The monitoring network within this area

Hydrionis holds 332 values from 2 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

332

Values held

1908–2026

Record spans

Gauges within the Upper Arkansas-John Martin Reservoir huc8 subbasin

2 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 ARKANSAS RIVER AT LAMAR, CO

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1913–2025.

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	ARKANSAS RIVER AT LAMAR, CO (m³/s)
1913	90.6
1915	708
1919	212
1920	708
1921	3,681
1922	92.0
1923	850
1925	447
1926	144
1927	623
1928	433
1929	1,283
1930	178
1932	108
1933	476
1934	983
1935	439
1936	1,028
1937	343
1938	252
1939	27.1
1940	116
1941	345
1942	1,133
1944	133
1945	135
1946	44.7
1947	148
1948	25.8
1949	705
1950	81.8
1951	54.4
1952	17.3
1953	69.4
1954	136
1955	88.9
1959	53.8
1960	51.0
1961	40.8
1962	105
1963	83.0
1964	192
1965	2,090
1966	45.3
1967	258
1968	44.2
1969	27.7
1970	25.9
1971	52.4
1972	69.4
1973	17.9
1974	15.2
1975	50.7
1976	39.1
1977	40.5
1978	27.7
1979	31.7
1980	32.0
1981	32.0
1982	54.7
1983	29.4
1984	50.4
1985	62.0
1986	59.7
1987	91.2
1988	49.6
1989	41.1
1990	24.6
1991	43.3
1992	50.7
1993	37.7
1994	66.5
1995	89.5
1996	142
1997	108
1998	91.5
1999	78.4
2000	34.3
2001	64.8
2002	44.5
2003	6.09
2004	36.0
2005	24.7
2006	30.6
2007	29.4
2008	22.7
2009	64.6
2010	23.4
2011	17.9
2012	4.08
2013	23.8
2014	62.0
2015	38.2
2016	25.9
2017	34.3
2018	53.5
2019	21.2
2020	27.6
2021	34.5
2022	21.8
2023	60.3
2024	18.4
2025	17.7

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	1913–2025
Completeness	91.2% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	6 separate periods inside 1913–2025 hold no value. The longest runs from 1916 to 1918 — 3 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1913 and is not continuous from it: 113 years separate the first value from the last, and 91% 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 ARKANSAS RIVER AT LAMAR, 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. 1949–2025.

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	ARKANSAS RIVER AT LAMAR, CO (mm)
1949	2.00
1950	2.00
1951	1.00
1952	1.00
1953	1.00
1954	1.00
1960	1.00
1961	1.00
1962	1.00
1963	1.00
1964	1.00
1965	7.00
1966	4.00
1967	4.00
1968	1.00
1969	1.00
1970	1.00
1971	1.00
1972	1.00
1973	2.00
1974	1.00
1975	1.00
1976	1.00
1977	1.00
1978	1.00
1979	1.00
1980	3.00
1981	2.00
1982	2.00
1983	3.00
1984	3.00
1985	4.00
1986	3.00
1987	10.0
1988	3.00
1989	2.00
1990	1.00
1991	1.00
1992	1.00
1993	1.00
1994	1.00
1995	5.00
1996	3.00
1997	3.00
1998	6.00
1999	9.00
2000	4.00
2001	2.00
2002	1.00
2003	0
2004	1.00
2005	2.00
2006	1.00
2007	1.00
2008	1.00
2009	1.00
2010	1.00
2011	1.00
2012	0
2013	0
2014	1.00
2015	2.00
2016	2.00
2017	2.00
2018	2.00
2019	3.00
2020	2.00
2021	1.00
2022	1.00
2023	2.00
2024	1.00
2025	1.00

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	1949–2025
Completeness	93.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	One period inside 1949–2025 holds no value: 1955 to 1959, 5 years with no reading. It is drawn as a break in the line and is never interpolated across.
Continuity	The record begins in 1949 and is not continuous from it: 77 years separate the first value from the last, and 94% 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 Upper Arkansas-John Martin Reservoir and what each holds
Gauge	Measures	Values	Record
ARKANSAS RIVER AT LAMAR, CO	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	287	1913–2026
ARKANSAS RIVER AT HOLLY, CO.	catchment area, annual maximum river flow	45	1908–2026

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 — 11020009. 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
ARKANSAS RIVER AT LAMAR, 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
ARKANSAS RIVER AT HOLLY, 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 3 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	119	yes, 20 or more
Values held	332	no
Distinct measurements	5	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-07133000.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 Arkansas-John Martin Reservoir gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-upper-arkansas-john-martin-reservoir/

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 Arkansas-John Martin Reservoir 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 confidence2025-04-18

Source: USGS — National Water Information System, USGS site 07133000, 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.