The monitoring network within this area

Hydrionis holds 1,458 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

1,458

Values held

1904–2026

Record spans

Gauges within the Upper Gunnison 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 GUNNISON RIVER BELOW GUNNISON TUNNEL, CO

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1906–2025.

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	GUNNISON RIVER BELOW GUNNISON TUNNEL, CO (m³/s)
1906	416
1907	360
1908	193
1909	368
1910	286
1911	323
1912	365
1913	192
1914	357
1915	198
1916	306
1917	442
1918	425
1919	241
1920	425
1921	538
1922	281
1923	278
1924	311
1925	174
1926	279
1927	283
1928	419
1929	345
1930	224
1931	76.2
1932	229
1933	309
1934	85.5
1935	343
1936	276
1937	267
1938	317
1939	134
1940	113
1941	276
1942	281
1943	222
1944	320
1945	161
1946	191
1947	246
1948	362
1949	351
1950	152
1951	183
1952	396
1953	273
1954	52.7
1955	120
1956	180
1957	476
1958	362
1959	146
1960	169
1961	121
1962	283
1963	71.1
1964	227
1965	292
1966	83.3
1967	45.0
1968	86.1
1970	273
1971	139
1972	122
1974	94.6
1975	96.0
1976	82.1
1977	84.7
1978	100.0
1979	75.6
1980	77.9
1982	48.1
1983	311
1984	294
1985	174
1986	127
1987	72.8
1988	54.4
1989	60.0
1991	131
1992	87.8
1993	146
1994	90.0
1995	268
1996	129
1997	136
1998	94.9
1999	84.4
2001	59.2
2002	54.9
2003	39.6
2004	41.9
2005	55.8
2006	52.7
2007	48.4
2008	223
2009	210
2010	129
2011	214
2013	23.3
2014	273
2015	218
2016	161
2017	360
2019	227
2020	86.6
2021	31.7
2022	78.4
2023	216
2024	190
2025	119

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	1906–2025
Completeness	94.2% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	7 separate periods inside 1906–2025 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1906 and is not continuous from it: 120 years separate the first value from the last, and 94% 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 GUNNISON RIVER BELOW GUNNISON TUNNEL, CO, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1911–2025.

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	GUNNISON RIVER BELOW GUNNISON TUNNEL, CO (mm)
1911	214
1912	211
1913	125
1914	205
1915	107
1916	184
1917	177
1918	142
1919	108
1920	201
1921	184
1922	129
1923	165
1924	129
1925	111
1926	116
1927	168
1928	168
1929	203
1930	117
1931	36.0
1932	123
1933	92.0
1934	31.0
1935	101
1936	128
1937	94.0
1938	154
1939	76.0
1940	49.0
1941	123
1942	141
1943	113
1944	128
1945	92.0
1946	66.0
1947	122
1948	149
1949	137
1950	68.0
1951	69.0
1952	171
1953	80.0
1954	25.0
1955	48.0
1956	68.0
1957	228
1958	140
1959	53.0
1960	85.0
1961	61.0
1962	137
1963	44.0
1964	72.0
1965	173
1966	31.0
1967	42.0
1968	65.0
1969	96.0
1970	158
1971	144
1972	66.0
1973	95.0
1974	92.0
1975	113
1976	61.0
1977	35.0
1978	60.0
1979	135
1980	132
1981	50.0
1982	90.0
1983	165
1984	260
1985	200
1986	165
1987	125
1988	63.0
1989	32.0
1990	29.0
1991	102
1992	65.0
1993	152
1994	67.0
1995	208
1996	115
1997	185
1998	86.0
1999	105
2000	75.0
2001	56.0
2002	39.0
2003	36.0
2004	38.0
2005	65.0
2006	80.0
2007	76.0
2008	146
2009	101
2010	60.0
2011	119
2012	46.0
2013	35.0
2014	95.0
2015	89.0
2016	83.0
2017	122
2018	50.0
2019	104
2020	50.0
2021	43.0
2022	36.0
2023	67.0
2024	76.0
2025	51.0

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	1911–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1911 to 2025 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.

528

Fullest snowpack recorded at Slumgullion, in 1997 (mm of water)

135

Thinnest, in 2026 (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 Slumgullion

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	Slumgullion (mm)
1981	194
1982	420
1983	342
1984	484
1985	384
1986	420
1987	486
1988	275
1989	284
1990	251
1991	361
1992	280
1993	330
1994	288
1995	473
1996	373
1997	528
1998	381
1999	440
2000	321
2001	423
2002	183
2003	277
2004	309
2005	457
2006	352
2007	387
2008	467
2009	353
2010	342
2011	387
2012	288
2013	263
2014	351
2015	299
2016	349
2017	362
2018	195
2019	503
2020	380
2021	288
2022	254
2023	311
2024	274
2025	273
2026	135

Read against the river

Slumgullion and GUNNISON RIVER NEAR GUNNISON, CO. both sit in this drainage area, and their records overlap by 44 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 Upper Gunnison and what each holds
Gauge	Measures	Values	Record
GUNNISON RIVER BELOW GUNNISON TUNNEL, CO	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	387	1906–2026
GUNNISON RIVER NEAR GUNNISON, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	329	1910–2026
CIMARRON RIVER AT CIMARRON, CO.	catchment area, annual maximum river flow	9	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 — 14020002. 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
GUNNISON RIVER BELOW GUNNISON TUNNEL, CO	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
GUNNISON RIVER NEAR GUNNISON, CO.	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
CIMARRON RIVER AT CIMARRON, CO.	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	1,458	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-09128000.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), Upper Gunnison gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-upper-gunnison/

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 Upper Gunnison 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 confidence2025-06-01

Source: USGS — National Water Information System, USGS site 09128000, 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.