Enders Reservoir — storage

Storage now, against this reservoir's own record

9.59 Mm³

Stored, September 2026

1st

Percentile among 75 Seps on record

-44.1%

Against the Sep 1991–2020 average

-6.6%

Change over the 12 months to 2026-09

Storage in September 2026 was lower than almost every other Sep on record, ranked against 75 other Seps held for this reservoir.

Storage, 1951–2026

Monthly mean storage

900 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 900 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 900 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
January 1959	52.7
April 1959	56.5
August 1959	44.2
December 1959	47.7
April 1960	60.5
July 1960	53.9
November 1960	44.1
March 1961	54.6
July 1961	47.1
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
August 1965	37.8
November 1965	39.8
March 1966	56.5
July 1966	44.2
November 1966	37.3
February 1967	50.8
June 1967	56.2
October 1967	30.0
February 1968	49.3
May 1968	55.8
September 1968	17.1
January 1969	35.7
May 1969	50.3
August 1969	23.6
December 1969	29.5
April 1970	45.1
August 1970	16.5
November 1970	21.8
March 1971	38.9
July 1971	40.7
November 1971	21.6
February 1972	34.5
June 1972	45.5
October 1972	17.5
February 1973	36.8
June 1973	48.7
September 1973	12.6
January 1974	32.0
May 1974	45.0
September 1974	17.3
December 1974	28.0
April 1975	41.7
August 1975	21.8
December 1975	28.0
March 1976	38.3
July 1976	36.5
November 1976	21.1
March 1977	34.5
June 1977	42.5
October 1977	17.7
February 1978	30.6
June 1978	38.8
September 1978	12.5
January 1979	23.3
May 1979	33.2
September 1979	16.0
January 1980	26.1
April 1980	34.2
August 1980	14.3
December 1980	22.2
April 1981	31.7
July 1981	30.6
November 1981	24.8
March 1982	34.1
July 1982	38.6
October 1982	25.5
February 1983	36.1
June 1983	45.4
October 1983	21.5
January 1984	30.5
May 1984	41.3
September 1984	18.7
January 1985	29.1
April 1985	35.7
August 1985	21.8
December 1985	24.5
April 1986	33.0
August 1986	18.9
November 1986	22.9
March 1987	31.3
July 1987	29.8
November 1987	22.4
February 1988	29.1
June 1988	35.3
October 1988	20.5
February 1989	28.2
May 1989	32.9
September 1989	16.8
January 1990	24.2
May 1990	31.1
August 1990	13.2
December 1990	19.5
April 1991	26.3
August 1991	15.8
November 1991	19.1
March 1992	26.3
July 1992	25.7
November 1992	23.3
March 1993	30.2
June 1993	34.9
October 1993	27.5
February 1994	34.9
June 1994	38.2
September 1994	25.2
January 1995	31.4
May 1995	38.0
September 1995	23.4
December 1995	28.0
April 1996	34.2
August 1996	28.4
December 1996	32.6
March 1997	37.3
July 1997	34.4
November 1997	27.8
March 1998	33.7
June 1998	35.9
October 1998	21.2
February 1999	24.9
June 1999	29.5
October 1999	20.6
January 2000	24.3
May 2000	29.2
September 2000	11.9
January 2001	16.8
April 2001	20.3
August 2001	11.4
December 2001	14.3
April 2002	18.0
July 2002	14.8
November 2002	13.5
March 2003	15.7
July 2003	15.9
October 2003	13.5
February 2004	14.4
June 2004	14.7
October 2004	13.9
January 2005	14.5
May 2005	15.4
September 2005	14.2
January 2006	14.4
May 2006	14.7
August 2006	13.6
December 2006	13.4
April 2007	14.8
August 2007	23.7
November 2007	20.9
March 2008	20.8
July 2008	20.4
November 2008	18.9
February 2009	19.2
June 2009	19.8
October 2009	18.6
February 2010	19.6
May 2010	20.8
September 2010	20.1
January 2011	20.9
May 2011	22.5
August 2011	22.4
December 2011	21.4
April 2012	22.7
August 2012	20.1
November 2012	18.5
March 2013	19.1
July 2013	18.0
November 2013	16.3
March 2014	16.6
June 2014	11.2
October 2014	10.9
February 2015	11.8
June 2015	13.5
September 2015	12.3
January 2016	12.7
May 2016	14.1
September 2016	12.6
December 2016	12.5
April 2017	11.8
August 2017	10.9
December 2017	10.6
March 2018	11.4
July 2018	11.5
November 2018	11.2
March 2019	12.0
June 2019	12.9
October 2019	11.8
February 2020	12.4
June 2020	12.6
October 2020	10.5
January 2021	10.8
May 2021	11.8
September 2021	10.3
January 2022	9.99
April 2022	10.3
August 2022	8.97
December 2022	7.96
April 2023	8.98
July 2023	10.5
November 2023	9.38
March 2024	10.5
July 2024	10.3
October 2024	9.29
February 2025	9.85
June 2025	10.4
October 2025	10.2
January 2026	10.4
May 2026	10.7
September 2026	9.59

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	9.59
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

