Echo Reservoir — storage

Storage now, against this reservoir's own record

27.09 Mm³

Stored, September 2026

36th

Percentile among 60 Seps on record

-12.3%

Against the Sep 1991–2020 average

-33.2%

Change over the 12 months to 2026-09

Storage in September 2026 was around the middle of the Sep record, ranked against 60 other Seps held for this reservoir.

Storage, 1967–2026

Monthly mean storage

715 monthly values, 1967 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 715 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 715 would be longer than this page and unusable with a screen reader.
Period	Echo Reservoir (Mm³)
January 1967	52.2
April 1967	68.6
July 1967	86.3
October 1967	31.8
January 1968	29.9
April 1968	62.7
July 1968	80.3
October 1968	39.2
January 1969	69.5
April 1969	36.8
July 1969	88.2
October 1969	29.4
January 1970	53.7
April 1970	76.6
July 1970	77.4
October 1970	42.5
January 1971	74.0
April 1971	72.1
July 1971	82.9
October 1971	45.0
January 1972	70.0
April 1972	81.7
July 1972	76.7
October 1972	36.8
January 1973	73.9
April 1973	55.9
July 1973	81.5
October 1973	46.9
January 1974	62.4
April 1974	59.6
July 1974	77.0
October 1974	33.8
January 1975	70.4
April 1975	68.1
July 1975	90.1
October 1975	50.7
January 1976	51.5
April 1976	70.8
July 1976	61.4
October 1976	17.4
December 1976	44.1
March 1977	60.6
June 1977	65.7
September 1977	24.4
December 1977	46.4
March 1978	59.0
June 1978	90.6
September 1978	42.6
December 1978	65.1
March 1979	79.1
June 1979	86.8
September 1979	20.4
December 1979	31.7
March 1980	67.0
June 1980	90.1
September 1980	44.0
December 1980	62.3
March 1981	73.7
June 1981	88.7
September 1981	22.5
December 1981	51.0
March 1982	66.1
June 1982	89.0
September 1982	52.9
December 1982	58.1
March 1983	63.4
June 1983	91.7
September 1983	64.3
January 1984	24.4
April 1984	39.3
July 1984	90.6
October 1984	37.5
January 1985	75.2
April 1985	61.3
July 1985	73.7
October 1985	37.7
February 1986	67.0
May 1986	54.2
August 1986	72.8
November 1986	73.0
February 1987	77.7
May 1987	86.0
August 1987	44.6
November 1987	34.2
February 1988	68.5
May 1988	88.6
August 1988	24.8
November 1988	34.5
February 1989	59.2
May 1989	88.6
August 1989	33.5
November 1989	22.3
February 1990	53.2
May 1990	80.5
August 1990	39.9
November 1990	30.0
February 1991	44.4
May 1991	69.8
August 1991	42.2
November 1991	47.9
February 1992	76.9
May 1992	75.4
August 1992	30.1
November 1992	10.8
February 1993	24.6
May 1993	71.9
August 1993	74.3
November 1993	53.8
February 1994	82.7
May 1994	89.7
August 1994	29.8
November 1994	36.4
February 1995	53.0
May 1995	80.1
August 1995	69.2
November 1995	61.3
February 1996	59.1
May 1996	66.7
August 1996	55.9
November 1996	52.9
January 1997	65.0
April 1997	33.2
July 1997	81.5
October 1997	54.4
January 1998	75.3
April 1998	56.9
July 1998	86.5
October 1998	56.3
January 1999	74.6
April 1999	68.3
July 1999	77.0
October 1999	37.1
January 2000	65.0
April 2000	65.3
July 2000	50.1
October 2000	13.1
January 2001	39.7
April 2001	61.9
July 2001	61.3
October 2001	26.7
January 2002	39.7
April 2002	58.0
July 2002	51.7
October 2002	25.1
January 2003	36.6
April 2003	53.6
July 2003	49.7
October 2003	11.1
January 2004	44.1
April 2004	63.1
July 2004	56.7
October 2004	18.9
January 2005	44.4
April 2005	72.0
July 2005	79.5
October 2005	25.9
January 2006	62.2
April 2006	66.4
July 2006	71.3
October 2006	33.3
January 2007	57.8
April 2007	80.4
July 2007	53.9
October 2007	18.4
January 2008	40.5
April 2008	67.0
July 2008	77.6
October 2008	27.1
January 2009	51.6
April 2009	79.0
July 2009	80.6
October 2009	37.1
January 2010	61.3
April 2010	81.1
July 2010	71.8
October 2010	31.3
January 2011	65.2
April 2011	42.9
July 2011	89.9
October 2011	49.0
January 2012	57.8
April 2012	83.3
July 2012	29.4
October 2012	7.54
January 2013	22.6
April 2013	39.3
July 2013	29.1
October 2013	12.6
January 2014	25.2
April 2014	46.6
July 2014	37.6
October 2014	16.4
January 2015	32.5
April 2015	51.9
July 2015	61.5
October 2015	23.1
January 2016	34.5
April 2016	53.6
July 2016	58.4
October 2016	20.3
December 2016	29.2
March 2017	39.4
June 2017	91.4
September 2017	32.0
December 2017	55.8
March 2018	75.6
June 2018	76.1
September 2018	16.3
December 2018	21.4
March 2019	36.0
June 2019	89.9
September 2019	46.1
December 2019	57.9
March 2020	73.8
June 2020	77.7
September 2020	22.5
December 2020	24.3
March 2021	36.7
June 2021	34.7
September 2021	10.6
December 2021	22.5
March 2022	35.6
June 2022	79.7
September 2022	46.0
December 2022	54.3
March 2023	61.2
June 2023	86.2
September 2023	63.6
December 2023	81.5
March 2024	68.5
June 2024	89.7
September 2024	50.2
December 2024	61.5
March 2025	77.5
June 2025	86.9
September 2025	40.6
December 2025	43.2
March 2026	56.2
June 2026	48.9
September 2026	27.1

