HydrionisGlobal Water Intelligence
Monitored reservoir

Cle Elum Lake

Cle Elum Lake is a federal reservoir operated by the United States Bureau of Reclamation in its Pacific Northwest region, with published operating records from 1906.

Storage recordCle Elum Lake and Dam (CLE)

Storage now, against this reservoir's own record

39.36 Mm³
Stored, September 2026
33rd
Percentile among 120 Seps on record
-69.5%
Against the Sep 1991–2020 average
+77.6%
Change over the 12 months to 2026-09

Storage in September 2026 was around the middle of the Sep record, ranked against 120 other Seps held for this reservoir.

Storage, 1906–2026

Monthly mean storage
1,440 monthly values, 1906 to 2026
Monthly mean storageMonthly mean storage: Cle Elum Lake in Mm³, from 1906.75 to 2026.6666666666667.0200400600Mm³1906.751921.751936.751951.751966.751981.751996.752011.75Year

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 1,440 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 1,440 would be longer than this page and unusable with a screen reader.
PeriodCle Elum Lake (Mm³)
October 19067.39
April 19079.86
October 19078.22
April 190837.4
October 190816.9
April 190933.1
October 19096.90
April 191035.2
October 191016.4
April 191133.3
October 191110.7
April 191233.3
October 19126.97
April 191323.7
October 19139.40
April 191431.4
October 191415.0
April 191534.0
October 19158.34
April 191633.1
October 19168.59
April 191733.0
October 191712.4
April 191834.4
November 191831.1
May 191936.6
November 191922.7
May 192034.6
November 192024.6
May 192136.1
November 192131.3
May 192235.1
November 192214.0
May 192336.4
November 192312.4
May 192436.2
November 192428.3
May 192536.9
November 192510.2
May 192633.1
November 192631.4
May 192735.4
November 192733.5
May 192837.0
November 192814.0
May 192935.6
November 192917.1
May 193033.7
November 193025.0
May 193135.4
November 193131.4
May 193239.8
November 193273.5
May 193356.3
November 1933293
May 1934363
November 1934197
May 1935446
November 1935214
May 1936461
November 1936181
May 1937404
November 1937279
May 1938507
November 1938264
May 1939539
November 1939256
May 1940540
November 1940135
May 1941370
November 1941121
May 1942380
December 1942170
June 1943534
December 1943381
June 1944518
December 1944214
June 1945540
December 1945133
June 1946502
December 1946363
June 1947537
December 1947309
June 1948539
December 1948289
June 1949539
December 1949198
June 1950493
December 1950308
June 1951542
December 1951283
June 1952533
December 1952109
June 1953542
December 1953307
June 1954513
December 1954361
June 1955532
December 1955384
June 1956520
December 1956390
June 1957525
December 195789.0
June 1958532
December 1958241
June 1959534
December 1959438
June 1960534
December 1960190
June 1961521
December 1961189
June 1962546
December 1962279
June 1963531
December 1963124
June 1964450
December 1964347
June 1965538
December 1965199
June 1966511
January 1967263
July 1967493
January 1968414
July 1968410
January 1969295
July 1969456
January 1970179
July 1970461
January 1971174
July 1971540
January 1972342
July 1972535
January 1973390
July 1973271
January 1974151
July 1974537
January 1975398
July 1975516
January 1976372
July 1976537
January 1977445
July 1977255
January 1978298
July 1978442
January 197975.2
July 1979463
January 1980448
July 1980477
January 1981261
July 1981382
January 198255.3
July 1982501
January 1983323
July 1983489
January 1984316
July 1984505
January 1985216
July 1985353
January 1986149
July 1986344
January 1987129
July 1987254
January 198838.4
July 1988365
January 1989242
July 1989389
January 1990222
July 1990478
February 1991444
August 1991311
February 1992341
August 199273.3
February 199398.5
August 199396.3
February 199449.0
August 199475.4
February 1995183
August 1995251
February 1996454
August 1996265
February 1997289
August 1997382
February 1998406
August 1998237
February 1999260
August 1999491
February 2000375
August 2000230
February 2001110
August 2001104
February 2002205
August 2002335
February 2003257
August 2003182
February 2004207
August 2004169
February 2005331
August 200583.6
February 2006139
August 2006253
February 2007312
August 2007210
February 2008164
August 2008303
February 2009392
August 2009206
February 2010208
August 2010280
February 2011411
August 2011440
February 2012388
August 2012360
February 2013342
August 2013213
February 2014234
August 2014235
March 2015510
September 201536.2
March 2016405
September 201683.2
March 2017240
September 2017135
March 2018349
September 201891.7
March 2019203
September 201930.8
March 2020273
September 2020101
March 2021272
September 2021119
March 2022400
September 2022177
March 2023226
September 202329.7
March 2024187
September 202425.7
March 2025111
September 202522.2
March 2026459
September 202639.4

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 12.0200400600Mm³123456789101112Month1991–2020 average 1: 244 Mm³1991–2020 average 2: 279 Mm³1991–2020 average 3: 308 Mm³1991–2020 average 4: 354 Mm³1991–2020 average 5: 434 Mm³1991–2020 average 6: 492 Mm³1991–2020 average 7: 412 Mm³1991–2020 average 8: 227 Mm³1991–2020 average 9: 129 Mm³1991–2020 average 10: 132 Mm³1991–2020 average 11: 170 Mm³1991–2020 average 12: 210 Mm³Most recent 12 months 1: 366 Mm³Most recent 12 months 2: 410 Mm³Most recent 12 months 3: 459 Mm³Most recent 12 months 4: 531 Mm³Most recent 12 months 5: 535 Mm³Most recent 12 months 6: 476 Mm³Most recent 12 months 7: 310 Mm³Most recent 12 months 8: 114 Mm³Most recent 12 months 9: 39.4 Mm³Most recent 12 months 10: 19.7 Mm³Most recent 12 months 11: 70.1 Mm³Most recent 12 months 12: 242 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)
Jan244366
Feb279410
Mar308459
Apr354531
May434535
Jun492476
Jul412310
Aug227114
Sep12939.4
Oct13219.7
Nov17070.1
Dec210242

Why this page shows a volume and not a percentage

Rate and persistence

+1.43 Mm³
Mean change per month over 12 months
1 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

Cle Elum Lake
Gauge location
Cle Elum LakeCle Elum Lake — 39.36 Mm³Cle Elum Lake — 39.36 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 Bureau of Reclamation — Reservoir operations and Colorado River data · US Government work — public domain
How the values came to existMeasured
Period held1906–2026
Completeness99.2% 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.
Continuity99% of the months between 1906 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), Cle Elum Lake reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usbr-7170/

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 Cle Elum Lake 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

1,440 monthly observations 1906–2026 Mm³
Spatially aggregatedHigh confidenceSeptember 2026

Source: USBR — Reservoir operations and Colorado River data, RISE catalogue item 129798. Licence: Open.

Method: Monthly mean of the daily values published by the Bureau of Reclamation in acre-feet, converted to Mm³. Months with fewer than 20 days of record are not published rather than averaged from a partial month.

Stored as a volume and not as a share of capacity: the operator publishes what is in the reservoir but not what it holds when full, so a percentage cannot be computed without inventing the denominator.

Retrieved 1 October 2026.

Monthly mean of the daily values published by the Bureau of Reclamation in acre-feet, converted to Mm³. Months with fewer than 20 days of record are not published rather than averaged from a partial month.

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