HydrionisGlobal Water Intelligence
Monitored reservoir

Don Pedro Res Nr La Grange CA

United States Geological Survey reservoir gauge 11287500 in CA, with published storage from 1930.

Storage record11287500

Storage now, against this reservoir's own record

1,933.36 Mm³
Stored, September 2026
76th
Percentile among 96 Seps on record
+10.0%
Against the Sep 1991–2020 average
-1.8%
Change over the 12 months to 2026-09

Storage in September 2026 was higher than most Seps on record, ranked against 96 other Seps held for this reservoir.

Storage, 1930–2026

Monthly mean storage
1,152 monthly values, 1930 to 2026
Monthly mean storageMonthly mean storage: Don Pedro Res Nr La Grange CA in Mm³, from 1930.75 to 2026.6666666666667.01,0002,000Mm³1930.751942.751954.751966.751978.751990.752002.752014.75Year

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 1,152 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 1,152 would be longer than this page and unusable with a screen reader.
PeriodDon Pedro Res Nr La Grange CA (Mm³)
October 193094.0
March 193167.0
August 193150.2
December 193154.1
May 1932252
October 1932181
March 1933180
August 1933277
January 1934117
May 1934263
October 193442.4
March 1935253
August 1935280
January 1936121
May 1936322
October 1936135
March 1937297
August 1937258
January 1938305
June 1938336
October 1938213
March 1939230
August 1939164
January 1940182
June 1940342
October 1940121
March 1941328
August 1941309
January 1942166
June 1942337
October 1942120
March 1943330
August 1943288
January 194484.6
June 1944332
November 194485.0
March 1945326
August 1945265
January 1946258
June 1946346
November 194683.9
March 1947246
August 1947143
January 194869.3
June 1948347
November 194850.6
April 1949214
August 1949179
January 195086.6
June 1950315
November 1950189
April 1951281
August 1951244
January 1952194
June 1952222
November 1952188
April 1953224
September 1953187
January 1954140
June 1954345
November 195476.4
April 1955123
September 195586.0
January 1956263
June 1956281
November 1956162
April 1957240
September 1957251
January 195895.8
June 1958319
November 1958236
April 1959240
September 195996.5
February 1960129
June 1960215
November 196081.2
April 1961188
September 196171.4
February 1962146
June 1962238
November 1962105
April 1963266
September 1963224
February 1964179
July 1964253
November 1964102
April 1965249
September 1965260
February 1966172
July 1966224
November 1966111
April 1967224
September 1967243
February 1968202
July 1968169
December 196894.3
April 1969211
September 1969195
February 1970213
July 1970334
December 1970340
April 1971446
September 1971443
February 1972675
July 1972587
December 1972468
April 19731,138
September 19731,148
February 19741,482
July 19742,177
December 19741,653
May 19751,953
September 19752,017
February 19761,670
July 19761,132
December 1976794
May 1977652
September 1977380
February 1978812
July 19782,045
December 19781,869
May 19792,112
October 19791,945
February 19802,094
July 19802,363
December 19801,948
May 19811,813
October 19811,378
February 19821,927
July 19822,478
December 19822,066
May 19831,904
October 19831,987
March 19841,821
July 19842,099
December 19841,854
May 19851,916
October 19851,480
March 19862,167
July 19862,267
December 19861,918
May 19871,711
October 19871,132
March 19881,190
July 19881,210
December 19881,241
May 19891,481
October 19891,337
March 19901,595
August 19901,280
December 19901,256
May 19911,356
October 19911,153
March 19921,385
August 19921,052
December 1992970
May 19932,047
October 19932,026
March 19942,004
August 19941,703
January 19951,909
May 19952,140
October 19952,079
March 19962,136
August 19962,228
January 19972,281
May 19972,074
October 19971,928
March 19982,009
August 19982,392
January 19992,027
June 19992,320
October 19991,987
March 20002,118
August 20002,234
January 20012,010
June 20011,964
October 20011,445
March 20021,843
August 20021,685
January 20031,648
June 20032,244
October 20031,819
March 20042,049
August 20041,796
January 20051,839
June 20052,411
November 20052,006
March 20062,057
August 20062,279
January 20071,988
June 20071,945
November 20071,517
March 20081,700
August 20081,433
January 20091,316
June 20092,171
November 20091,739
April 20102,087
August 20102,246
January 20112,058
June 20112,224
November 20111,945
April 20121,943
August 20121,676
January 20131,664
June 20131,774
November 20131,263
April 20141,339
September 2014981
January 2015999
June 2015980
November 2015794
April 20161,602
September 20161,652
January 20172,142
June 20172,342
November 20171,975
April 20182,248
September 20181,905
January 20191,797
June 20192,365
November 20191,968
April 20202,075
September 20201,782
February 20211,726
June 20211,597
November 20211,242
April 20221,562
September 20221,338
February 20231,881
June 20232,067
November 20232,012
April 20242,106
September 20241,937
February 20251,807
July 20252,251
November 20251,892
April 20262,209
September 20261,933

