HydrionisGlobal Water Intelligence
Monitored reservoir

Lk Eleanor Nr Hetch Hetchy CA

United States Geological Survey reservoir gauge 11277500 in CA, with published storage from 1918.

Storage record11277500

Storage now, against this reservoir's own record

24.07 Mm³
Stored, September 2026
55th
Percentile among 93 Seps on record
+9.2%
Against the Sep 1991–2020 average

Storage in September 2026 was around the middle of the Sep record, ranked against 93 other Seps held for this reservoir.

Storage, 1918–2026

Monthly mean storage
1,133 monthly values, 1918 to 2026
Monthly mean storageMonthly mean storage: Lk Eleanor Nr Hetch Hetchy CA in Mm³, from 1918.75 to 2026.6666666666667.010203040Mm³1918.751941.66666666666671953.51965.58333333333331978.66666666666671990.52003.08333333333332014.9166666666667Year

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 1,133 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 1,133 would be longer than this page and unusable with a screen reader.
PeriodLk Eleanor Nr Hetch Hetchy CA (Mm³)
October 191820.8
March 19193.40
July 191932.2
January 19313.49
June 193133.5
November 19313.12
March 193232.1
August 193231.0
January 19332.83
June 193333.8
October 19334.45
March 193431.3
August 193417.9
January 193521.2
May 193533.1
October 193523.0
March 193632.0
August 193632.5
December 19368.92
May 193733.2
October 193711.3
February 193833.0
July 193835.2
December 193818.1
May 193935.4
September 193914.9
February 194031.9
July 194034.0
December 19407.27
April 194132.0
September 194121.5
February 194229.5
July 194233.3
November 194217.2
April 194330.4
September 194319.4
February 19443.57
June 194433.1
November 194417.7
April 194530.1
August 194528.6
January 194629.3
June 194632.3
November 19469.33
March 194723.8
August 19475.40
January 19489.69
June 194831.7
October 194816.1
March 19492.57
August 194920.5
January 19503.48
May 195030.4
October 195010.9
March 195129.5
August 195120.9
December 195111.7
May 195231.4
October 195217.3
February 195326.7
July 195333.3
December 19536.13
May 195431.1
September 195422.6
February 195516.7
July 195532.8
December 195513.9
April 195625.1
September 19564.64
February 195716.8
July 195711.4
November 19570.184
April 195821.1
September 19580.013
January 19598.19
June 19594.31
November 19590.022
April 196014.7
August 196011.3
January 19617.70
June 196114.7
January 19626.56
May 196222.7
October 196214.9
March 196310.9
August 196332.0
December 196311.4
May 196413.4
October 19645.21
April 19654.93
August 196532.7
January 19661.97
June 196612.7
February 19672.93
July 196732.6
December 196718.9
May 196832.9
November 19681.75
April 19697.86
September 196932.0
February 197029.3
June 197033.4
November 19702.56
April 19714.12
September 197112.6
February 19722.12
March 19732.88
August 197323.2
January 19746.85
May 197427.5
October 197423.4
March 19753.08
July 197533.3
December 19753.46
May 19765.04
October 19760.703
February 19771.46
July 19770.619
December 19772.87
May 197820.5
September 197832.6
February 19792.54
July 197932.2
December 19791.89
April 198025.8
September 198028.4
February 198111.6
July 198131.4
November 198112.2
April 198231.7
September 198232.6
January 198324.2
June 198331.4
November 198329.7
April 198418.6
August 198431.9
January 19852.48
June 198532.4
November 19850.244
March 198628.8
August 198631.2
January 19871.83
June 198733.1
October 198721.4
March 198823.8
August 19880.168
January 198911.4
May 198927.6
October 198913.2
March 19903.39
July 199025.1
December 19900.163
May 19915.91
October 19914.70
February 19922.54
July 19929.85
December 19921.81
May 199328.0
September 199324.7
February 199427.8
July 199415.7
December 19940.022
January 199614.7
June 199632.1
November 19966.53
April 199731.7
August 199728.1
January 19989.21
June 199832.0
October 199824.0
March 199922.0
August 199923.4
January 200026.2
May 200031.1
October 20004.24
March 20015.08
August 200129.7
December 200121.6
May 200230.3
October 200226.7
March 20036.84
July 200330.5
December 200324.5
May 200433.1
September 200426.0
February 200528.0
July 200530.6
December 200529.3
April 200624.6
September 200623.8
February 200718.3
July 200732.0
November 200725.9
April 200819.5
September 200825.4
February 200917.7
June 200933.6
November 200926.4
April 201026.2
September 201023.0
January 201128.1
June 201130.2
November 20111.54
March 201225.7
August 201225.5
January 201328.6
June 201331.5
October 201321.3
March 201427.3
August 201426.4
January 201515.8
May 201530.2
October 20150
March 20169.82
August 201627.0
December 201626.5
May 201730.3
October 201733.1
March 201813.1
July 201830.6
December 201820.6
May 201929.8
September 201926.3
February 202025.4
July 202030.9
December 202012.1
April 202131.6
September 202125.4
February 202225.9
July 202231.9
November 202221.6
April 202320.3
September 202331.4
February 202429.3
June 202432.8
November 202418.8
April 202528.9
September 202524.9
January 202629.2
September 202624.1

