Mekong River Basin (Northeast)
Tributaries of the Mekong River (Northeastern Thailand)
General overview of the Mekong River Basin (Northeastern Thailand): Each of the 8 provinces has 29 sub-basins, covering areas in 8 provinces: Udon Thani, Nong Khai, Nong Bua Lamphu, Loei, Sakon Nakhon, Nakhon Phanom, Mukdahan, and Amnat Charoen.
The entire Mekong River Basin (Northeast) covers approximately 46,932 square kilometers, divided into 29 sub-basins and 5 basin groups. It encompasses 9 provinces: Loei, Nong Khai, Udon Thani, Nong Bua Lamphu, Sakon Nakhon, Nakhon Phanom, Mukdahan, Amnat Charoen, and Ubon Ratchathani, along with 82 districts, 618 sub-districts, and 5,608 villages. The sub-basin boundaries and basin groupings exhibit unique characteristics of the Mekong River Basin (Northeast), namely that all streams within each sub-basin flow into the Mekong River, a natural international waterway.
Most rivers in the Mekong basin are less than 50 kilometers long and have a steep slope, making them highly susceptible to erosion. Heavy rainfall can cause severe flash floods. Agricultural land is located along the riverbanks, while residential areas are found in the middle and lower reaches of the river.
1. Suay River Basin: Drainage area of 1,336.96 sq km or 835,601.07 rai.
The area is mostly flat, especially in the lower part of the river basin, which is in the north near the confluence of the Mekong River. There are scattered swamps and marshes. The upper areas, in the south, are characterized by gentle slopes and low hills in the headwaters, with numerous tributaries. The area covers two provinces: [Province Name - omitted for privacy].
Udon Thani and Nong Khai have five tributary basins: Upper Huai Nam Suai, Huai Thong, Middle Huai Nam Suai, Lam Nam Phen, and Lower Huai Nam Suai. In 2007, the population was approximately 267,925 people (covering the entire area).
Problem situation
– Shortage of water for agriculture and consumption.
- flood
2. The Mong River Basin: Drainage area of 2,645.92 sq km or 1,653,702.18 rai.
It comprises the end of the Phu Phan mountain range, separating the upper and lower river basins in a northwest-southeast direction. The headwaters of other tributaries to the south consist only of hills and slopes. The majority of the land is flat to plains, covering four provinces: Loei, Nong Bua Lamphu, Udon Thani, and Nong Khai. There are six tributary basins: Upper Nam Mong, Huai Nam Bon, Middle Nam Mong, Huai Seet, Huai Thon, and Lower Nam Mong. The population in 2007 was approximately 338,847 people.
Problem situation
– Shortage of water for agriculture and consumption.
– Flooding and riverbank erosion.
Water quality
3. San River Basin: Drainage area of 881.65 sq km or 551,032.15 rai.
The area comprises high mountain ranges throughout most of the watershed, especially in the south and east, which are the headwater areas with an elevation of approximately 1,300 meters above mean sea level. The elevation gradually decreases towards the central area, which has a relatively steep slope. There are only small areas of flat land, mainly along the banks of the main rivers, namely the San River and Huai Nam Khao Man. The area covers Loei Province and has three tributary basins: Huai Nam Khao Man, Upper San River, and Lower San River. The population in 2007 was approximately 37,840 people.
Problem situation
– Shortage of water for agriculture and consumption.
– Flooding and riverbank erosion.
– Water pollution
4. Som River Basin: Drainage area 1,118.95 sq km or 699,343.32 rai.
The area comprises high mountain ranges in the east, with the western mountain range reaching approximately 600 meters above mean sea level (m.a.s.l.), higher than the eastern range which is approximately 500 m.a.s.l. From both mountain ranges, the land gradually slopes down towards the rivers in the central part of the area. The terrain is mostly mountainous and sloping, with limited flat land, mostly scattered along the riverbanks. It covers two provinces: Udon Thani and Nong Khai, and has three tributary basins: the Upper Som River, Huai Nam Rang, and the Lower Huai Nam Som. The estimated population is approximately 88,163 people (covering the entire area).
Problem situation
– Lack of regulations on water usage.
