Dorena Lake, OR — storage

Storage now, against this reservoir's own record

57.73 Mm³

Stored, September 1974

92nd

Percentile among 25 Seps on record

+7.6%

Change over the 12 months to 1974-09

Storage in September 1974 was higher than almost every other Sep on record, ranked against 25 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, 1949–1974

Monthly mean storage

300 monthly values, 1949 to 1974

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 300 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 300 would be longer than this page and unusable with a screen reader.
Period	Dorena Lake Near Cottage Grove, OR (Mm³)
October 1949	1.35
November 1949	4.85
January 1950	12.8
February 1950	17.5
March 1950	44.3
April 1950	64.4
June 1950	88.9
July 1950	88.3
August 1950	84.0
September 1950	69.4
November 1950	24.1
December 1950	9.04
January 1951	11.2
February 1951	21.4
April 1951	62.4
May 1951	83.7
June 1951	88.2
July 1951	83.6
September 1951	75.7
October 1951	57.0
November 1951	13.6
December 1951	10.4
February 1952	16.7
March 1952	45.1
April 1952	64.3
May 1952	85.7
July 1952	88.6
August 1952	75.7
September 1952	49.5
October 1952	20.1
December 1952	8.87
January 1953	21.1
February 1953	21.0
March 1953	41.7
May 1953	86.0
June 1953	89.9
July 1953	87.9
August 1953	70.2
October 1953	18.5
November 1953	22.8
December 1953	18.3
January 1954	15.0
March 1954	40.2
April 1954	63.1
May 1954	71.3
June 1954	78.6
August 1954	63.1
September 1954	34.9
October 1954	18.4
November 1954	8.80
January 1955	9.78
February 1955	18.5
March 1955	44.3
April 1955	64.5
June 1955	89.5
July 1955	88.5
August 1955	51.4
September 1955	11.8
November 1955	18.7
December 1955	45.3
January 1956	23.9
February 1956	22.3
April 1956	64.5
May 1956	85.5
June 1956	89.6
July 1956	88.4
September 1956	18.8
October 1956	16.5
November 1956	10.3
December 1956	19.3
February 1957	33.7
March 1957	59.4
April 1957	67.6
May 1957	79.1
July 1957	70.5
August 1957	26.2
September 1957	14.0
October 1957	14.7
December 1957	29.0
January 1958	14.7
February 1958	31.2
March 1958	41.3
May 1958	81.2
June 1958	92.1
July 1958	85.9
August 1958	29.6
October 1958	3.55
November 1958	11.5
December 1958	9.69
January 1959	17.2
March 1959	44.9
April 1959	71.2
May 1959	87.1
June 1959	91.2
August 1959	33.4
September 1959	18.2
October 1959	19.9
November 1959	9.98
January 1960	10.7
February 1960	28.0
March 1960	51.1
April 1960	67.6
June 1960	91.3
July 1960	84.6
August 1960	52.6
September 1960	25.3
November 1960	19.9
December 1960	10.6
January 1961	9.10
February 1961	49.2
April 1961	63.8
May 1961	87.3
June 1961	91.8
July 1961	86.0
September 1961	50.8
October 1961	37.3
November 1961	30.1
December 1961	18.9
February 1962	21.7
March 1962	46.3
April 1962	64.5
May 1962	86.2
July 1962	85.7
August 1962	61.2
September 1962	17.2
October 1962	4.99
December 1962	13.4
January 1963	8.87
February 1963	28.4
March 1963	47.7
May 1963	91.4
June 1963	91.3
July 1963	89.5
August 1963	58.5
October 1963	9.42
November 1963	13.0
December 1963	9.54
January 1964	23.1
March 1964	42.8
April 1964	65.0
May 1964	88.6
June 1964	90.7
August 1964	51.7
September 1964	20.8
October 1964	12.7
November 1964	11.0
January 1965	26.0
February 1965	23.4
March 1965	35.7
April 1965	51.6
June 1965	82.3
July 1965	74.5
August 1965	48.0
September 1965	23.6
November 1965	8.90
December 1965	9.61
January 1966	23.6
February 1966	19.4
April 1966	63.1
May 1966	72.0
June 1966	66.2
July 1966	55.3
September 1966	18.5
October 1966	12.9
November 1966	13.3
December 1966	11.3
February 1967	25.2
March 1967	43.1
April 1967	65.1
May 1967	84.6
July 1967	82.1
August 1967	51.3
September 1967	23.7
October 1967	17.4
December 1967	9.72
January 1968	10.2
February 1968	28.4
March 1968	48.8
May 1968	78.0
June 1968	89.6
July 1968	81.7
August 1968	42.1
October 1968	18.2
November 1968	16.0
December 1968	12.4
January 1969	10.4
March 1969	42.5
April 1969	61.3
May 1969	85.5
June 1969	89.6
August 1969	78.0
September 1969	51.7
October 1969	26.4
November 1969	9.00
January 1970	41.6
February 1970	33.8
March 1970	49.5
April 1970	68.3
June 1970	87.4
July 1970	77.8
August 1970	51.1
September 1970	22.7
November 1970	12.7
December 1970	4.83
January 1971	42.8
February 1971	28.1
April 1971	64.3
May 1971	84.9
June 1971	90.1
July 1971	87.7
September 1971	49.5
October 1971	22.5
November 1971	15.2
December 1971	21.0
February 1972	25.7
March 1972	66.9
April 1972	66.2
May 1972	84.7
July 1972	84.4
August 1972	71.9
September 1972	54.7
October 1972	30.4
December 1972	10.5
January 1973	13.2
February 1973	23.5
March 1973	50.2
May 1973	89.2
June 1973	88.3
July 1973	80.9
August 1973	66.9
October 1973	29.9
November 1973	22.4
December 1973	16.6
January 1974	32.3
March 1974	43.4
April 1974	66.8
May 1974	85.2
June 1974	90.6
August 1974	76.1
September 1974	57.7

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

+0.34 Mm³

Mean change per month over 12 months

1 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

Dorena Lake Near Cottage Grove, OR

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	1949–1974
Completeness	96.2% 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	96% of the months between 1949 and 1974 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-14155000.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), Dorena Lake Near Cottage Grove, OR reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-14155000/

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 Dorena Lake Near Cottage Grove, OR 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

300 monthly observations 1949–1974 Mm³

Spatially aggregatedHigh confidenceSeptember 1974

Source: USGS — National Water Information System, 14155000. 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.