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	50.3	47.5
Feb	54.1	51.1
Mar	57.1	56.2
Apr	62.6	60.0
May	73.2	54.6
Jun	78.7	48.9
Jul	65.1	41.8
Aug	45.4	32.6
Sep	30.9	27.1
Oct	28.4	35.9
Nov	37.0	39.2
Dec	44.7	43.2

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

715 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 715 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 715 would be longer than this page and unusable with a screen reader.
Period	Echo Reservoir (m)
1967	1,687
1967.25	1,691
1967.5	1,694
1967.75	1,682
1968	1,682
1968.25	1,689
1968.5	1,693
1968.75	1,684
1969	1,691
1969.25	1,683
1969.5	1,694
1969.75	1,681
1970	1,688
1970.25	1,692
1970.5	1,692
1970.75	1,685
1971	1,692
1971.25	1,691
1971.5	1,693
1971.75	1,686
1972	1,691
1972.25	1,693
1972.5	1,692
1972.75	1,684
1973	1,692
1973.25	1,688
1973.5	1,693
1973.75	1,686
1974	1,689
1974.25	1,689
1974.5	1,692
1974.75	1,683
1975	1,691
1975.25	1,690
1975.5	1,694
1975.75	1,687
1976	1,687
1976.25	1,691
1976.5	1,689
1976.75	1,677
1976.9166666666667	1,685
1977.1666666666667	1,689
1977.4166666666667	1,690
1977.6666666666667	1,680
1977.9166666666667	1,686
1978.1666666666667	1,689
1978.4166666666667	1,695
1978.6666666666667	1,685
1978.9166666666667	1,690
1979.1666666666667	1,693
1979.4166666666667	1,694
1979.6666666666667	1,679
1979.9166666666667	1,682
1980.1666666666667	1,690
1980.4166666666667	1,695
1980.6666666666667	1,685
1980.9166666666667	1,689
1981.1666666666667	1,692
1981.4166666666667	1,694
1981.6666666666667	1,679
1981.9166666666667	1,687
1982.1666666666667	1,690
1982.4166666666667	1,694
1982.6666666666667	1,687
1982.9166666666667	1,689
1983.1666666666667	1,690
1983.4166666666667	1,695
1983.6666666666667	1,690
1984	1,680
1984.25	1,684
1984.5	1,695
1984.75	1,684
1985	1,692
1985.25	1,689
1985.5	1,692
1985.75	1,684
1986.0833333333333	1,690
1986.3333333333333	1,688
1986.5833333333333	1,691
1986.8333333333333	1,691
1987.0833333333333	1,692
1987.3333333333333	1,694
1987.5833333333333	1,686
1987.8333333333333	1,683
1988.0833333333333	1,691
1988.3333333333333	1,694
1988.5833333333333	1,680
1988.8333333333333	1,683
1989.0833333333333	1,689
1989.3333333333333	1,694
1989.5833333333333	1,683
1989.8333333333333	1,679
1990.0833333333333	1,688
1990.3333333333333	1,693
1990.5833333333333	1,684
1990.8333333333333	1,682
1991.0833333333333	1,686
1991.3333333333333	1,691
1991.5833333333333	1,685
1991.8333333333333	1,686
1992.0833333333333	1,692
1992.3333333333333	1,692
1992.5833333333333	1,682
1992.8333333333333	1,675
1993.0833333333333	1,680
1993.3333333333333	1,691
1993.5833333333333	1,692
1993.8333333333333	1,688
1994.0833333333333	1,693
1994.3333333333333	1,694
1994.5833333333333	1,682
1994.8333333333333	1,683
1995.0833333333333	1,687
1995.3333333333333	1,693
1995.5833333333333	1,691