– Shortage of water for agriculture and consumption.
– Water pollution, flooding, forest degradation
5. The third section of the Mekong River basin: Drainage area of 690.01 sq km or 431,259.25 rai.
The area is surrounded by mountains on the south, west, and east sides, with an elevation of approximately 1,000 meters above mean sea level, gradually sloping down towards the north. The terrain is predominantly high mountains and serves as the headwaters of many small, steep tributaries that flow into the Hueng River, a tributary of the Mekong River to the north. It covers part of Loei Province and has three river basins: the Upper Third Section of the Mekong River, the Nam Hu River, and the Lower Third Section of the Mekong River. The population is 15,158 people (covering the entire area).
Problem situation
– Shortage of water for domestic use and consumption.
– Shallow water sources
– Watershed forests are destroyed, leading to drought.
– Flooding of agricultural areas.
6. The fourth section of the Mekong River basin: Drainage area of 794.09 sq km or 496,308.27 rai.
The area comprises mountain ranges scattered throughout the watershed, particularly in the south, which is the headwater area with an elevation of approximately 600 meters above mean sea level (m.a.s.l.). The elevation of the mountain range gradually decreases towards the north, reaching approximately 300 m.a.s.l. These mountain ranges give rise to numerous small, steep tributaries that flow into the Hueng River, which is part of the Mekong River upstream. The area covers Loei Province and has three sub-watersheds: the Upper Mekong River Section 4, the Khan River, and the Lower Mekong River Section 4. The population is 45,351 people (entire area).
Problem situation
- Shortage of water for agriculture and consumption; competition for water for agriculture.
– Shallow water, collapsing riverbanks.
7. The fifth section of the Mekong River basin: Drainage area of 1,760.84 sq km or 1,100,522.29 rai.
The area comprises mountain ranges distributed throughout most of the watershed, with elevations of approximately 600 meters above mean sea level. These mountain ranges give rise to numerous small, steep tributaries from the south that flow into the Mekong River in the north. The terrain is predominantly mountainous and sloping, with limited flat land. It covers three provinces: Loei, Udon Thani, and Nong Khai, and has four sub-watersheds: the Upper Mekong River Section 5, Huai Nam Chom, Huai Sa Ngao, and the Lower Mekong River Section 5. The population is 95,307 people (entire area).
Problem situation
– Shortage of water for agriculture.
– Flooding problem
– The riverbank has collapsed.
8. The Sixth Section of the Mekong River Basin: Drainage area of 553.45 sq km or 345,908.56 rai.
It is a lowland area along the Mekong River, so the landscape is mostly flat land. There are numerous swamps and marshes scattered throughout the area, and several short streams flow directly into the Mekong River. It covers two provinces: Udon Thani and Nong Khai, and has one tributary basin, the Sixth Section of the Mekong River. The population is 147,434 people (covering the entire area).
Problem situation
– Shortage of water for agriculture and consumption.
– Flooding problem
9. The Mekong River Basin, Part 7: Drainage area of 2,556.85 sq km or 1,473,033.05 rai.
The boundaries of the river basin are to the north, east, and west of the Mekong River, which forms the border between Thailand and the Lao People's Democratic Republic. To the south, it lies along the watershed divide of the Songkhram River, Huai Khong, Huai Hee, and its tributaries that flow directly into the Mekong River. The general topography consists of flat land adjacent to the Mekong River, with higher elevations south of the basin. There is relatively little plain land along the riverbanks. The area covers two provinces: Nong Khai and Nakhon Phanom. There are four sub-basins: the Upper Mekong River (Section 7), the Middle Mekong River (Section 7), Huai Bangbat, and the Lower Mekong River (Section 7). The population is approximately 338,847 people (covering the entire area).
Problem situation
- Shortage of water for agriculture and consumption; flooding; riverbank erosion.
– Lack of awareness regarding water resource conservation.
– Lack of established water user organizations.
