This list is arranged by drainage basin, with respective tributaries indented under each larger stream's name. 

1.     Tonlé Sap 

Tonle Sap refers to a seasonally inundated freshwater lake, the Tonlé Sap Lake and an attached river, the 120 km (75 mi) long Tonlé Sap River, that connects the lake to the Mekong. They form the central part of a complex hydrological system, situated in the 12,876 km2 (4,971 sq mi) Cambodian floodplain covered with a mosaic of natural and agricultural habitats that the Mekong replenishes with water and sediments annually. The central plain formation is the result of millions of years of Mekong alluvial deposition and discharge. From a geological perspective, the Tonlé Sap Lake and Tonlé Sap River are a current freeze-frame representation of the slowly, but ever shifting Lower Mekong Basin. Annual fluctuation of the Mekong's water volume, supplemented by the Asian Monsoon regime causes the unique flow reversal of the Tonle Sap River.

2.     The Bassac River 

The Bassac River  (commonly called Tonle Bassac ទន្លេបាសាក់) is a distributary of the Tonlé Sap and Mekong River. The river starts in Phnom PenhCambodia, and flows southerly, crossing the border into Vietnam near Châu Đốc. In Vietnam it is known as the Hậu River (Sông Hậu or Hậu Giang in Vietnamese).

The Bassac River is an important transportation corridor between Cambodia and Vietnam, with barges and other crafts plying the waters. A city of the same name was once the west-bank capital of the kingdom of Champasak., a recommissioned repair ship originally built for the United States Navy during World War II, served on the Bassac River during the Second Indochina War.

3.     Boribo River

Boribo River  is a river in Cambodia. It rises in the Aural mountains in Pursat and crosses Baribour District in Kampong Chhnang Province before entering the Tonlé Sap lake. It is a major tributary of the Tonlé Sap.

4.     Chinit River 

Chinit River  (alternates: Stung Chinit or Stoeng Chinith) is a river of Cambodia. Located in Kampong Thom Province, it is a major tributary of the Tonlé Sap Lake ("Great Lake"), which joins the Tonlé Sap River at the downstream end in the larger Mekong basin. Somewhat unusually the river is looped back into the same river system, which accounts for its length of 264 kilometres (164 mi), leaving Tonlé Sap lake and entering its river again downstream. The prehistoric archaeological site of Samrong Sen is located on the river bank. Water resource projects, commencing in 1971 and in 2003, have had various measures of success. The river is an important trade route.

5.     The Kah Bpow

The Kah Bpow  is a river flowing through the town of Koh Kong in south-west Cambodia. It flows through Smach Meanchey District and much of Koh Kong Province.

6.     The Kong River

The Kong River also known as the Xe Kong or the Se Kong (Lao: Se Kong, (Vietnamese: sông Sê Kông) is a river in Southeast Asia. The river originates in Thừa Thiên–Huế Province in Central Vietnam and flows 480 kilometres (300 mi) through southern Laos and eastern Cambodia. It joins the Mekong River near Stung Treng town of Cambodia. Part of its course forms the international boundary between Laos and Cambodia.

7.     Krang Ponley River 

Krang Ponley River  is a river of Cambodia. A tributary of the Tonle Sap, it flows for 89.37 kilometres (55.53 mi)

8.     The Mongkol Borei River 

The Mongkol Borei River  is a river in Mongkol Borei District in Banteay Meanchey Province in western Cambodia. It flows from the border of Prachin Buri province in Thailand and runs through Mongkol Borei and neighbouring districts. It is a major tributary of the Tonlé Sap.

9.     The Sangkhae River

The Sangkhae River  (also spelled Stung Sangkae or Stung Sangké) is one of the main rivers in Battambang Province in north western Cambodia. The Sangker River is approximately 250 kilometres (160 mi) long. It flows through 6 districts and 27 communes in Battambang province before draining into the Tonlé Sap lake. The average depth of the river, based on raw data provided by the Battambang's Department of Water Resource (2013) is during the dry season 2.35 metres (7.7 ft) and during the wet season 6.79 metres (22.3 ft).

10.      Serei Sophorn River 

Serei Sophorn River  is a river, which flows through Banteay Meanchey province in Cambodia. It is a major tributary of the Tonlé Sap.

Source: Wikipedia

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