Tonlé Sap (Khmer: ទន្លេ​សាប) is a river in Cambodia that connects the Tonlé Sap lake with the Mekong river.[1][2] The river is known for its unique seasonal reversal, which plays a crucial role in supporting biodiversity, sustaining local livelihoods, enhancing agricultural productivity, and contributing to the ecological, economic, and cultural vitality of the region.[3][4][5]

Tonlé Sap
Tonlé Sap river in Phnom Penh
Tonlé Sap River is located in Cambodia
Tonlé Sap River
EtymologyFresh water river
Native nameទន្លេ​សាប (Khmer)
Location
CountryCambodia
ProvincesKampong Thom province, Kampong Chhnang province, Kampong Cham province, Kandal province, Phnom Penh
Physical characteristics
SourceTonlé Sap Lake
MouthMekong
 • location
Phnom Penh
 • coordinates
11°33′48″N 104°56′20″E / 11.56344°N 104.93901°E / 11.56344; 104.93901
Length147 kilometres (91 mi)
Basin features
Tributaries 
 • leftSteung Saen River, Chinit River
BridgesPrek Kdam Bridge, Prek Pnov Bridge, Chroy Changvar Bridge
Inland portsPhnom Penh Autonomous Port

Etymology

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In Khmer, Tonlé/ទន្លេ means "river"[6] and Sap/សាប means "fresh water".[7] Therefore, Tonlé Sap (ទន្លេ​សាប) is the name of the river while the lake is called "Boeng Tonlé Sap" (បឹង​ទន្លេសាប, where Boeng/បឹង​ means "lake").[8]

Geography

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From the lake, the Tonlé Sap flows 147 kilometres (91 mi) southeast to its confluence with the Mekong river near Phnom Penh, the capital of Cambodia. During the dry season, the Mekong and Tonlé Sap rivers merge, but in the monsoon season (May to October), the Mekong's floods cause the Tonlé Sap river to reverse its flow.[2] The reversal carries water, along with fish eggs and larvae, into the Tonle Sap Lake, where they find a nutrient-rich environment that supports their feeding and growth.[9]

The confluence of the Mekong, Tonlé Sap, and Bassac rivers, known as Chaktomuk, holds significant ecological and economic importance for Cambodia. It is a crucial source of drinking water for around 1.5 million residents of Phnom Penh, as well as supplying water for various industrial and commercial activities. Chaktomuk also receives both treated and untreated wastewater. As a key transportation hub in the region, it accommodates a wide range of vessels, including large sea-going cargo ships, high-speed passenger boats, and small fishing boats, all of which can dock and unload goods, materials, people, and food at the Phnom Penh Autonomous Port.[10] This port, located along the Tonlé Sap river approximately 3-4 km upstream from the confluence, is an international facility managed by the Cambodian Ministry of Public Works and Transport and the Ministry of Economy and Finance.[11]

Culture

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The Bon Om Touk, or Water Festival, is one of Cambodia's most prominent cultural events, celebrated annually on the Tonlé Sap River. This festival marks the end of the rainy season and the reversal of the river's flow, symbolizing the start of the fishing season. The highlight of the festival is the boat races, which attract thousands of participants and spectators to Phnom Penh, particularly around the Royal Palace area.[12] The festival not only celebrates the unique hydrological phenomenon of the Tonle Sap but also underscores the river's importance to Cambodian culture and livelihoods.[5][13]

Impact of upstream Mekong dams

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Concerns over the impact of upstream Mekong dams on the natural reversal of the Tonle Sap River are growing. These dams, particularly those in China and Laos, disrupt critical seasonal flooding patterns, leading to delays or failures in the river's annual reversal.[14] This disruption causes the Tonle Sap Lake to expand and contract less predictably, reducing fish stocks and agricultural productivity. Consequently, the livelihoods and food security of millions of Cambodians who depend on the lake and river are threatened.[15][16] Studies indicate that this disruption diminishes floodplain fertility and alters flood dynamics, emphasizing the urgent need for sustainable water management.[17]

References

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  1. ^ Oeurng, Chantha; et al. (25 March 2019). "Assessing Climate Change Impacts on River Flows in the Tonle Sap Lake Basin, Cambodia". Water. 11 (3): 618. doi:10.3390/w11030618.
  2. ^ a b Olson, Kenneth R.; Morton, Lois Wright (May 2018). "Tonle Sap Lake and River and confluence with the Mekong River in Cambodia" (PDF). Journal of Soil and Water Conservation. 73 (3).
  3. ^ "The Weakening Pulse of Tonle Sap". NASA MODIS Web. 22 December 2022.
  4. ^ Prak, Chan Thul (21 July 2020). "Fishermen without fish as Cambodia's river reversal runs late". Reuters.
  5. ^ a b Agnes Alpuerto (16 November 2018). "When the river flows backwards". Khmer Times.
  6. ^ "English-Khmer Dictionary".
  7. ^ "English-Khmer Dictionary".
  8. ^ "English-Khmer Dictionary".
  9. ^ Eyler, Brian; Kwan, Regan (16 February 2024). "Mekong Floodpulse". Stimson Center.
  10. ^ Dietsch, Benjamin J.; Densmore, Brenda K.; Wilson, Richard C. (2014). "Hydrographic survey of Chaktomuk, the confluence of the Mekong, Tonlé Sap, and Bassac Rivers near Phnom Penh, Cambodia, 2012" (PDF). Scientific Investigations Report. 2014-5227. United States Geological Survey.
  11. ^ JICA. "The Study on the Master Plan for Maritime and Port Sectors in Cambodia – Final Report" (PDF).
  12. ^ "ASEAN wishes Cambodians a happy Water Festival". Khmer Times. 28 November 2023.
  13. ^ Yow Hong Chieh (13 Feb 2024). "Bon Om Touk, Cambodia's Thrilling Water Festival". Medium.
  14. ^ Roney, Tyler (11 February 2022). "Interview: Is it too late to save Tonle Sap lake?". Dialogue Earth.
  15. ^ Seiff, Abby (15 October 2020). "Did Cambodia's Most Famous River Stop Changing Course?". VICE.
  16. ^ Eyler, Brian (15 August 2019). "When will this year's Tonle Sap reversal occur?". Stimson Center.
  17. ^ Pokhrel, Yadu; Shin, Sanghoon; Lin, Zihan; Yamazaki, Dai; Qi, Jiaguo (10 December 2018). "Potential Disruption of Flood Dynamics in the Lower Mekong River Basin Due to Upstream Flow Regulation". Scientific Reports. 8. doi:10.1038/s41598-018-35823-4.