1995.8333333333333	1,689
1996.0833333333333	1,689
1996.3333333333333	1,690
1996.5833333333333	1,688
1996.8333333333333	1,687
1997	1,690
1997.25	1,683
1997.5	1,693
1997.75	1,688
1998	1,692
1998.25	1,688
1998.5	1,694
1998.75	1,688
1999	1,692
1999.25	1,691
1999.5	1,692
1999.75	1,684
2000	1,690
2000.25	1,690
2000.5	1,687
2000.75	1,676
2001	1,684
2001.25	1,689
2001.5	1,689
2001.75	1,681
2002	1,684
2002.25	1,689
2002.5	1,687
2002.75	1,680
2003	1,684
2003.25	1,688
2003.5	1,687
2003.75	1,675
2004	1,685
2004.25	1,690
2004.5	1,688
2004.75	1,678
2005	1,686
2005.25	1,691
2005.5	1,693
2005.75	1,680
2006	1,689
2006.25	1,690
2006.5	1,691
2006.75	1,683
2007	1,689
2007.25	1,693
2007.5	1,688
2007.75	1,678
2008	1,685
2008.25	1,690
2008.5	1,692
2008.75	1,681
2009	1,687
2009.25	1,693
2009.5	1,693
2009.75	1,684
2010	1,689
2010.25	1,693
2010.5	1,691
2010.75	1,682
2011	1,690
2011.25	1,685
2011.5	1,694
2011.75	1,687
2012	1,689
2012.25	1,693
2012.5	1,681
2012.75	1,673
2013	1,679
2013.25	1,684
2013.5	1,681
2013.75	1,675
2014	1,680
2014.25	1,686
2014.5	1,684
2014.75	1,677
2015	1,682
2015.25	1,687
2015.5	1,689
2015.75	1,680
2016	1,683
2016.25	1,688
2016.5	1,689
2016.75	1,679
2016.9166666666667	1,681
2017.1666666666667	1,684
2017.4166666666667	1,695
2017.6666666666667	1,682
2017.9166666666667	1,688
2018.1666666666667	1,692
2018.4166666666667	1,692
2018.6666666666667	1,677
2018.9166666666667	1,679
2019.1666666666667	1,683
2019.4166666666667	1,694
2019.6666666666667	1,686
2019.9166666666667	1,689
2020.1666666666667	1,692
2020.4166666666667	1,692
2020.6666666666667	1,679
2020.9166666666667	1,680
2021.1666666666667	1,684
2021.4166666666667	1,683
2021.6666666666667	1,675
2021.9166666666667	1,679
2022.1666666666667	1,683
2022.4166666666667	1,693
2022.6666666666667	1,686
2022.9166666666667	1,688
2023.1666666666667	1,689
2023.4166666666667	1,694
2023.6666666666667	1,690
2023.9166666666667	1,693
2024.1666666666667	1,691
2024.4166666666667	1,694
2024.6666666666667	1,687
2024.9166666666667	1,689
2025.1666666666667	1,692
2025.4166666666667	1,694
2025.6666666666667	1,685
2025.9166666666667	1,685
2026.1666666666667	1,688
2026.4166666666667	1,687
2026.6666666666667	1,681

What came in, and what was let out

Monthly mean inflow against release

Both as the publisher reports them, in the same unit, on the same monthly axis

Inflow
Release

These two share a chart because they share a unit, a time basis and a subject — which most pairs of series do not. Read together they are the operating record: where release exceeds inflow the reservoir is being drawn down, and where inflow exceeds release it is filling. They do not close the balance exactly, because evaporation, seepage, precipitation onto the surface and bank storage are all real and none is in either line.

