{"id":"sweden-river-discharge","slug":"sweden-river-discharge","name":"Sweden Historical River Discharge Dataset","description":"Daily river discharge for the Swedish national hydrological network, from 1851 to the present: 694 gauging stations across 87 main drainage basins, taken exactly as SMHI publishes it. The deepest openly licensed daily river record Hydrionis holds.","methodology":"Collected from the SMHI open data hydrological service under CC BY 4.0. Values are stored as SMHI publishes them and are not recomputed: SMHI derives each daily discharge from its own sub-daily measurement and rating curves, and a mean recalculated by Hydrionis from whatever sub-daily data happened to be exposed would be a different statistic under the same name. SMHI marks every value checked-and-approved, roughly-checked or unchecked, and all three levels are stored — the roughly-checked periods sit inside continuous records rather than at their ends, so excluding them would leave silent gaps. Each series states which of its periods carry which level, and takes the weakest as its confidence. Values carrying an unrecognised quality code, or an empty cell, are refused rather than converted.","domains":["river-flow"],"metricIds":["river-flow-mean"],"subjectScope":"Swedish hydrological gauging stations with a corrected archive","cadence":"daily","version":"1.0.0","released":"2026-08-25","changelog":[{"version":"1.0.0","date":"2026-08-25","summary":"First release. Sweden becomes the deepest river record on the platform.","additions":["Daily discharge for 694 stations across 87 main drainage basins, 1851 onward.","Catchment name, official basin number and basin area carried onto every station."]}],"limitations":["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.","Quality is not uniform across a record. About 96% of values are checked and approved by SMHI; the rest are roughly checked or not yet checked, and they are not confined to recent data — one station carries an unchecked year in 1923. Each series names its own periods rather than leaving a reader to assume.","A great many Swedish rivers are regulated for hydropower. Discharge at a regulated station reflects operating decisions as much as hydrology, and a change in the record may be a change in operation rather than in rainfall or runoff. SMHI does not publish a regulation flag through this service, so Hydrionis cannot mark which stations are affected.","Rating curves are revised over a century-long record, and a revision changes the discharge computed from the same water level. SMHI republishes corrected values rather than annotating breaks, so a long series is not guaranteed to be homogeneous even where it is continuous.","Twenty-four stations in the network publish no corrected archive at all and are absent, and two returned a header with no values. Both are closed or very short-lived gauges."],"observationCount":9518238,"seriesCount":694,"subjectCount":694,"from":1851,"to":2026,"sourceIds":["se-smhi-hydro"],"units":["m³/s"],"redistributable":true,"commerciallyReusable":true,"citation":"Hydrionis (2026), Sweden Historical River Discharge Dataset, version 1.0.0. Retrieved from https://hydrionis.com/data/datasets/sweden-river-discharge/","downloads":[{"file":"/downloads/observations-river-flow-se-smhi-hydro.csv","format":"CSV","label":"river-flow observations from SMHI, part 1 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part2.csv","format":"CSV","label":"river-flow observations from SMHI, part 2 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part3.csv","format":"CSV","label":"river-flow observations from SMHI, part 3 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part4.csv","format":"CSV","label":"river-flow observations from SMHI, part 4 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part5.csv","format":"CSV","label":"river-flow observations from SMHI, part 5 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part6.csv","format":"CSV","label":"river-flow observations from SMHI, part 6 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part7.csv","format":"CSV","label":"river-flow observations from SMHI, part 7 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part8.csv","format":"CSV","label":"river-flow observations from SMHI, part 8 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part9.csv","format":"CSV","label":"river-flow observations from SMHI, part 9 of 10 (1,000,000 rows)"},{"file":"/downloads/observations-river-flow-se-smhi-hydro-part10.csv","format":"CSV","label":"river-flow observations from SMHI, part 10 of 10 (563,204 rows)"}],"apiPath":"/api/v1/datasets/sweden-river-discharge.json","lastFetched":"2026-10-01","fields":[{"id":"river-flow-mean","name":"Mean river flow","definition":"Average volumetric discharge past a gauging station over a stated period.","unit":"m³/s","nativeGeography":["river-gauge"],"comparabilityNotes":"Flow is a property of a specific gauge on a specific reach, and cannot be attributed to a river as a whole. Two gauges on the same river can differ by an order of magnitude. Where a station measures flow through a sluice, lock or pumping station — much of the Dutch network does — discharge is signed and a negative value means water moving in the reverse direction, which is a real operating state and not an error. Managed flow of that kind is not comparable with discharge at a natural gauging station, because it reflects operational decisions as well as hydrology."}]}