HydrionisGlobal Water Intelligence
Monitored reservoir

Pathfinder Reservoir

Pathfinder Reservoir is a federal reservoir operated by the United States Bureau of Reclamation in its Great Plains region, with published operating records from 1945.

Storage recordPathfinder Reservoir and Dam

Storage now, against this reservoir's own record

219.22 Mm³
Stored, September 2026
19th
Percentile among 81 Seps on record
-66.4%
Against the Sep 1991–2020 average
-43.7%
Change over the 12 months to 2026-09

Storage in September 2026 was lower than most Seps on record, ranked against 81 other Seps held for this reservoir.

Storage, 1945–2026

Monthly mean storage
972 monthly values, 1945 to 2026
Monthly mean storageMonthly mean storage: Pathfinder Reservoir in Mm³, from 1945.75 to 2026.6666666666667.05001,0001,500Mm³1945.751955.91666666666671966.08333333333331976.251986.41666666666671996.58333333333332006.752016.9166666666667Year

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 972 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 972 would be longer than this page and unusable with a screen reader.
PeriodPathfinder Reservoir (Mm³)
October 194585.5
February 1946414
June 1946411
October 1946124
February 1947474
June 1947605
October 1947302
February 1948678
July 1948589
November 1948335
March 1949620
July 19491,002
November 1949727
March 19501,091
July 19501,122
November 1950796
March 19511,120
July 1951907
November 1951596
March 19521,076
July 19521,133
November 1952717
March 19531,032
July 1953875
December 1953843
April 19541,107
August 1954526
December 1954483
April 1955604
August 1955412
December 1955356
April 1956618
August 1956119
December 1956247
April 1957439
August 1957405
December 1957661
April 1958957
August 195856.1
December 19580.460
May 1959286
September 1959118
January 1960176
May 1960333
September 196078.2
January 1961292
May 1961285
September 196163.4
January 1962175
May 1962413
September 1962310
January 1963630
May 1963492
September 1963125
January 1964124
May 1964345
October 196480.2
February 1965127
June 1965290
October 1965247
February 1966545
June 1966430
October 1966202
February 1967221
June 1967297
October 1967330
February 1968437
June 1968489
October 1968222
February 1969422
June 1969377
October 1969103
March 1970385
July 1970621
November 1970703
March 19711,090
July 19711,074
November 19711,016
March 19721,135
July 1972975
November 1972898
March 19731,147
July 19731,200
November 1973983
March 19741,195
July 19741,028
November 1974904
March 19751,135
August 19751,044
December 1975916
April 19761,079
August 1976836
December 1976838
April 1977902
August 1977447
December 1977408
April 1978632
August 1978696
December 1978633
April 1979928
August 1979777
December 1979743
April 19801,101
August 1980884
January 1981817
May 1981957
September 1981515
January 1982598
May 1982726
September 1982498
January 1983731
May 19831,080
September 19831,061
January 19841,102
May 19841,130
September 19841,101
January 19851,102
May 19851,095
September 1985799
January 1986859
June 19861,259
October 19861,051
February 19871,110
June 19871,103
October 1987894
February 1988994
June 19881,114
October 1988617
February 1989809
June 1989717
October 1989350
February 1990422
June 1990517
October 1990297
February 1991344
June 1991409
November 1991375
March 1992391
July 1992321
November 1992251
March 1993261
July 1993359
November 1993406
March 1994520
July 1994469
November 1994308
March 1995340
July 1995695
November 1995843
March 19961,009
July 19961,146
November 1996986
April 19971,121
August 19971,073
December 19971,121
April 19981,217
August 19981,103
December 19981,062
April 19991,209
August 19991,176
December 19991,145
April 20001,220
August 2000873
December 2000847
April 2001954
August 2001669
December 2001592
April 2002678
September 2002349
January 2003422
May 2003443
September 2003333
January 2004392
May 2004400
September 2004239
January 2005294
May 2005261
September 2005293
January 2006345
May 2006367
September 2006252
January 2007292
May 2007323
September 2007211
February 2008259
June 2008380
October 2008447
February 2009491
June 2009614
October 2009876
February 2010905
June 20101,237
October 2010931
February 2011998
June 20111,303
October 2011914
February 2012967
June 2012930
October 2012492
February 2013523
July 2013480
November 2013425
March 2014459
July 2014848
November 2014826
March 2015860
July 20151,064
November 2015971
March 20161,060
July 20161,259
November 20161,107
March 20171,175
July 20171,207
November 20171,008
March 20181,035
July 2018945
December 2018768
April 2019800
August 20191,177
December 20191,077
April 20201,222
August 2020866
December 2020795
April 2021802
August 2021824
December 2021790
April 2022797
August 2022503
December 2022417
April 2023458
August 2023831
December 2023861
May 2024973
September 2024723
January 2025743
May 2025710
September 2025389
January 2026426
May 2026402
September 2026219

