Lake Havasu — storage

Storage now, against this reservoir's own record

641.29 Mm³

Stored, September 2026

4th

Percentile among 83 Seps on record

-10.0%

Against the Sep 1991–2020 average

-11.0%

Change over the 12 months to 2026-09

Storage in September 2026 was lower than almost every other Sep on record, ranked against 83 other Seps held for this reservoir.

Storage, 1938–2026

Monthly mean storage

1,037 monthly values, 1938 to 2026

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 1,037 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 1,037 would be longer than this page and unusable with a screen reader.
Period	Lake Havasu (Mm³)
October 1938	91.5
February 1939	589
July 1939	592
November 1939	648
March 1940	617
August 1940	591
December 1940	531
April 1941	492
September 1941	545
January 1942	502
May 1942	421
October 1942	592
February 1943	735
June 1943	800
November 1943	763
March 1944	754
July 1944	839
December 1944	718
April 1945	784
August 1945	799
January 1946	722
May 1946	830
September 1946	797
February 1947	768
June 1947	830
October 1947	774
March 1948	726
July 1948	831
November 1948	763
April 1949	773
August 1949	806
December 1949	802
May 1950	836
September 1950	777
January 1951	761
June 1951	805
October 1951	747
February 1952	734
August 1952	769
June 1953	832
November 1953	766
June 1954	837
November 1954	762
May 1955	839
December 1955	748
April 1956	795
August 1956	789
February 1957	749
July 1957	820
December 1957	727
May 1958	816
October 1958	688
February 1959	672
July 1959	724
November 1959	688
March 1960	670
August 1960	706
December 1960	687
April 1961	713
September 1961	676
January 1962	668
May 1962	739
October 1962	686
February 1963	660
June 1963	734
November 1963	666
March 1964	662
July 1964	713
December 1964	665
April 1965	673
August 1965	685
January 1966	675
May 1966	738
September 1966	692
February 1967	660
June 1967	741
October 1967	675
March 1968	671
July 1968	731
November 1968	670
April 1969	715
August 1969	704
December 1969	672
May 1970	744
September 1970	697
January 1971	665
June 1971	746
October 1971	689
February 1972	668
July 1972	735
November 1972	672
March 1973	683
August 1973	730
December 1973	678
April 1974	714
September 1974	700
January 1975	671
May 1975	743
October 1975	685
February 1976	678
June 1976	747
November 1976	692
March 1977	685
July 1977	735
December 1977	674
April 1978	711
August 1978	702
January 1979	673
May 1979	696
September 1979	685
February 1980	678
June 1980	718
October 1980	680
March 1981	686
July 1981	738
November 1981	682
April 1982	719
August 1982	719
December 1982	691
May 1983	741
September 1983	668
February 1984	683
June 1984	683
October 1984	682
March 1985	682
July 1985	704
November 1985	692
April 1986	696
August 1986	723
December 1986	702
May 1987	747
September 1987	710
January 1988	680
June 1988	742
October 1988	685
February 1989	673
July 1989	729
November 1989	683
March 1990	675
August 1990	721
December 1990	671
April 1991	722
September 1991	714
January 1992	693
May 1992	748
October 1992	666
February 1993	723
June 1993	744
November 1993	688
March 1994	699
July 1994	729
December 1994	697
April 1995	692
August 1995	712
January 1996	681
May 1996	735
September 1996	737
February 1997	724
June 1997	743
October 1997	700
March 1998	693
July 1998	702
November 1998	671
April 1999	712
August 1999	734
December 1999	687
May 2000	718
September 2000	700
January 2001	709
June 2001	696
October 2001	703
February 2002	685
July 2002	705
November 2002	698
March 2003	687
August 2003	733
December 2003	679
April 2004	691
September 2004	723
January 2005	713
May 2005	727
October 2005	703
February 2006	689
June 2006	686
November 2006	705
March 2007	685
July 2007	705
December 2007	705
April 2008	680
August 2008	693
January 2009	681
May 2009	739
September 2009	720
February 2010	711
June 2010	730
October 2010	723
March 2011	707
July 2011	715
November 2011	720
April 2012	720
August 2012	727
December 2012	692
May 2013	724
September 2013	728
January 2014	666
June 2014	726
October 2014	724
February 2015	694
July 2015	728
November 2015	687
March 2016	707
August 2016	724
December 2016	682
April 2017	716
September 2017	713
January 2018	678
May 2018	709
October 2018	726
February 2019	711
June 2019	722
November 2019	716
March 2020	720
July 2020	709
December 2020	685
April 2021	697
August 2021	717
January 2022	685
May 2022	714
September 2022	714
February 2023	702
June 2023	711
October 2023	718
March 2024	695
July 2024	726
November 2024	706
April 2025	709
August 2025	716
December 2025	638
May 2026	666
September 2026	641