10. The eighth section of the Mekong River basin, with a drainage area of 1,145.17 square kilometers or 715,729.72 rai.
A watershed boundary, approximately 160-190 meters above mean sea level, forms the boundary between the Mekong River sub-basin (Section 8) and the Nam Kam sub-basin along the eastern side of the Ti River basin and the Mekong River in Nakhon Phanom Province. The western part of the basin is the source of the main streams: Huai Bo, Huai Bang Ko, and Huai Bang Huak. The upper part of the basin consists of high, steep mountains and rolling hills; the central area is a plain to gently undulating plain; and the lower area is relatively flat to level. It covers an area of Nakhon Phanom Province and has three tributary basins: Huai Bo, Huai Bang Ko, and Huai Bang Huak. The population is 214,086 people.
Problem situation
– Shortage of water for agriculture and consumption.
– Flooding of agricultural areas.
- Inefficient water management.
11. Mekong River Basin Section 9: Drainage area of 449.92 sq km or 281,202.05 rai.
A watershed boundary, approximately 200 meters above mean sea level, forms the boundary between the Mekong River sub-basin section 9 and the Huai Nam Kam and Huai Bang Sai sub-basins. The eastern part of the basin borders the Mekong River in Mukdahan Province, while the western part is the source of the Huai Chanod stream. The upper part of the basin consists of high, steep, and undulating mountains; the central part is a plain to gently undulating hill; and the lower part is relatively flat to level. It covers areas in two provinces: Nakhon Phanom and Mukdahan. Mukdahan has one sub-basin, the Mekong River section 9, with a population of 66,243 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
Water quality
12. Huai Khong Watershed: Watershed area 709.31 sq km or 443,320.44 rai.
The northern boundary of the watershed lies on the watershed divide between Huai Khong and its tributaries flowing into the Mekong River; the eastern boundary lies on the watershed divide between Huai Sao and Huai Hee; the western boundary lies on the watershed divide of Huai Ang Ha, which is located in the 7th section of the Mekong River basin; and the southern boundary lies on the watershed divide between Huai Khong and Huai Khamin and the confluence of Huai Khong and the Songkhram River. It covers areas of Nong Khai Province and has two sub-basins: the main Huai Khong and Huai Khao. The population is 63,836 people.
Problem situation
- Shortage of water for agriculture and consumption; flooding; riverbank erosion.
– Flooding of agricultural areas.
– There were no improvements to the crop cultivation system.
13. Huai Dan Watershed: Watershed area 675.77 sq km or 422,353.44 rai.
The northern boundary of the area lies at the confluence of Huai Dan and Huai Luang streams; the eastern boundary lies on the watershed divide of Huai Dan and Huai Luang streams; and the southern boundary lies on the watershed divide of the northeastern Mekong and Chi rivers.
The area is predominantly flat, sloping from the south and east to the north. The elevation ranges from approximately 170 to 190 meters above mean sea level. It covers parts of Udon Thani Province and has two tributary basins: the Upper Huai Dan and the Lower Huai Dan. The population is 121,244 people (covering the entire area).
Problem situation
- Shortage of water for agriculture and consumption; flooding; riverbank erosion.
– Flooding of agricultural areas.
– There were no improvements to the crop cultivation system.
14. Huai Luang Watershed: Watershed area 3,417.64 sq km or 2,136,023.07 rai.
The northern boundary of the river basin extends to the Mekong River, the border between Thailand and Laos. The eastern boundary lies on the watershed divide between the Huai Luang and Songkhram Rivers and the Huai Khong River. The western and southern boundaries are bordered by the Phu Phan Mountains on the watershed divide. The southern part of the basin is encircled by the Phu Phan mountain range from west to south, with the land sloping down to the Huai Luang Dam. It covers an area of three provinces: Udon Thani, Nong Khai, and Nong Bua Lamphu, and has seven sub-basins: Huai Luang Section 1, Huai Luang Section 2, Huai Luang Section 3, Huai Luang Section 4, Huai Luang Section 5, Huai Chiam, and Huai Luang Section 6. The population is 765,899 people.
Problem situation
- Shortage of water for agriculture and consumption; flooding; riverbank erosion.
– There has been encroachment on the reservoir area.
– Lack of management.