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 12.02505007501,000Mm³123456789101112Month1991–2020 average 1: 688 Mm³1991–2020 average 2: 705 Mm³1991–2020 average 3: 727 Mm³1991–2020 average 4: 741 Mm³1991–2020 average 5: 774 Mm³1991–2020 average 6: 808 Mm³1991–2020 average 7: 782 Mm³1991–2020 average 8: 706 Mm³1991–2020 average 9: 652 Mm³1991–2020 average 10: 661 Mm³1991–2020 average 11: 680 Mm³1991–2020 average 12: 691 Mm³Most recent 12 months 1: 426 Mm³Most recent 12 months 2: 431 Mm³Most recent 12 months 3: 430 Mm³Most recent 12 months 4: 418 Mm³Most recent 12 months 5: 402 Mm³Most recent 12 months 6: 377 Mm³Most recent 12 months 7: 282 Mm³Most recent 12 months 8: 242 Mm³Most recent 12 months 9: 219 Mm³Most recent 12 months 10: 400 Mm³Most recent 12 months 11: 415 Mm³Most recent 12 months 12: 421 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)
Jan688426
Feb705431
Mar727430
Apr741418
May774402
Jun808377
Jul782282
Aug706242
Sep652219
Oct661400
Nov680415
Dec691421

Why this page shows a volume and not a percentage

Water level

Monthly mean water surface elevation
972 monthly values
Monthly mean water surface elevationMonthly mean water surface elevation: Pathfinder Reservoir in m, from 1945.75 to 2026.6666666666667.1,7401,7601,780m1945.751955.91666666666671966.08333333333331976.251986.41666666666671996.58333333333332006.752016.9166666666667Year

An elevation above a datum, not a depth of water and not a distance below the crest. Levels at different reservoirs are measured against different datums and must not be read against one another; this line is comparable only with its own history. Elevation and volume are not proportional either — a metre near the bottom of a reservoir holds far less water than a metre near the top, because the surface area grows with height.

