The monitoring network within this area

Hydrionis holds 343 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.

Gauges

343

Values held

1911–2026

Record spans

Gauges within the Ketchikan huc8 subbasin

3 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 FISH C NR KETCHIKAN AK

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1915–2025.

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	FISH C NR KETCHIKAN AK (m³/s)
1915	114
1917	71.9
1919	63.4
1920	116
1921	73.6
1922	98.5
1923	111
1926	68.8
1927	72.2
1929	72.2
1930	89.8
1933	60.9
1934	83.3
1935	84.4
1939	52.4
1940	77.6
1941	59.5
1943	89.8
1945	77.0
1947	82.1
1948	76.2
1949	110
1951	64.3
1952	68.5
1953	49.8
1954	95.4
1956	80.1
1958	77.6
1959	117
1960	96.3
1961	153
1963	106
1964	98.8
1966	82.1
1967	64.6
1968	66.5
1969	88.6
1971	58.3
1972	69.4
1974	63.1
1976	85.0
1977	82.7
1978	103
1979	128
1980	108
1981	75.9
1982	110
1984	73.6
1986	58.6
1987	81.6
1988	105
1989	61.2
1990	83.3
1992	92.6
1993	105
1994	42.5
1995	60.9
1997	77.0
1999	121
2000	93.7
2001	92.9
2002	69.4
2003	90.6
2005	60.9
2007	52.4
2008	64.6
2010	87.2
2011	104
2012	67.1
2013	53.0
2014	78.2
2015	69.9
2017	71.6
2019	45.0
2020	77.9
2022	66.5
2023	77.0
2025	72.2

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	1915–2025
Completeness	70.3% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	29 separate periods inside 1915–2025 hold no value. The longest runs from 1936 to 1938 — 3 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1915 and is not continuous from it: 111 years separate the first value from the last, and 70% 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 FISH C NR KETCHIKAN AK, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1916–2024.

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	FISH C NR KETCHIKAN AK (mm)
1916	3,540
1917	5,102
1918	3,996
1919	3,713
1920	3,370
1921	4,343
1922	3,911
1923	4,208
1924	5,027
1925	3,855
1926	4,524
1927	3,537
1928	4,238
1929	3,918
1930	4,543
1931	4,086
1932	4,664
1933	4,524
1934	4,416
1939	5,219
1940	3,688
1941	3,559
1942	3,530
1943	4,348
1944	3,973
1945	3,266
1946	3,947
1947	4,361
1948	4,101
1949	5,071
1950	3,768
1951	3,357
1952	4,262
1953	4,763
1954	4,609
1955	4,281
1956	4,116
1957	3,255
1958	4,692
1959	5,001
1960	5,059
1961	4,636
1962	4,831
1963	4,268
1964	4,746
1965	3,002
1966	4,363
1967	4,577
1968	4,646
1969	4,132
1970	4,155
1971	4,230
1972	4,660
1973	3,773
1974	4,949
1975	3,731
1976	5,087
1977	3,696
1978	3,532
1979	3,831
1980	4,580
1981	4,125
1982	2,911
1983	3,758
1984	4,155
1985	3,450
1986	4,177
1987	4,819
1988	4,788
1989	3,817
1990	3,912
1991	5,263
1992	4,609
1993	3,705
1994	4,322
1995	3,804
1996	3,294
1997	4,949
1998	3,217
1999	5,146
2000	4,852
2001	4,884
2002	4,262
2003	4,397
2004	4,109
2005	4,910
2006	3,872
2007	4,867
2008	4,417
2009	3,718
2010	4,326
2011	4,862
2012	4,325
2013	4,061
2014	4,408
2015	4,669
2016	3,687
2017	4,149
2018	2,773
2019	4,081
2020	5,306
2021	5,130
2022	4,475
2023	4,244
2024	3,933

About this series

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	1916–2024
Completeness	96.3% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	One period inside 1916–2024 holds no value: 1935 to 1938, 4 years with no reading. It is drawn as a break in the line and is never interpolated across.
Continuity	The record begins in 1916 and is not continuous from it: 109 years separate the first value from the last, and 96% of the years between them are held. The span is not the record.
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

Every gauge Hydrionis holds within this area

Gauges within the Ketchikan and what each holds
Gauge	Measures	Values	Record
FISH C NR KETCHIKAN AK	catchment area, annual maximum river flow, mean river flow, mean river flow, water year	314	1915–2026
MAHONEY C NR KETCHIKAN AK	catchment area, annual maximum river flow	20	1923–2026
KETCHIKAN C AT KETCHIKAN AK	catchment area, annual maximum river flow	9	1911–2026

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 — 19010102. 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
FISH C NR KETCHIKAN AK	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
MAHONEY C NR KETCHIKAN AK	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
KETCHIKAN C AT KETCHIKAN AK	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 2 of them, which makes it a profile, not indexed.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	1	no
Years spanned	116	yes, 20 or more
Values held	343	no
Distinct measurements	4	yes, 2 or more
Publishers measuring it	1	no
Official identifiers	1	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/gauge-usgs-15072000.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), Ketchikan gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-ketchikan/

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 Ketchikan 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 confidence2025-05-28

Source: USGS — National Water Information System, USGS site 15072000, 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.