15. Huai Hee Watershed: Watershed area 743.60 sq km or 464,750.04 rai.
The eastern boundary of the watershed lies on the watershed divide of the Phu Kiu mountain range and the watershed divide of the Huai Bangbat tributaries and the Huai Sai Yai tributary, which flow into the Huai Hee reservoir. The northern boundary lies on the watershed divide of Huai Hee and the tributaries flowing into Kut Thing Yai. The western boundary lies on the watershed divide of Huai Hee and the Songkhram River. The southern boundary lies at the confluence of Huai Hee and the Songkhram River. It covers areas in two provinces: Nong Khai and Nakhon Phanom, and has three sub-watersheds: Upper Huai Hee, Huai Sai Yai, and Lower Huai Hee. The population is 85,194 people.
Problem situation
- Shortage of water for agriculture and consumption; flooding.
– The water is contaminated with toxins and of poor quality.
– Lack of a management plan for the organization.
16. Huai Nam Puan Watershed: Watershed area 1,084.00 sq km or 677,498.45 rai.
It comprises two important tributaries: the Suan River, which flows from the northern mountain range to the south and joins the Puan River, which flows from the higher slopes in the north before merging with the Loei River. The terrain is mostly gently sloping from the headwaters to the main river, and the area along both banks of the main river and throughout the river basin has low mountain ranges. It covers three sub-basins within Loei Province: Huai Nam Suai, Upper Huai Nam Puan, and Lower Huai Nam Puan. The population is 106,775 people (entire area).
Problem situation
– Shortage of water for agriculture and domestic use.
- flood
– Drought
17. Huai Nam Man Watershed: Watershed area 619.59 sq km or 387,246.51 rai.
The area comprises high mountain ranges throughout most of the watershed. Plains are scarce, particularly along the Man River in the central part of the area, forming narrow plains along the riverbanks from the central watershed to the Hueng River. The mountain range to the south, which forms the upper watershed, consists of steep mountains of varying elevations, gradually decreasing towards the north, which forms the lower watershed. The area covers Loei Province and has two sub-watersheds: the Upper Man River and the Lower Man River. The population is 30,284 people (entire area).
Problem situation
– Shortage of water for agriculture and domestic use.
- flood
– Water pollution
– The riverbank has collapsed.
18. Lower Loei River Basin. Basin area: 2,922.32 sq km or 1,826,450.32 rai.
There are steep mountain ranges to the south and west, which form the headwaters and give rise to several important tributaries, including the Loei River, Nam Khu River, Nam Thob River, Nam Huay River, Nam Lai River, and Nam Man River. The highest mountain ranges are located in the south, which is the source of the Loei River, and gradually decrease in elevation towards the north. The lower areas of the river basin are plains and large sloping plains, covering the entire province of Loei. There are 9 sub-basins: Loei River Section 1, Nam Khu River, Loei River Section 2, Nam Thob River, Loei River Section 3, Huay Nam Huay Stream, Nam Lai Stream, Nam Man Stream, and Loei River Section 4. The population is 262,507 people (full area).
Problem situation
– Shortage of water for agriculture and domestic use.
-There is no place to throw away trash.
- flood
– Water pollution
– The riverbank has collapsed.
– There is a lot of sediment in the water.
– Water pollution occurred.
19. Upper Songkhram River Basin. Basin area: 3,270.81 sq km or 2,044.72 rai.
The northern boundary of the river basin lies on the watershed divide between the Songkhram River and Huai Hee and Huai Khong. To the east, it divides the Songkhram River into the Lower Songkhram sub-basin, at the confluence of Huai Khong and the Songkhram River. To the west, it lies on the watershed divide between Huai Luang and the Songkhram River. To the south, it borders the Phu Phan Mountains on a watershed divide. The general area ranges from plains to slopes, covering three provinces: Udon Thani, Nong Khai, and Sakon Nakhon. There are eight sub-basins: Upper Songkhram River Section 1, Huai San Chot, Huai Pha Lat, Huai Thuan; Upper Songkhram River Section 2, Huai Khon, Huai Khammit; and Upper Songkhram River Section 3. The population is 474,294 people (entire area).
Problem situation
– Shortage of water for agriculture.
– Shortage of water for consumption and domestic use.
