The monitoring network within this area

Hydrionis holds 972 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

972

Values held

1896–2026

Record spans

Gauges within the Purgatoire 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 PURGATOIRE RIVER NEAR LAS ANIMAS, CO

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1922–2024.

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	PURGATOIRE RIVER NEAR LAS ANIMAS, CO (m³/s)
1922	160
1923	804
1925	340
1926	379
1927	1,388
1928	708
1929	906
1930	343
1949	892
1950	326
1951	498
1952	159
1953	592
1954	1,099
1955	1,982
1956	402
1957	156
1958	275
1959	127
1960	143
1961	115
1962	110
1963	196
1964	91.7
1965	1,770
1966	490
1967	328
1968	328
1969	402
1970	125
1971	238
1972	623
1973	105
1974	50.7
1975	17.1
1976	161
1977	88.9
1978	109
1979	71.6
1980	54.4
1981	189
1982	66.3
1983	86.9
1984	68.2
1985	56.4
1986	76.2
1987	82.1
1988	41.3
1989	43.0
1990	81.3
1991	32.6
1992	72.5
1993	45.0
1994	54.7
1995	79.9
1996	80.1
1997	70.8
1998	56.9
1999	147
2000	51.3
2001	53.8
2002	45.0
2003	51.8
2004	97.4
2005	64.3
2006	44.7
2007	30.0
2008	60.3
2010	40.2
2011	38.8
2012	69.4
2013	62.3
2014	81.0
2015	99.4
2017	58.0
2018	59.2
2019	22.0
2020	27.9
2021	107
2022	32.8
2023	70.2
2024	29.2

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	1922–2024
Completeness	79.6% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	4 separate periods inside 1922–2024 hold no value. The longest runs from 1931 to 1948 — 18 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1922 and is not continuous from it: 103 years separate the first value from the last, and 80% 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 PURGATOIRE RIVER AT TRINIDAD, 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. 1897–1980.

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	PURGATOIRE RIVER AT TRINIDAD, CO. (mm)
1897	85.0
1898	59.0
1910	32.0
1911	45.0
1916	32.0
1917	30.0
1918	38.0
1919	72.0
1920	42.0
1921	52.0
1922	23.0
1923	77.0
1924	55.0
1925	28.0
1926	55.0
1927	34.0
1928	40.0
1929	36.0
1930	46.0
1931	39.0
1932	25.0
1933	29.0
1934	16.0
1935	35.0
1936	22.0
1937	42.0
1938	43.0
1939	21.0
1940	24.0
1941	94.0
1942	123
1943	20.0
1944	58.0
1945	33.0
1946	17.0
1947	50.0
1948	55.0
1949	45.0
1950	15.0
1951	11.0
1952	40.0
1953	27.0
1954	20.0
1955	71.0
1956	14.0
1957	77.0
1958	50.0
1959	19.0
1962	29.0
1963	14.0
1964	19.0
1965	57.0
1966	31.0
1967	27.0
1968	37.0
1969	33.0
1970	31.0
1971	16.0
1972	10.0
1973	42.0
1974	11.0
1975	22.0
1976	16.0
1977	14.0
1978	20.0
1979	24.0
1980	36.0

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	1897–1980
Completeness	79.8% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	3 separate periods inside 1897–1980 hold no value. The longest runs from 1899 to 1909 — 11 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1897 and is not continuous from it: 84 years separate the first value from the last, and 80% 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

1 automated snow station sits inside this drainage area, weighing the snowpack rather than measuring how deep it is.

493

Fullest snowpack recorded at Whiskey Ck, in 1993 (mm of water)

67

Thinnest, in 2006 (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 Whiskey Ck

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	Whiskey Ck (mm)
1981	90.0
1982	274
1983	444
1984	319
1985	279
1986	222
1987	411
1988	157
1989	272
1990	194
1991	271
1992	249
1993	493
1994	374
1995	356
1996	234
1997	334
1998	267
1999	146
2000	204
2001	253
2002	141
2003	265
2004	238
2005	421
2006	67.0
2007	233
2008	355
2009	253
2010	276
2011	214
2012	232
2013	190
2014	225
2015	260
2016	161
2017	325
2018	84.0
2019	390
2020	245
2021	281
2022	197
2023	187
2024	207
2025	108
2026	74.0

Why the snow is not read against the river here

These two series do not overlap in time: Peak snow water equivalent runs 1980–2026 and Mean river flow, water year runs 1896–1979.

Every gauge Hydrionis holds within this area

Gauges within the Purgatoire and what each holds
Gauge	Measures	Values	Record
PURGATOIRE RIVER AT TRINIDAD, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	241	1896–2026
PURGATOIRE RIVER NEAR LAS ANIMAS, CO	catchment area, annual maximum river flow	88	1922–2026
PURGATOIRE RIVER AT NINEMILE DAM, NR HIGBEE, CO.	catchment area, annual maximum river flow	69	1924–2026
PURGATOIRE RIVER NEAR ALFALFA, CO.	catchment area, annual maximum river flow	23	1905–2026

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 — 11020010. 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
PURGATOIRE RIVER AT TRINIDAD, 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
PURGATOIRE RIVER NEAR LAS ANIMAS, 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
PURGATOIRE RIVER AT NINEMILE DAM, NR HIGBEE, 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
PURGATOIRE RIVER NEAR ALFALFA, 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	3	yes, 3 or more
Years spanned	131	yes, 20 or more
Values held	972	no
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-07124500.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), Purgatoire gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-purgatoire/

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 Purgatoire 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 confidence1981-08-11

Source: USGS — National Water Information System, USGS site 07124500, 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.