓄作用大大降低。同时荆江已演变为典型的弯曲河道 ,成为防洪的重点地段。荆江大堤的修建隔断了江湖联系 ,改变了中游河湖关系。所有这些因素都使得中游洪灾日益加重。为了实现区域可持续发展 ,迫切需要建立一套完善的抗洪减灾防御体系。  相似文献   

6.
This paper gives an account of the assessment and quantification of the water balance and the hydrogeological processes related to lake–groundwater interaction in the Pampa Plain by using hydrogeochemical, isotopic and flow numerical modeling techniques. La Salada is a permanent shallow lake, with an area of 5.8 km2, located on the SE of Buenos Aires Province. A total of 29 lake water samples and 15 groundwater samples were collected for both hydrochemical analysis and environmental stable isotope determination. Water table depths were measured in wells closed to the lake. Groundwater samples appear grouped on the Local Meteoric Water Line, suggesting a well-mixed system and that rainfall is the main recharge source to the aquifer. Water evaporation process within La Salada is also corroborated by its isotopic composition. The model that best adjusts to La Salada Lake hydrochemical processes includes evaporation from groundwater, calcite precipitation with CO2 release and cationic exchange. The annual water balance terms for the lake basin indicates for each hydrological component the following values: 1.16 E08 m3 rainfall, 8.15 E07 m3 evapotranspiration, 1.90 E06 m3 runoff, 1.55 E07 m3 groundwater recharge, 6.01 E06 m3 groundwater discharge to the lake, 9.54 E06 m3 groundwater discharge to the river, 5.00 E05 m3 urban extraction and 4.90 E06 m3 lake evaporation. Integrated analysis of hydrochemical and isotopic information helped to calibrate the groundwater flow model, to validate the conceptual model and to quantitatively assess the basin water balance.  相似文献   

7.
Wular Lake, one of the largest freshwater lakes of Jhelum River Basin, is showing signs of deterioration due to the anthropogenic impact and changes in the land use/land cover (LULC) and hydrometeorological climate of the region. The present study investigated the impacts of temporal changes in LULC and meteorological and hydrological parameters to evaluate the current status of Wular Lake environs using multisensor, multitemporal satellite and observatory data. Satellite images acquired for the years 1992, 2001, 2005, and 2008 were used for determining changes in the LULC in a buffer area of 5 km2 around the Wular Lake. LULC mapping and change analysis using the visual interpretation technique indicated significant changes around the Wular Lake during the last two decades. Reduction in lake area from 24 km2 in 1992 to 9 km2 in 2008 (?62.5 %) affected marshy lands, the habitat of migratory birds, which also exhibited drastic reduction from 85 km2 in 1992 to 5 km2 in 2008 (?94.117 %). Marked development of settlements (642.85 %) in the peripheral area of the Wular Lake adversely affected its varied aquatic flora and fauna. Change in climatic conditions, to a certain extent, is also responsible for the decrease in water level and water spread of the lake as witnessed by decreased discharge in major tributaries (Erin and Madhumati) draining into the Wular Lake.  相似文献   

8.
Lake Qinghai in the Qinghai-Tibet plateau is the largest lake in China. This study firstly reported the geochemistry of Cd in the lake. Water samples were collected from Lake Qinghai (n = 69) and Buha River (n = 12), while sediment (n = 22) and topsoil (n = 45) samples were collected from the lake and around the lake area, respectively. In addition, pore water samples (n = 20) were separated from sediment samples. Water samples were analyzed for pH, K, Na, Ca, Mg, Cl, S, and Cd, while sediment and topsoil samples were analyzed for K, Na, Ca, Mg, Al, Fe, Mn, S, Sc, and Cd. The average concentration of Cd was 0.014 μg L?1 in the water of Lake Qinghai and 0.007 μg L?1 in the water of Buha River. However, the average concentration of Cd was 0.320 μg L?1 in the sediment pore water, much higher than that in the lake water and river water. Cadmium concentration in the lake water might be mainly controlled by salinity, while it in the pore water might be mainly controlled by carbonate minerals. Cadmium concentration in the river water might be controlled by alkalinity and pH. The average concentration of Cd in the sediment was 0.284 mg kg?1. The enrichment of Cd in the lake sediment was significantly higher than that in the topsoil around the lake. Anthropogenic atmospheric deposition of Cd did not led to the increase in dissolved Cd level in the lake water, but led to its enrichment in the lake sediment.  相似文献   