The reservoir's year

Seasonal storage profile

Each calendar month's reference average, against the most recent year

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
Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	689	638
Feb	692	632
Mar	698	637
Apr	705	653
May	726	666
Jun	728	664
Jul	721	665
Aug	716	659
Sep	713	641
Oct	704	646
Nov	699	663
Dec	693	638

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.

Water level

Monthly mean water surface elevation

1,000 monthly values

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 1,000 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 1,000 would be longer than this page and unusable with a screen reader.
Period	Lake Havasu (m)
1938.9166666666667	135
1939.25	135
1939.5833333333333	135
1940	136
1940.3333333333333	135
1940.6666666666667	135
1942.1666666666667	135
1943	136
1944	137
1944.75	137
1945.0833333333333	137
1945.9166666666667	137
1946.6666666666667	137
1947	136
1947.4166666666667	137
1947.75	136
1948.0833333333333	136
1948.4166666666667	137
1948.75	136
1949.0833333333333	135
1949.5	137
1949.8333333333333	136
1950.1666666666667	137
1950.5	137
1951	137
1951.5833333333333	137
1952	136
1952.3333333333333	137
1952.6666666666667	136
1953.3333333333333	137
1953.6666666666667	136
1954.0833333333333	136
1954.5	137
1954.9166666666667	136
1955.25	137
1955.5833333333333	137
1955.9166666666667	137
1956.3333333333333	137
1956.6666666666667	137
1957	136
1957.3333333333333	137
1957.6666666666667	136
1958.0833333333333	136
1958.4166666666667	137
1958.75	136
1959.0833333333333	136
1959.4166666666667	137
1959.75	136
1960.1666666666667	136
1960.5	137
1960.8333333333333	136
1961.1666666666667	136
1961.5	137
1961.9166666666667	136
1962.25	136
1962.5833333333333	136
1962.9166666666667	136
1963.25	136
1963.5833333333333	136
1964	136
1964.3333333333333	137
1964.6666666666667	136
1965	136
1965.3333333333333	137
1965.75	136
1966.0833333333333	136
1966.4166666666667	137
1966.75	136
1967.0833333333333	136
1967.4166666666667	137
1967.8333333333333	136
1968.1666666666667	136
1968.5	137
1968.8333333333333	136
1969.1666666666667	136
1969.5	137
1969.9166666666667	136
1970.25	136
1970.5833333333333	137
1970.9166666666667	136
1971.25	137
1971.6666666666667	136
1972	136
1972.3333333333333	137
1972.6666666666667	136
1973	136
1973.3333333333333	137
1973.75	136
1974.0833333333333	136
1974.4166666666667	137
1974.75	136
1975.0833333333333	136
1975.5	137
1975.8333333333333	136
1976.1666666666667	136
1976.5	137
1976.8333333333333	136
1977.1666666666667	136
1977.5833333333333	137
1977.9166666666667	136
1978.25	136
1978.5833333333333	136
1978.9166666666667	136
1979.3333333333333	136
1979.6666666666667	136
1980	136
1980.3333333333333	137
1980.6666666666667	136
1981	136
1981.4166666666667	137
1981.75	136
1982.0833333333333	136
1982.4166666666667	137
1982.75	136
1983.1666666666667	136
1983.5	136
1983.8333333333333	136
1984.1666666666667	136
1984.5	136
1984.8333333333333	136
1985.25	136
1985.5833333333333	136
1985.9166666666667	136
1986.25	136
1986.5833333333333	137
1986.9166666666667	136
1987.3333333333333	137
1987.6666666666667	136
1988	136
1988.3333333333333	137
1988.6666666666667	136
1989.0833333333333	136
1989.4166666666667	137
1989.75	136
1990.0833333333333	136
1990.4166666666667	137
1990.75	136
1991.1666666666667	136
1991.5	137
1991.8333333333333	136
1992.1666666666667	136
1992.5	137
1992.9166666666667	136
1993.25	137
1993.5833333333333	137
1993.9166666666667	136
1994.25	136
1994.5833333333333	136
1995	136
1995.3333333333333	137
1995.6666666666667	137
1996	136
1996.3333333333333	137
1996.75	137
1997.0833333333333	137
1997.4166666666667	137
1997.75	136
1998.0833333333333	136
1998.4166666666667	137
1998.8333333333333	136
1999.1666666666667	136
1999.5	137
1999.8333333333333	136
2000.1666666666667	136
2000.5833333333333	137
2000.9166666666667	136
2001.25	137
2001.5833333333333	137
2001.9166666666667	136
2002.25	137
2002.6666666666667	136
2003	136
2003.3333333333333	137
2003.6666666666667	136
2004	135
2004.3333333333333	136
2004.75	137
2005.0833333333333	137
2005.4166666666667	137
2005.75	136
2006.0833333333333	136
2006.5	136
2006.8333333333333	136
2007.1666666666667	136
2007.5	136
2007.8333333333333	136
2008.1666666666667	136
2008.5833333333333	136
2008.9166666666667	136
2009.25	136
2009.5833333333333	136
2009.9166666666667	136
2010.3333333333333	137
2010.6666666666667	136
2011	136
2011.3333333333333	137
2011.6666666666667	137
2012	136
2012.4166666666667	137
2012.75	137
2013.0833333333333	137
2013.4166666666667	137
2013.75	136
2014.1666666666667	137
2014.5	137
2014.8333333333333	136
2015.1666666666667	137
2015.5	137
2015.8333333333333	136
2016.25	137
2016.5833333333333	137
2016.9166666666667	136
2017.25	137
2017.5833333333333	137
2018	136
2018.3333333333333	136
2018.6666666666667	136
2019	136
2019.3333333333333	137
2019.6666666666667	137
2020.0833333333333	136
2020.4166666666667	137
2020.75	136
2021.0833333333333	136
2021.4166666666667	137
2021.75	137
2022.1666666666667	136
2022.5	137
2022.8333333333333	136
2023.1666666666667	136
2023.5	137
2023.9166666666667	136
2024.25	136
2024.5833333333333	137
2024.9166666666667	136
2025.25	136
2025.5833333333333	137
2026	136
2026.3333333333333	137
2026.6666666666667	136

