The monitoring network within this area

Hydrionis holds 4,164 values from 8 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.

8

Gauges

4,164

Values held

1888–2026

Record spans

Gauges within the St. Vrain huc8 subbasin

8 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 ST. VRAIN CREEK AT LYONS, CO.

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1888–2013.

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	ST. VRAIN CREEK AT LYONS, CO. (m³/s)
1888	15.1
1889	15.5
1890	19.1
1891	39.6
1895	32.0
1896	42.5
1897	28.9
1898	17.1
1899	33.4
1900	26.0
1901	24.3
1902	14.6
1903	48.4
1904	24.1
1905	47.0
1906	33.1
1907	31.7
1908	18.4
1909	32.6
1910	13.2
1911	18.7
1912	32.6
1913	13.9
1914	43.6
1915	27.0
1916	17.6
1917	35.1
1918	48.1
1919	266
1920	20.8
1921	58.0
1922	16.3
1923	47.3
1924	63.1
1925	11.6
1926	31.1
1927	17.1
1928	28.6
1929	21.7
1930	57.8
1931	41.1
1932	24.2
1933	32.0
1934	17.8
1935	66.3
1936	23.6
1937	34.8
1938	46.7
1939	27.7
1940	19.1
1941	297
1942	42.8
1943	34.8
1944	27.2
1945	28.3
1946	60.6
1947	66.8
1948	23.2
1949	84.1
1950	20.2
1951	111
1952	45.6
1953	27.5
1954	8.07
1955	19.3
1956	21.2
1957	86.6
1958	36.5
1959	24.3
1960	20.3
1961	71.9
1962	32.3
1963	36.8
1964	13.0
1965	52.1
1966	34.3
1967	56.9
1968	18.0
1969	82.1
1970	27.1
1971	49.8
1972	26.6
1973	38.5
1974	18.2
1975	26.1
1976	23.6
1977	20.7
1978	44.2
1979	29.7
1980	66.0
1981	11.8
1982	45.3
1983	41.6
1984	37.9
1985	29.4
1986	31.7
1987	30.6
1988	16.1
1989	28.3
1990	25.7
1991	36.2
1992	15.5
1993	23.2
1994	24.7
1995	119
1996	31.7
1997	46.4
1998	18.7
2013	674

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	1888–2013
Completeness	86.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	2 separate periods inside 1888–2013 hold no value. The longest runs from 1999 to 2012 — 14 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1888 and is not continuous from it: 126 years separate the first value from the last, and 87% 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 ST. VRAIN CREEK AT LYONS, 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. 1896–1997.

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	ST. VRAIN CREEK AT LYONS, CO. (mm)
1896	173
1897	321
1898	173
1899	316
1900	275
1901	208
1902	124
1905	272
1906	259
1907	341
1908	141
1909	292
1910	110
1911	160
1912	265
1913	169
1914	324
1915	252
1916	205
1917	275
1918	230
1919	138
1920	234
1921	319
1922	125
1923	339
1924	276
1925	126
1926	293
1927	193
1928	223
1929	196
1930	162
1931	135
1932	149
1933	220
1934	124
1935	200
1936	239
1937	162
1938	255
1939	134
1940	122
1941	193
1942	290
1943	214
1944	181
1945	203
1946	133
1947	297
1948	153
1949	273
1950	142
1951	252
1952	279
1953	144
1954	74.0
1955	106
1956	140
1957	357
1958	190
1959	175
1960	156
1961	232
1962	152
1963	130
1964	106
1965	254
1966	81.0
1967	178
1968	143
1969	305
1970	210
1971	224
1972	143
1973	226
1974	156
1975	198
1976	120
1977	88.0
1978	224
1979	265
1980	320
1981	92.0
1982	198
1983	318
1984	287
1985	167
1986	231
1987	167
1988	133
1989	124
1990	192
1991	179
1992	149
1993	191
1994	145
1995	345
1996	235
1997	307

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	1896–1997
Completeness	98.0% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	One period inside 1896–1997 holds no value: 1903 to 1904, 2 years with no reading. It is drawn as a break in the line and is never interpolated across.
Continuity	The record begins in 1896 and is not continuous from it: 102 years separate the first value from the last, and 98% 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

The snow standing above this water

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

549

Fullest snowpack recorded at Lake Eldora, in 1996 (mm of water)

102

Thinnest, in 1981 (mm of water)

March

Month the pack is usually at its fullest

June

Month the pack has gone by, in half of years

Peak snowpack at Lake Eldora

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	Lake Eldora (mm)
1979	253
1980	416
1981	102
1982	228
1983	338
1984	393
1985	219
1986	251
1987	243
1988	286
1989	307
1990	355
1991	225
1992	293
1993	345
1994	317
1995	299
1996	549
1997	442
1998	354
1999	233
2000	299
2001	210
2002	157
2003	383
2004	149
2005	240
2006	298
2007	316
2008	318
2009	345
2010	247
2011	415
2012	241
2013	216
2014	436
2015	281
2016	305
2017	312
2018	241
2019	306
2020	353
2021	279
2022	234
2023	259
2024	306
2025	292
2026	142

Read against the river

Lake Eldora and ST. VRAIN CREEK AT LYONS, CO. both sit in this drainage area, and their records overlap by 18 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 St. Vrain and what each holds
Gauge	Measures	Values	Record
ST. VRAIN CREEK AT LYONS, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	347	1888–2026
BOULDER CREEK NEAR ORODELL, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	296	1888–2026
MIDDLE BOULDER CREEK AT NEDERLAND, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	260	1907–2026
ST. VRAIN CREEK AT MOUTH, NEAR PLATTEVILLE, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	249	1927–2026
BOULDER CREEK AT MOUTH NEAR LONGMONT, CO	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	248	1927–2026
SOUTH BOULDER CREEK NEAR ELDORADO SPRINGS, CO.	catchment area, annual maximum river flow	104	1888–2026
NORTH ST. VRAIN CREEK NEAR ALLENS PARK, CO.	catchment area, annual maximum river flow	17	1926–2026
LEFT HAND CREEK NEAR BOULDER, CO.	catchment area, annual maximum river flow	17	1929–2026

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 — 10190005. 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
ST. VRAIN CREEK AT LYONS, 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
BOULDER CREEK NEAR ORODELL, 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
MIDDLE BOULDER CREEK AT NEDERLAND, 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
ST. VRAIN CREEK AT MOUTH, NEAR PLATTEVILLE, 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
BOULDER CREEK AT MOUTH NEAR LONGMONT, 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
SOUTH BOULDER CREEK NEAR ELDORADO SPRINGS, 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
NORTH ST. VRAIN CREEK NEAR ALLENS PARK, 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
LEFT HAND CREEK NEAR BOULDER, 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 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	6	yes, 3 or more
Years spanned	139	yes, 20 or more
Values held	4,164	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-06724000.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), St. Vrain gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-st-vrain/

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 St. Vrain 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 confidence2013-09-12

Source: USGS — National Water Information System, USGS site 06724000, 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.