The reservoir's year

Seasonal storage profile
Each calendar month's reference average, against the most recent year
Seasonal storage profileSeasonal storage profile: 1991–2020 average, Most recent 12 months in Mm³, from 1 to 12.010203040Mm³123456789101112Month1991–2020 average 1: 17.0 Mm³1991–2020 average 2: 17.5 Mm³1991–2020 average 3: 18.8 Mm³1991–2020 average 4: 23.6 Mm³1991–2020 average 5: 29.1 Mm³1991–2020 average 6: 30.2 Mm³1991–2020 average 7: 29.0 Mm³1991–2020 average 8: 25.8 Mm³1991–2020 average 9: 22.0 Mm³1991–2020 average 10: 18.7 Mm³1991–2020 average 11: 17.6 Mm³1991–2020 average 12: 16.8 Mm³Most recent 12 months 1: 29.2 Mm³Most recent 12 months 2: 27.2 Mm³Most recent 12 months 3: 27.1 Mm³Most recent 12 months 4: 31.7 Mm³Most recent 12 months 7: 32.2 Mm³Most recent 12 months 8: 26.7 Mm³Most recent 12 months 9: 24.1 Mm³Most recent 12 months 10: 21.0 Mm³Most recent 12 months 11: 22.4 Mm³Most recent 12 months 12: 25.7 Mm³
  • 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
Period1991–2020 average (Mm³)Most recent 12 months (Mm³)
Jan17.029.2
Feb17.527.2
Mar18.827.1
Apr23.631.7
May29.1—
Jun30.2—
Jul29.032.2
Aug25.826.7
Sep22.024.1
Oct18.721.0
Nov17.622.4
Dec16.825.7

Why this page shows a volume and not a percentage

Rate and persistence

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

Lk Eleanor Nr Hetch Hetchy CA
Gauge location
Lk Eleanor Nr Hetch Hetchy CALk Eleanor Nr Hetch Hetchy CA — 24.07 Mm³Lk Eleanor Nr Hetch Hetchy CA — 24.07 Mm³

About this data

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 existMeasured
Period held1918–2026
Completeness86.6% 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.
Continuity87% of the months between 1918 and 2026 are held. Monthly means of the publisher's own daily record.
Last read from the publisher2026-10-01
RedistributionPermitted by the upstream licences
Commercial reusePermitted by the upstream licences. No Hydrionis access tier can widen this.
MethodologyHow this was produced

Use this data

Use this data

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), Lk Eleanor Nr Hetch Hetchy CA reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-11277500/

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 Lk Eleanor Nr Hetch Hetchy CA 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

1,133 monthly observations 1918–2026 Mm³
Spatially aggregatedHigh confidenceSeptember 2026

Source: USGS — National Water Information System, 11277500. 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.

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