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 972 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 972 would be longer than this page and unusable with a screen reader.
PeriodPathfinder Reservoir (m)
1945.751,754
1946.08333333333331,769
1946.41666666666671,769
1946.751,757
1947.08333333333331,770
1947.41666666666671,773
1947.751,765
1948.08333333333331,775
1948.51,773
1948.83333333333331,766
1949.16666666666671,774
1949.51,780
1949.83333333333331,776
1950.16666666666671,781
1950.51,782
1950.83333333333331,777
1951.16666666666671,782
1951.51,779
1951.83333333333331,774
1952.16666666666671,781
1952.51,782
1952.83333333333331,776
1953.16666666666671,780
1953.51,778
1953.91666666666671,778
1954.251,781
1954.58333333333331,772
1954.91666666666671,771
1955.251,774
1955.58333333333331,769
1955.91666666666671,768
1956.251,774
1956.58333333333331,757
1956.91666666666671,764
1957.251,770
1957.58333333333331,769
1957.91666666666671,775
1958.251,779
1958.58333333333331,751
1958.91666666666671,739
1959.33333333333331,765
1959.66666666666671,757
19601,761
1960.33333333333331,767
1960.66666666666671,755
19611,765
1961.33333333333331,765
1961.66666666666671,754
19621,761
1962.33333333333331,769
1962.66666666666671,766
19631,774
1963.33333333333331,771
1963.66666666666671,758
19641,758
1964.33333333333331,767
1964.751,755
1965.08333333333331,758
1965.41666666666671,765
1965.751,764
1966.08333333333331,772
1966.41666666666671,770
1966.751,762
1967.08333333333331,763
1967.41666666666671,766
1967.751,767
1968.08333333333331,770
1968.41666666666671,771
1968.751,763
1969.08333333333331,769
1969.41666666666671,768
1969.751,757
1970.16666666666671,768
1970.51,774
1970.83333333333331,776
1971.16666666666671,781
1971.51,781
1971.83333333333331,780
1972.16666666666671,782
1972.51,780
1972.83333333333331,779
1973.16666666666671,782
1973.51,782
1973.83333333333331,780
1974.16666666666671,782
1974.51,780
1974.83333333333331,779
1975.16666666666671,782
1975.58333333333331,781
1975.91666666666671,779
1976.251,781
1976.58333333333331,778
1976.91666666666671,778
1977.251,779
1977.58333333333331,770
1977.91666666666671,769
1978.251,774
1978.58333333333331,775
1978.91666666666671,774
1979.251,779
1979.58333333333331,777
1979.91666666666671,776
1980.251,781
1980.58333333333331,778
19811,777
1981.33333333333331,779
1981.66666666666671,772
19821,774
1982.33333333333331,776
1982.66666666666671,771
19831,776
1983.33333333333331,781
1983.66666666666671,781
19841,781
1984.33333333333331,782
1984.66666666666671,781
19851,781
1985.33333333333331,781
1985.66666666666671,777
19861,778
1986.41666666666671,783
1986.751,781
1987.08333333333331,781
1987.41666666666671,781
1987.751,779
1988.08333333333331,780
1988.41666666666671,781
1988.751,774
1989.08333333333331,777
1989.41666666666671,776
1989.751,767
1990.08333333333331,769
1990.41666666666671,772
1990.751,766
1991.08333333333331,767
1991.41666666666671,769
1991.83333333333331,768
1992.16666666666671,769
1992.51,766
1992.83333333333331,764
1993.16666666666671,764
1993.51,768
1993.83333333333331,769
1994.16666666666671,772
1994.51,771
1994.83333333333331,766
1995.16666666666671,767
1995.51,775
1995.83333333333331,778
1996.16666666666671,780
1996.51,782
1996.83333333333331,780
1997.251,782
1997.58333333333331,781
1997.91666666666671,782
1998.251,783
1998.58333333333331,781
1998.91666666666671,781
1999.251,783
1999.58333333333331,782
1999.91666666666671,782
2000.251,783
2000.58333333333331,778
2000.91666666666671,778
2001.251,779
2001.58333333333331,775
2001.91666666666671,773
2002.251,775
2002.66666666666671,767
20031,769
2003.33333333333331,770
2003.66666666666671,767
20041,769
2004.33333333333331,769
2004.66666666666671,763
20051,765
2005.33333333333331,764
2005.66666666666671,765
20061,767
2006.33333333333331,768
2006.66666666666671,764
20071,765
2007.33333333333331,766
2007.66666666666671,762
2008.08333333333331,764
2008.41666666666671,768
2008.751,770
2009.08333333333331,771
2009.41666666666671,774
2009.751,778
2010.08333333333331,779
2010.41666666666671,783
2010.751,779
2011.08333333333331,780
2011.41666666666671,784
2011.751,779
2012.08333333333331,780
2012.41666666666671,779
2012.751,771
2013.08333333333331,772
2013.51,771
2013.83333333333331,770
2014.16666666666671,770
2014.51,778
2014.83333333333331,778
2015.16666666666671,778
2015.51,781
2015.83333333333331,780
2016.16666666666671,781
2016.51,783
2016.83333333333331,781
2017.16666666666671,782
2017.51,783
2017.83333333333331,780
2018.16666666666671,780
2018.51,779
2018.91666666666671,777
2019.251,777
2019.58333333333331,782
2019.91666666666671,781
2020.251,783
2020.58333333333331,778
2020.91666666666671,777
2021.251,777
2021.58333333333331,778
2021.91666666666671,777
2022.251,777
2022.58333333333331,771
2022.91666666666671,769
2023.251,770
2023.58333333333331,778
2023.91666666666671,778
2024.33333333333331,780
2024.66666666666671,776
20251,776
2025.33333333333331,776
2025.66666666666671,769
20261,770
2026.33333333333331,769
2026.66666666666671,763

Rate and persistence

-14.18 Mm³
Mean drawdown per month over 12 months
5 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

Pathfinder Reservoir
Gauge location
Pathfinder ReservoirPathfinder Reservoir — 219.22 Mm³Pathfinder Reservoir — 219.22 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 held1945–2026
Completeness98.8% 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.
Continuity99% of the months between 1945 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), Pathfinder Reservoir reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usbr-433/

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 Pathfinder Reservoir 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

972 monthly observations 1945–2026 Mm³
Spatially aggregatedHigh confidenceSeptember 2026

Source: USBR — Reservoir operations and Colorado River data, RISE catalogue item 644. 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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