Multidecadal variability of the Tonle Sap Lake flood pulse regime

The economic value of the Tonle Sap Lake Floodplain to Cambodia is among the highest provided to a nation by a single ecosystem around the world. The flow of Mekong River is the primary factor affecting the Tonle Sap Lake Floodplain. The Tonle Sap Lake also plays a very important role in regulating the downstream flood of Mekong River. Hence, it is necessary to understand its temporal changes of lake surface and water storage and to analyse its relation with the flood processes of Mekong River. Monthly lake surface and water storage from July 2013 to May 2014 were first monitored based on remote sensing data. The relationship between water surface and accumulative water storage change was then established. In combination with hydrological modelling results of Mekong River Basin, the relation between the lake’s water storage and the runoff of Mekong River was analysed. It is found that the water storage has a sharp increase from September to December and, after reaching its maximum in December, water storage quickly decreases with a 38.8&thinsp;billion&thinsp;m<sup>3</sup> of drop in only half month time from December to January, while it keeps rather stable at a lower level in other months. There is a two months’ time lag between the maximum lake water storage and the Mekong River peak flood, which shows the lake’s huge flood regulation role to downstream Mekong River. It shows that this remote sensing approach is feasible and reliable in quantitative monitoring of data scarce lakes.

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Characteristics of the Annual Maximum and Minimum Water Temperatures in Tonle Sap Lake, Cambodia from 2000 to 2019

Remote Sensing ◽

10.3390/rs13193972 ◽

2021 ◽

Vol 13 (19) ◽

pp. 3972

Author(s):

Yoichi Fujihara ◽

Koki Okuyama ◽

Keisuke Hoshikawa ◽

Hideto Fujii ◽

Takashi Nakamura ◽

...

Keyword(s):

Water Temperature ◽

Water Level ◽

Air Temperature ◽

Flood Pulse ◽

Water Level Fluctuations ◽

Annual Maximum ◽

Water Level Change ◽

Level Change ◽

Tonle Sap Lake ◽

Tonle Sap

The Tonle Sap Lake contains unique hydrological environments and ecosystems. Although water temperature is an important consideration in lake management, information on the water temperature of the lake is limited. Thus, we investigated the characteristics of the daytime water temperatures of the Tonle Sap Lake from 2000 to 2019 using MOD11A1, a Moderate Resolution Imaging Spectroradiometers (MODIS) product. Moreover, the relationship between water temperature fluctuations and hydrological–meteorological conditions was analyzed. The maximum and minimum daytime water temperatures were recorded in May (30.7 °C) and January (24.6 °C), respectively, each a month after the maximum and minimum air temperatures were recorded. The annual maximum, average, and minimum water levels showed a downward trend (−0.14, −0.08, and −0.01 m/y, respectively). The annual maximum water temperature increased at a rate of 0.17 °C/decade, whereas the annual minimum water temperature decreased at a rate of 0.91 °C/decade. The annual maximum daytime water temperature had a strong negative correlation with water level change (flood pulse) and a weaker correlation with air temperature. The annual minimum daytime water temperature presented the strongest positive correlation with water level change (flood pulse) in the previous year. However, there was no correlation between the annual minimum daytime water temperature and air temperature. These results indicate that water temperature in the Tonle Sap Lake is mainly affected by water level fluctuations, which are mainly driven by flood pulses.

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Dynamics of bacterial community in Tonle Sap Lake, a large tropical flood-pulse system in Southeast Asia

The Science of The Total Environment ◽

10.1016/j.scitotenv.2019.01.351 ◽

2019 ◽

Vol 664 ◽

pp. 414-423 ◽

Cited By ~ 6

Author(s):

Porsry Ung ◽

Chanthol Peng ◽

Sokunsreiroat Yuk ◽

Reasmey Tan ◽

Vannak Ann ◽

...

Keyword(s):

Bacterial Community ◽

Southeast Asia ◽

Flood Pulse ◽

Pulse System ◽

Tonle Sap Lake ◽

Tonle Sap

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Water, livelihoods and climate change adaptation in the Tonle Sap Lake area, Cambodia: learning from the past to understand the future

Journal of Water and Climate Change ◽

10.2166/wcc.2010.010 ◽

2010 ◽

Vol 1 (1) ◽

pp. 87-101 ◽

Cited By ~ 48

Author(s):

Paula Nuorteva ◽

Marko Keskinen ◽

Olli Varis

Keyword(s):

Climate Change ◽

Adaptive Capacity ◽

Climate Change Adaptation ◽

Environmental Changes ◽

Land Use Changes ◽

Rural Livelihoods ◽

Flood Pulse ◽

Lake Area ◽

Tonle Sap Lake ◽

Tonle Sap

The changing environment is expected to intensify the challenges that people in developing countries are facing, particularly among the groups whose livelihoods depend on natural resources. The adaptive capacity of livelihoods largely defines the extent to which people can cope with future environmental changes, whether caused by climate change or other factors such as land use changes and water resources development. This article analyses the resilience and adaptive capacity of rural livelihoods around Cambodia's Tonle Sap Lake, an exceptional lake-floodplain system dominated by flood pulse. The research findings demonstrate that despite the people's tradition of adapting to the remarkable seasonal variation of water and related resources, their capacity to adapt to unusual environmental changes is weak, with the poorest being clearly the most vulnerable group. Reasons for the weak resilience include villages' relatively homogenous livelihood structures, unjust governance practices, increasing inequality and the lack of opportunities for livelihood diversification. It is concluded that while climate change is likely to pose a remarkable challenge to people's livelihoods in the longer term, climate change adaptation activities should also take into account other environmental changes. Equally critical is the understanding of the broader socio-political context and its dynamics in increasing—and decreasing—livelihood resilience.

