La Garonne — monitoring and records

The monitoring network on this water

Hydrionis holds 5,264 values from 6 gauges on this water. Discharge is a property of a gauge and its reach, not of this water as a whole, so this page reports the network and its records rather than a single figure.

Gauges

5,264

Values held

1910–2026

Record spans

50,100 km²

Catchment above the deepest gauge

The seasonal shape

An annual mean says how much water a river carried. A monthly record says when — and on most rivers the difference between a wet winter and a dry summer is larger than the difference between one year and the next.

Monthly mean flow at La Garonne à Portet-sur-Garonne

Each month's mean discharge as the publisher computed it, which shows the seasonal shape an annual mean flattens away. 1910–2026.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Taken as the publisher computes it rather than recomputed by Hydrionis from daily values: the publisher knows which of its readings passed validation. Months the gauge did not cover are absent rather than interpolated, and the line breaks where they fall.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
European drought	Drought declaration	2022-05-01 – 2022-10-31	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Hurricane Katrina water and sanitation collapse — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	La Garonne à Portet-sur-Garonne (m³/s)
1910	437
1911	187
1912	83.6
1913	68.7
1914	138
1915	447
1916	109
1917	127
1918	147
1919	295
1920	349
1921	167
1922	136
1923	161
1924	344
1925	46.6
1926	216
1927	203
1928	286
1929	174
1930	176
1931	278
1932	140
1933	139
1934	109
1935	404
1936	280
1937	55.2
1938	188
1939	333
1940	129
1941	212
1942	256
1943	151
1944	80.9
1945	321
1946	124
1947	153
1948	291
1949	73.1
1950	137
1951	206
1952	279
1953	180
1954	109
1955	448
1956	237
1957	120
1958	114
1959	180
1960	212
1961	423
1962	135
1963	172
1964	85.4
1965	196
1966	262
1967	246
1968	294
1969	173
1970	225
1971	117
1972	297
1973	105
1974	117
1975	171
1976	77.8
1977	137
1978	171
1979	217
1980	266
1981	487
1982	194
1983	155
1984	180
1985	163
1986	226
1987	183
1988	168
1989	66.7
1990	48.5
1991	139
1992	79.0
1993	128
1994	284
1995	312
1996	191
1997	250
1998	143
1999	202
2000	111
2001	208
2002	62.0
2003	247
2004	449
2005	170
2006	105
2007	41.3
2008	143
2009	227
2010	160
2011	81.1
2012	132
2013	306
2014	392
2015	124
2016	123
2017	87.9
2018	276
2019	107
2020	151
2021	255
2022	359
2023	90.8
2024	120
2025	187
2026	174

About this series

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source	Office français de la biodiversité / SCHAPI — Hydrométrie — French river flow and stage · Licence Ouverte / Open Licence v2.0 (Etalab)
How the values came to exist	Measured
Period held	1910–2026
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1910 to 2026 is held.
Last read from the publisher	2026-10-01
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

Every gauge Hydrionis holds here

Gauges on the La Garonne and what each holds
Gauge	Measures	Values	Record
La Garonne à Portet-sur-Garonne	mean monthly river flow	1,400	1910–2026
La Garonne au Mas-d'Agenais et à Tonneins	mean monthly river flow	899	1914–1988
La Garonne [totale] à Saint-Gaudens [Valentine - récent]	mean monthly river flow	864	1912–1983
La Garonne à Arlos et à Saint-Béat	mean monthly river flow	736	1921–2026
La Garonne à Lamagistère	mean monthly river flow	717	1967–2026
La Garonne à Verdun-sur-Garonne	mean monthly river flow	648	1972–2026

How these gauges were attached to this water

Named by the publisher Each gauge here names this water in the publisher’s own station record. Hydrionis has not inferred the connection from station names.

