The monitoring network within this area

Hydrionis holds 2,710 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

2,710

Values held

1910–2026

Record spans

Gauges within the Blue 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 BLUE RIVER AT DILLON, CO.

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1911–1960.

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 (0 events)

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	BLUE RIVER AT DILLON, CO. (m³/s)
1911	23.8
1912	28.9
1913	15.5
1914	33.4
1915	18.8
1916	14.7
1917	26.9
1918	25.5
1919	14.4
1920	24.1
1921	31.1
1922	13.8
1923	28.3
1924	33.4
1925	11.1
1926	30.6
1927	18.7
1928	29.2
1929	16.9
1930	16.8
1931	14.3
1932	14.1
1933	20.8
1934	11.4
1935	22.9
1936	22.0
1937	16.7
1938	20.7
1939	16.4
1940	11.1
1941	18.5
1942	20.2
1943	16.5
1944	18.2
1945	17.3
1946	16.6
1947	27.4
1948	26.6
1949	26.9
1950	18.6
1951	24.1
1952	25.6
1953	26.3
1954	5.61
1955	7.19
1956	17.6
1957	21.6
1958	23.0
1959	15.5
1960	14.1

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	1911–1960
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1911 to 1960 is held.
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 BLUE RIVER AT DILLON, 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. 1911–1960.

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 (0 events)

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	BLUE RIVER AT DILLON, CO. (mm)
1911	314
1912	436
1913	327
1914	495
1915	315
1916	318
1917	385
1918	423
1919	255
1920	328
1921	463
1922	266
1923	425
1924	323
1925	269
1926	439
1927	343
1928	387
1929	318
1930	303
1931	232
1932	283
1933	260
1934	199
1935	245
1936	404
1937	206
1938	334
1939	275
1940	187
1941	266
1942	284
1943	286
1944	230
1945	289
1946	270
1947	414
1948	336
1949	359
1950	256
1951	384
1952	327
1953	289
1954	140
1955	203
1956	257
1957	390
1958	270
1959	241
1960	225

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	1911–1960
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1911 to 1960 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

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

615

Fullest snowpack recorded at Copper Mountain, in 2011 (mm of water)

179

Thinnest, in 1981 (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 Copper Mountain

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	Copper Mountain (mm)
1979	416
1980	455
1981	179
1982	436
1983	463
1984	453
1985	378
1986	370
1987	267
1988	339
1989	324
1990	310
1991	279
1992	320
1993	465
1994	386
1995	508
1996	548
1997	512
1998	380
1999	391
2000	406
2001	344
2002	285
2003	459
2004	240
2005	317
2006	457
2007	392
2008	489
2009	436
2010	275
2011	615
2012	250
2013	316
2014	538
2015	374
2016	406
2017	404
2018	340
2019	516
2020	472
2021	293
2022	338
2023	379
2024	380
2025	389
2026	182

Why the snow is not read against the river here

These two series do not overlap in time: Peak snow water equivalent runs 1978–2026 and Mean river flow, water year runs 1910–1959.

Every gauge Hydrionis holds within this area

Gauges within the Blue and what each holds
Gauge	Measures	Values	Record
BLUE RIVER AT DILLON, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	187	1910–2026
SNAKE RIVER AT DILLON, CO.	catchment area, annual maximum river flow	44	1911–2026
TENMILE CREEK AT DILLON, CO.	catchment area, annual maximum river flow	41	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 — 14010002. 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
BLUE RIVER AT DILLON, 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
SNAKE RIVER AT DILLON, 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
TENMILE CREEK AT DILLON, 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	1	no
Years spanned	117	yes, 20 or more
Values held	2,710	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-09047000.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), Blue gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-blue/

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 Blue 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 confidence1960-06-18

Source: USGS — National Water Information System, USGS site 09047000, 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.