- flood
– Saline soil
20. Lower Songkhram River Basin. Basin area: 3,065.60 sq km or 1,916,000.96 rai.
The watershed area is bordered to the north by streams in the Mekong River basin, section 7; to the east by the Mekong River; to the west by the confluence of Huai Khong and the Songkhram River; and to the south by the confluence of Huai Nam Oun and the Songkhram River. The terrain ranges from plains to gentle slopes, followed by undulating hills. The majority of the land consists of grasslands or low shrubland interspersed with field crops. The area covers two provinces: Sakon Nakhon and Nakhon Phanom, and has six tributary basins: Huai Sang, Lower Songkhram River section 1, Huai Nod, Lower Songkhram River section 2, Huai Nam Mao, and Lower Songkhram River section 3. The population is 294,217 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
– Lack of water management.
– Problems with forest resources.
21. Huai Nam Yam Watershed: Watershed area 1,730.08 sq km or 1,081,298.29 rai.
To the north, it lies on the watershed divide between the tributaries of Huai Nam Yam and the tributaries of the Songkhram River, and the confluence of Huai Nam Yam and the Songkhram River. To the east, it lies on the watershed divide between Huai Nam Yam and Huai Nam Oun. To the west, it lies on the watershed divide between Huai Nam Yam and the tributaries of the Songkhram River. To the south, it lies on the Phu Pha Lek and Phu Pha Thong watersheds, which are the watershed divide between the upper Songkhram River sub-basin, the Huai Nam Oun sub-basin, and the Huai Nam Yam sub-basin. The area consists of plains interspersed with uplands, covering two provinces: Sakon Nakhon and Nakhon Phanom. Its tributaries include the upper Nam Yam River, Huai Thong, and the lower Nam Yam River. The population is 212,146 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
– The riverbank has collapsed.
- Water quality problems.
22. Huai Nam Oun Watershed: Watershed area 3,542.89 sq km or 2,214,306.43 rai.
The area is bordered to the north by the watershed divide of Huai Nam Oun and Huai Nam Yam streams, and the confluence of Huai Nam Oun and the Songkhram River. To the east, it lies on the watershed divide of Huai Nam Oun and its tributaries flowing into Nong Han Lake, and between Huai Nam Oun and Huai Nam Phung. Further east, it is bordered by the Phu Pha Thong mountain range, which forms a dividing line between the upper Songkhram River, Huai Nam Yam, and Huai Nam Oun sub-basins. To the south, it is bordered by the watershed along the Phu Khao Ko, Phu Nang Ngoi, and Phu Khiao mountains. The area covers two provinces: Sakon Nakhon and Nakhon Phanom, and has four sub-basins: the upper Nam Oun, Huai Pla Hang, the middle Nam Oun, and the lower Nam Oun. The population is 400,429 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
– Lack of water management.
– Poor soil quality.
23. Huai Thuy Watershed: Watershed area 782.64 sq km or 489,148.67 rai.
It is characterized by a narrow band in the northernmost part of the region, with rolling hills leading up to them, supported by the Khorat Formation. The Huai Thuy River originates from a plateau south of Kusumal District, Sakon Nakhon Province, and flows into Ban Pak Thuy, Tha Uthen District, Nakhon Phanom Province, covering areas of two provinces: Sakon Nakhon and Nakhon Phanom. It has two tributary basins: Upper Huai Thuy and Lower Huai Thuy. The population is 86,731 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
– Environmental pollution.
– Inefficient water storage for utilization.
24. Mae Phung River Basin. Basin area: 836.54 sq km or 522,837.24 rai.
A watershed boundary, approximately 300-500 meters above mean sea level, forms the boundary between the Nam Phung sub-basin and the Huai Nam Oun, Huai Nam Kam, and Huai Bang Sai sub-basins in Sakon Nakhon Province. These basins, located to the north and west of the main basin, are the source of the Nam Phung River. The upper basin area consists of high, steep, and undulating mountains and hills, while the middle to lower areas are plains to gently undulating hills. The area covers part of Sakon Nakhon Province and has two sub-basins: the Upper Nam Phung and the Lower Nam Phung. The population is 44,278 people.
Problem situation
– Shortage of water for agriculture and consumption.
– Poor water management; inefficient and ineffective utilization.
