Lake Sumner, NM — storage

Storage now, against this reservoir's own record

35.35 Mm³

Stored, January 2017

43rd

Percentile among 52 Jans on record

+6.9%

Against the Jan 1991–2020 average

-36.8%

Change over the 12 months to 2017-01

Storage in January 2017 was around the middle of the Jan record, ranked against 52 other Jans held for this reservoir.

Storage, 1965–2017

Monthly mean storage

615 monthly values, 1965 to 2017

Monthly means of the publisher's daily record. Volume, not percentage of capacity — see below for why.

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

240 of 615 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 615 would be longer than this page and unusable with a screen reader.
Period	Lake Sumner Nr Fort Sumner, NM (Mm³)
October 1965	53.4
January 1966	59.4
March 1966	52.9
June 1966	35.6
August 1966	38.4
November 1966	73.4
January 1967	83.4
April 1967	86.0
July 1967	29.2
September 1967	66.8
December 1967	74.7
February 1968	86.8
May 1968	55.3
July 1968	35.6
October 1968	71.4
January 1969	84.1
March 1969	79.9
June 1969	71.0
August 1969	21.7
November 1969	82.9
January 1970	95.6
April 1970	104
July 1970	58.2
September 1970	46.1
December 1970	59.0
February 1971	71.6
May 1971	15.9
July 1971	9.97
October 1971	38.6
January 1972	58.2
March 1972	64.4
June 1972	5.84
August 1972	12.6
November 1972	87.4
February 1973	107
May 1973	124
July 1973	137
October 1973	111
January 1974	120
March 1974	115
June 1974	43.7
August 1974	13.1
November 1974	33.7
January 1975	47.8
April 1975	61.1
July 1975	11.3
September 1975	22.9
December 1975	36.2
February 1976	46.4
May 1976	7.67
July 1976	23.8
October 1976	12.7
January 1977	33.5
March 1977	32.2
June 1977	16.0
August 1977	13.6
November 1977	46.3
January 1978	48.9
April 1978	9.55
July 1978	5.80
September 1978	6.65
December 1978	25.0
February 1979	37.0
May 1979	68.9
July 1979	125
October 1979	110
January 1980	105
March 1980	111
June 1980	61.3
August 1980	6.03
November 1980	18.4
January 1981	31.5
April 1981	38.3
July 1981	10.9
September 1981	40.6
December 1981	47.5
February 1982	57.6
May 1982	5.01
July 1982	16.7
October 1982	22.4
January 1983	37.3
March 1983	47.4
June 1983	18.9
August 1983	7.92
November 1983	14.9
January 1984	27.0
April 1984	32.2
July 1984	16.1
September 1984	21.9
December 1984	36.9
February 1985	49.4
May 1985	52.0
July 1985	38.7
October 1985	23.6
December 1985	44.1
March 1986	60.6
June 1986	35.5
August 1986	49.4
November 1986	72.2
January 1987	82.6
April 1987	76.8
June 1987	63.4
September 1987	45.9
December 1987	43.6
February 1988	56.6
May 1988	37.7
July 1988	27.0
October 1988	23.2
December 1988	30.9
March 1989	43.4
June 1989	20.5
August 1989	17.1
November 1989	20.3
January 1990	32.0
April 1990	38.4
June 1990	18.5
September 1990	10.1
December 1990	17.3
February 1991	24.9
May 1991	14.2
July 1991	4.97
October 1991	52.4
December 1991	64.0
March 1992	57.1
June 1992	53.9
August 1992	48.1
November 1992	20.3
January 1993	32.3
April 1993	40.2
June 1993	50.3
September 1993	45.3
December 1993	25.8
February 1994	36.7
May 1994	36.5
July 1994	52.1
October 1994	17.7
December 1994	23.5
March 1995	34.8
June 1995	29.8
August 1995	40.2
November 1995	32.4
January 1996	48.1
April 1996	46.5
June 1996	15.7
September 1996	13.4
December 1996	32.6
February 1997	43.8
May 1997	37.2
July 1997	42.9
October 1997	43.8
December 1997	25.8
March 1998	45.6
May 1998	42.8
August 1998	25.8
November 1998	16.2
January 1999	26.3
April 1999	31.0
June 1999	51.0
September 1999	52.2
November 1999	30.4
February 2000	35.9
May 2000	28.9
July 2000	27.0
October 2000	11.6
December 2000	32.3
March 2001	44.1
May 2001	32.0
August 2001	30.4
November 2001	10.7
January 2002	14.4
April 2002	1.85
June 2002	1.24
September 2002	3.04
November 2002	7.03
February 2003	17.5
May 2003	14.0
July 2003	3.91
October 2003	6.23
December 2003	12.6
March 2004	7.70
May 2004	7.60
August 2004	4.24
November 2004	21.6
January 2005	31.7
April 2005	39.4
June 2005	53.0
September 2005	49.5
November 2005	37.3
February 2006	29.1
May 2006	20.5
July 2006	17.8
October 2006	27.8
December 2006	33.4
March 2007	35.4
May 2007	31.4
August 2007	29.3
November 2007	23.8
January 2008	32.0
April 2008	26.6
June 2008	20.7
September 2008	18.2
November 2008	16.7
February 2009	28.9
May 2009	16.8
July 2009	15.5
October 2009	19.9
December 2009	27.5
March 2010	36.1
May 2010	23.7
August 2010	20.6
October 2010	19.2
January 2011	28.1
April 2011	19.8
June 2011	12.0
September 2011	3.60
November 2011	4.45
February 2012	17.3
April 2012	5.40
July 2012	4.35
October 2012	5.16
December 2012	10.0
March 2013	13.1
May 2013	6.60
August 2013	6.39
October 2013	39.7
January 2014	48.4
April 2014	50.7
June 2014	35.9
September 2014	45.2
November 2014	46.2
February 2015	57.9
April 2015	54.2
July 2015	39.8
October 2015	38.1
December 2015	52.1
March 2016	55.2
May 2016	37.7
August 2016	27.2
October 2016	23.9
January 2017	35.3

