The monitoring network within this area

Hydrionis holds 1,733 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.

2

Gauges

1,733

Values held

1904–2026

Record spans

Gauges within the Lake Chelan huc8 subbasin

2 monitoring points, positioned as the publisher records them.

Flood peaks, as measured

This gauge's flood record, as measured. Unlike a daily mean it is the discharge at the moment the river was highest, which is the figure flood frequency analysis is built on.

Largest measured flow of each year at STEHEKIN RIVER AT STEHEKIN, WA

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1911–2025.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Published by the gauge's own operator from its sub-daily record; Hydrionis stores the figure rather than recomputing it. A year the gauge did not cover produces no value rather than a low one, and the gaps are stated below the chart. A peak is a property of this gauge and its reach: a larger flood upstream or downstream of it is not in this series.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
Hurricane Katrina water and sanitation collapse	Flood	2005-08-29 – 2005-09-30	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	STEHEKIN RIVER AT STEHEKIN, WA (m³/s)
1911	345
1912	201
1913	182
1914	206
1915	100.0
1927	314
1928	323
1929	171
1930	134
1931	217
1932	289
1933	343
1934	283
1935	216
1936	365
1937	259
1938	259
1939	259
1940	226
1942	237
1943	231
1944	153
1945	243
1946	213
1947	225
1948	535
1949	300
1951	360
1952	210
1953	191
1954	267
1955	351
1956	371
1957	252
1958	343
1959	260
1960	292
1961	357
1962	195
1964	286
1965	233
1966	237
1967	394
1968	408
1969	314
1970	314
1971	272
1972	408
1973	151
1974	470
1975	289
1977	164
1978	286
1980	212
1982	282
1983	343
1984	274
1985	227
1986	334
1987	377
1988	300
1989	240
1990	416
1992	187
1993	331
1994	184
1995	257
1997	331
1998	217
1999	343
2001	203
2002	254
2003	201
2005	213
2006	354
2008	343
2010	182
2011	200
2012	230
2013	245
2014	229
2016	238
2017	354
2019	182
2020	320
2021	273
2023	317
2025	162

About this series

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	United States Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Measured
Period held	1911–2025
Completeness	76.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	17 separate periods inside 1911–2025 hold no value. The longest runs from 1916 to 1926 — 11 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1911 and is not continuous from it: 115 years separate the first value from the last, and 77% of the years between them are held. The span is not the record.
Last read from the publisher	2026-10-01
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

How much of the rain came back out

A discharge in cubic metres per second cannot be compared with anything: the larger number may only mean the larger catchment. Divided by the area draining to the gauge it becomes a depth of water over that land, which answers a question a reader already has — of the rain that fell here, how much came back out as river?

Water leaving the catchment above CHELAN RIVER AT CHELAN, WA, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1904–2024.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Computed by Hydrionis from the published annual mean flow and the catchment area the station's own publisher states. It is not a water balance: the difference between rainfall and runoff is not evaporation alone but also change in groundwater storage, water abstracted and taken elsewhere, and water imported by transfer schemes — which is why a catchment can yield more runoff than the rain that fell on it without anything being measured wrongly. A different area figure rescales every value here by the ratio between them.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
Hurricane Katrina water and sanitation collapse	Flood	2005-08-29 – 2005-09-30	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	CHELAN RIVER AT CHELAN, WA (mm)
1904	1,012
1905	907
1906	796
1907	837
1908	845
1909	762
1910	1,069
1911	687
1912	694
1913	800
1914	798
1915	514
1916	991
1917	749
1918	878
1919	841
1920	659
1921	1,023
1922	685
1923	753
1924	661
1925	816
1926	470
1927	656
1928	608
1929	579
1930	443
1931	547
1932	674
1933	954
1934	1,018
1935	958
1936	639
1937	602
1938	842
1939	589
1940	619
1941	424
1942	632
1943	822
1944	434
1945	551
1946	807
1947	654
1948	978
1949	764
1950	966
1951	1,083
1952	706
1953	726
1954	968
1955	764
1956	1,182
1957	830
1958	695
1959	1,003
1960	936
1961	780
1962	593
1963	659
1964	764
1965	741
1966	629
1967	822
1968	942
1969	840
1970	552
1971	974
1972	1,140
1973	507
1974	1,046
1975	806
1976	1,010
1977	418
1978	830
1979	509
1980	670
1981	715
1982	880
1983	831
1984	776
1985	549
1986	650
1987	646
1988	608
1989	716
1990	812
1991	1,004
1992	632
1993	535
1994	558
1995	889
1996	1,034
1997	1,063
1998	746
1999	1,010
2000	809
2001	403
2002	860
2003	677
2004	731
2005	583
2006	855
2007	970
2008	732
2009	609
2010	838
2011	964
2012	893
2013	765
2014	777
2015	724
2016	951
2017	960
2018	854
2019	574
2020	712
2021	834
2022	818
2023	632
2024	571

