Lake Shrinkage Research Articles

Dissolved inorganic carbon determines the abundance of microbial primary producers and primary production in Tibetan Plateau lakes.

Climate change globally accelerates the shrinkage of inland lakes, resulting in increases in both water salinity and dissolved inorganic carbon (DIC). The increases of salinity and DIC generate contrasting effects on microbial primary producers and primary production, however, their combined effects remain unclear in aquatic ecosystems. We hypothesized that increased DIC mitigates the constraints of enhanced salinity on microbial primary producers and primary production. To test this, we employed isotope labeling and molecular methods to explore primary production and four dominant types of microbial primary producers (form IA, IB, IC and ID) in lakes on the Tibetan Plateau. Results showed that DIC was positively correlated with the abundance of the form IAB and ID microbial primary producers and primary production (all P <0.001) and offset salinity constraints. Structural equation models elucidated that DIC substantially enhanced primary production by stimulating the abundance of form ID microbial primary producers. The abundance of form ID primary producers explained more variations (14.6%) of primary production than form IAB (6%) and physicochemical factors (6.8%). Diatoms (form ID) played a determinant role in primary production in the lakes by adapting to high DIC and high salinity. Our findings suggest that inland lakes may support higher primary productivity in future climate change scenarios.

Mechanism of the Rapid Shrinkage of Limboto Lake in Gorontalo, Indonesia

This study explores the mechanisms behind the rapid shrinkage of Limboto Lake, Gorontalo, Indonesia, using remotely sensed imagery and river outcrop investigation data. The results show that more than 70% of the sedimentation resulting in shrinkage is contributed by riverbank erosion causing rivers to drain into the lake during the period 2003–2017. From geological investigation, it is found that the lowland area to the west of Limboto Lake comprises 1 m of flood sediments, followed by at least 5 m of fine-grained inner bay sediments. Severe riverbank erosion is also observed at many points. Hence, it is concluded that the shrinkage of Limboto Lake resulted from rapid-induced rapid erosion of inner bay sediments formed during plate collision which readily flowed into and were deposited in Limboto Lake; this created a delta, especially on the west side of the lake. Accelerated sedimentation caused by river erosion has led to rapid lake shrinkage. This phenomenon could be typical of the transformation of enclosed seas into lakes by the rapid uplifting movement of land in collision zones.

Isotopic dynamics of precipitation and its regional and local drivers in a plateau inland lake basin, Southwest China

Shrinkage of plateau lakes under climate strength has drawn growing attention. Because of its intricate implication to hydro-meteorological condition and climate system, stable isotopes in precipitation (e.g. δ2Hp and δ18Op) provide us a powerful tool to understand the climate-hydrologic dynamics in shrinking lakes. However, how the regional atmospheric circulation, moisture sources and local fractionation processes drive isotopic variability from temporal to spatial scale has rarely been reported for remote plateau lakes. Hence, we collected a total of 98 rainfall samples at the south and the north shores of Chenghai lake, Yunnan-Guizhou Plateau to study the potential driving forces of precipitation isotope variability during the wet season of 2019. Based on backward trajectories of air masses obtained from HYSPLIT model, 68% of moisture came from δ18O depleted ocean (Indian Ocean, Bay of Bengal, South China Sea and Pacific Ocean), and the rainout process promoted the isotopic depletion when moisture arrived at the study basin. Evapotranspiration increased the heavy isotope ratios in precipitation originated from continents (northern China inland and western continents). The temporal dynamics of δ18Op and δ2Hp were in phase with the convection activities intensity underlined the influence from large-scale atmospheric circulation. Local meteorological factors played a secondary role in isotope variability. Precipitation amount-effect strongly affected isotope ratios while mild anti-temperature effect was observed at daily scale. Interestingly, the rainfall isotope ratios showed different mechanisms in govern at lake south shore and north shore, with a distance of 19 km in between. This south-to-north difference can be explained by either lower 1.03% sub-evaporation in the south shore or 7% of recycled moisture contributing to precipitation in the north shore. Our findings discover the driving forces for δ18Op variation and provide solid interpretations for hydro-climate change in Southwest China.