The reservoir's year

Seasonal storage profile

Each calendar month's reference average, against the most recent year

1991–2020 average
Most recent 12 months

Twelve separate averages, one per calendar month. A January average describes Januaries only. Months are plotted 1–12.

View the data behind this chart

Underlying data
Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	33.1	35.3
Feb	36.6	56.8
Mar	33.5	55.2
Apr	29.9	50.7
May	27.9	37.7
Jun	27.6	38.7
Jul	25.9	30.7
Aug	25.6	27.2
Sep	26.6	28.9
Oct	24.2	23.9
Nov	24.6	25.1
Dec	28.5	31.1

Why this page shows a volume and not a percentage

Percentage full is a division, and the denominator is missing

“Percentage full” is the figure a drought is discussed in, and it is stored volume divided by capacity. Capacity is published on several different bases — gross, usable, live, and the figure at a particular spillway or licence condition — and dividing a stored volume by the wrong one produces a percentage confidently wrong by the ratio between them, at exactly the moment the number matters most.

Hydrionis holds storage measurements for this reservoir and does not hold a compatible authoritative capacity figure for it, so percentage full is not calculated. The volume above is what was actually measured. Where you need a percentage, take the publisher’s own capacity on its own stated basis and divide it yourself — the source is linked below, and knowing which basis you used is the whole point.

Rate and persistence

-1.71 Mm³

Mean drawdown per month over 12 months

0 of 24

Recent months below the 20th percentile for their own month

Rates are computed only across an unbroken run of months, so a rate is never divided by a period in which some of the change was not observed. Percentile counts compare each month with the same calendar month in every other year held.

Location

Lake Sumner Nr Fort Sumner, NM

Gauge location

About this data

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	1965–2017
Completeness	96.7% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	Storage is a managed quantity. A falling line can be a rule curve, a scheduled release or a transfer to another system rather than a shortage of water, and nothing here distinguishes them. No capacity figure on a stated basis is held for this reservoir, so no percentage of capacity is computed.
Continuity	97% of the months between 1965 and 2017 are held. Monthly means of the publisher's own daily 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

Use this data

Machine-readable JSON /api/v1/observations/by-subject/reservoir-usgs-08384000.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), Lake Sumner Nr Fort Sumner, NM reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-08384000/

Cite Hydrionis where you rely on the compilation, the normalisation, the eligibility judgements or a chart. Where you use an unmodified published value, the publisher’s attribution is the one that is required; crediting Hydrionis as well is welcome and is not something Hydrionis can require of you.

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 Lake Sumner Nr Fort Sumner, NM record 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 this comes from

615 monthly observations 1965–2017 Mm³

Spatially aggregatedHigh confidenceJanuary 2017

Source: USGS — National Water Information System, 08384000. Licence: Open.

Method: Monthly mean of daily reservoir storage published by the USGS in acre-feet and converted to millions of cubic metres. Months with fewer than 20 days of record are not published rather than averaged from a partial month.

Reservoir storage is managed as well as observed: a drawdown may reflect an operating rule, flood-control rule curve or scheduled release rather than a shortage. Compare a month against the same month in other years, and do not read a fall as a supply signal without knowing the operating regime.

Retrieved 1 October 2026.

Monthly mean of daily reservoir storage published by the USGS in acre-feet and converted to millions of cubic metres. Months with fewer than 20 days of record are not published rather than averaged from a partial month.