Finland Historical River Discharge Dataset

Methodology

Ingested 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 — 671 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.

Attribution required:

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

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)

Suggested citation

Hydrionis (2026), Finland Historical River Discharge Dataset, version 1.0.0. Retrieved from https://hydrionis.com/data/datasets/finland-river-discharge/

Cite the version. Hydrionis datasets change as publishers release and as methods are revised, and a citation without a version cannot be checked later.

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 at ingestion rather than through a separate linkage pass.

Getting the data

Machine-readable metadata for this dataset is at /api/v1/datasets/finland-river-discharge.json. For bulk extracts, higher-volume access or commercial licensing, see data enquiries.