Changes of inundation area and water turbidity of Tonle Sap Lake: responses to climate changes or upstream dam construction?

Using long-term Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat satellite observations, the inundation changes of Tonle Sap Lake between 1988 and 2018 were investigated. The results show that the inundation area was stable before 2000, followed by a significant shrinking trend between 2000 and 2018. Quantitative remote sensing retrievals for concentrations of the total suspended sediments (TSS) also demonstrate an evident increasing trend (7.92 mg l−1yr−1) since 2000. A strong correlation (R2 = 0.67) was found between the annual mean inundation area and concurrent precipitation in a region located in the lower basin of the Mekong River (mostly outside the drainage basin of Tonle Sap Lake). A multiple general linear model (GLM) regression further pointed to the precipitation variation as a major contributor (76.1%) to the interannual fluctuation of the inundation area, while the dams constructed in China only contributed to 6.9%. The limited impacts of Chinese dams on the inundation area of the lake could be revealed through the limited fraction of water discharge from the Mekong River within China (∼17%). The analysis also found significant impacts of inundation changes on the recent lake turbidity increase in the dry seasons. We clearly revealed that the contribution of dam construction in China to the recent lake shrinkage was insignificant when compared with the impacts of the precipitation decrease. The results of this study provide important scientific evidence for settling water volume-related transboundary disputes regarding the control of the inundation area and water turbidity of Tonle Sap Lake.

Hundred-year spatial trajectory of lake coverage changes in response to human activities over Wuhan

Environmental changes induced by ongoing anthropogenic activities have caused severe lake degradation. Because of the lack of long-term records, few studies have investigated the change in Wuhan lakes, and the effect of human activities on regional lake changes prior to 1973 has not been systematically studied yet. Therefore, in this study, historical maps and Landsat images were combined to track these changes from the 1920s to 2015. Three phases could be identified over the nearly 100-year study period. The most dramatic lake reduction (−21.53 km2 yr−1) occurred during Phase II (1950s–1980s) rather than Phase III (after the 1980s), as indicated by previous studies; the decreased lake area in Phase II was almost double that in Phase III. This reduction could be attributed to major hydraulic engineering projects during Phase II based on the watershed-scale analysis. In addition, land-use conversion over the past 45 years was used to quantify the impact of human exploitation on lakes. The shrinkage of lakes was predominately driven by agricultural activities, such as reclamation (39.2%) and aquaculture development (29.0%), and urbanization was a secondary driving force (19.8%), despite the rapid economic development of Wuhan. This study therefore provides a practical guide for lake protection in other areas similar to Wuhan.

Monitoring and Assessment of Water Level Fluctuations of the Lake Urmia and Its Environmental Consequences Using Multitemporal Landsat 7 ETM+ Images.

The declining water level in Lake Urmia has become a significant issue for Iranian policy and decision makers. This lake has been experiencing an abrupt decrease in water level and is at real risk of becoming a complete saline land. Because of its position, assessment of changes in the Lake Urmia is essential. This study aims to evaluate changes in the water level of Lake Urmia using the space-borne remote sensing and GIS techniques. Therefore, multispectral Landsat 7 ETM+ images for the years 2000, 2010, and 2017 were acquired. In addition, precipitation and temperature data for 31 years between 1986 and 2017 were collected for further analysis. Results indicate that the increased temperature (by 19%), decreased rainfall of about 62%, and excessive damming in the Urmia Basin along with mismanagement of water resources are the key factors in the declining water level of Lake Urmia. Furthermore, the current research predicts the potential environmental crisis as the result of the lake shrinking and suggests a few possible alternatives. The insights provided by this study can be beneficial for environmentalists and related organizations working on this and similar topics.