25. Huai Nam Kam watershed. Watershed area: 2,678.20 sq km or 1,673,877.26 rai.
A watershed boundary of approximately 300 meters above mean sea level (MSL) separates the Kam River sub-basin from the Phung River sub-basin, the eighth sub-basin of the Mekong River, and the Huai Chanod sub-basin in Sakon Nakhon Province. To the north and west of the basin are the headwaters of the Bang and Kam rivers. The upper part of the basin consists of steep, sloping mountains and hills; the middle part is a plain to gently undulating terrain; and the lower part is relatively flat to level. It covers areas in two provinces: Sakon Nakhon and Nakhon Phanom, and has six tributary basins: Kam River Section 1, Kam River Section 2, Upper Bang River, Lower Bang River, Kam River Section 3, and Kam River Section 4. The population is 423,664 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
– Wastewater
– Water management problems.
26. Huai Bang Sai Watershed. Watershed area: 1,398.44 sq km or 874,027.31 rai.
A watershed boundary of approximately 300 meters above mean sea level (MSL) separates the Huai Bang Sai sub-basin from the Kam, Huai Chanod, Huai Muk, and Huai Bang Yi sub-basins in Mukdahan Province. The northern and western parts of the basin are the origins of the Huai Bang Sai stream. The upper part of the basin consists of high, steep, and undulating mountains; the middle part is plain to gently undulating; and the lower part is relatively flat to level. It covers areas in three provinces: Sakon Nakhon, Nakhon Phanom, and Mukdahan. There are four sub-basins: Huai Bang Sai Part 1, Huai Bang Sai Part 2, Huai Bang Sai Part 3, and Huai Bang Sai Part 4. The population is 60,873 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
Water quality
– Tourist attractions; water lacks maintenance.
27. Huai Muk Watershed: Drainage area 797.18 sq km or 498,237.73 rai.
A watershed boundary forms to the west, approximately 332 meters above mean sea level, separating the Huai Muk and Huai Bang Yi sub-basins in Mukdahan Province. This is the source of the Huai Muk River. The upper part of the basin consists of high, steep, and undulating mountains and hills; the middle part is plain to gently undulating; and the lower part is relatively flat to level. It covers an area of Mukdahan Province and has two sub-basins: Upper Huai Muk and Lower Huai Muk. The population is 117,468 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
Water quality
– Tourist attractions; water lacks maintenance.
28. Huai Bang Yi Watershed: Watershed area 1,564.42 sq km or 977,761.43 rai.
A mountain range, approximately 400 meters above mean sea level, forms a boundary between the Huai Bang Yi sub-basin and the Huai Bang Sai sub-basin, the Huai Muk sub-basin, and the lower Mekong River sub-basin in Mukdahan Province. The northern and western parts of the basin are the source of the Huai Bang Yi stream. The upper basin area consists of steep and undulating mountains and hills; the middle area is plain to gently undulating; and the lower area is relatively flat to level. It covers an area of Mukdahan Province and has three sub-basins: Upper Huai Bang Yi, Middle Huai Bang Yi, and Lower Huai Bang Yi. The population is 112,834 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
Water quality
29. Lower Mekong Basin. Drainage area: 3,358.68 sq km or 2,099,175.86 rai.
The general topography features a mountain range approximately 500 meters above mean sea level located to the north and west of the basin. This range forms a boundary between the lower Mekong River basin and the Huai Bang Yi tributary, stretching from Mukdahan to Ubon Ratchathani provinces. The upper basin consists of steep, sloping mountains and hills, forming the source of the Huai Bang Yi stream. The central area is a plain to gently undulating terrain, while the lower area is relatively flat to level. The population is 235,602 people.
Problem situation
– Shortage of water for agriculture and consumption.
- flood
Water quality
Guidelines and procedures for the use of water from public water sources.
Current issues concerning water resources.
– Water shortage
– Competition for water.
– Wasteful and inefficient use of water.
– Water pollution
– Floods and droughts
The problem of using water from natural or public sources for consumption, agriculture, industry, commerce, tourism, and other activities currently has a significant impact on the river basin ecosystem and water users within the basin.
