The monitoring network within this area

Hydrionis holds 2,246 values from 4 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.

4

Gauges

2,246

Values held

1908–2026

Record spans

Gauges within the Clackamas huc8 subbasin

4 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 CLACKAMAS RIVER AT ESTACADA, OR

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1909–2025.

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	CLACKAMAS RIVER AT ESTACADA, OR (m³/s)
1909	790
1910	379
1912	677
1913	586
1914	408
1915	187
1917	262
1919	674
1920	847
1921	1,254
1923	1,699
1924	807
1926	620
1927	847
1929	289
1931	1,722
1932	711
1933	518
1934	442
1936	685
1937	663
1939	340
1940	538
1941	651
1942	1,206
1943	259
1945	575
1946	1,303
1948	1,512
1949	705
1950	668
1951	411
1953	1,152
1954	408
1955	1,206
1957	745
1958	660
1959	527
1960	510
1961	651
1962	750
1963	496
1964	2,461
1966	479
1967	671
1968	841
1969	767
1970	1,022
1971	946
1972	1,818
1974	1,699
1975	702
1977	155
1979	586
1980	844
1982	1,206
1983	951
1984	524
1986	1,226
1987	985
1989	648
1990	699
1991	476
1992	524
1994	408
1995	736
1996	1,951
1997	963
1998	977
1999	1,019
2001	198
2002	648
2003	643
2005	436
2006	1,011
2007	702
2009	1,031
2010	436
2011	1,237
2012	824
2014	535
2015	861
2017	617
2019	835
2020	337
2021	878
2022	549
2024	459
2025	566

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	1909–2025
Completeness	76.1% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	28 separate periods inside 1909–2025 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1909 and is not continuous from it: 117 years separate the first value from the last, and 76% 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 CLACKAMAS RIVER AT ESTACADA, OR, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1909–2024.

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	CLACKAMAS RIVER AT ESTACADA, OR (mm)
1909	1,661
1910	1,315
1911	1,084
1912	1,464
1913	1,331
1914	1,184
1915	1,186
1916	1,760
1917	1,775
1918	1,347
1919	1,561
1920	1,360
1921	1,944
1922	1,098
1923	1,533
1924	1,122
1925	1,282
1926	1,010
1927	1,589
1928	1,223
1929	1,090
1930	883
1931	1,029
1932	1,438
1933	1,672
1934	1,220
1935	1,056
1936	1,225
1937	1,588
1938	1,370
1939	1,046
1940	1,142
1941	1,000
1942	1,309
1943	1,511
1944	780
1945	1,438
1946	1,646
1947	1,355
1948	1,581
1949	1,528
1950	2,078
1951	1,642
1952	1,144
1953	1,903
1954	1,513
1955	1,836
1956	1,592
1957	1,382
1958	1,467
1959	1,375
1960	1,514
1961	1,623
1962	1,423
1963	1,234
1964	1,646
1965	1,237
1966	1,343
1967	1,232
1968	1,569
1969	1,533
1970	1,533
1971	1,944
1972	1,986
1973	1,377
1974	1,933
1975	1,711
1976	1,273
1977	1,265
1978	1,066
1979	1,219
1980	1,398
1981	1,301
1982	1,680
1983	1,691
1984	1,717
1985	1,202
1986	1,476
1987	1,000
1988	1,321
1989	1,176
1990	1,345
1991	1,325
1992	965
1993	1,234
1994	1,182
1995	1,831
1996	2,136
1997	1,728
1998	1,558
1999	1,724
2000	1,241
2001	981
2002	1,265
2003	1,295
2004	1,240
2005	1,037
2006	1,693
2007	1,333
2008	1,523
2009	1,451
2010	1,523
2011	1,546
2012	1,879
2013	1,229
2014	1,576
2015	1,094
2016	1,336
2017	1,772
2018	1,166
2019	1,041
2020	1,119
2021	1,194
2022	1,555
2023	1,117
2024	1,423

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	1909–2024
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1909 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.

543

Fullest snowpack recorded at Clackamas Lake, in 2008 (mm of water)

32

Thinnest, in 2015 (mm of water)

March

Month the pack is usually at its fullest

May

Month the pack has gone by, in half of years

Peak snowpack at Clackamas Lake

Water years 1981–2026. 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	Clackamas Lake (mm)
1981	81.0
1982	366
1983	252
1984	293
1985	525
1986	359
1987	328
1988	293
1989	417
1990	323
1991	126
1992	63.0
1993	426
1994	183
1995	261
1996	122
1997	514
1998	288
1999	369
2000	426
2001	174
2002	458
2003	73.0
2004	306
2005	85.0
2006	402
2007	237
2008	543
2009	399
2010	125
2011	272
2012	322
2013	231
2014	137
2015	32.0
2016	229
2017	409
2018	212
2019	351
2020	275
2021	341
2022	370
2023	401
2024	321
2025	226
2026	81.0

Why the snow is not read against the river here

OAK GROVE FORK ABOVE POWERPLANT INTAKE, OR. measures a powerplant intake, not a natural channel. What passes through it is an operating decision — how much was diverted, and when — so comparing it with what the sky or the mountain delivered would describe the operator rather than the hydrology.

Every gauge Hydrionis holds within this area

Gauges within the Clackamas and what each holds
Gauge	Measures	Values	Record
CLACKAMAS RIVER AT ESTACADA, OR	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	387	1908–2026
OAK GROVE FORK ABOVE POWERPLANT INTAKE, OR.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	360	1909–2026
CLACKAMAS RIVER ABOVE THREE LYNX CREEK, OR	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	356	1909–2026
CLACKAMAS RIVER AT BIG BOTTOM, OR	catchment area, annual maximum river flow	51	1921–2026

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 — 17090011. 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
CLACKAMAS RIVER AT ESTACADA, OR	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
OAK GROVE FORK ABOVE POWERPLANT INTAKE, OR.	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
CLACKAMAS RIVER ABOVE THREE LYNX CREEK, OR	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
CLACKAMAS RIVER AT BIG BOTTOM, OR	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 5 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	4	yes, 3 or more
Years spanned	119	yes, 20 or more
Values held	2,246	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-14210000.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), Clackamas gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-clackamas/

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 Clackamas 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 confidence2025-02-23

Source: USGS — National Water Information System, USGS site 14210000, 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.