Socio-hydrological framework for investigating farmers’ activities affecting the shrinkage of Urmia Lake; hybrid data mining and agent-based modelling

ABSTRACT Developing a general framework to capture the complexities associated with the non-linear and adaptive nature of farmers facing water resources scarcity is a challenging problem. This paper integrates agent-based modelling (ABM) and a data mining method to develop a hybrid socio-hydrological framework to provide future insights for policy-makers. The data associated with the farmers’ main characteristics were collected through field surveys and interviews. Afterwards, the association rule was employed to discover the main patterns representing the farmers’ agricultural decisions. The discovered patterns were then used as the behavioural rules in ABM to simulate the agricultural activities. The proposed framework has been was applied to explore the interactions between agricultural activities and the main river feeding the Urmia-Lake, Iran. The outcomes indicate that farmers’ acquisitive traits and belongings have significant impacts on their socio-hydrological interactions. The reported values of the efficiency criteria may support the satisfactory performance of the proposed framework.

Tracking Lake and Reservoir Changes in the Nenjiang Watershed, Northeast China: Patterns, Trends, and Drivers

In terms of evident climate change and human activities, investigating changes in lakes and reservoirs is critical for sustainable protection of water resources and ecosystem management over the Nenjiang watershed (NJW), an eco-sensitive semi-arid region and the third-largest inland waterbody cluster in China. In this study, we established a multi-temporal dataset documenting lake and reservoir (area ≥ 1 km2) changes in this region using an object-oriented image classification method and Landsat series images from 1980 to 2015. Using the structural equation model (SEM), we analyzed the diverse impacts of climatic and anthropogenic variables on lake changes. Results indicated that lakes experienced significant changes with fluctuations over the past 35 years including obvious declines in the total area (by 42%) and number (by 51%) from 1980 to 2010 and a slight increase in the total lake area and number from 2010 to 2015. More than 235 lakes in the size class of 1–10 km2 decreased to small lakes (area &lt; 1 km2), while 59 lakes covering 243.75 km2 disappeared. Total reservoir area and number had continuous increases during the investigated 35 years, with an areal expansion of 54.9% from 919 km2 to 1422 km2, and a number increase by 65.3% from 78 to 129. The SEM revealed that the lake area in the NJW had a significant correlation with the mean annual precipitation (MAP), suggesting that the MAP decline clarified most of the lake shrinkage in the NJW. Furthermore, agricultural consumption of water had potential impacts on lake changes, suggested by the significant relationship between cropland area and lake area.

The Holocene history of the Faiyum Lake (Egypt) based on sediment characteristics, diatoms and ostracods contents

There are relatively few Holocene lake sediment core sequences available for north-east Africa. This study examines the developmental history of Faiyum Lake (Egypt) by detailed lithostratigraphic description together with microfossils and geochemistry, of two adjacent lake sediment cores. The recovered sedimentary sequence consists of predominantly lacustrine facies divisible into five sedimentary units. Early Holocene sediments (Unit II; c. 9.9–8 ka cal BP), overlying late Pleistocene aeolian sands (Unit I), comprise sub-mm laminations (non-glacial varves) of white diatomite and calcite inter-bedded with yellowish-green mineralogenic layers indicating a deep freshwater lake phase. Early middle Holocene sediments (Unit III, c. 8 to 6 ka cal BP) consists by pockets of non-glacial varved laminae intercalated with turbidites and increasing thick silty clay layers, indicating a shallow freshwater lake phase with increasing nutrients. The late middle Holocene lake phase, Unit IV (c. 6 to 4 ka cal BP) is grey massive mud with occasional thick (>1 cm) diatomite-carbonate layers and thin gypsum and iron-hydroxides layers indicative of a lake shrinking phase but with a large level fluctuation sand evaporation phases when freshwater inflow diminished. The late Holocene lake phase (unit V, c. 4 ka cal BP-present) reveals bioturbation and increasing fine sand with artifacts corresponding to further lake level declines and fluctuations as water management intensifies during and after Middle Kingdom and Ptolemaic times. Together with geochemical and microfossil evidence, sedimentology of the studied cores indicate a series of major environment changes affecting the whole lake system throughout the Holocene.