9.
Basin‐floor topography influences the flow path of hyperpycnal plumes and delta morphology during progradation of the Red River delta in Lake Texoma, USA. The Red River discharge is typically a hyperpycnal plume due to elevated total dissolved solids. Because the river plume is a bottom‐hugging hyperpycnal flow, lake bathymetry and topography strongly influence deposition and subsequent delta morphology. In addition to elevated total dissolved solid concentrations compared with Lake Texoma water, the density contrast of the Red River outflow is increased by high suspended‐sediment concentrations during high‐discharge events. Steep lateral slopes in the Lake Texoma basin deflect hyperpycnal river plumes and, subsequently, change the delta progradation direction before the delta reaches the opposite bank of the lake. Analysis of multi‐temporal aerial and satellite images indicates that the hyperpycnal delta follows the steepest lake‐bottom gradients, corresponding to the pre‐impoundment river thalweg (i.e. bypassing shallow parts of the lake). An analytical model for the hyperpycnal‐plume trajectory indicates plume deflection during low‐discharge or high‐discharge events, towards the deepest part of the basin. The magnitude of plume deflection is a function of river discharge and basin‐margin gradients. Plume deflection can vary between 10° and 80° from the channel axis towards the old river thalweg. The high deflection appears in the case of maximum basin side gradients of 12·8° and in conditions of low river discharge. During low‐discharge periods, the Red River delta builds a lobate shape with multiple terminal distributary channels whereas, during high‐discharge periods the Red River delta builds an elongate shape with a single large distributary channel. The elongate morphology of the delta is formed through the development of a single distributary channel and abandonment of the other distributaries. Therefore, the lobate shaped delta is expected to be preserved in the rock record.  相似文献   

10.
Knowledge of Himalayan cryosphere seems to be an outstanding requirement for assessment of glacier storage, water balance analysis, planning of water resources and flood hazard monitoring. A stepwise approach through mapping glaciers and glacial lakes using satellite remote sensing data and investigating potential glacial lake outburst flood (GLOF) hazards was adopted for the three Hindukush, Karakoram and Himalayan (HKH) ranges of Pakistan. The findings of the study revealed 5,218 glaciers in the cryosphere of HKH ranges. The cumulative glacial cover of over 15,000 km2 contains ice reserves of about 2,738 km3. About 46 % of the Karakoram glaciers are contributing 77 % to the total glacial cover and 87 % to the cumulative ice reserves of the country. The 33 % Himalayan glaciers and 21 % Hindukush glaciers contribute only 3 and 10 % ice reserves, respectively. Among 2,420 glacial lakes identified in the three HKH ranges, 52 were classified as critical lakes that can pose GLOF hazard for the downstream communities. Most of the potential hazardous lakes lie in the Karakoram and Himalayan ranges, the monitoring of which is crucial to reduce high risk of future floods hazard in this fragile mountain ecosystem of the Himalayan region.  相似文献   

