Jackson Lake, WY — storage

Storage now, against this reservoir's own record

199.12 Mm³

Stored, September 1985

2nd

Percentile among 43 Seps on record

Storage in September 1985 was lower than almost every other Sep on record, ranked against 43 other Seps held for this reservoir.

No percentage departure from the Sep average is published here. No long-term average is held for this month, so there is nothing to compare with.

Storage, 1937–1985

Monthly mean storage

516 monthly values, 1937 to 1985

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 516 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 516 would be longer than this page and unusable with a screen reader.
Period	Jackson Lake Near Moran, WY (Mm³)
October 1937	292
December 1937	349
February 1938	418
April 1938	493
July 1938	1,010
September 1938	569
November 1938	541
January 1939	608
March 1939	672
May 1939	924
August 1939	640
October 1939	402
December 1939	438
February 1940	497
April 1940	570
June 1940	1,017
August 1940	407
November 1940	251
January 1941	308
March 1941	360
May 1941	523
July 1941	699
September 1941	295
December 1941	391
February 1942	464
April 1942	526
June 1942	948
August 1942	678
October 1942	403
December 1942	470
March 1943	574
May 1943	642
July 1943	1,052
September 1943	845
November 1943	805
January 1944	821
April 1944	905
June 1944	1,051
August 1944	669
October 1944	378
December 1944	428
February 1945	490
May 1945	659
July 1945	1,044
September 1945	719
November 1945	749
January 1946	817
March 1946	757
May 1946	916
August 1946	671
October 1946	517
December 1946	597
February 1947	667
April 1947	732
June 1947	1,051
September 1947	605
November 1947	627
January 1948	698
March 1948	761
May 1948	844
July 1948	924
September 1948	313
December 1948	380
February 1949	451
April 1949	467
June 1949	1,014
August 1949	625
October 1949	357
January 1950	458
March 1950	541
May 1950	565
July 1950	1,041
September 1950	699
November 1950	773
January 1951	812
April 1951	522
June 1951	972
August 1951	972
October 1951	775
December 1951	834
February 1952	811
May 1952	682
July 1952	942
September 1952	417
November 1952	383
January 1953	453
March 1953	531
May 1953	650
August 1953	681
October 1953	299
December 1953	359
February 1954	440
April 1954	518
June 1954	959
September 1954	468
November 1954	437
January 1955	500
March 1955	565
May 1955	698
July 1955	928
September 1955	304
December 1955	343
February 1956	449
April 1956	319
June 1956	901
August 1956	787
October 1956	475
January 1957	82.3
March 1957	168
May 1957	357
July 1957	1,008
September 1957	781
November 1957	746
January 1958	753
April 1958	572
June 1958	974
August 1958	851
October 1958	594
December 1958	582
February 1959	586
May 1959	684
July 1959	1,013
September 1959	718
November 1959	653
January 1960	602
March 1960	589
June 1960	995
August 1960	827
October 1960	442
December 1960	432
February 1961	365
April 1961	171
June 1961	586
September 1961	5.08
November 1961	63.8
January 1962	130
March 1962	191
May 1962	479
July 1962	1,010
October 1962	645
December 1962	654
February 1963	704
April 1963	759
June 1963	1,051
August 1963	876
October 1963	736
January 1964	765
March 1964	781
May 1964	799
July 1964	1,034
September 1964	740
November 1964	718
February 1965	722
April 1965	535
June 1965	796
August 1965	955
October 1965	786
December 1965	848
February 1966	862
May 1966	879
July 1966	996
September 1966	704
November 1966	589
January 1967	607
March 1967	624
June 1967	877
August 1967	879
October 1967	698
December 1967	726
February 1968	742
April 1968	752
June 1968	971
September 1968	764
November 1968	757
January 1969	778
March 1969	804
May 1969	792
July 1969	1,030
October 1969	708
December 1969	743
February 1970	773
April 1970	776
June 1970	930
August 1970	921
October 1970	688
January 1971	727
March 1971	747
May 1971	525
July 1971	1,041
September 1971	782
November 1971	742
February 1972	777
April 1972	686
June 1972	861
August 1972	937
October 1972	725
December 1972	751
February 1973	781
May 1973	867
July 1973	1,008
September 1973	785
November 1973	761
January 1974	788
March 1974	813
June 1974	814
August 1974	907
October 1974	725
December 1974	736
February 1975	764
April 1975	786
July 1975	995
September 1975	740
November 1975	737
January 1976	771
March 1976	784
May 1976	587
July 1976	1,009
October 1976	699
December 1976	706
February 1977	730
April 1977	774
June 1977	807
August 1977	390
November 1977	305
January 1978	367
March 1978	408
May 1978	463
July 1978	758
September 1978	662
November 1978	669
February 1979	698
April 1979	630
June 1979	748
August 1979	677
October 1984	339
December 1984	344
March 1985	328
May 1985	214
July 1985	344
September 1985	199

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

14 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

Jackson Lake Near Moran, WY

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	1937–1985
Completeness	87.8% 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	88% of the months between 1937 and 1985 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-13010500.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), Jackson Lake Near Moran, WY reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-13010500/

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 Jackson Lake Near Moran, WY 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

516 monthly observations 1937–1985 Mm³

Spatially aggregatedHigh confidenceSeptember 1985

Source: USGS — National Water Information System, 13010500. 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.