In Water‐Limited Landscapes, an Anthropocene Exchange: Trading Lakes for Irrigated Agriculture

AbstractLakes—quintessential features of Earth's surface prized from perspectives of water security, aquatic ecosystems, and recreation alike—are shrinking in water‐limited regions of all of Earth's inhabited continents. Here we assessed Landsat‐derived long‐term decrease in global lake area relative to historical lake extent aiming to determine the role of recent Anthropocene levels of irrigated agriculture in the global phenomenon of lake desiccation. As of 2015, 11% (1.8 · 105km2) of global lake area has already been lost, primarily due to increased water consumption in support of irrigated agriculture in endorheic basins within water‐limited regions. However, current levels of irrigated agriculture portend substantial additional shrinkage of global lakes before reaching new equilibria with present‐day inflows, with an additional 60–130% increase in endorheic lake loss anticipated. The time required for shrinking lakes to attain new equilibria ranges from decades to centuries depending on lake hyposometry. Even a small decrease in lake area can portend lake transition from exorheic to endorheic and dramatic reductions in water quality. Thus, lake area changes severely understate the perilous condition of global lakes. The watershed area contributing to shrinking (endorheic and exorheic) lakes accounts for 18% of Earth's land area, far too large for the irrigated agriculture therein to be transferred elsewhere in order to save these lakes, though continued developments in the efficiency of water consumption in agriculture and urban areas can save significant quantities of water. This suggests that global lake shrinkage may be a harbinger signaling mankind having exceeded Earth's sustainable carrying capacity.

Shrinkage and protection of inland lakes on the regional scale: A case study of Hubei Province, China

The changes of lakes directly affect the sustainable development of regional ecological environment and social economy. Affected by the environmental changes and human activities, most of the inland lakes globally have suffered from the area shrinkage and wetland degradation. The protection and restoration of lakes have become a hot public issue. In this study, a lake spatial database of Hubei Province (China) is built to analyze the temporal-spatial dynamic change of lakes in Hubei Province from 1974 to 2014, with the analysis models of lake dynamic change rate (LDCR), lake landscape shape index (LLSI), and lake centroid shift rate (LCSR). The results are as follows: (1) Lakes in Hubei Province showed a shrinking and fragmenting trend from 1975 to 2014. The total area of lakes decreased by 23.08%, and the number of lake increased by 68.03%. (2) The value of LLSI firstly increased and then decreased after 1995, meaning that the lake disturbance degree of human activities decreased firstly and then increased. (3) The lake centroids of Hubei Province were in the Jianghan Plain and shifted to the northwest by 33.67 km from 1975 to 2014, due to the lake shrinkage was more serious in the southeastern than in the northwest. The situation of inland lakes’ shrinkage and degeneration is still very severe. The national and local governments should strengthen the lake management and protection, curb the lake shrinkage and degradation, and promote the healthy and sustainable development of lakes.

Changes in Lake Area in the Inner Mongolian Plateau under Climate Change: The Role of the Atlantic Multidecadal Oscillation and Arctic Sea Ice

AbstractThe lake area in the Inner Mongolian Plateau (IMP) has experienced a rapid reduction in recent decades. Previous studies have highlighted the important role of intensive human activities in IMP lake shrinkage. However, this study found that climate change–induced summer precipitation variations can exert great influences on the IMP lake area variations. The results suggest that the decadal shift in the IMP summer precipitation may be the predominant contributor to lake shrinkage. Further analysis reveals that the Atlantic multidecadal oscillation (AMO) and Arctic sea ice concentration (SIC) play important roles in the IMP summer precipitation variations. The AMO seems to provide beneficial large-scale circulation fields for the decadal variations in the IMP summer precipitation, and the Arctic SIC decline is favorable for weakening the IMP summer precipitation intensity after the late 1990s. Evidence indicates that the vorticity advection related to the Arctic SIC decline can result in the generation of Rossby wave resources in the midlatitudes. Then, the strengthened wave resources become favorable for enhancing the stationary wave propagation across Eurasia and inducing cyclonic circulation over the Mongolia–Baikal regions, which might bring more rainfall northward and weaken the IMP summer precipitation intensity. Consequently, due to the decreased rainfall and gradual warming after the late 1990s, the lake area in the IMP has experienced a downward trend in recent years.