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 717 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 717 would be longer than this page and unusable with a screen reader.
Period	Inflow (m³/s)	Release (m³/s)
1967	3.53	0.543
1967.25	3.22	1.37
1967.5	14.5	19.9
1967.75	5.43	6.15
1968	6.64	5.65
1968.25	8.36	2.04
1968.5	9.42	19.1
1968.75	6.12	0.038
1969	6.22	7.29
1969.25	21.1	10.8
1969.5	13.4	17.1
1969.75	6.78	5.03
1970	6.73	2.70
1970.25	3.32	1.45
1970.5	8.25	16.8
1970.75	6.54	3.83
1971	6.57	3.79
1971.25	10.2	10.3
1971.5	11.5	18.2
1971.75	6.51	5.97
1972	6.68	4.80
1972.25	13.7	12.4
1972.5	6.93	14.8
1972.75	6.35	4.36
1973	6.44	3.20
1973.25	6.75	1.65
1973.5	8.30	12.0
1973.75	4.00	6.53
1974	6.11	4.57
1974.25	13.4	15.3
1974.5	6.91	14.5
1974.75	6.08	1.67
1975	4.79	0.716
1975.25	5.22	17.0
1975.5	20.1	21.8
1975.75	6.31	7.21
1976	5.58	5.34
1976.25	10.6	6.78
1976.5	5.04	15.2
1976.75	5.74	2.84
1977	2.69	1.03
1977.25	2.29	1.35
1977.5	3.22	8.90
1977.75	5.57	0.494
1978	1.29	0.057
1978.25	6.87	0.057
1978.5	5.88	15.2
1978.75	5.91	4.14
1979	6.18	3.43
1979.25	6.24	4.32
1979.5	4.64	15.6
1979.75	4.65	4.67
1980	5.70	0.143
1980.25	12.0	16.4
1980.5	7.83	14.3
1980.75	5.97	4.09
1981	1.22	0.508
1981.25	4.52	0.229
1981.5	3.95	14.9
1981.75	6.43	1.00
1982	3.91	2.54
1982.25	11.5	24.1
1982.5	14.8	17.6
1982.75	12.0	8.06
1983	9.75	6.79
1983.25	18.3	23.8
1983.5	20.0	22.1
1983.75	7.78	4.94
1984	6.64	18.3
1984.25	18.2	19.6
1984.5	14.4	14.1
1984.75	11.9	14.9
1985	7.26	16.4
1985.25	24.5	18.6
1985.5	7.04	14.9
1985.75	9.64	3.95
1986	—	0.291
1986.25	29.9	29.2
1986.5	12.7	14.5
1986.75	8.31	7.00
1987	6.08	5.95
1987.25	7.72	5.28
1987.5	7.42	13.2
1987.75	5.94	3.79
1988	4.96	0.057
1988.25	3.37	0.065
1988.5	7.02	16.8
1988.75	6.46	0.029
1989	2.10	0.029
1989.25	7.10	2.66
1989.5	5.74	17.2
1989.75	3.65	3.58
1990	4.50	0.029
1990.25	5.43	1.76
1990.5	12.3	16.2
1990.75	6.01	1.18
1991	1.89	0
1991.25	3.02	0.150
1991.5	5.92	17.1
1991.75	6.05	3.41
1992	1.37	0.0055
1992.25	2.26	3.29
1992.5	5.79	11.7
1992.75	1.40	0.013
1993	1.80	0.011
1993.25	8.65	3.76
1993.5	13.1	16.7
1993.75	8.69	9.24
1994	2.95	0.707
1994.25	5.74	3.70
1994.5	7.83	16.8
1994.75	6.77	0.465
1995	1.89	0.016
1995.25	7.02	4.78
1995.5	25.8	28.6
1995.75	7.50	4.72
1996	5.07	5.74
1996.25	16.7	12.0
1996.5	7.71	16.1
1996.75	7.51	5.62
1996.9166666666667	5.91	3.56
1997.1666666666667	12.3	14.9
1997.4166666666667	33.0	29.1
1997.6666666666667	8.20	11.6
1997.9166666666667	6.58	6.57
1998.1666666666667	9.30	12.3
1998.4166666666667	35.3	30.4
1998.6666666666667	7.12	9.84
1998.9166666666667	7.60	7.69
1999.1666666666667	7.50	11.1
1999.4166666666667	29.0	24.5
1999.6666666666667	7.30	11.8
1999.9166666666667	5.84	1.83
2000.1666666666667	3.71	5.71
2000.4166666666667	8.24	13.4
2000.6666666666667	5.35	6.43
2000.9166666666667	3.30	0
2001.1666666666667	2.40	0
2001.4166666666667	6.20	9.15
2001.6666666666667	4.66	8.24
2001.9166666666667	1.51	0
2002.1666666666667	2.25	0
2002.4166666666667	4.62	7.24
2002.6666666666667	3.16	4.86
2002.9166666666667	1.48	0
2003.1666666666667	2.62	0
2003.4166666666667	5.75	8.24
2003.6666666666667	5.84	10.4
2003.9166666666667	4.29	0
2004.1666666666667	2.93	0
2004.4166666666667	4.31	6.45
2004.6666666666667	4.05	8.84
2004.9166666666667	2.69	0
2005.1666666666667	3.88	0
2005.4166666666667	23.3	22.7
