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

242.19 Mm³
Stored, August 2026
13th
Percentile among 81 Augs on record
-65.7%
Against the Aug 1991–2020 average
-48.5%
Change over the 12 months to 2026-08

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

Storage, 1945–2026

Monthly mean storage
971 monthly values, 1945 to 2026
Monthly mean storageMonthly mean storage: Pathfinder Reservoir in Mm³, from 1945.75 to 2026.5833333333333.05001,0001,500Mm³1945.751955.91666666666671966.08333333333331976.251986.41666666666671996.58333333333332006.752016.9166666666667Year

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 971 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 971 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
June 1948745
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
November 1953727
March 19541,065
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
April 1959240
August 1959217
December 1959119
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
September 1964101
January 196596.8
May 1965206
September 1965209
February 1966545
June 1966430
October 1966202
February 1967221
June 1967297
October 1967330
February 1968437
June 1968489
October 1968222
February 1969422
June 1969377
October 1969103
February 1970319
June 1970570
October 1970665
February 1971987
June 19711,106
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
July 19751,137
November 1975888
March 19761,061
July 19761,025
November 1976787
March 1977916
August 1977447
December 1977408
April 1978632
August 1978696
December 1978633
April 1979928
August 1979777
December 1979743
April 19801,101
August 1980884
December 1980748
April 1981980
August 1981667
December 1981532
April 1982742
August 1982590
December 1982628
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
May 19861,226
September 19861,076
January 19871,066
May 19871,160
September 1987894
January 1988941
May 19881,127
September 1988640
January 1989732
June 1989717
October 1989350
February 1990422
June 1990517
October 1990297
February 1991344
June 1991409
October 1991366
February 1992380
June 1992349
October 1992242
February 1993254
June 1993317
October 1993396
February 1994485
June 1994542
October 1994293
March 1995340
July 1995695
November 1995843
March 19961,009
July 19961,146
November 1996986
March 19971,107
July 19971,166
November 19971,093
March 19981,213
July 19981,174
November 1998997
March 19991,170
July 19991,227
November 19991,138
March 20001,212
July 20001,050
December 2000847
April 2001954
August 2001669
December 2001592
April 2002678
August 2002381
December 2002406
April 2003442
August 2003350
December 2003381
April 2004415
August 2004243
December 2004286
April 2005293
August 2005292
December 2005337
April 2006355
September 2006252
January 2007292
May 2007323
September 2007211
January 2008251
May 2008254
September 2008429
January 2009484
May 2009546
September 2009849
January 2010901
May 20101,056
September 2010943
January 2011963
May 20111,223
September 2011917
January 2012936
June 2012930
October 2012492
February 2013523
June 2013493
October 2013407
February 2014457
June 2014785
October 2014810
February 2015855
June 20151,002
October 2015950
February 20161,058
June 20161,339
October 20161,091
February 20171,137
June 20171,272
October 2017992
March 20181,035
July 2018945
November 2018765
March 2019791
July 20191,274
November 20191,070
March 20201,139
July 2020987
November 2020811
March 2021769
July 2021922
November 2021787
March 2022815
July 2022696
November 2022407
March 2023444
July 2023861
December 2023861
April 2024891
August 2024819
December 2024738
April 2025735
August 2025470
December 2025421
April 2026418
August 2026242

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: 389 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
Sep652389
Oct661400
Nov680415
Dec691421

Why this page shows a volume and not a percentage

Water level

Monthly mean water surface elevation
971 monthly values
Monthly mean water surface elevationMonthly mean water surface elevation: Pathfinder Reservoir in m, from 1945.75 to 2026.5833333333333.1,7401,7601,780m1945.751955.91666666666671966.08333333333331976.251986.41666666666671996.58333333333332006.752016.9166666666667Year

