Finland Historical River Discharge Dataset

What this looks like

One real series from the dataset, and real rows from the head of its published extract. Neither is a mock-up: the rows below are the same rows, unchanged, that are in the file you would download.

Mean river flow at Muroleenkoski

The longest single series this dataset holds — 59,808 daily values, one of 672. Drawn from 600 of them, evenly spaced across the record. The dataset is not this chart.

Drawn to show the shape and resolution of what the dataset contains, not to make a point about Muroleenkoski. Gaps are breaks, never interpolated.

View the data behind this chart

Underlying data
Period	Muroleenkoski (m³/s)
1863	25.0
1864	56.0
1865	15.5
1866	29.0
1867	35.0
1868	14.0
1869	16.9
1870	46.0
1871	17.1
1872	23.0
1873	61.0
1874	20.0
1875	48.0
1876	3.90
1877	13.1
1878	93.0
1879	61.0
1880	11.0
1881	12.0
1882	37.0
1883	12.0
1884	74.0
1885	8.30
1886	17.1
1887	27.0
1888	19.8
1889	12.9
1890	37.0
1891	25.0
1892	11.5
1893	29.0
1894	31.0
1895	16.9
1896	26.0
1897	21.0
1898	46.0
1899	65.0
1900	33.0
1901	26.0
1902	21.0
1903	30.0
1904	70.0
1905	29.0
1906	34.0
1907	24.0
1908	27.0
1909	1.95
1910	47.0
1911	22.0
1912	32.0
1913	72.0
1914	22.0
1915	17.1
1916	35.0
1917	40.0
1918	40.0
1919	59.0
1920	24.0
1921	22.0
1922	27.0
1923	39.0
1924	35.0
1925	60.0
1926	16.9
1927	18.0
1928	40.0
1929	40.0
1930	57.0
1931	48.0
1932	43.0
1933	33.0
1934	14.0
1935	58.0
1936	39.0
1937	39.0
1938	28.0
1939	24.0
1940	19.0
1941	20.0
1942	5.00
1943	42.0
1944	57.0
1945	76.0
1946	24.0
1947	33.0
1948	11.0
1949	41.0
1950	15.0
1951	59.0
1952	34.0
1953	19.8
1954	47.0
1955	66.0
1956	39.0
1957	40.0
1958	53.0
1959	26.0
1960	26.0
1961	43.0
1962	40.0
1963	53.0
1964	34.0
1965	41.0
1966	34.0
1967	46.0
1968	38.0
1969	38.0
1970	24.0
1971	40.0
1972	33.0
1973	40.0
1974	45.0
1975	135
1976	24.0
1977	30.0
1978	47.0
1979	28.0
1980	83.0
1981	46.0
1982	45.0
1983	88.0
1984	45.0
1985	32.0
1986	49.0
1987	60.0
1988	48.0
1989	46.0
1990	48.0
1991	26.0
1992	76.0
1993	66.0
1994	25.0
1995	49.0
1996	21.0
1997	53.0
1998	40.0
1999	41.0
2000	47.0
2001	88.0
2002	47.0
2003	11.5
2004	39.0
2005	66.0
2006	26.0
2007	94.0
2008	82.0
2009	44.0
2010	18.5
2011	24.0
2012	57.0
2013	53.0
2014	50.0
2015	71.0
2016	59.0
2017	31.0
2018	44.6
2019	13.3
2020	118
2021	63.7
2022	33.0
2023	46.9
2024	65.0
2025	62.9
2026	33.0

Sample rows

12 of 10,375,908 rows Taken from the start of observations-river-flow-fi-syke-hydrologia.csv. These are sample rows, not the dataset.

Sample rows from the Finland Historical River Discharge Dataset extract
`metric_id`	`subject_id`	`subject_kind`	`value`	`censored`	`censor_operator`	`censor_threshold`	`censor_limit`	`censor_reported`	`unit`	`period_start`	`period_end`	`period_kind`	`basis`	`confidence`	`source_id`	`source_ref`	`qualifier`	`superseded`	`retrieved`
river-flow-mean	fi-syke-0100150	geography	5	—	—	—	—	—	m³/s	1959-01-01	1959-01-01	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	7.8	—	—	—	—	—	m³/s	1959-01-02	1959-01-02	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	7.8	—	—	—	—	—	m³/s	1959-01-03	1959-01-03	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	7	—	—	—	—	—	m³/s	1959-01-04	1959-01-04	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	7.1	—	—	—	—	—	m³/s	1959-01-05	1959-01-05	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	6.3	—	—	—	—	—	m³/s	1959-01-06	1959-01-06	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	6.7	—	—	—	—	—	m³/s	1959-01-07	1959-01-07	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	6.8	—	—	—	—	—	m³/s	1959-01-08	1959-01-08	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	6.6	—	—	—	—	—	m³/s	1959-01-09	1959-01-09	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	5.8	—	—	—	—	—	m³/s	1959-01-10	1959-01-10	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	7.2	—	—	—	—	—	m³/s	1959-01-11	1959-01-11	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01
river-flow-mean	fi-syke-0100150	geography	6.4	—	—	—	—	—	m³/s	1959-01-12	1959-01-12	day	measured	high	fi-syke-hydrologia	0100150	—	—	2026-10-01

Download these rows as CSV — the same twelve, with the column header, for testing a loader before committing to the full file.

