river flow · Thailand
Mekong at Chiang Saen
Wet-season mean discharge
Modelled demonstration series · not observed data
This one has a caveat that honesty requires: upstream dams alter this gauge as much as rainfall does, so a low reading is not purely a climate signal. What is not ambiguous is the consequence. A weak flood pulse means a weak Tonle Sap reversal, and that fishery feeds tens of millions of people protein.
75 years, modelled
Same reading, two normals
| Normal | Mean | σ | Pct | Return |
|---|---|---|---|---|
| 1951–1980 | 4200 m³/s | −0.70σ | 24th | 1 in 4.1 years |
| 1991–2020 | 3614 m³/s | +0.04σ | 52nd | 1 in 2.1 years |
Today would rank 38 of 76 for lowest value in the modelled series. Nothing about the reading changes between rows — only the yardstick.
The season here
The Mekong's wet-season pulse is what drives the entire lower-basin fishery and reverses the flow of the Tonle Sap each year.
Where this series comes from
MODELLED SERIES — not observed. Parameters set from published Chiang Saen gauge wet-season discharge climatology; lognormal transform applied. The 75 annual values are synthesised by the seeded generator. Upstream regulation is a real and large confounder on this gauge and is not separated out here.
Every number on this page comes from a modelled series: 75 annual values synthesised by a seeded generator from published climatological parameters for Mekong at Chiang Saen. It shows how anomaly reasoning works. It is not a measurement and must not be cited as one.
How to read σ
σ counts standard deviations from this place's own normal. The sigma guide · return periods.
More river flow stations
Open Mekong at Chiang Saen on the field →