Lapväärtinjoki (Isojoki)
2 monitoring stations within this area in Finland, holding 20,692 values between 1970 and 2026. An area that drains to one outlet, not a single channel. The gauges below are within it and sit on different watercourses inside it.
The monitoring network within this area
Hydrionis holds 20,692 values from 2 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.
The longest record here
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
| Period | Perus (m³/s) |
|---|---|
| 1980 | 11.1 |
| 1981 | 18.3 |
| 1982 | 14.7 |
| 1983 | 10.1 |
| 1984 | 15.5 |
| 1985 | 11.4 |
| 1986 | 14.8 |
| 1987 | 12.2 |
| 1988 | 15.4 |
| 1989 | 14.3 |
| 1990 | 9.30 |
| 1991 | 12.3 |
| 1992 | 16.6 |
| 1993 | 11.3 |
| 1994 | 11.6 |
| 1995 | 13.7 |
| 1996 | 10.3 |
| 1997 | 12.2 |
| 1998 | 16.0 |
| 1999 | 12.2 |
| 2000 | 14.2 |
| 2001 | 11.6 |
| 2002 | 8.21 |
| 2003 | 9.78 |
| 2004 | 12.9 |
| 2005 | 13.2 |
| 2006 | 12.3 |
| 2007 | 14.3 |
| 2008 | 15.7 |
| 2009 | 8.44 |
| 2010 | 8.67 |
| 2011 | 13.7 |
| 2012 | 17.7 |
| 2013 | 12.1 |
| 2014 | 11.1 |
| 2015 | 15.6 |
| 2016 | 11.8 |
| 2017 | 12.1 |
| 2018 | 8.15 |
| 2019 | 11.2 |
| 2020 | 19.0 |
| 2021 | 11.0 |
| 2022 | 13.8 |
| 2023 | 15.2 |
| 2024 | 17.1 |
| 2025 | 12.5 |
Every gauge Hydrionis holds within this area
| Gauge | Measures | Values | Record |
|---|---|---|---|
| Perus | mean river flow | 17,040 | 1980–2026 |
| Perus | mean river flow | 3,652 | 1970–1979 |
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 — 37. 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.
| Gauge | Evidence | Established |
|---|---|---|
| Perus | Stated by the publisher on the record this gauge’s observations came from. | With the observations |
| Perus | 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 2 of them, which makes it a profile, not indexed.
| Signal | Held | Counts |
|---|---|---|
| Gauges holding a real record | 2 | no |
| Years spanned | 57 | yes, 20 or more |
| Values held | 20,692 | yes, 1000 or more |
| Distinct measurements | 1 | no |
| Publishers measuring it | 1 | no |
| Official identifiers | 1 | recorded, not counted |
Where these figures come from
Source: Syke — Hydrologiarajapinta — Finnish national hydrological archive, 3700300. 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.
1 of these values (under 1%) are interpolated by Syke rather than measured, and are marked as such in its own archive. Station in the Lapväärtinjoki (Isojoki) main drainage basin, Peruksen a sub-basin. Discharge is a property of this gauge and this reach, not of the river as a whole.
Retrieved 26 August 2026.