Enders Reservoir — storage

Storage now, against this reservoir's own record

10.08 Mm³

Stored, August 2026

3rd

Percentile among 75 Augs on record

-42.8%

Against the Aug 1991–2020 average

-1.5%

Change over the 12 months to 2026-08

Storage in August 2026 was lower than almost every other Aug on record, ranked against 75 other Augs held for this reservoir.

Storage, 1951–2026

Monthly mean storage

899 monthly values, 1951 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 899 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 899 would be longer than this page and unusable with a screen reader.
Period	Enders Reservoir (Mm³)
October 1951	44.7
February 1952	54.3
June 1952	42.6
September 1952	35.4
January 1953	38.8
May 1953	42.9
September 1953	34.0
December 1953	39.6
April 1954	53.1
August 1954	46.2
December 1954	45.9
March 1955	54.1
July 1955	51.2
November 1955	41.8
March 1956	53.3
June 1956	53.1
October 1956	40.4
February 1957	49.6
June 1957	53.2
September 1957	46.7
January 1958	54.5
May 1958	55.0
September 1958	52.1
December 1958	51.4
April 1959	56.5
August 1959	44.2
December 1959	47.7
March 1960	60.6
July 1960	53.9
November 1960	44.1
March 1961	54.6
June 1961	55.2
October 1961	28.7
February 1962	47.6
June 1962	57.5
October 1962	26.6
January 1963	40.5
May 1963	53.5
September 1963	19.2
January 1964	38.6
April 1964	51.2
August 1964	27.3
December 1964	32.5
April 1965	49.6
July 1965	55.5
November 1965	39.8
March 1966	56.5
July 1966	44.2
October 1966	32.3
February 1967	50.8
June 1967	56.2
October 1967	30.0
January 1968	44.7
May 1968	55.8
September 1968	17.1
January 1969	35.7
April 1969	47.3
August 1969	23.6
December 1969	29.5
April 1970	45.1
July 1970	34.7
November 1970	21.8
March 1971	38.9
July 1971	40.7
October 1971	17.0
February 1972	34.5
June 1972	45.5
October 1972	17.5
January 1973	32.4
May 1973	47.0
September 1973	12.6
January 1974	32.0
May 1974	45.0
August 1974	19.8
December 1974	28.0
April 1975	41.7
August 1975	21.8
November 1975	23.8
March 1976	38.3
July 1976	36.5
November 1976	21.1
February 1977	31.4
June 1977	42.5
October 1977	17.7
February 1978	30.6
May 1978	37.9
September 1978	12.5
January 1979	23.3
May 1979	33.2
August 1979	19.1
December 1979	23.5
April 1980	34.2
August 1980	14.3
November 1980	19.8
March 1981	29.4
July 1981	30.6
November 1981	24.8
February 1982	32.0
June 1982	40.7
October 1982	25.5
February 1983	36.1
May 1983	43.4
September 1983	20.2
January 1984	30.5
May 1984	41.3
September 1984	18.7
December 1984	26.2
April 1985	35.7
August 1985	21.8
December 1985	24.5
March 1986	31.4
July 1986	28.5
November 1986	22.9
March 1987	31.3
June 1987	36.6
October 1987	20.1
February 1988	29.1
June 1988	35.3
September 1988	18.7
January 1989	26.1
May 1989	32.9
September 1989	16.8
December 1989	22.2
April 1990	29.7
August 1990	13.2
December 1990	19.5
March 1991	24.6
July 1991	22.4
November 1991	19.1
March 1992	26.3
June 1992	29.1
October 1992	22.0
February 1993	28.4
June 1993	34.9
September 1993	26.0
January 1994	33.1
May 1994	39.2
September 1994	25.2
January 1995	31.4
April 1995	36.1
August 1995	26.8
December 1995	28.0
April 1996	34.2
July 1996	33.1
November 1996	31.0
March 1997	37.3
July 1997	34.4
October 1997	26.5
February 1998	32.3
June 1998	35.9
October 1998	21.2
January 1999	23.7
May 1999	28.5
September 1999	19.5
January 2000	24.3
April 2000	28.4
August 2000	11.6
December 2000	15.6
April 2001	20.3
July 2001	16.3
November 2001	13.6
March 2002	17.2
July 2002	14.8
October 2002	12.9
February 2003	15.1
June 2003	16.9
October 2003	13.5
January 2004	14.1
May 2004	15.0
September 2004	13.9
January 2005	14.5
May 2005	15.4
August 2005	14.8
December 2005	14.1
April 2006	14.8
August 2006	13.6
November 2006	13.2
March 2007	14.5
July 2007	24.9
November 2007	20.9
February 2008	20.8
June 2008	21.0
October 2008	18.7
February 2009	19.2
May 2009	19.6
September 2009	18.7
January 2010	19.4
May 2010	20.8
August 2010	20.5
December 2010	20.5
April 2011	22.0
August 2011	22.4
November 2011	21.2
March 2012	22.4
July 2012	21.2
November 2012	18.5
February 2013	18.9
June 2013	18.6
October 2013	16.4
February 2014	16.6
May 2014	13.9
September 2014	11.0
January 2015	11.5
May 2015	12.9
August 2015	12.8
December 2015	12.4
April 2016	13.6
August 2016	12.9
December 2016	12.5
March 2017	13.2
July 2017	11.1
November 2017	10.4
March 2018	11.4
June 2018	11.9
October 2018	11.1
February 2019	11.8
June 2019	12.9
September 2019	12.2
January 2020	12.2
May 2020	12.9
September 2020	10.9
December 2020	10.6
April 2021	11.6
August 2021	10.7
December 2021	9.81
March 2022	10.3
July 2022	9.45
November 2022	7.92
March 2023	8.88
June 2023	10.4
October 2023	9.37
February 2024	10.2
June 2024	10.8
September 2024	9.67
January 2025	9.74
May 2025	10.2
September 2025	10.3
December 2025	10.2
April 2026	10.6
August 2026	10.1