911 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 911 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 911 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
1956.5833333333333	948
1956.8333333333333	947
1957.1666666666667	948
1957.5	948
1957.8333333333333	947
1958.1666666666667	949
1958.4166666666667	949
1958.75	948
1959.0833333333333	948
1959.4166666666667	949
1959.75	947
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
1964.8333333333333	944
1965.0833333333333	947
1965.4166666666667	948
1965.75	945
1966.0833333333333	948
1966.4166666666667	949
1966.6666666666667	944
1967	947
1967.3333333333333	949
1967.6666666666667	943
1968	947
1968.25	949
1968.5833333333333	943
1968.9166666666667	944
1969.25	947
1969.5833333333333	943
1969.8333333333333	943
1970.1666666666667	946
1970.5	945
1970.8333333333333	942
1971.1666666666667	946
1971.4166666666667	948
1971.75	941
1972.0833333333333	945
1972.4166666666667	947
1972.75	941
1973.0833333333333	946
1973.3333333333333	947
1973.6666666666667	940
1974	945
1974.3333333333333	947
1974.6666666666667	941
1974.9166666666667	944
1975.25	947
1975.5833333333333	942
1975.9166666666667	944
1976.25	946
1976.5	946
1976.8333333333333	942
1977.1666666666667	945
1977.5	944
1977.8333333333333	942
1978.0833333333333	944
1978.4166666666667	946
1978.75	940
1979.0833333333333	943
1979.4166666666667	945
1979.6666666666667	941
1980	943
1980.3333333333333	946
1980.6666666666667	940
1981	943
1981.3333333333333	945
1981.5833333333333	943
1981.9166666666667	944
1982.25	945
1982.5833333333333	944
1982.9166666666667	944
1983.1666666666667	946
1983.5	946
1983.8333333333333	943
1984.1666666666667	946
1984.5	946
1984.75	942
1985.0833333333333	945
1985.4166666666667	946
1985.75	942
1986.0833333333333	944
1986.3333333333333	945
1986.6666666666667	942
1987	944
1987.3333333333333	945
1987.6666666666667	941
1987.9166666666667	943
1988.25	945
1988.5833333333333	942
1988.9166666666667	943
1989.25	945
1989.5833333333333	941
1989.8333333333333	942
1990.1666666666667	944
1990.5	942
1990.8333333333333	941
1991.1666666666667	943
1991.4166666666667	944
1991.75	941
1992.0833333333333	943
1992.4166666666667	944
1992.75	942
1993	944
1993.3333333333333	945
1993.6666666666667	943
1994	945
1994.3333333333333	946
1994.5833333333333	943
1994.9166666666667	944
1995.25	946
1995.5833333333333	944
1995.9166666666667	944
1996.1666666666667	945
1996.5	945
1996.8333333333333	945
1997.1666666666667	946
1997.5	945
1997.8333333333333	944
1998.0833333333333	945
1998.4166666666667	945
1998.75	942
1999.0833333333333	944
1999.4166666666667	945
1999.6666666666667	942
2000	943
2000.3333333333333	945
2000.6666666666667	940
2001	942
2001.25	943
2001.5833333333333	940
2001.9166666666667	941
2002.25	942
2002.5833333333333	940
2002.8333333333333	940
2003.1666666666667	941
2003.5	941
2003.8333333333333	940
2004.1666666666667	941
2004.4166666666667	941
2004.75	941
2005.0833333333333	941
2005.4166666666667	941
2005.75	941
2006.0833333333333	941
2006.3333333333333	941
2006.6666666666667	940
2007	941
2007.3333333333333	941
2007.6666666666667	943
2007.9166666666667	943
2008.25	943
2008.5833333333333	942
2008.9166666666667	942
2009.25	942
2009.5	942
2009.8333333333333	942
2010.1666666666667	942
2010.5	943
2010.8333333333333	942
2011.0833333333333	943
2011.4166666666667	943
2011.75	943
2012.0833333333333	943
2012.4166666666667	943
2012.6666666666667	942
2013	942
2013.3333333333333	942
2013.6666666666667	941
2014	941
2014.3333333333333	941
2014.5833333333333	939
2014.9166666666667	940
2015.25	940
2015.5833333333333	940
2015.9166666666667	940
2016.1666666666667	940
2016.5	941
2016.8333333333333	940
2017.1666666666667	940
2017.5	940
2017.75	939
2018.0833333333333	940
2018.4166666666667	940
2018.75	940
2019.0833333333333	940
2019.3333333333333	940
2019.6666666666667	940
2020	940
2020.3333333333333	940
2020.6666666666667	939
2020.9166666666667	939
2021.25	940
2021.5833333333333	939
2021.9166666666667	939
2022.25	939
2022.5833333333333	939
2022.8333333333333	938
2023.1666666666667	939
2023.5	939
2023.8333333333333	939
2024.1666666666667	939
2024.4166666666667	939
2024.75	939
2025.0833333333333	939
2025.4166666666667	939
2025.75	939
2026	939
2026.3333333333333	939
2026.6666666666667	939

Rate and persistence

-0.06 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	98.7% 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.
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	2026-10-01
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-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 2026-10-05, 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

900 monthly observations 1951–2026 Mm³

Spatially aggregatedHigh confidenceSeptember 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 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.