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Seasonal increases in fish trophic niche plasticity within a flood-pulse river ecosystem (Tonle Sap Lake, Cambodia)

Ecosphere ◽

10.1002/ecs2.1881 ◽

2017 ◽

Vol 8 (7) ◽

pp. e01881 ◽

Cited By ~ 19

Author(s):

Thomas Pool ◽

Gordon Holtgrieve ◽

Vittoria Elliott ◽

Kevin McCann ◽

Bailey McMeans ◽

...

Keyword(s):

Flood Pulse ◽

Trophic Niche ◽

River Ecosystem ◽

Tonle Sap Lake ◽

Tonle Sap

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Seasonal variations in diet composition, diet breadth and dietary overlap between three commercially important fish species within a flood-pulse system: The Tonle Sap Lake (Cambodia)

PLoS ONE ◽

10.1371/journal.pone.0198848 ◽

2018 ◽

Vol 13 (6) ◽

pp. e0198848 ◽

Cited By ~ 8

Author(s):

Kong Heng ◽

Mathieu Chevalier ◽

Sovan Lek ◽

Pascal Laffaille

Keyword(s):

Seasonal Variations ◽

Diet Composition ◽

Diet Breadth ◽

Flood Pulse ◽

Pulse System ◽

Dietary Overlap ◽

Tonle Sap Lake ◽

Tonle Sap ◽

Commercially Important ◽

Important Fish

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Groundwater discharge and phosphorus dynamics in a flood-pulse system: Tonle Sap Lake, Cambodia

Journal of Hydrology ◽

10.1016/j.jhydrol.2017.03.049 ◽

2017 ◽

Vol 549 ◽

pp. 79-91 ◽

Cited By ~ 11

Author(s):

William C. Burnett ◽

Gullaya Wattayakorn ◽

Ratsirin Supcharoen ◽

Khamfeuane Sioudom ◽

Veasna Kum ◽

...

Keyword(s):

Groundwater Discharge ◽

Flood Pulse ◽

Pulse System ◽

Phosphorus Dynamics ◽

Tonle Sap Lake ◽

Tonle Sap

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Holocene environmental change in Tonle Sap, Cambodia based on fossil diatoms

Science and Technology Development Journal - Natural Sciences ◽

10.32508/stdjns.v1it5.530 ◽

2018 ◽

Vol 1 (T5) ◽

pp. 5-17

Author(s):

Hang Thi Gia Nguyen ◽

Thuyen Xuan Le

Keyword(s):

Sediment Cores ◽

Flood Pulse ◽

Radiometric Dating ◽

Mekong River ◽

P Value ◽

Diatom Assemblages ◽

Tonle Sap Lake ◽

Tonle Sap ◽

The Impact ◽

Aulacoseira Granulata

Tonle Sap Lake (“Great Lake”, Cambodia) is a biggest inland freshwater body. The size of the lake is changed dynamically following monsoon via connected to the Mekong river, especially the flood pulse. The flood pulse on Tonle Sap has affected considerably the lake’s ecological property as well diatom assemblages. The present study aimed to assess the impact of the flood pulse to diatom assemblages by time. Two short sediment cores from Tonle Sap Lake with the depth of 1.54 m and 1.27 m respectively below the lake floor were collected in May 2013 and 2015 and one short sediment core with the depth of 1.68 m was collected from the confluence of the Mekong River and Tonle Sap River in May, 2013. The sedimentations were dated by using radiometric dating (210Pb and 137Cs). Succession of fossil diatom assemblages was calculated by Rarefaction index (ES) and species richness is by Hill's N2 index. A total of 70 diatom species was released, and the diversity of diatom assemblages was extremely fluctuated in function of time (p-value = 0.0045***). Especially, 6 diatom taxa: Aulacoseira distans, Aulacoseira granulata, Aulacoseira granulata var. angustissima, Gyrosigma acuminatum, Gyrosigma attenuatum and Paralia sulcata characterized by the highest relative abundance (>1 %). In term of ecology, these species are the epipelic diatoms living commonly in eutrophication and high suspendid solid conditions. In fact, it is clear that the onset of flood pulses affected considerably the studied diatom assemblages in particular, and made sense to bio-community in general; also the lacustrine environment of Tonle Sap lake was changed very strongly in response to this shift of hydrological regime.

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