2005.6666666666667	6.34	12.8
2005.9166666666667	4.23	0
2006.1666666666667	4.83	4.45
2006.4166666666667	15.6	18.6
2006.6666666666667	7.39	10.6
2006.9166666666667	3.01	0
2007.1666666666667	4.61	0.165
2007.4166666666667	7.19	12.8
2007.6666666666667	5.12	9.08
2007.9166666666667	2.76	0.023
2008.1666666666667	3.56	0.038
2008.4166666666667	18.6	18.4
2008.6666666666667	6.86	10.9
2008.9166666666667	3.05	0.026
2009.1666666666667	3.93	0.089
2009.4166666666667	29.0	29.2
2009.6666666666667	7.54	12.9
2009.9166666666667	2.79	0.026
2010.1666666666667	2.22	0.308
2010.4166666666667	27.1	28.3
2010.6666666666667	6.36	9.95
2010.9166666666667	4.26	0.031
2011.1666666666667	15.0	22.0
2011.4166666666667	53.8	45.3
2011.6666666666667	7.35	13.9
2011.9166666666667	6.01	7.03
2012.1666666666667	7.06	3.45
2012.4166666666667	4.92	16.7
2012.6666666666667	7.66	7.77
2012.9166666666667	1.91	0.0086
2013.1666666666667	2.28	0.019
2013.4166666666667	8.23	11.6
2013.6666666666667	6.00	7.22
2013.9166666666667	1.57	0.039
2014.1666666666667	2.62	0.058
2014.4166666666667	7.03	12.7
2014.6666666666667	6.79	10.5
2014.9166666666667	1.92	0.020
2015.1666666666667	2.07	0.024
2015.4166666666667	7.46	9.44
2015.6666666666667	4.04	9.62
2015.9166666666667	1.47	0.024
2016.1666666666667	2.52	0.024
2016.4166666666667	7.80	12.0
2016.6666666666667	6.50	9.05
2016.9166666666667	1.95	0.017
2017.1666666666667	13.7	14.3
2017.4166666666667	23.2	23.6
2017.6666666666667	4.59	8.89
2017.9166666666667	2.84	0.027
2018.1666666666667	4.46	0.199
2018.4166666666667	6.63	15.3
2018.6666666666667	4.62	9.55
2018.9166666666667	1.70	0.017
2019.1666666666667	2.56	0.038
2019.4166666666667	21.5	17.6
2019.6666666666667	5.64	8.16
2019.9166666666667	1.89	0.026
2020.1666666666667	6.57	5.50
2020.4166666666667	8.21	10.9
2020.6666666666667	5.56	10.5
2020.9166666666667	1.50	0.015
2021.1666666666667	2.06	0.023
2021.4166666666667	4.61	8.85
2021.6666666666667	2.21	3.32
2021.9166666666667	1.69	0.015
2022.1666666666667	2.37	0.017
2022.4166666666667	8.49	6.53
2022.6666666666667	7.02	10.1
2022.9166666666667	1.59	0.023
2023.1666666666667	8.56	10.4
2023.4166666666667	21.4	12.3
2023.6666666666667	8.11	9.71
2023.9166666666667	2.07	3.99
2024.1666666666667	7.33	5.79
2024.4166666666667	23.9	24.4
2024.6666666666667	7.08	8.73
2024.9166666666667	1.64	0.019
2025.1666666666667	2.62	0.035
2025.4166666666667	7.52	10.9
2025.6666666666667	5.46	8.22
2025.9166666666667	1.66	0.027
2026.1666666666667	2.09	0.021
2026.4166666666667	7.42	9.58
2026.6666666666667	2.97	4.14

Rate and persistence

-1.12 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

Echo 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	1967–2026
Completeness	99.3% 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 1967 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-320.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), Echo Reservoir reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usbr-320/

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 Echo 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

715 monthly observations 1967–2026 Mm³

Spatially aggregatedHigh confidenceSeptember 2026

Source: USBR — Reservoir operations and Colorado River data, RISE catalogue item 314. 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.