Rate and persistence

-6.64 Mm³

Mean drawdown per month over 12 months

12 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

Lake Havasu

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 Bureau of Reclamation — Reservoir operations and Colorado River data · US Government work — public domain
How the values came to exist	Measured
Period held	1938–2026
Completeness	97.1% 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	97% of the months between 1938 and 2026 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-usbr-3515.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), Lake Havasu reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usbr-3515/

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 Lake Havasu 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

1,037 monthly observations 1938–2026 Mm³

Spatially aggregatedHigh confidenceSeptember 2026

Source: USBR — Reservoir operations and Colorado River data, RISE catalogue item 6129. 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.

Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	689	638
Feb	692	632
Mar	698	637
Apr	705	653
May	726	666
Jun	728	664
Jul	721	665
Aug	716	659
Sep	713	641
Oct	704	646
Nov	699	663
Dec	693	638

Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	689	638
Feb	692	632
Mar	698	637
Apr	705	653
May	726	666
Jun	728	664
Jul	721	665
Aug	716	659
Sep	713	641
Oct	704	646
Nov	699	663
Dec	693	638

Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	689	638
Feb	692	632
Mar	698	637
Apr	705	653
May	726	666
Jun	728	664
Jul	721	665
Aug	716	659
Sep	713	641
Oct	704	646
Nov	699	663
Dec	693	638