11.
One of the most far-reaching glacier-related hazards in the Tian Shan Mountains of Kyrgyzstan is glacial lake outburst floods (GLOFs) and related debris flows. An improved understanding of the formation and evolution of glacial lakes and debris flow susceptibility is therefore essential to assess and mitigate potential hazards and risks. Non-stationary glacier lakes may fill periodically and quickly; the potential for them to outburst increases as water volume may change dramatically over very short periods of time. After the outburst or drainage of a lake, the entire process may start again, and thus these non-stationary lakes are of particular importance in the region. In this work, the Teztor lake complex, located in Northern Kyrgyzstan, was selected for the analysis of outburst mechanisms of non-stationary glacial lakes, their formation, as well as the triggering of flows and development of debris flows and floods downstream of the lakes. The different Teztor lakes are filled with water periodically, and according to field observations, they tend to outburst every 9–10 years on average. The most important event in the area dates back to 1953, and another important event occurred on July 31, 2012. Other smaller outbursts have been recorded as well. Our study shows that the recent GLOF in 2012 was caused by a combination of intense precipitation during the days preceding the event and a rapid rise in air temperatures. Analyses of features in the entrainment and depositional zones point to a total debris flow volume of about 200,000 m3, with discharge ranging from 145 to 340 m3 s?1 and flow velocities between 5 and 7 m s?1. Results of this study are key for a better design of sound river corridor planning and for the assessment and mitigation of potential GLOF hazards and risks in the region.  相似文献   

12.
Five similar glacial-lake outburst floods (GLOFs) occurred in April, October, December 2008, March and September 2009 in the Northern Patagonia Icefield. On each occasion, Cachet 2 Lake, dammed by the Colonia Glacier, released circa 200-million m3 water into the Colonia River. Refilling has occurred rapidly, such that further outbreak floods can be expected. Pipeflow calculations of the subglacial tunnel drainage and 1D hydraulic models of the river flood give consistent results, with an estimated peak discharge surpassing 3,000 m3 s?1. These floods were larger in magnitude than any flood on record, according to gauged data since 1963. However, geomorphological analysis of the Colonia valley shows physical evidence of former catastrophic outburst floods from a larger glacial-lake, with flood discharges possibly as high as 16,000 m3 s?1. Due to potential impacts of climate change on glacier dynamics in the area, jökulhlaups may increase future flood risks for infrastructure and population. This is particularly relevant in view of the current development of hydropower projects in Chilean Patagonia.  相似文献   

13.
基于1956-2015年洞庭湖主要控制站实测水文数据,运用Mann-Kendall检验法、主成分分析法对比分析了近60 a来洞庭湖东、南、西三个湖区水位演变特征及其影响因素。结果表明：从调弦口堵口至葛洲坝截流后,南咀和城陵矶站同流量下水位均升高,但南咀站平均水位受三口分流能力减弱而下降（0.03 m）,城陵矶站平均水位受湖盆泥沙淤积和长江干流顶托作用而上升（1.33 m）;三峡水库运行后,湖盆冲淤基本持平,湖泊同流量下水位基本不变,由于该时段长江流域整体为相对枯水期,因而与葛洲坝截流后相比湖泊年平均水位下降约0.31~0.58 m。近60 a来南咀站平均水位呈显著下降趋势（p<0.05）,而城陵矶站水位呈显著上升趋势（p<0.01）,说明湖泊水位影响因素作用存在空间异质性。洞庭湖年内水位存在涨（4-5月）~丰（6-9月）~退（10-11月）~枯（12月-次年3月）的变化特征,葛洲坝运行期丰水期水位上涨明显,三峡运行期各月水位均有下降,受水库调度方式影响7-10月水位降幅最大。洞庭湖流域降水量、四水入湖和出湖径流大小以及长江干流水情是洞庭湖水位变化的主要影响因素,三口来沙变异条件下的洞庭湖冲淤量变化是湖泊水位变化的次要因素。  相似文献   

14.
The “Water-Sediment Regulation Scheme” (WSRS) is critically important to the hydrologic evaluation of the Yellow River estuary since a huge pulse of water and sediment are delivered into the sea during a short period. We used the natural geochemical tracers radium (223Ra, 224Ra, 226Ra) and radon (222Rn) isotopes as well as other hydrological parameters to investigate the mixing variations and submarine groundwater discharge (SGD) in the Yellow River estuary under the influence of the 2013 WSRS. Dramatically elevated radium and radon isotopic activities were observed during this WSRS compared with activities measured during a non-WSRS period. Radium “water ages” indicated that the offshore transport rate nearly tripled when the river discharge increased from 400 to 3400 m3/s. We calculated the SGD flux in the Yellow River estuary based on a radium mass balance model as well as radium and radon time-series models. The SGD flux was estimated at 0.02~0.20 m/day during a non-WSRS period and 0.67~1.22 m/day during the 2013 WSRS period. The results also indicate that large river discharge tends to lead more intense SGD along the river channel direction with a large amount of fresh SGD.  相似文献   