Linkages between land cover change, lake shrinkage, and sublacustrine influence determined from remote sensing of select Rift Valley Lakes in Kenya

The Great Rift Valley system is home to many volcanic and tectonic lakes including some of the world's oldest and deepest lakes. These lakes host a rich heritage of biodiversity that is endangered by recent drastic hydrologic changes due to multiple natural and anthropogenic stressors in the catchment areas of some of the lakes. This study utilized Landsat TM, ETM+, and OLI data to conduct a systematic investigation of the relationship between hydrological dynamics in the basins of four Rift Valley lakes (Nakuru, Baringo, Bogoria, and Elementaita) and recent land cover and land-use change. The Modified Normalized Difference Water Index (MNDWI) proved to be more accurate and robust for delineating water surface areas when compared to the output of Normalized Difference Vegetation Index (NDVI) and classification algorithms. NDVI was successful when delineating water surface at Lake Baringo but not in Lakes Bogoria, Nakuru, and Elementaita, whose surfaces were dominated by algae. All the lakes expanded substantially after 2010 submerging surrounding areas leading to disruption of livelihoods, property damage, and displacement of thousands of people. The recent drastic hydrologic changes have multiple causations including land cover and land use change, increase in rainfall, and possible change in geogenic water input due to tectonic activity. The rapid rise in water levels appears to have altered the biogeochemical balance of the hypersaline lakes with severe ramifications on the rich biodiversity that is supported by the lakes.

Succession of bacterial community and methanotrophy during lake shrinkage

The shrinkage of vast inland lakes affects microbially mediated soil biogeochemical processes, which are critical for maintaining ecosystem sustainability, such as microbial diversity and a balanced CH4 budget. Here we aimed to elucidate shifts in the bacterial community and methanotrophy during the shrinkage of a saline lake. Sediments and soils along a gradient transecting a saline lake, saline riparian land, and grassland were collected. The succession of microbial communities was characterized by high-throughput sequencing of the V4-V5 region of 16S rRNA genes coupled to non-metric multidimensional scaling (NMDS), linear discriminant effect size (LEfSe), community assembly, and co-occurrence network analyses. We further incubated these samples under a 10% CH4 (v/v) atmospheric condition to determine the response of methane oxidation potentials and of methanotrophs to lake shrinkage by using pmoA-based qPCR and amplicon sequencing. LEfSe and NMDS analyses showed significant differences in bacterial communities among 3 stages of lake shrinkage. The microbial taxa with the highest increase were phylogenetically affiliated with unclassified Rhizobiales, Panacagrimonas, and Pseudomonas in saline and grassland soils when compared with sediments. Microbial community assembly was largely determined by deterministic rather than stochastic processes (NTI > 2). The drastic increase of Methylocystis-like (type II) methanotrophs was observed during lake shrinkage, while type I methanotrophs showed a decreasing trend. However, upon consuming high-concentration methane of about 10%, type I methanotrophs dominated methane-oxidizing communities in lake sediment (Methylomonas), riparian saline soil (Methylomicrobium), and grassland soil (Methylobacter). Structural equation model identified soil pH, C/N ratio, and soil texture as key factors affecting methane oxidation rates and the methanotrophic community. Lake shrinkage showed profound impacts on the overall bacterial communities and methane oxidizers. Soil physico-chemical properties likely shaped the bacterial community and phylogenetically distinct methanotrophs during lake shrinkage.