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	19.7	10.4
Feb	20.4	10.6
Mar	21.2	10.6
Apr	21.8	10.6
May	22.3	10.7
Jun	22.7	10.7
Jul	20.4	10.5
Aug	17.6	10.1
Sep	17.2	10.3
Oct	17.4	10.2
Nov	18.0	10.2
Dec	18.6	10.2

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

910 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 910 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 910 would be longer than this page and unusable with a screen reader.
Period	Enders Reservoir (m)
1950.8333333333333	934
1951.1666666666667	942
1951.5	946
1951.75	947
1952.0833333333333	949
1952.4166666666667	947
1952.75	945
1953.0833333333333	946
1953.3333333333333	947
1953.6666666666667	945
1954	947
1954.3333333333333	948
1954.6666666666667	947
1954.9166666666667	947
1955.25	948
1955.5833333333333	947
1955.9166666666667	947
1956.25	949
1956.5	948
1956.8333333333333	947
1957.1666666666667	948
1957.5	948
1957.8333333333333	947
1958.0833333333333	948
1958.4166666666667	949
1958.75	948
1959.0833333333333	948
1959.4166666666667	949
1959.6666666666667	946
1960	948
1960.3333333333333	949
1960.6666666666667	947
1961	948
1961.3333333333333	949
1961.5833333333333	945
1961.9166666666667	946
1962.25	949
1962.5833333333333	947
1962.9166666666667	945
1963.1666666666667	948
1963.5	946
1963.8333333333333	944
1964.1666666666667	947
1964.5	947
1964.75	943
1965.0833333333333	947
1965.4166666666667	948
1965.75	945
1966.0833333333333	948
1966.3333333333333	949
1966.6666666666667	944
1967	947
1967.3333333333333	949
1967.6666666666667	943
1967.9166666666667	946
1968.25	949
1968.5833333333333	943
1968.9166666666667	944
1969.25	947
1969.5	947
1969.8333333333333	943
1970.1666666666667	946
1970.5	945
1970.8333333333333	942
1971.0833333333333	945
1971.4166666666667	948
1971.75	941
1972.0833333333333	945
1972.4166666666667	947
1972.6666666666667	940
1973	945
1973.3333333333333	947
1973.6666666666667	940
1974	945
1974.25	947
1974.5833333333333	942
1974.9166666666667	944
1975.25	947
1975.5833333333333	942
1975.8333333333333	943
1976.1666666666667	946
1976.5	946
1976.8333333333333	942
1977.1666666666667	945
1977.4166666666667	947
1977.75	941
1978.0833333333333	944
1978.4166666666667	946
1978.75	940
1979	943
1979.3333333333333	945
1979.6666666666667	941
1980	943
1980.3333333333333	946
1980.6666666666667	940
1980.9166666666667	943
1981.25	945
1981.5833333333333	943
1981.9166666666667	944
1982.25	945
1982.5	946
1982.8333333333333	944
1983.1666666666667	946
1983.5	946
1983.8333333333333	943
1984.0833333333333	945
1984.4166666666667	947
1984.75	942
1985.0833333333333	945
1985.4166666666667	946
1985.6666666666667	941
1986	944
1986.3333333333333	945
1986.6666666666667	942
1987	944
1987.25	945
1987.5833333333333	942
1987.9166666666667	943
1988.25	945
1988.5833333333333	942
1988.8333333333333	943
1989.1666666666667	944
1989.5	944
1989.8333333333333	942
1990.1666666666667	944
1990.4166666666667	945
1990.75	941
1991.0833333333333	943
1991.4166666666667	944
1991.75	941
1992	943
1992.3333333333333	944
1992.6666666666667	942
1993	944