15.
An investigation using environmental isotopes (δ18O and δD) was conducted to gain insight into the hydrological processes of the Ganga Alluvial Plain, northern India. River-water, shallow-groundwater and lake-water samples from the Gomati River Basin were analyzed. During the winter season, the δ18O and δD compositions of the Gomati River water ranged from ?1.67 to ?7.62 ‰ and ?25.08 to ?61.50 ‰, respectively. Deuterium excess values in the river water (+0.3 to ?13 ‰) and the lake water (?20 ‰) indicate the significance of evaporation processes. Monthly variation of δ18O and δD values of the Gomati River water and the shallow groundwater follows a similar trend, with isotope-depleted peaks for δ18O and δD synchronized during the monsoon season. The isotopically depleted peak values of the river water (δ18O?=??8.30 ‰ and δD?=??57.10 ‰) can be used as a proxy record for the isotopic signature of the monsoon precipitation in the Ganga Alluvial Plain.  相似文献   

16.
《China Geology》2023,6(2):216-227
Yanhu Lake basin (YHB) is a typical alpine lake on the northeastern Tibetan Plateau (TP). Its continuous expansion in recent years poses serious threats to downstream major projects. As a result, studies of the mechanisms underlying lake expansion are urgently needed. The elasticity method within the Budyko framework was used to calculate the water balance in the Yanhu Lake basin (YHB) and the neighboring Tuotuo River basin (TRB). Results show intensification of hydrological cycles and positive trends in the lake area, river runoff, precipitation, and potential evapotranspiration. Lake expansion was significant between 2001 and 2020 and accelerated between 2015 and 2020. Precipitation increase was the key factor underlying the hydrological changes, followed by glacier meltwater and groundwater. The overflow of Yanhu Lake was inevitable because it was connected to three other lakes and the water balance of all four lakes was positive. The high salinity lake water diverted downstream will greatly impact the water quality of the source area of the Yangtze River and the stability of the permafrost base of the traffic corridor.©2023 China Geology Editorial Office.  相似文献   

17.
长江中下游河湖水量交换过程   总被引：1，自引：0，他引：1       下载免费PDF全文
长江中下游的河湖水交换关系典型且复杂,为描述河湖水量相互交换过程,提出了河湖水量交换系数的概念,即某一时段内由支流汇入湖泊的径流量与湖泊泄入干流径流量的比值,表示河湖水量交换的激烈程度。根据水量平衡原理推导出河湖水量交换系数计算的经验公式,并把河湖水量交换过程分为3种状态:“湖分洪”、“稳定”和“湖补河”。近60多年来河湖水交换系数年际变化趋势表明:洞庭湖与长江干流的水交换状态从“湖分洪”到“稳定”,再到“湖补河”状态发展;鄱阳湖与长江干流的水交换系数在稳定状态附近波动,河湖水交换状态无明显趋势性变化,河湖系统演化稳定。河湖水交换系数与长江干流径流量相关性良好,而与湖泊支流径流量相关性较差,表明长江干流径流量的大小是河湖水量交换过程的主控因素。  相似文献   

