Swanson Lake, Nebr. — storage

Storage now, against this reservoir's own record

96.85 Mm³

Stored, September 1994

71st

Percentile among 29 Seps on record

-14.5%

Change over the 12 months to 1994-09

Storage in September 1994 was higher than most Seps on record, ranked against 29 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, 1965–1994

Monthly mean storage

348 monthly values, 1965 to 1994

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 348 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 348 would be longer than this page and unusable with a screen reader.
Period	Swanson Lake Near Trenton, Nebr. (Mm³)
October 1965	151
November 1965	148
January 1966	148
February 1966	148
April 1966	149
May 1966	148
July 1966	138
August 1966	121
October 1966	95.9
November 1966	103
January 1967	118
February 1967	129
March 1967	137
May 1967	150
June 1967	152
August 1967	138
September 1967	122
November 1967	124
December 1967	128
February 1968	140
March 1968	146
April 1968	150
June 1968	150
July 1968	130
September 1968	98.9
October 1968	97.2
December 1968	104
January 1969	109
March 1969	129
April 1969	138
June 1969	149
July 1969	139
August 1969	116
October 1969	109
November 1969	126
January 1970	141
February 1970	147
April 1970	150
May 1970	149
July 1970	129
August 1970	94.8
October 1970	71.0
November 1970	73.0
December 1970	78.1
February 1971	90.9
March 1971	106
May 1971	134
June 1971	143
August 1971	98.0
September 1971	77.3
November 1971	77.6
December 1971	83.0
January 1972	87.9
March 1972	103
April 1972	107
June 1972	124
July 1972	128
September 1972	92.2
October 1972	90.3
December 1972	105
January 1973	114
March 1973	139
April 1973	152
May 1973	153
July 1973	130
August 1973	119
October 1973	110
November 1973	118
January 1974	136
February 1974	148
April 1974	149
May 1974	150
July 1974	134
August 1974	99.1
September 1974	79.4
November 1974	78.5
December 1974	82.8
February 1975	95.4
March 1975	105
May 1975	120
June 1975	135
August 1975	96.6
September 1975	78.9
November 1975	75.8
December 1975	79.7
January 1976	86.4
March 1976	106
April 1976	113
June 1976	117
July 1976	93.6
September 1976	33.9
October 1976	33.0
December 1976	35.1
January 1977	38.4
February 1977	45.1
April 1977	75.6
May 1977	90.9
July 1977	71.3
August 1977	52.2
October 1977	48.3
November 1977	49.9
January 1978	57.1
February 1978	61.0
April 1978	79.0
May 1978	86.1
June 1978	90.6
August 1978	44.2
September 1978	35.5
November 1978	34.1
December 1978	34.9
February 1979	39.6
March 1979	50.2
May 1979	65.1
June 1979	66.3
August 1979	58.8
September 1979	45.7
October 1979	43.7
December 1979	50.4
January 1980	56.3
March 1980	77.6
April 1980	96.0
June 1980	118
July 1980	101
September 1980	66.5
October 1980	65.2
November 1980	66.2
January 1981	75.8
February 1981	82.0
April 1981	111
May 1981	132
July 1981	135
August 1981	122
October 1981	110
November 1981	113
January 1982	123
February 1982	130
March 1982	140
May 1982	155
June 1982	171
August 1982	141
September 1982	128
November 1982	132
December 1982	138
February 1983	147
March 1983	149
May 1983	159
June 1983	159
July 1983	138
September 1983	92.2
October 1983	89.0
December 1983	91.9
January 1984	96.6
March 1984	122
April 1984	140
June 1984	161
July 1984	146
August 1984	118
October 1984	99.3
November 1984	103
January 1985	114
February 1985	122
April 1985	141
May 1985	150
July 1985	131
August 1985	106
October 1985	85.3
November 1985	90.0
December 1985	94.6
February 1986	112
March 1986	120
May 1986	131
June 1986	128
August 1986	83.2
September 1986	71.9
November 1986	75.2
December 1986	80.2
February 1987	92.4
March 1987	101
April 1987	112
June 1987	129
July 1987	112
September 1987	74.9
October 1987	73.3
December 1987	80.1
January 1988	83.5
March 1988	100.0
April 1988	110
June 1988	124
July 1988	101
August 1988	82.8
October 1988	73.1
November 1988	73.5
January 1989	81.2
February 1989	86.3
April 1989	99.7
May 1989	102
July 1989	95.2
August 1989	74.1
September 1989	65.8
November 1989	67.3
December 1989	70.6
February 1990	82.3
March 1990	90.8
May 1990	106
June 1990	111
August 1990	55.7
September 1990	45.5
November 1990	45.8
December 1990	48.4
January 1991	50.3
March 1991	62.5
April 1991	70.5
June 1991	87.2
July 1991	69.9
September 1991	46.7
October 1991	45.7
December 1991	56.3
January 1992	64.8
March 1992	87.9
April 1992	97.2
May 1992	100
July 1992	89.1
August 1992	78.0
October 1992	80.0
November 1992	83.5
January 1993	93.8
February 1993	102
April 1993	126
May 1993	134
June 1993	139
August 1993	118
September 1993	113
November 1993	120
December 1993	127
February 1994	141
March 1994	151
May 1994	163
June 1994	156
August 1994	109
September 1994	96.8

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

-1.37 Mm³

Mean drawdown per month over 12 months

0 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

Swanson Lake Near Trenton, Nebr.

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	1965–1994
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 1965 and 1994 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-06829000.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), Swanson Lake Near Trenton, Nebr. reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-06829000/

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 Swanson Lake Near Trenton, Nebr. 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

348 monthly observations 1965–1994 Mm³

Spatially aggregatedHigh confidenceSeptember 1994

Source: USGS — National Water Information System, 06829000. 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.