About this series

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	United States Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Derived Computed by Hydrionis
Period held	1904–2024
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1904 to 2024 is held.
Inputs last read	2026-10-01 · when the records this was computed from were last read from their publishers
Calculation date	2026-08-24 · when the calculation method was last versioned, not a reading of any publisher
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

The snow standing above this water

2 automated snow stations sit inside this drainage area, weighing the snowpack rather than measuring how deep it is.

1,891

Fullest snowpack recorded at Park Creek Ridge, in 1999 (mm of water)

333

Thinnest, in 2005 (mm of water)

April

Month the pack is usually at its fullest

June

Month the pack has gone by, in half of years

Peak snowpack at Park Creek Ridge

Water years 1979–2026. Each point is the fullest month of that snow season.

A water year runs October to September and is named for the year it ends, so the snow of one winter stays in one point. The value is the fullest month, not the fullest day: a pack that peaked sharply mid-month reads lower here than a single measurement taken at the right moment would.

View the data behind this chart

Underlying data
Period	Park Creek Ridge (mm)
1979	724
1980	1,152
1981	744
1982	1,365
1983	1,218
1984	892
1985	999
1986	938
1987	1,089
1988	1,094
1989	1,274
1990	1,353
1991	1,655
1992	1,174
1993	689
1994	637
1995	995
1996	1,280
1997	1,865
1998	1,108
1999	1,891
2000	1,144
2001	663
2002	1,536
2003	956
2004	925
2005	333
2006	1,377
2007	1,387
2008	1,436
2009	779
2010	1,049
2011	1,253
2012	1,519
2013	1,120
2014	1,159
2015	560
2016	1,352
2017	1,279
2018	1,270
2019	876
2020	1,084
2021	1,334
2022	1,017
2023	996
2024	741
2025	852
2026	671

Read against the river

Park Creek Ridge and STEHEKIN RIVER AT STEHEKIN, WA both sit in this drainage area, and their records overlap by 46 years. That is the span the two have in common, not a count of years both actually hold — either record may have gaps inside it. The two are shown separately rather than on one axis: millimetres of stored water and cubic metres per second are not commensurable, and a difference between them would mean nothing.

Being in the same drainage area does not put the snowpack upstream of the gauge. A subbasin is an area, and snow on one tributary can join the river below a gauge on another — so a weak relationship here may say more about which tributary was measured than about the snow.

Every gauge Hydrionis holds within this area

Gauges within the Lake Chelan and what each holds
Gauge	Measures	Values	Record
STEHEKIN RIVER AT STEHEKIN, WA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	344	1911–2026
CHELAN RIVER AT CHELAN, WA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	285	1904–2026

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 — 17020009. 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
STEHEKIN RIVER AT STEHEKIN, WA	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
CHELAN RIVER AT CHELAN, WA	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02

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 4 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	2	no
Years spanned	123	yes, 20 or more
Values held	1,733	yes, 1000 or more
Distinct measurements	6	yes, 2 or more
Publishers measuring it	2	yes, 2 or more
Official identifiers	1	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/gauge-usgs-12451000.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

Suggested citation for Hydrionis

Hydrionis (2026), Lake Chelan gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-lake-chelan/

Cite Hydrionis where you rely on values Hydrionis computed, on the method that produced them, or on the compilation itself. The underlying measurements remain the publishers’ and their attribution requirements apply to you directly.

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 Lake Chelan 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.

None of the contributing licences requires attribution. Crediting the publishers is still good practice and they are listed above.

Where these figures come from

MeasuredHigh confidence2025-05-29

Source: USGS — National Water Information System, USGS site 12451000, annual peak streamflow. Licence: Open.

Method: The instantaneous maximum discharge of each water year as published by USGS, dated to the day it occurred. One value per October-to-September water year; where the publisher lists both a systematic and a historic peak for a year, the larger is the annual maximum. Values the publisher marks as maximum daily averages are not held here, because they are not instantaneous peaks. Values marked as bounded rather than measured are held as censored observations carrying the bound. Cubic feet per second are converted to cubic metres per second and the publisher unit is recorded alongside.

Rating curves are extrapolated at extreme discharges, so the largest values in a peak series carry the largest measurement uncertainty. Data from the U.S. Geological Survey National Water Information System, a work of the United States government and therefore in the public domain.

Retrieved 1 October 2026.