Lake Lowell — storage

Storage now, against this reservoir's own record

167.30 Mm³

Stored, September 1965

100th

Percentile among 48 Seps on record

+32.3%

Change over the 12 months to 1965-09

Storage in September 1965 was higher than almost every other Sep on record, ranked against 48 other Seps held for this reservoir. It is the highest in the held record for this month.

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, 1917–1965

Monthly mean storage

576 monthly values, 1917 to 1965

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 576 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 576 would be longer than this page and unusable with a screen reader.
Period	Lake Lowell Nr Caldwell ID (Mm³)
October 1917	17.9
December 1917	19.2
March 1918	148
May 1918	162
August 1918	57.1
October 1918	28.7
December 1918	41.2
March 1919	148
May 1919	179
August 1919	24.0
October 1919	19.4
December 1919	61.1
March 1920	145
May 1920	194
August 1920	46.2
October 1920	16.9
December 1920	101
March 1921	180
May 1921	214
August 1921	78.0
October 1921	41.8
January 1922	108
March 1922	152
May 1922	198
August 1922	46.9
October 1922	13.0
January 1923	82.3
March 1923	144
May 1923	184
August 1923	102
October 1923	39.3
January 1924	80.4
March 1924	183
May 1924	144
August 1924	12.5
October 1924	6.87
January 1925	59.8
March 1925	167
May 1925	186
August 1925	51.7
October 1925	29.7
January 1926	109
March 1926	178
May 1926	155
August 1926	27.4
October 1926	8.86
January 1927	71.9
March 1927	176
May 1927	196
August 1927	89.4
October 1927	78.5
January 1928	120
March 1928	193
June 1928	146
August 1928	54.8
October 1928	18.1
January 1929	78.2
March 1929	135
June 1929	181
August 1929	70.6
October 1929	13.9
January 1930	95.2
March 1930	173
June 1930	144
August 1930	49.7
October 1930	18.3
January 1931	92.1
March 1931	128
June 1931	96.4
August 1931	14.1
October 1931	8.62
January 1932	44.5
March 1932	126
June 1932	211
August 1932	84.4
October 1932	13.7
January 1933	83.8
March 1933	143
June 1933	171
August 1933	50.1
October 1933	11.1
January 1934	96.1
March 1934	154
June 1934	74.5
August 1934	16.6
October 1934	8.13
January 1935	92.8
March 1935	143
June 1935	172
August 1935	55.7
November 1935	26.5
January 1936	91.7
March 1936	155
June 1936	197
August 1936	70.7
November 1936	15.2
January 1937	101
March 1937	148
June 1937	138
August 1937	39.3
November 1937	19.7
January 1938	102
March 1938	182
June 1938	204
August 1938	128
November 1938	82.2
January 1939	115
March 1939	170
June 1939	148
August 1939	50.2
November 1939	43.7
January 1940	107
March 1940	176
June 1940	161
August 1940	53.9
November 1940	49.3
January 1941	110
March 1941	173
June 1941	210
August 1941	109
November 1941	77.0
January 1942	113
April 1942	214
June 1942	217
August 1942	99.5
November 1942	46.4
January 1943	113
April 1943	209
June 1943	213
August 1943	118
November 1943	76.6
January 1944	121
April 1944	206
June 1944	198
August 1944	91.0
November 1944	35.9
January 1945	106
April 1945	208
June 1945	214
August 1945	87.3
November 1945	36.8
January 1946	113
April 1946	208
June 1946	176
August 1946	74.9
November 1946	50.4
January 1947	113
April 1947	211
June 1947	203
August 1947	75.7
November 1947	120
January 1948	127
April 1948	215
June 1948	209
September 1948	47.9
November 1948	80.0
January 1949	110
April 1949	204
June 1949	161
September 1949	34.7
November 1949	56.1
January 1950	114
April 1950	209
June 1950	181
September 1950	48.4
November 1950	91.1
January 1951	118
April 1951	208
June 1951	200
September 1951	55.7
November 1951	94.3
January 1952	119
April 1952	201
June 1952	171
September 1952	54.4
November 1952	98.9
January 1953	118
April 1953	213
June 1953	214
September 1953	57.0
November 1953	89.6
January 1954	118
April 1954	210
June 1954	179
September 1954	73.2
November 1954	124
January 1955	130
April 1955	194
June 1955	150
September 1955	32.7
November 1955	98.2
February 1956	119
April 1956	198
June 1956	182
September 1956	70.1
November 1956	118
February 1957	149
April 1957	209
June 1957	174
September 1957	54.8
November 1957	113
February 1958	188
April 1958	206
June 1958	197
September 1958	104
November 1958	126
February 1959	166
April 1959	207
June 1959	195
September 1959	41.0
November 1959	27.5
February 1960	69.6
April 1960	205
June 1960	186
September 1960	83.6
November 1960	136
February 1961	144
April 1961	206
June 1961	190
September 1961	73.3
November 1961	84.5
February 1962	138
April 1962	197
July 1962	150
September 1962	111
November 1962	144
February 1963	158
April 1963	204
July 1963	177
September 1963	129
November 1963	149
February 1964	169
April 1964	195
July 1964	177
September 1964	126
November 1964	171
February 1965	202
April 1965	215
July 1965	194
September 1965	167

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

+3.40 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

Lake Lowell Nr Caldwell 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	1917–1965
Completeness	98.0% 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	98% of the months between 1917 and 1965 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-13203500.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), Lake Lowell Nr Caldwell ID reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-13203500/

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 Lake Lowell Nr Caldwell 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

576 monthly observations 1917–1965 Mm³

Spatially aggregatedHigh confidenceSeptember 1965

Source: USGS — National Water Information System, 13203500. 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.