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 971 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 971 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
1948.41666666666671,776
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
1953.83333333333331,776
1954.16666666666671,781
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
1959.251,763
1959.58333333333331,762
1959.91666666666671,758
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
1964.66666666666671,756
19651,756
1965.33333333333331,762
1965.66666666666671,762
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
1970.08333333333331,766
1970.41666666666671,773
1970.751,775
1971.08333333333331,780
1971.41666666666671,781
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
1975.51,782
1975.83333333333331,779
1976.16666666666671,781
1976.51,780
1976.83333333333331,777
1977.16666666666671,779
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
1980.91666666666671,776
1981.251,780
1981.58333333333331,775
1981.91666666666671,772
1982.251,776
1982.58333333333331,773
1982.91666666666671,774
1983.33333333333331,781
1983.66666666666671,781
19841,781
1984.33333333333331,782
1984.66666666666671,781
19851,781
1985.33333333333331,781
1985.66666666666671,777
19861,778
1986.33333333333331,783
1986.66666666666671,781
19871,781
1987.33333333333331,782
1987.66666666666671,779
19881,779
1988.33333333333331,782
1988.66666666666671,774
19891,776
1989.41666666666671,776
1989.751,767
1990.08333333333331,769
1990.41666666666671,772
1990.751,766
1991.08333333333331,767
1991.41666666666671,769
1991.751,768
1992.08333333333331,768
1992.41666666666671,767
1992.751,763
1993.08333333333331,764
1993.41666666666671,766
1993.751,769
1994.08333333333331,771
1994.41666666666671,772
1994.751,765
1995.16666666666671,767
1995.51,775
1995.83333333333331,778
1996.16666666666671,780
1996.51,782
1996.83333333333331,780
1997.16666666666671,781
1997.51,782
1997.83333333333331,781
1998.16666666666671,783
1998.51,782
1998.83333333333331,780
1999.16666666666671,782
1999.51,783
1999.83333333333331,782
2000.16666666666671,783
2000.51,781
2000.91666666666671,778
2001.251,779
2001.58333333333331,775
2001.91666666666671,773
2002.251,775
2002.58333333333331,768
2002.91666666666671,769
2003.251,770
2003.58333333333331,767
2003.91666666666671,768
2004.251,769
2004.58333333333331,764
2004.91666666666671,765
2005.251,765
2005.58333333333331,765
2005.91666666666671,767
2006.251,767
2006.66666666666671,764
20071,765
2007.33333333333331,766
2007.66666666666671,762
20081,764
2008.33333333333331,764
2008.66666666666671,770
20091,771
2009.33333333333331,772
2009.66666666666671,778
20101,779
2010.33333333333331,781
2010.66666666666671,779
20111,780
2011.33333333333331,783
2011.66666666666671,779
20121,779
2012.41666666666671,779
2012.751,771
2013.08333333333331,772
2013.41666666666671,771
2013.751,769
2014.08333333333331,770
2014.41666666666671,777
2014.751,777
2015.08333333333331,778
2015.41666666666671,780
2015.751,779
2016.08333333333331,781
2016.41666666666671,784
2016.751,781
2017.08333333333331,782
2017.41666666666671,783
2017.751,780
2018.16666666666671,780
2018.51,779
2018.83333333333331,777
2019.16666666666671,777
2019.51,783
2019.83333333333331,781
2020.16666666666671,782
2020.51,780
2020.83333333333331,777
2021.16666666666671,777
2021.51,779
2021.83333333333331,777
2022.16666666666671,777
2022.51,775
2022.83333333333331,769
2023.16666666666671,770
2023.51,778
2023.91666666666671,778
2024.251,779
2024.58333333333331,777
2024.91666666666671,776
2025.251,776
2025.58333333333331,771
2025.91666666666671,769
2026.251,769
2026.58333333333331,763

Rate and persistence

-18.97 Mm³
Mean drawdown per month over 12 months
4 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 — 242.19 Mm³Pathfinder Reservoir — 242.19 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
Completeness98.7% 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 publisher2026-09-01
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 2026-09-02, 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

971 monthly observations 1945–2026 Mm³
Spatially aggregatedHigh confidenceAugust 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 September 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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