Lake O' The Cherokees, OK — storage

Storage now, against this reservoir's own record

1,644.23 Mm³

Stored, September 2026

10th

Percentile among 85 Seps on record

-13.7%

Against the Sep 1991–2020 average

-0.8%

Change over the 12 months to 2026-09

Storage in September 2026 was lower than almost every other Sep on record, ranked against 85 other Seps held for this reservoir.

Storage, 1940–2026

Monthly mean storage

1,014 monthly values, 1940 to 2026

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 1,014 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 1,014 would be longer than this page and unusable with a screen reader.
Period	Lake O' The Cherokees At Langley, OK (Mm³)
April 1940	99.7
August 1940	829
December 1942	2,133
May 1943	2,223
September 1943	1,755
January 1944	1,459
May 1944	2,080
October 1944	2,017
February 1945	1,762
June 1945	2,112
October 1945	2,186
March 1946	2,063
July 1946	1,956
November 1946	1,673
March 1947	1,888
August 1947	1,888
December 1947	1,397
April 1948	1,734
August 1948	2,100
January 1949	1,687
May 1949	2,165
September 1949	1,747
January 1950	1,847
May 1950	1,928
October 1950	1,995
February 1951	1,670
June 1951	2,133
October 1951	2,044
March 1952	2,063
July 1952	1,675
November 1952	1,235
March 1953	1,075
August 1953	944
December 1953	919
April 1954	870
August 1954	846
January 1955	1,277
May 1955	1,695
September 1955	1,679
January 1956	1,386
June 1956	1,528
October 1956	1,334
February 1957	1,345
June 1957	2,460
October 1957	1,593
March 1958	1,854
July 1958	2,111
November 1958	1,567
March 1959	1,651
August 1959	1,849
December 1959	1,565
April 1960	1,900
August 1960	1,874
January 1961	1,532
May 1961	2,375
September 1961	1,977
January 1962	1,586
June 1962	2,047
October 1962	1,975
February 1963	1,527
June 1963	1,783
November 1963	1,358
March 1964	1,371
July 1964	1,982
November 1964	1,529
April 1965	2,082
August 1965	1,818
December 1965	1,535
April 1966	1,723
August 1966	1,767
January 1967	1,437
May 1967	1,838
September 1967	1,700
January 1968	1,612
June 1968	2,062
October 1968	1,650
February 1969	1,784
June 1969	2,092
November 1969	1,794
March 1970	1,650
July 1970	2,005
November 1970	1,845
April 1971	1,803
August 1971	1,886
December 1971	1,975
April 1972	1,728
September 1972	1,796
January 1973	2,051
May 1973	2,329
September 1973	1,806
January 1974	1,993
June 1974	2,201
October 1974	1,872
February 1975	2,120
June 1975	2,084
November 1975	1,549
March 1976	1,604
July 1976	2,143
November 1976	1,549
April 1977	1,687
August 1977	1,859
December 1977	1,816
April 1978	2,145
September 1978	1,655
January 1979	1,596
May 1979	1,985
September 1979	1,686
February 1980	1,636
June 1980	1,997
October 1980	1,533
February 1981	1,618
June 1981	1,927
November 1981	1,996
March 1982	1,978
July 1982	2,014
November 1982	1,697
April 1983	2,200
August 1983	1,754
December 1983	1,909
April 1984	2,198
September 1984	1,899
January 1985	2,124
May 1985	2,106
September 1985	2,006
February 1986	1,917
June 1986	1,894
October 1986	2,387
February 1987	2,053
July 1987	1,905
November 1987	1,869
March 1988	2,033
July 1988	1,932
November 1988	1,807
April 1989	1,897
August 1989	1,998
December 1989	1,844
April 1990	2,186
September 1990	1,879
January 1991	2,010
May 1991	1,910
September 1991	1,873
February 1992	1,876
June 1992	2,103
October 1992	1,982
February 1993	2,073
July 1993	2,137
November 1993	1,971
March 1994	1,977
July 1994	1,988
December 1994	1,922
April 1995	1,971
August 1995	1,885
December 1995	1,875
April 1996	1,917
September 1996	1,859
January 1997	1,896
May 1997	2,019
September 1997	1,839
February 1998	1,918
June 1998	2,009
October 1998	2,134
February 1999	2,037
July 1999	2,183
November 1999	1,873
March 2000	1,930
July 2000	2,056
December 2000	1,890
April 2001	1,911
August 2001	1,950
December 2001	1,927
May 2002	2,113
September 2002	1,835
January 2003	1,859
May 2003	2,012
September 2003	1,859
February 2004	1,967
June 2004	2,014
October 2004	1,889
February 2005	1,951
July 2005	2,070
November 2005	1,830
March 2006	1,898
July 2006	1,994
December 2006	1,878
April 2007	1,977
August 2007	2,065
December 2007	1,903
May 2008	2,185
September 2008	1,991
January 2009	1,897
May 2009	2,270
October 2009	2,068
February 2010	1,939
June 2010	2,041
October 2010	1,848
March 2011	1,981
July 2011	2,007
November 2011	1,888
March 2012	2,015
July 2012	1,989
December 2012	1,898
April 2013	1,982
August 2013	2,089
December 2013	1,897
May 2014	1,951
September 2014	1,841
January 2015	1,897
May 2015	2,123
October 2015	1,893
February 2016	1,897
June 2016	2,022
October 2016	1,964
March 2017	1,898
July 2017	2,005
November 2017	1,897
March 2018	1,948
August 2018	1,965
December 2018	1,900
April 2019	1,903
August 2019	2,108
December 2019	1,921
May 2020	2,130
September 2020	1,935
January 2021	1,662
May 2021	1,718
October 2021	1,671
February 2022	1,619
June 2022	1,764
October 2022	1,613
March 2023	1,678
July 2023	1,722
November 2023	1,644
March 2024	1,619
August 2024	1,680
December 2024	1,620
April 2025	1,752
August 2025	1,682
January 2026	1,619
May 2026	1,711
September 2026	1,644

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	1,947	1,619
Feb	1,936	1,616
Mar	1,973	1,647
Apr	1,987	1,722
May	2,105	1,711
Jun	2,121	1,873
Jul	2,069	1,805
Aug	1,951	1,692
Sep	1,906	1,644
Oct	1,909	1,624
Nov	1,926	1,620
Dec	1,936	1,622

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

-1.17 Mm³

Mean drawdown per month over 12 months

11 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 O' The Cherokees At Langley, OK

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	1940–2026
Completeness	97.1% 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 1940 and 2026 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-07190000.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 O' The Cherokees At Langley, OK reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-07190000/

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 O' The Cherokees At Langley, OK 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

1,014 monthly observations 1940–2026 Mm³

Spatially aggregatedHigh confidenceSeptember 2026

Source: USGS — National Water Information System, 07190000. 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.