Holocene paleoenvironmental evolution of the Acıgöl paleo maar lake (Nevşehir, Central Anatolia)

Acigol (Nevsehir, Central Anatolia) is a drained crater lake. Acigol maar was formed by the violent vapor explosions due to the interaction of hot rhyolitic magma with the (sub-)surface water during the latest Pleistocene. A 844 cm-deep borehole was drilled at the maar and 713 cm-thick Acigol Core Succession (ACS) was retrieved. The ACS is mainly composed of lower laminated and upper non-laminated mudstones (sandy, silty, and clayey) with rare organic and volcanic interlayers. Eleven ostracod taxa (Cypris pubera, Plesiocypridopsis newtoni, Heterocypris salina, Eucypris cf. heinrichi, Candona candida, Candona meerfeldiana, Pseudocandona marchica, Cyclocypris sp., Ilyocypris bradyi, Limnocythere inopinata, and Darwinula stevensoni) were determined in this study. Along with ostracods, gastropods (Gyraulus piscinarum and Stagnicola sp.), pelecypods (Pisidium personatum), charophytes, and fish remains were also observed, while diatoms are the most frequent and abundant assemblage of the ACS. The assemblage at the lower parts of ACS mainly indicates wetter, freshwater to oligohaline, and oligotrophic and relatively deep lacustrine conditions alternating with short lake shrinkage intervals. On the other hand, the fauna at the upper part of the ACS points out to saline, shallow, and warmer lacustrine conditions.

Study on the effect of Dongting Lake's shrinkage on the flooding

In order to better understand the effect of the lake shrinkage on the flood process in a large lake,a quantitative analysis of the relationship between the lake shrinkage and the flooding in Dongting Lake was conducted,for which Jingjiang-Dongting Lake hydrodynamic model was applied and different scenarios of water area in the Dongting Lake were assumed. The results show that the water level and peak discharge will increase,and the peak time will occur earlier with the shrinkage of the lake. The water level in the West and South Dongting Lake would increase by around 2.0 m and the water level in the East Dongting Lake would increase by around 0.4 m if the area of Dongting Lake was shrunk from 2 670 km2to 1 380 km2 when the 1996-type flood occurred in Dongting Lake. Moreover,the arrival time of the peak water level at Chenglingji station would be about 11 hours earlier,and the peak discharge would increase by about 4 300 m3/s. Hence,the flood disaster would be more severe in the Dongting Lake area if the lake continues to shrink from now on. In addition,the water surface slope changes a little in the West and South Dongting Lake. But the water surface slope increases a lot near the Lujiao station due to the water level in the East Dongting Lake is affected by both of the lake shrinkage and the water level in Yangtze River.

Extreme Lake Level Changes on the Tibetan Plateau Associated With the 2015/2016 El Niño

AbstractAlthough the impact of El Niño–Southern Oscillation on the Tibetan Plateau (TP) is reflected through stable isotopes of precipitation and ice cores, the hydroclimate response of TP lakes to El Niño–Southern Oscillation is seldom investigated. Here we show that significant lake water deficit occurred on the central TP (CTP) due to a dramatic decrease in precipitation 2016 El Ni/2016 El Niño event, followed by extreme lake water surplus in 2016 and 2017 over most of the TP (except the eastern CTP). Similar but weaker lake shrinkage and afterward expansion can also be found during historical El Niño events. Further exploration reveals that the CTP dry anomaly during El Niño events tends to bridge the dry anomalies over India and northern China, thereby forming a dry zone along the northwestern edge of the Asian monsoon domain. This study may shed light on the prediction of lake level changes on the TP.

