Mekong Floods History

DavidFL

0
Staff member
Subscribed
Jan 16, 2003
14,731
5,566
113
70
Chiang Khong
www.thegtrider.com
31 July / 4th August 2024

With 4 days of rain @ Chiang Khong & a rapid 5 metre rise in the river in the last few days got me to thinking about the last flood & when was the great flood?

1.30pm 31st July 2024
1722707666080.jpeg


11.45am Thursday 1st August.
1722620315712.jpeg


11.30am Friday 2nd August.
1722665747348.jpeg


1722620123275.jpeg


My last recollections of real high water @ Chiang Khong are in 2008 & 2018.

2008 Chiang Khong & the old the ferry landing, with the international immigration / customs crossing.
1722620604508.jpeg



1722620655573.png


Today, the same ferry port with the river rising.
1722620724817.jpeg


2008 @ Rai Saeng Arun Resort
1722620847702.jpeg


2015 a view of the Rai Saeng Arun damage.

1722621408260.jpeg



But from what I can see all records refer to 1966 as the great flood.

The Mekong river has exceeded its highest recorded level of 12.38 metres in 1966, inundating homes and farmland from 9 August in the northern province of Chiang Rai all the way to the northeastern province of Nakhon Phanom.

It affected Thailand & Laos, with Vientiane particularly hard hit.
The cause was typhoon Phyllis that blew in from the West & Vietnam, to remain stationary over northern Laos & SW China for a few weeks, dumping massive amounts of rain.
1722621565355.jpeg


All that water drained into the Mekong, flowed downstream & flooded all the riverside communities that had very little flood protection in those days.

Some areas of Chiang Khong district suffered flooding for 2 months.

1722619780343.jpeg


1722619603186.jpeg


1722619797533.jpeg


Vientiane suffered for much longer with the flood waters as far as the Pratu Xay monument.

1722619271855.jpeg


300 people died in Laos from those 1966 floods.
Most of the country's rice crop was wiped out & it was near famine!




The Mekong flood level of 1966 was actually surpassed by the 2008 flood, but there were effective flood protections measures in place so the damage was perhaps not as great.

The 2008 Flood
Tropical storm Kammuri was the main culprit for the flood in 2008, a La Nina year.
It rained continuously for a couple of weeks in August.
Note too that 2024 is also a La Nina year, starting now!
The origin of the floodwater was more or less evenly split between China below Jinghong and the large left-bank tributaries in northern Lao PDR.
A rapid water level rise at Luang Prabang occurred one day before water levels rose at Man An tributary station in China.
Whilst there was some flooding upstream from Vientiane / Nong Khai, downstream, including Vientiane & Nong Khai, was particularly bad on both sides of the Khong.
Khon Kaen had more than 1.5 times the mean annual rainfall of 1,250 mm.
At Pakxan over 800 mm was recorded over the 10 days 11-20 August, once up to 200 mm in 1 day.

For the 10-day Laos record in 1927 Xepon had 1,255 mm & in 1996 Attapeu had 1,020 mm.

2018 Flood
Extreme rainfall in July and August from tropical storm Son-Tinh caused the Xe Pian-Xe Namnoy dam to collapse in Attapeu.

A month later Tropical storm Bebinca followed to bring intense rain & flooding to both N Laos & N Thailand.
1722703465355.jpeg


It ended up in N Thailand for an extended period.
1722703584372.jpeg


The old Houei Xai port 31st July 2018 with the Khong up.
1722703923787.jpeg


1722703949791.jpeg


The Chiang Khong cargo port 1st August 2018
1722704149293.jpeg



The Mekong flooding between Thailand & Laos can be divided into 2 regions, above & below Vientiane / Nong Khai.

Upstream from from Vientiane, the only rivers, feeding into the Mekong are
A From Thailand
1. Ruak.
2. Kok + Fang + Nam Lao.
3. Nam Kham.
4. Nam Ing.
5. Nam Loei.
N From Laos
1. Nam Ma.
2. Nam Tha
3. Nam Ou
4. Nam Khan
If these catchment areas feed large amounts of water into the Mekong they can cause flooding.
Generally though, these tributaries only make a small contribution to the overall flow of the Mekong.

Downstream from Vientiane the main rivers feeding into the Mekong are
A From N E Thailand.
1. Songkhram
2. Mun
3. Chi
The Mun - Chi system contributes only 10% to the average flood volume at that point on the mainstream.
B From Laos.
1. Nam Khan.
2. Nam Ngum / Nam Lik / Soong.
3. Nam Kading / Nam Theun..
4. Nam Ngiap.
5. Nam Xan.
6. Nam Hinboun.
7. Xe Bangfai.
8. Xe Banghiang.
The combined mean annual flow of all tributaries between Vientiane and Pakse is 171 km3, almost 40% of the total for the Mekong.
These big tributaries are significant contributors to the Mekong's water supply, especially in the wet.

Laos Historic Flood Pattern: During the last 30 years (1966 to 1995), 22 notable floods have occurred with an average frequency of once in 1.4 years.
Of these 22 historic floods, only four were large, covering the whole country (1966, 1971, 1978 and 1995), giving an average frequency of once in every 7.5 years.
source: FLOOD MANAGEMENT AND MITIGATION IN THE MEKONG RIVER BASIN


Historical records of the Mekong floods from 1960.
1722620958912.jpeg


Another version of flood data for Laos
1722667570010.jpeg


Enjoy. Watching the Khong go up & down can be a wonderful experience.

1722707038159.jpeg


1722707174776.jpeg


1722706802540.jpeg


1722707004366.jpeg


1722707192840.jpeg


See also

 
Last edited:

DavidFL

0
Staff member
Subscribed
Jan 16, 2003
14,731
5,566
113
70
Chiang Khong
www.thegtrider.com
In September 2024 the Mekong was again in flood, after massive rain from Typhoon Yagi, that drowned North Vietnam, N Lao, N Thailand & Myanmar.

A report from Mekong Butterfly Fly Group detailed the big Mekong floods as 1966, 1971, 2008, 2011, 2018 and 2024.

The most severe occurred in 2018, when the Mekong water level remained high for nearly 3 months, causing enormous damage, and the main factor that year was the drainage of dams in Laos and Thailand.

A chart for the hydrological station at Chiang Saen.

1726511633175.jpeg



The Chiang Khong Buk Port - old ferry crossing under water 12 September 2024.

1726511955505.jpeg


1726512013815.jpeg


1726512029188.jpeg


1726512056107.jpeg