What each gauge’s link to this water rests on
Gauge	Evidence	Established
La Garonne à Portet-sur-Garonne	Stated by the publisher — Hub'Eau hydrometry site reference, libelle_cours_eau, code_cours_eau and surface_bv fields — https://hubeau.eaufrance.fr/api/v2/hydrometrie/referentiel/sites	2026-10-02
La Garonne au Mas-d'Agenais et à Tonneins	Stated by the publisher — Hub'Eau hydrometry site reference, libelle_cours_eau, code_cours_eau and surface_bv fields — https://hubeau.eaufrance.fr/api/v2/hydrometrie/referentiel/sites	2026-10-02
La Garonne [totale] à Saint-Gaudens [Valentine - récent]	Stated by the publisher — Hub'Eau hydrometry site reference, libelle_cours_eau, code_cours_eau and surface_bv fields — https://hubeau.eaufrance.fr/api/v2/hydrometrie/referentiel/sites	2026-10-02
La Garonne à Arlos et à Saint-Béat	Stated by the publisher — Hub'Eau hydrometry site reference, libelle_cours_eau, code_cours_eau and surface_bv fields — https://hubeau.eaufrance.fr/api/v2/hydrometrie/referentiel/sites	2026-10-02
La Garonne à Lamagistère	Stated by the publisher — Hub'Eau hydrometry site reference, libelle_cours_eau, code_cours_eau and surface_bv fields — https://hubeau.eaufrance.fr/api/v2/hydrometrie/referentiel/sites	2026-10-02
La Garonne à Verdun-sur-Garonne	Stated by the publisher — Hub'Eau hydrometry site reference, libelle_cours_eau, code_cours_eau and surface_bv fields — https://hubeau.eaufrance.fr/api/v2/hydrometrie/referentiel/sites	2026-10-02

What this record holds

Hydrionis decides which waters get a page, and which of those are offered to search, from what is actually held rather than from how the page reads. Five signals are counted; this record has 3 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	6	yes, 3 or more
Years spanned	117	yes, 20 or more
Values held	5,264	yes, 1000 or more
Distinct measurements	1	no
Publishers measuring it	1	no
Official identifiers	2	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/gauge-fr-o2000010.json
How to cite this, and who you must credit
How these figures were produced
Request this at a different scale, format or geography

No bulk download is offered here, which is a licence position rather than a product one: at least one contributing publisher does not permit redistribution. The values can be read on the page, cited, and pointed to at source.

Attribution and citation

Attribution you are required to give

These are conditions of the licences the underlying data is published under. They are obligations to the publishers, not to Hydrionis, and they apply to you directly whether or not you mention Hydrionis at all.

Source: Hub’Eau / Système d’information sur l’eau, under Licence Ouverte (Etalab).

Office français de la biodiversité / SCHAPI — Licence Ouverte / Open Licence v2.0 (Etalab) (licence text)

Suggested citation for Hydrionis

Hydrionis (2026), La Garonne gauge records, accessed 2026-10-05, hydrionis.com/waters/france-la-garonne/

Cite Hydrionis where you rely on the compilation, the normalisation, the eligibility judgements or a chart. Where you use an unmodified published value, the publisher’s attribution is the one that is required; crediting Hydrionis as well is welcome and is not something Hydrionis can require of you.

Recommended, not required. Hydrionis does not claim rights over unmodified public data it relayed, and doing arithmetic on somebody else’s measurements does not make them Hydrionis’s. Cite the version and the access date: the La Garonne gauge records changes as publishers release and as methods are revised, and a citation without both cannot be checked later. Full guidance is on cite and reuse.

Where these figures come from

MeasuredHigh confidenceSeptember 2026

Source: Hub'Eau — Hydrométrie — French river flow and stage, O2000010. Licence: Open — attribution required (attribution required).

Method: Monthly mean discharge (QmM) computed by the publisher from its validated sub-hourly record, reported in litres per second and converted to cubic metres per second as they are collected. Where a site has been measured by more than one station, the station with the longest published series is used rather than blending stations whose values for the same month can differ.

Measured on La Garonne.

Retrieved 1 October 2026.