Permanent disappearance and seasonal fluctuation of urban lake area in Wuhan, China monitored with long time series remotely sensed images from 1987 to 2016

ABSTRACTLakes are important to the healthy functioning of the urban ecosystem. The urban lakes in Wuhan, China, which is known as ‘city of hundreds of lakes’, are facing substantial threats mainly due to rapid urbanization. This paper focused on detecting the spatial and temporal change of urban lakes in Wuhan, using a long time series of Landsat and HJ-1A remotely sensed data from 1987 to 2016. The permanent disappearance and seasonal fluctuation of 28 main urban lakes were analysed, and their relationships with climatic change and human activities were discussed. The results show that most lakes in Wuhan had shrunk over the past 30 years resulting in a permanent change from water to land. The shrinkage was also most apparent in the central region of the city. Seasonal fluctuations of lake area were evident for most lakes but the relative important driving variable of lake area change varied between sub-periods of time for different lakes. The explanatory power of impervious surface to five-year permanent water change is 91.75%, suggesting that urbanization – as increasing impervious surface – had led to the shrinkage of urban lakes in Wuhan. In all, 128.28 km2 five-year permanent water disappeared from 1987 to 2016.

Impacts of Climate Change on Lake Fluctuations in the Hindu Kush-Himalaya-Tibetan Plateau

Lakes in the Hindu Kush-Himalaya-Tibetan (HKHT) regions are crucial indicators for the combined impacts of regional climate change and resultant glacier retreat. However, they lack long-term systematic monitoring and thus their responses to recent climatic change still remain only partially understood. This study investigated lake extent fluctuations in the HKHT regions over the past 40 years using Landsat (MSS/TM/ETM+/OLI) images obtained from the 1970s to 2014. Influenced by different regional atmospheric circulation systems, our results show that lake changing patterns are distinct from region to region, with the most intensive lake shrinking observed in northeastern HKHT (HKHT Interior, Tarim, Yellow, Yangtze), while the most extensive expansion was observed in the western and southwestern HKHT (Amu Darya, Ganges Indus and Brahmaputra), largely caused by the proliferation of small lakes in high-altitude regions during 1970s–1995. In the past 20 years, extensive lake expansions (~39.6% in area and ~119.1% in quantity) were observed in all HKHT regions. Climate change, especially precipitation change, is the major driving force to the changing dynamics of the lake fluctuations; however, effects from the glacier melting were also significant, which contributed approximately 31.9–40.5%, 16.5–39.3%, 12.8–29.0%, and 3.3–6.1% of runoff to lakes in the headwaters of the Tarim, Amu Darya, Indus, and Ganges, respectively. We consider that the findings in this paper could have both immediate and long-term implications for dealing with water-related hazards, controlling glacial lake outburst floods, and securing water resources in the HKHT regions, which contain the headwater sources for some of the largest rivers in Asia that sustain 1.3 billion people.

Dynamic changes in lakes in the Hoh Xil region before and after the 2011 outburst of Zonag Lake

Zonag, Kusai, Hedin Noel and Yanhu Lakes are independent inland lakes in the Hoh Xil region on the Qinghai-Tibet Plateau. In September 2011, Zonag Lake burst after the water level had increased for many years. Floods flowed through Kusai and Hedin Noel Lakes into Yanhu Lake; since then, the four small endorheic catchments merged into one larger catchment. This hydrological process caused the rapid shrinkage of Zonag Lake and continuous expansion of Yanhu Lake. In this study, based on satellite images, meteorological data and field investigations, we examined the dynamic changes in the four lakes and analyzed the influencing factors. The results showed that before 2011, the trends in the four lake areas were similar and displayed several stages. The change in the area of Zonag Lake corresponded well to the change in annual precipitation (AP), but the magnitude of the change was less than that of a non-glacier-fed lake. Although increased precipitation was the dominant factor that caused Zonag Lake to expand, increased glacier melting and permafrost thawing due to climate warming also had significant effects. After the 2011 outburst of Zonag Lake, due to the increasing AP and accelerating glacier melting, the increases in water volume of the three lakes were absorbed by Yanhu Lake, and Yanhu Lake expanded considerably. According to the rapid growth rates in water level and lake area, Yanhu Lake is likely to burst in 1–2 years.