Cascade Res — storage

Storage now, against this reservoir's own record

692.92 Mm³

Stored, September 1996

81st

Percentile among 37 Seps on record

-12.3%

Change over the 12 months to 1996-09

Storage in September 1996 was higher than most Seps on record, ranked against 37 other Seps held for this reservoir.

No percentage departure from the Sep average is published here. No long-term average is held for this month, so there is nothing to compare with.

Storage, 1959–1996

Monthly mean storage

441 monthly values, 1959 to 1996

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 441 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 441 would be longer than this page and unusable with a screen reader.
Period	Cascade Res At Cascade ID (Mm³)
October 1959	599
December 1959	619
February 1960	602
April 1960	685
May 1960	806
July 1960	800
September 1960	540
November 1960	427
January 1961	344
March 1961	362
April 1961	418
June 1961	773
August 1961	620
October 1961	409
December 1961	322
February 1962	246
March 1962	253
May 1962	500
July 1962	814
September 1962	572
November 1962	653
January 1963	707
March 1963	787
April 1963	810
June 1963	874
August 1963	743
October 1963	526
December 1963	499
February 1964	453
March 1964	425
May 1964	565
July 1964	850
September 1964	642
November 1964	512
January 1965	618
February 1965	527
April 1965	340
June 1965	806
August 1965	827
October 1965	665
December 1965	685
January 1966	693
March 1966	607
May 1966	738
July 1966	772
September 1966	429
November 1966	279
January 1967	198
February 1967	200
April 1967	259
June 1967	661
August 1967	750
October 1967	515
December 1967	479
January 1968	454
March 1968	467
May 1968	570
July 1968	774
September 1968	550
November 1968	467
December 1968	490
March 1969	377
May 1969	583
July 1969	844
September 1969	569
November 1969	430
January 1970	385
February 1970	440
April 1970	436
June 1970	814
August 1970	762
October 1970	581
January 1971	619
February 1971	563
April 1971	357
June 1971	815
August 1971	808
October 1971	637
December 1971	582
January 1972	506
March 1972	387
May 1972	411
July 1972	833
September 1972	610
November 1972	513
December 1972	514
February 1973	507
April 1973	534
June 1973	740
August 1973	589
October 1973	327
December 1973	461
January 1974	536
March 1974	420
May 1974	452
July 1974	868
September 1974	712
November 1974	614
December 1974	575
February 1975	502
April 1975	401
June 1975	602
August 1975	762
October 1975	606
November 1975	649
January 1976	654
March 1976	498
May 1976	610
July 1976	854
September 1976	688
November 1976	599
December 1976	579
February 1977	503
April 1977	515
June 1977	490
August 1977	341
October 1977	274
November 1977	290
January 1978	388
March 1978	426
May 1978	664
July 1978	862
September 1978	727
October 1978	663
December 1978	600
February 1979	520
April 1979	512
June 1979	760
August 1979	569
September 1979	436
November 1979	303
January 1980	346
April 1980	483
June 1980	837
August 1980	774
October 1980	577
November 1980	553
January 1981	636
March 1981	722
May 1981	860
July 1981	828
September 1981	548
October 1981	492
December 1981	579
February 1982	595
April 1982	463
June 1982	740
August 1982	824
September 1982	736
November 1982	667
January 1983	563
March 1983	569
May 1983	560
July 1983	848
September 1983	740
October 1983	654
December 1983	627
February 1984	559
April 1984	586
June 1984	788
August 1984	739
September 1984	614
November 1984	534
January 1985	552
March 1985	555
May 1985	741
July 1985	806
August 1985	680
October 1985	503
December 1985	550
February 1986	593
April 1986	600
June 1986	848
July 1986	853
September 1986	596
November 1986	558
January 1987	574
March 1987	608
May 1987	750
July 1987	720
August 1987	612
October 1987	440
December 1987	440
February 1988	450
April 1988	504
June 1988	717
July 1988	704
September 1988	498
November 1988	469
January 1989	493
March 1989	525
May 1989	734
June 1989	836
August 1989	681
October 1989	546
December 1989	559
February 1990	586
April 1990	666
June 1990	863
July 1990	838
September 1990	689
November 1990	622
January 1991	581
March 1991	574
May 1991	673
June 1991	819
August 1991	699
October 1991	547
December 1991	563
February 1992	508
April 1992	589
May 1992	699
July 1992	649
September 1992	463
November 1992	461
January 1993	424
March 1993	412
April 1993	505
June 1993	859
August 1993	711
October 1993	560
December 1993	560
February 1994	567
April 1994	612
May 1994	705
July 1994	671
September 1994	432
November 1994	420
January 1995	451
March 1995	563
April 1995	654
June 1995	846
August 1995	845
October 1995	765
December 1995	819
February 1996	703
March 1996	651
May 1996	711
July 1996	852
September 1996	693

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.

Rate and persistence

-8.08 Mm³

Mean drawdown per month over 12 months

3 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

Cascade Res At Cascade ID

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 Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Measured
Period held	1959–1996
Completeness	96.7% 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	97% of the months between 1959 and 1996 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-usgs-13244500.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), Cascade Res At Cascade ID reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-13244500/

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 Cascade Res At Cascade ID 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

441 monthly observations 1959–1996 Mm³

Spatially aggregatedHigh confidenceSeptember 1996

Source: USGS — National Water Information System, 13244500. Licence: Open.

Method: Monthly mean of daily reservoir storage published by the USGS in acre-feet and converted to millions of cubic metres. Months with fewer than 20 days of record are not published rather than averaged from a partial month.

Reservoir storage is managed as well as observed: a drawdown may reflect an operating rule, flood-control rule curve or scheduled release rather than a shortage. Compare a month against the same month in other years, and do not read a fall as a supply signal without knowing the operating regime.

Retrieved 1 October 2026.

Monthly mean of daily reservoir storage published by the USGS in acre-feet and converted to millions of cubic metres. Months with fewer than 20 days of record are not published rather than averaged from a partial month.