1993.3333333333333	945
1993.5833333333333	944
1993.9166666666667	945
1994.25	946
1994.5833333333333	943
1994.9166666666667	944
1995.1666666666667	945
1995.5	946
1995.8333333333333	944
1996.1666666666667	945
1996.5	945
1996.75	944
1997.0833333333333	945
1997.4166666666667	946
1997.75	944
1998.0833333333333	945
1998.4166666666667	945
1998.6666666666667	942
1999	943
1999.3333333333333	944
1999.6666666666667	942
2000	943
2000.25	944
2000.5833333333333	940
2000.9166666666667	941
2001.25	943
2001.5833333333333	940
2001.8333333333333	940
2002.1666666666667	942
2002.5	941
2002.8333333333333	940
2003.1666666666667	941
2003.4166666666667	942
2003.75	940
2004.0833333333333	941
2004.4166666666667	941
2004.75	941
2005	941
2005.3333333333333	941
2005.6666666666667	941
2006	941
2006.3333333333333	941
2006.5833333333333	940
2006.9166666666667	940
2007.25	941
2007.5833333333333	943
2007.9166666666667	943
2008.1666666666667	943
2008.5	943
2008.8333333333333	942
2009.1666666666667	942
2009.5	942
2009.75	942
2010.0833333333333	942
2010.4166666666667	943
2010.75	942
2011.0833333333333	943
2011.3333333333333	943
2011.6666666666667	943
2012	943
2012.3333333333333	943
2012.6666666666667	942
2012.9166666666667	942
2013.25	942
2013.5833333333333	942
2013.9166666666667	941
2014.25	941
2014.5	940
2014.8333333333333	939
2015.1666666666667	940
2015.5	940
2015.8333333333333	940
2016.0833333333333	940
2016.4166666666667	941
2016.75	940
2017.0833333333333	940
2017.4166666666667	940
2017.75	939
2018	939
2018.3333333333333	940
2018.6666666666667	940
2019	940
2019.3333333333333	940
2019.5833333333333	940
2019.9166666666667	940
2020.25	940
2020.5833333333333	940
2020.9166666666667	939
2021.1666666666667	940
2021.5	940
2021.8333333333333	939
2022.1666666666667	939
2022.5	939
2022.75	938
2023.0833333333333	938
2023.4166666666667	939
2023.75	939
2024.0833333333333	939
2024.3333333333333	939
2024.6666666666667	939
2025	939
2025.3333333333333	939
2025.6666666666667	939
2025.9166666666667	939
2026.25	939
2026.5833333333333	939

Rate and persistence

-0.01 Mm³

Mean drawdown per month over 12 months

24 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

Enders Reservoir

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	1951–2026
Completeness	98.6% 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.
Continuity	99% of the months between 1951 and 2026 are held. Monthly means of the publisher's own daily record.
Last read from the publisher	2026-09-01
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-3656.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), Enders Reservoir reservoir records, accessed 2026-09-02, hydrionis.com/reservoirs/reservoir-usbr-3656/

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 Enders 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

899 monthly observations 1951–2026 Mm³

Spatially aggregatedHigh confidenceAugust 2026

Source: USBR — Reservoir operations and Colorado River data, RISE catalogue item 133983. 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.