Tonle Sap is the biggest freshwater lake in Southeast Asia and is one of the world’s most efficient inland fisheries. The Tonle Sap Lake, positioned inside the Cambodian floodplain, is seasonally inundated through several tributaries, prominently through the Srêng and Sên rivers being the perennial northern tributaries. The lake is likewise connected to the 120km lengthy Tonle Sap River which connects the lake to the Mekong River. The Mekong River yearly replenishes and sediments this complicated hydrological system, which in turn helps a mosaic of herbal and agricultural habitats at the Cambodian floodplain.
The important undeniable is in particular an end result of hundreds of thousands of years of Mekong alluvial deposition, erosion and sedimentation. Since the lake is one of the world’s most numerous and efficient ecosystems, it's miles critical to Cambodia’s meals delivery and in a roundabout way impacts the livelihood of big numbers of a predominantly rural population, including the Angkorian or Khmer civilization, now called Cambodia. Moreover, the lake acts as a herbal flood water reservoir for the Mekong device and is a critical supply of irrigation for rice fields at some stage in the dry season.
The Tonle Sap Lake occupies a depressed landform within the Cambodian floodplain, a geological melancholy of the large alluvial floodplain within the Lower Mekong basin, which has been fashioned with the aid of the collision of the Indian and Eurasian plate. The Cambodian floodplain consists of a maximum of lowland Cambodia, Mekong delta of Vietnam, a small part of Southern Laos, a small part of Japanese Thailand and is traversed with the aid of using the Mekong River. The Lower Mekong basin consists of the decrease of 1/2 of the Mekong river’s duration of 2,six hundred km and the encompassing drainage basin of around 607,000 sq.km. The decrease basin is functionally subdivided into 4 geographic regions: Northern highlands, Khorat Plateau, Tonle Sap Basin and the Great Lake or the Tonle Sap Lake.
The Mekong River flows via a vast valley to the east of the Khorat Plateau and enters the Tonle Sap Basin north of Pakse, Laos. The Tonle Sap basin is a massive alluvial simple surrounded with the aid of using hills, traversed with the aid of using mainstreams that split on the southern give up right into a complicated community of channels, one in every of that is the Tonle Sap River. The western and important part of the Basin include the Great Lake.
The water extent of the Mekong River yearly fluctuates and is supported by means of the Asian monsoon regime from June to November. This annual fluctuation performs an essential function within the flooding and drainage of the Tonle Sap. Flooding or drainage is a feature of the specific go with the drift reversal of the Tonle Sap River in the course of the moist season. In this season, influx from the Mekong, amplified via way of means of the monsoon, begins of evolved in May or June and reaches a most via way of means of past due August, wherein a swollen Mekong reverses the southeastward go with the drift of the Tonle Sap River, which floods the lake and will increase the Tonle Sap’s location from 2,500 sq.km to about 16,000 sq.km. In addition to that, the lake’s extent and period will increase yearly in the course of this season from 1 cubic kilometers to eighty cubic kilometers and from one hundred sixty km to 250 km respectively.
The lake reaches its most length in November and the monsoon ceases in that month, lowering the Mekong go with the drift to its minimum. During the dry season, the Great Lake drains into the Mekong River thru the Tonle Sap River, which has reverted to the downstream route and allowed the drainage from the lake and inundated the floodplain. As a result, the a hundred and twenty km lengthy Tonlé Sap River flows six months a 12 months from the southeast (Mekong) to northwest (lake) and the relaxation six months inside the contrary route.
This hydrological cycle helps the lake’s wealthy biodiversity, along with fish, natural world and plants. Many neighborhood groups depend on the lake’s wealthy biodiversity for their livelihoods wherein 40% of the populace in Cambodia depend upon the Great Lake and its floodplains for his or her profits and meals supply. When the Tonle Sap floods, the encircling regions turn out to be the main breeding floor for fish, especially carp. Fishing for the duration of this time is unlawful to save you from disruption of mating. When the water stages cross down at the end of the moist season, floating homes are mounted and fishing is authorized again. Moreover, ancient studies have proven that the ancient Angkorian civilization took advantage of climate situations to assist their rice crop fields.
Farmers created their personal irrigation device wherein they might dig big reservoirs for the duration of the moist season, amassing water that might be launched for the duration of the dry season. This doubled and every now and then even tripled the range of rice vegetation consistent with year, imparting the kingdom with sufficient harvest for a year.
Tonle Sap Lake is taken into consideration as a biodiversity hotspot because of the big sort of interconnected eco-areas having an excessive diploma of biodiversity. In fact, the lake turned into a UNESCO biosphere reserve in 1997. It is domestic to at least 149 species of fish, 11 of which might be globally threatened and 6 of which might be near-threatened species. Some of the outstanding avian species which are observed right here consist of the spot-billed pelican, Manchurian reed warbler, Bengal florican, grey-headed fish eagle, extra adjutant, and the Oriental darter.
The Tonle Sap additionally homes a sizable reptile populace which incorporates many freshwater snakes and the almost extinct Siamese crocodiles. The lake is likewise domestic to one in all the biggest freshwater fish within the world - the Mekong large catfish. What’s specific about this species is that it's far prone to chemical modifications within the ecosystem, making it an excellent and early indicator of ability modifications within the river ecosystem.
Utilization and Threats
The lake and surrounding ecosystems face numerous threats such as deforestation, infrastructure improvement and weather etrade. All Mekong riparian states - China, Laos, Myanmar, Thailand, Cambodia, and Vietnam—have built a collection of dams to take advantage of the river’s hydroelectric potential. These dams are notion to be an extreme risk to the Tonlé Sap eco-vicinity in view that they lessen the circulation of the lake and decrease connectivity. Climate extrade has additionally decreased the once a year river circulate the lake after a sequence of droughts in Cambodia for the duration of 2010. This had without delay impacted the fisheries and meals safety of the population.
Seasons of the Tonle Sap Lake
During the wet season from mid-May to starting October, the water stage of the Mekong River is 4 instances better than within the dry months. Large water portions glide through the Tonle Sap River within the Tonle Sap Lake, the floor of that may attain as much as 16,000 sq. km. Its most intensity then is 14 m. In November, while the Mekong River contains much less water, the glide route of the Tonle Sap River changes. Then large portions of water glide lower back from Tonle Sap Lake to the Mekong River, and the floor of the lake shrinks to 2,500 sq. km, its most intensity quantities to 2 - three m only. Due to this particular herbal phenomenon Tonle Sap Lake may be very wealthy in freshwater fish. In the floodplains rice has been cultivated for centuries.