The monitoring network within this area

Hydrionis holds 62,607 values from 3 gauges within it. Discharge is a property of a gauge and its reach, not of this drainage area, so this page reports the network and its records rather than a single figure.

3

Gauges

62,607

Values held

1911–2026

Record spans

Gauges within the Simojoki drainage basin

3 monitoring points, positioned as the publisher records them.

How low, how high and how variable this gauge runs

A hydrograph says what happened; these say how often. Read off Hosionkoski's whole daily record between 1962 and 2026, they describe the shape of the record rather than any day in it — and they belong to this gauge and its reach, not to this drainage area.

4.300 m³/s

Q95 low flow

14.630 m³/s

Q50 median flow

53.000 m³/s

Q10 high flow

Largest day of each water year at Hosionkoski

The highest daily mean discharge in each October-to-September water year, 1962–2025.

These are the largest daily means, not flood peaks. A peak lasting hours is averaged across a whole day here, so the true instantaneous maximum on the same day was higher — sometimes far higher on a fast-responding catchment. Flood frequency work needs a publisher's own instantaneous series; Hydrionis holds one for 2,236 American gauges and not for this one, so the two are never drawn together. A water year the gauge did not substantially cover produces no value at all rather than a low one.

View the data behind this chart

Underlying data
Period	Hosionkoski (m³/s)
1962	111
1963	173
1964	195
1965	167
1966	284
1967	211
1968	283
1969	203
1970	309
1971	157
1972	328
1973	210
1974	265
1976	320
1977	212
1978	229
1979	208
1980	283
1981	276
1982	229
1983	265
1984	274
1985	230
1986	180
1987	157
1988	336
1989	184
1990	101
1991	277
1992	341
1993	245
1994	242
1995	183
1996	292
1997	252
1998	196
1999	254
2000	290
2001	242
2002	159
2003	103
2004	165
2005	164
2006	152
2007	283
2008	202
2009	133
2010	104
2011	277
2012	173
2013	121
2014	261
2015	244
2016	233
2017	191
2018	173
2019	247
2020	224
2021	186
2022	203
2023	188
2024	122
2025	133

The longest record here

Mean river flow at Hosionkoski

Annual means of the daily record, 1962–2025. One gauge, not this drainage area.

Annual means computed by Hydrionis from the published daily record, drawn only for years with at least 300 days held. They summarise this gauge's own record and say nothing about any other watercourse in this area.

View the data behind this chart

Underlying data
Period	Hosionkoski (m³/s)
1962	30.0
1963	16.7
1964	25.3
1965	31.3
1966	27.5
1967	32.4
1968	20.0
1969	19.6
1970	21.0
1971	23.4
1972	24.4
1973	26.0
1974	26.5
1975	27.0
1976	19.6
1977	26.6
1978	14.9
1979	23.4
1980	15.5
1981	34.2
1982	26.2
1983	27.6
1984	25.0
1985	26.3
1986	22.4
1987	24.6
1988	17.6
1989	32.0
1990	18.7
1991	27.5
1992	36.1
1993	27.7
1994	21.6
1995	27.3
1996	22.7
1997	19.4
1998	37.3
1999	28.8
2000	34.8
2001	22.8
2002	15.5
2003	20.5
2004	26.5
2005	32.1
2006	15.4
2007	26.7
2008	32.0
2009	22.5
2010	24.9
2011	22.6
2012	39.7
2013	24.2
2014	25.3
2015	44.7
2016	30.9
2017	23.9
2018	18.2
2019	23.9
2020	38.4
2021	32.8
2022	22.3
2023	26.4
2024	27.8
2025	24.2

Every gauge Hydrionis holds within this area

Gauges within the Simojoki and what each holds
Gauge	Measures	Values	Record
Hosionkoski	mean river flow	23,618	1962–2026
Simo	mean river flow	22,553	1965–2026
Simo	mean river flow	16,436	1911–1955

How these gauges were attached to this water

Assigned by the publisher to a numbered basin Every gauge here is assigned to this drainage area by its own publisher, which issues the area an official code — 64. A drainage area is not a river: it contains the tributaries as well as the main channel, and a gauge in it may be on any of them.

What each gauge’s link to this water rests on
Gauge	Evidence	Established
Hosionkoski	Stated by the publisher on the record this gauge’s observations came from.	With the observations
Simo	Stated by the publisher on the record this gauge’s observations came from.	With the observations
Simo	Stated by the publisher on the record this gauge’s observations came from.	With the observations

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	3	yes, 3 or more
Years spanned	116	yes, 20 or more
Values held	62,607	yes, 1000 or more
Distinct measurements	1	no
Publishers measuring it	1	no
Official identifiers	1	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/fi-syke-6400310.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.

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), Simojoki gauge records, accessed 2026-10-05, hydrionis.com/waters/finland-simojoki/

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 Simojoki 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 confidence2026-09-30

Source: Syke — Hydrologiarajapinta — Finnish national hydrological archive, 6400310. Licence: Open — attribution required (attribution required).

Method: Daily discharge exactly as the Finnish Environment Institute publishes it. Syke computes the daily value from its own measurement and rating curves; Hydrionis does not recompute it, because a mean derived from whatever sub-daily data happens to be exposed would be a different statistic under the same name. Values Syke flags as possibly erroneous are not stored.

32 of these values (under 1%) are interpolated by Syke rather than measured, and are marked as such in its own archive. Station in the Simojoki main drainage basin, Hosionkosken a sub-basin. Discharge is a property of this gauge and this reach, not of the river as a whole.

Retrieved 1 October 2026.