scholarly journals Drastic decline of floodpulse in the Cambodian floodplains (the Mekong River and the Tonle Sap system)

2021 ◽  
Author(s):  
Samuel De Xun Chua ◽  
Xi Xi Lu ◽  
Chantha Oeurng ◽  
Ty Sok ◽  
Carl Grundy-Warr
Keyword(s):  
Reverse Flow ◽  
Mekong Delta ◽  
Water Levels ◽  
Water Withdrawal ◽  
Lake Area ◽  
Wet Season ◽  
Tonle Sap Lake ◽  
Tonle Sap ◽  
Maximum Water ◽  
Flooding Season

Abstract. The Cambodian floodplains experience a yearly floodpulse that is essential to sustain fisheries and the agricultural calendar. Sixty years of data from 1960–2019 are used to track the changes to the floodpulse there. We find that minimum water levels in 2010–2019 have increased by up to 1.55 m at Kratie and maximum water levels have decreased by up to 0.79 m at Prek Kdam when compared to 1960–1991 levels, causing a reduction of the annual flood extent. Concurrently, the duration of the flooding season has decreased by about 26 days (Kompong Cham) – 40 days (Chaktomuk), with the season starting later and ending much earlier. Along the Tonle Sap River, the average annual reverse flow from the Mekong to the Tonle Sap Lake has decreased by 56.5 %, from 48.7 km3 in 1962–1972 to 31.7 km3 in 2010–2018. As a result, wet-season water levels at Tonle Sap Lake has dropped by 1.05 m in 2010–2019 since 1996–2009, corresponding to a 20.6 % shrinkage of the Lake area. In addition to known upstream contributors such as hydropower dams, two anthropogenic causes of the drastic alterations to the floodpulse are identified: irrigation and channel incision. We estimate that water withdrawal in the Cambodian floodplains is occurring at a rate of (2.1 ± 0.3) km3/yr and incision-induced water levels reduction is in the order of (0.43–1.02) m. As the floodpulse is essential for the ecological habitats, fisheries and livelihoods of the region, its reduction will pose major implications throughout the basin, from the Tonle Sap system to the Vietnamese Mekong Delta downstream.

scholarly journals Estimating Real-Time Water Area of Dongting Lake Using Water Level Information

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1240
Author(s):  
Yuannan Long ◽  
Rong Tang ◽  
Changshan Wu ◽  
Changbo Jiang ◽  
Shixiong Hu
Keyword(s):  
Linear Regression ◽  
Water Level ◽  
Real Time ◽  
Yangtze River Basin ◽  
Water Area ◽  
Dongting Lake ◽  
Water Levels ◽  
Lake Area ◽  
Level Information ◽  
Maximum Water

Dongting Lake, the second largest freshwater lake in China, is an important water source for the Yangtze River Basin. The water area of Dongting Lake fluctuates significantly daily, which may cause flooding and other relevant disasters. Although remote sensing techniques may provide lake area estimates with reasonable accuracy, they are not available in real-time and may be susceptible to weather conditions. To address this issue, this paper attempted to examine the relationship between lake area and the water levels at the hydrological stations. Multi-temporal water area data were derived through analyzing Moderate Resolution Imaging Spectroradiometer (MODIS) imagery using the Automatic Water Extraction Index (AWEI). Then we analyzed the inter- and intra-annual variations in the water area of the Dongting Lake. Corresponding water level information at hydrological stations of the Dongting Lake were obtained. Simple linear regression (SLR) models and stepwise multiple linear regression (SMLR) models were constructed using water levels and water level differences from the upstream and downstream hydrological stations. We used the data from 2004 to 2012 and 2012, respectively, to build the model, and applied the data from 2013 to 2015 to evaluate the models. Results suggest that the maximum water area of the Dongting Lake during 2000–2015 has a clear decreasing trend. The variations in the water area were characterized by hydrological seasons, with the annual minimum and maximum water areas occurring in January and September, respectively. The water level at the Chengjingji station, and water level differences between upstream stations and the Chengjingji station, play a major role in estimating the water area. Further, results also show that the SMLR established in 2012 performs the best in estimating water area of the Dongting Lake, especially with high water levels.

Socio-Economic Changes in Cambodia’s Unique Tonle Sap Lake Area: A Spatial Approach

2015 ◽  
Vol 9 (3) ◽  
pp. 413-432 ◽  
Author(s):  
Aura Salmivaara ◽  
Matti Kummu ◽  
Olli Varis ◽  
Marko Keskinen
Keyword(s):  
Lake Area ◽  
Economic Changes ◽  
Tonle Sap Lake ◽  
Tonle Sap ◽  
Spatial Approach

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

2010 ◽  
Vol 1 (1) ◽  
pp. 87-101 ◽  
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.

A Machine Learning Framework to Predict Reverse Flow and Water Level: A Case Study of Tonle Sap Lake

2021 ◽  
pp. 127168
Author(s):  
Khosro Morovati ◽  
Pouria Nakhaei ◽  
Fuqiang Tian ◽  
Mahmut Tudaji ◽  
Shiyu Hou
Keyword(s):  
Machine Learning ◽  
Water Level ◽  
Reverse Flow ◽  
Learning Framework ◽  
Tonle Sap Lake ◽  
Tonle Sap

scholarly journals Morphological Characteristics of Cambodia Mekong Delta and Tonle Sap Lake and Its Response to River-Lake Water Exchange Pattern

2020 ◽  
Vol 12 (04) ◽  
pp. 275-302
Author(s):  
Zhaoming Xu ◽  
Changwen Li ◽  
Anqiang Li ◽  
Zhongqiong You ◽  
Wei Yao ◽  
...  
Keyword(s):  
Lake Water ◽  
Water Exchange ◽  
Morphological Characteristics ◽  
Mekong Delta ◽  
Tonle Sap Lake ◽  
Tonle Sap
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