The reservoir's year

Seasonal storage profile
Each calendar month's reference average, against the most recent year
Seasonal storage profileSeasonal storage profile: 1991–2020 average, Most recent 12 months in Mm³, from 1 to 12.01,0002,000Mm³123456789101112Month1991–2020 average 1: 1,743 Mm³1991–2020 average 2: 1,808 Mm³1991–2020 average 3: 1,860 Mm³1991–2020 average 4: 1,898 Mm³1991–2020 average 5: 1,959 Mm³1991–2020 average 6: 2,050 Mm³1991–2020 average 7: 2,024 Mm³1991–2020 average 8: 1,884 Mm³1991–2020 average 9: 1,758 Mm³1991–2020 average 10: 1,685 Mm³1991–2020 average 11: 1,661 Mm³1991–2020 average 12: 1,688 Mm³Most recent 12 months 1: 2,023 Mm³Most recent 12 months 2: 2,099 Mm³Most recent 12 months 3: 2,128 Mm³Most recent 12 months 4: 2,209 Mm³Most recent 12 months 5: 2,354 Mm³Most recent 12 months 6: 2,356 Mm³Most recent 12 months 7: 2,209 Mm³Most recent 12 months 8: 2,045 Mm³Most recent 12 months 9: 1,933 Mm³Most recent 12 months 10: 1,898 Mm³Most recent 12 months 11: 1,892 Mm³Most recent 12 months 12: 1,918 Mm³
  • 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
Period1991–2020 average (Mm³)Most recent 12 months (Mm³)
Jan1,7432,023
Feb1,8082,099
Mar1,8602,128
Apr1,8982,209
May1,9592,354
Jun2,0502,356
Jul2,0242,209
Aug1,8842,045
Sep1,7581,933
Oct1,6851,898
Nov1,6611,892
Dec1,6881,918

Why this page shows a volume and not a percentage

Rate and persistence

-3.02 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

Don Pedro Res Nr La Grange CA
Gauge location
Don Pedro Res Nr La Grange CADon Pedro Res Nr La Grange CA — 1,933.36 Mm³Don Pedro Res Nr La Grange CA — 1,933.36 Mm³

About this data

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 existMeasured
Period held1930–2026
Completeness99.0% 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.
Continuity99% of the months between 1930 and 2026 are held. Monthly means of the publisher's own daily record.
Last read from the publisher2026-10-01
RedistributionPermitted by the upstream licences
Commercial reusePermitted by the upstream licences. No Hydrionis access tier can widen this.
MethodologyHow this was produced

Use this data

Use this data

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), Don Pedro Res Nr La Grange CA reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usgs-11287500/

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 Don Pedro Res Nr La Grange CA 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

1,152 monthly observations 1930–2026 Mm³
Spatially aggregatedHigh confidenceSeptember 2026

Source: USGS — National Water Information System, 11287500. 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.

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