18.
洞庭湖萎缩对湖内洪水影响   总被引：1，自引：0，他引：1       下载免费PDF全文
为了更好地理解湖泊萎缩对湖内洪水过程的影响,在假定洞庭湖将继续萎缩的前提下,通过建立荆江-洞庭湖水动力模型,定量分析洞庭湖萎缩对湖内洪水的影响。研究结果表明,湖内水位及洪峰流量随湖泊面积的萎缩而增加,洪峰水位到达时刻随着湖泊萎缩而提前。若遇1996年型洪水,洞庭湖面积若从目前的2 670 km2减小至1 380 km2时,西洞庭湖及南洞庭湖内最高水位将抬高2.0 m左右,东洞庭湖水位将抬升0.4 m左右,城陵矶站点洪峰水位到达时刻将提前约11 h,洪峰流量增加约4 800 m3/s。因此,若洞庭湖湖泊面积在目前基础上（面积2 670 km2）继续萎缩,湖区特别是西洞庭湖及南洞庭湖将面临更为严峻的洪水灾害。虽然湖泊萎缩对西洞庭湖与南洞庭湖内水面坡降影响较小,但东洞庭湖内水位同时受湖泊萎缩及长江来流的影响,水面坡降发生较大变化,在距离蔡家洲80~110 km（鹿角站附近）河段水面坡降出现大幅增大。  相似文献   

19.
Todhunter  P. E. 《Natural Hazards》2021,106(3):2797-2824

Devils Lake, a terminal lake in northeast North Dakota (USA), has experienced catastrophic flooding since 1993. From January 31, 1993, to December 31, 2014, lake level rose from 433.62 to 442.44 m, lake area expanded from 179.9 to 653.5 km2, and lake volume increased from 0.70 to 3.80 km3. More than $1 billion ($USD) has been spent in government payments to mitigate direct, primary, tangible flood damages. This paper provides a case study of the hydrological basis of the Devils Lake flood disaster. The unique geomorphic setting, paleoclimatic record, and hydroclimatic conditions of the region are summarized, and a wide range of hydroclimatic data is examined to provide a broad understanding of the physical basis of the flood disaster. The primary cause of the disaster was a transition to a sustained wetter climate that resulted in a dramatic response in basin hydrological variables in 1993. The transition from a long-term dry period to a long-term wet period caused the lake water budget to begin to change from an atmosphere-controlled water budget dominated by precipitation input to an amplifier lake water budget dominated by surface runoff input to the lake. Other important hydrological factors include a nonlinear precipitation–runoff relationship following the long-term drought, fill-spill and fill-merge hydrological behavior that is characteristic of wetland complexes, an increase in the lake area-to-basin area ratio, and the critical role of frozen soils in controlling infiltration and runoff production of spring snowmelt. Engineering works to manage lake volume through two outlets have reduced, but not entirely eliminated, future flood risk.

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20.
冰湖溃决洪水(Glacial lake outburst flood,简称GLOF)灾害是冰川区最常见、危害最大的灾害类型之一,历来是国内外学者研究的关键科学问题。在全球变暖的大背景下,冰川退缩加剧,其下游冰湖扩张快速,湖面升高,溃决风险提高。青藏高原尤其是东南部地区孕育着大量的冰湖,在过去的几十年间,冰湖溃决洪水威胁着当地人民的生产生活。基于LANDSAT遥感影像,本文获取了青藏高原东南部雅弄冰川和来古冰湖1986年、1990年、1994年、1997年、2000年、2003年、2005年、2011年、2013年和2017年共10期湖面面积,并结合实地测量的冰湖水深资料,计算了冰湖对应年份的储水量,建立冰湖面积与储水量变化序列;结合野外调查从冰湖面积与水量变化趋势和突发事件两方面探讨冰湖溃决可能性;利用BREACH模型和SMPDBK模型估算和模拟来古冰湖溃决洪水,做灾害预警分析。结果表明,1986~2017年冰湖上湖变化不大,而来谷下湖处于持续扩张中,面积由1986年的1.151±0.070 km^2扩张至2017年的3.148±0.097 km^2,水量由0.645×10^8 m^3增加至2.143×10^8 m^3,雅弄冰川在1986~2013年持续后退,在2013~2017年突然前进;经讨论其溃决风险得出冰川滑动入湖导致湖水瞬时涌出从而造成溃坝的可能性较高;利用BREACH模型及SMPDBK模型对来古冰湖溃决洪水模拟结果表明,当来古下湖湖水受冰体挤压抬升发生溃决时,溃决洪水将严重威胁然乌镇及其上游居民的生命和财物安全。  相似文献   

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