Methodology

Collected from the Syke Hydrologiarajapinta OData service under CC BY 4.0, with no key and no registration. Values are stored as Syke publishes them and are not recomputed: Syke derives each daily discharge from its own measurement and rating curves, and a mean recalculated by Hydrionis would be a different statistic under the same name. Syke carries a per-value quality flag; values flagged as possibly erroneous are refused, because Hydrionis cannot show a per-point flag on a chart and a doubted value plotted beside a trusted one is indistinguishable from it. Interpolated values are stored and described on the series, on the reasoning that interpolation is a stated method rather than a doubt and that removing it would punch holes in the middle of continuous records. Station coordinates are published as degrees-minutes-seconds integers and are converted; read as decimal degrees they would place Finnish gauges in the Indian Ocean.

What this dataset cannot tell you

Read before relying on these figures

Discharge is a property of a gauging station and its reach, not of a river. Two stations on the same watercourse routinely differ by an order of magnitude, and no figure here describes a river as a whole.
Finnish rivers are extensively regulated for hydropower and for lake level management. Discharge at a regulated station reflects operating decisions as much as hydrology, and Syke does not publish a regulation flag through this interface, so Hydrionis cannot mark which stations are affected.
A small number of values carry an interpolation flag and are stored as such. They are a stated method rather than a measurement, and each series says how many it holds.
Values Syke itself flags as possibly erroneous are absent. That is a deliberate refusal rather than a gap in the publisher’s archive, and a reader reconstructing Syke’s own record should go to Syke.
Forty stations in the network hold fewer than a year of usable days and are absent. Most are short-lived or very recently opened.

Coverage

Subjects	Finnish hydrological gauging stations reporting discharge — 672 held
Period	1847–2026
Units	m³/s
Update cadence	Daily
Identifier	`finland-river-discharge` v1.0.0

Fields

Data dictionary →

Every metric this dataset carries, with the unit it is stored in and the geography level it is reported at. Full definitions are in the data dictionary.

Identifier	Field	Unit	Reported at
`river-flow-mean`	Mean river flow Average volumetric discharge past a gauging station over a stated period.	m³/s	river-gauge

Rights and access

Licence position

Open with attribution. Derivative use true; redistribution true; commercial reuse true.

Permitted uses

Public display
Derived analysis
API delivery
Bulk download
Commercial use

Available to: Public, Developer, Research, Professional, Enterprise. These follow from the rights of the contributing publishers, not from a Hydrionis pricing decision — no access tier can widen what a publisher withheld.

Contributing sources

Suomen ympäristökeskus (Finnish Environment Institute) — Hydrologiarajapinta — Finnish national hydrological archive (CC BY 4.0)

Attribution and citation

Cite and reuse →

Two different obligations, deliberately kept apart. One is a condition of somebody else's licence; the other is a request Hydrionis has no standing to enforce.

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.

Contains data from the Finnish Environment Institute (Syke), licensed under CC BY 4.0.

Suomen ympäristökeskus (Finnish Environment Institute) — CC BY 4.0 (licence text)

Suggested citation for Hydrionis

Hydrionis (2026), Finland Historical River Discharge Dataset, version 1.0.0, accessed 2026-10-05, hydrionis.com/data/datasets/finland-river-discharge/

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: Finland Historical River Discharge Dataset 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.

Changelog

Version 1.0.0 — 2026-08-26

First release. Finland becomes the largest single archive on the platform by measured days.

Additions

Daily discharge for 671 stations across 62 main drainage basins.
Main drainage basin name and official code carried onto every station, so Finnish gauges join the water graph as they are collected rather than through a separate linkage pass.

Use this data

Every bulk extract ships with a companion metadata file carrying this dataset’s version, its sources, their licences, the attribution you are required to give and the suggested citation — so the terms travel with the file rather than staying on this page.

About this data

The fields a professional user needs to judge whether this is fit for a particular purpose. Deliberately not a score.

About this data

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	Suomen ympäristökeskus (Finnish Environment Institute) — Hydrologiarajapinta — Finnish national hydrological archive · CC BY 4.0
How the values came to exist	Mixed across the series — the basis is recorded on every individual value.
Period held	1847–2026
Known gaps	Discharge is a property of a gauging station and its reach, not of a river. Two stations on the same watercourse routinely differ by an order of magnitude, and no figure here describes a river as a whole. Finnish rivers are extensively regulated for hydropower and for lake level management. Discharge at a regulated station reflects operating decisions as much as hydrology, and Syke does not publish a regulation flag through this interface, so Hydrionis cannot mark which stations are affected. A small number of values carry an interpolation flag and are stored as such. They are a stated method rather than a measurement, and each series says how many it holds.
Continuity	Version 1.0.0, released 2026-08-26. 1 recorded version; breaking changes and corrections are listed in the changelog above.
Last read from the publisher	2026-10-01 · publisher updates daily
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