HydrionisGlobal Water Intelligence
Monitored reservoir

Alder Reservoir At Alder, WA

United States Geological Survey reservoir gauge 12085000 in WA, with published storage from 1965.

Storage record12085000

Storage now, against this reservoir's own record

248.72 Mm³
Stored, June 2026
35th
Percentile among 61 Juns on record
+3.3%
Against the Jun 1991–2020 average

Storage in June 2026 was around the middle of the Jun record, ranked against 61 other Juns held for this reservoir.

Storage, 1965–2026

Monthly mean storage
724 monthly values, 1965 to 2026
Monthly mean storageMonthly mean storage: Alder Reservoir At Alder, WA in Mm³, from 1965.75 to 2026.4166666666667.0100200300Mm³1965.751973.416666666666719811988.58333333333331996.16666666666672003.752011.33333333333332018.9166666666667Year

Monthly means of the publisher's daily record. Volume, not percentage of capacity: without a capacity whose definition is stated, fullness cannot be computed.

View the data behind this chart
Underlying data
PeriodAlder Reservoir At Alder, WA (Mm³)
October 1965248
November 1965186
December 1965165
January 1966157
February 1966128
April 1966216
May 1966259
June 1966274
July 1966284
August 1966285
September 1966272
October 1966210
November 1966144
December 1966218
January 1967261
February 1967264
March 1967219
April 1967167
May 1967166
June 1967245
July 1967280
August 1967285
September 1967280
October 1967263
November 1967249
December 1967198
January 1968228
February 1968275
March 1968281
April 1968261
May 1968256
June 1968284
July 1968285
August 1968284
September 1968280
October 1968260
November 1968253
December 1968266
January 1969257
February 1969178
March 1969118
April 1969147
May 1969206
June 1969280
July 1969285
August 1969284
September 1969273
October 1969241
November 1969212
December 1969185
January 1970214
February 1970280
March 1970239
April 1970201
May 1970188
June 1970230
July 1970265
August 1970274
September 1970253
October 1970219
November 1970171
December 1970205
January 1971236
February 1971282
March 1971254
April 1971242
May 1971242
June 1971250
July 1971275
August 1971284
September 1971269
October 1971213
November 1971151
December 1971131
January 1972153
February 1972225
March 1972243
April 1972228
May 1972218
June 1972255
July 1972267
August 1972283
September 1972273
October 1972236
November 1972194
December 1972191
January 1973237
February 1973172
March 1973122
April 1973122
May 1973164
June 1973208
July 1973243
August 1973234
September 1973207
October 1973179
November 1973178
December 1973225
January 1974241
February 1974209
March 1974179
April 1974187
May 1974179
June 1974248
July 1974269
August 1974276
September 1974273
October 1974227
November 1974179
December 1974226
January 1975251
February 1975229
March 1975212
April 1975136
May 1975182
June 1975250
July 1975271
August 1975279
September 1975276
October 1975254
November 1975273
December 1975256
January 1976258
February 1976224
March 1976151
April 1976139
May 1976220
June 1976251
July 1976279
August 1976282
September 1976274
October 1976222
November 1976172
December 1976148
January 1977151
February 1977153
March 1977168
April 1977181
May 1977232
June 1977277
July 1977280
August 1977280
September 1977257
October 1977188
November 1977208
December 1977220
January 1978193
February 1978191
March 1978150
April 1978178
May 1978244
June 1978278
July 1978285
August 1978282
September 1978272
October 1978254
November 1978220
December 1978206
January 1979146
February 1979187
March 1979250
April 1979259
May 1979276
June 1979265
July 1979256
August 1979237
September 1979221
October 1979197
November 1979178
December 1979228
January 1980242
February 1980241
March 1980239
April 1980247
May 1980278
June 1980277
July 1980278
August 1980262
September 1980242
October 1980218
November 1980231
December 1980258
January 1981246
February 1981243
March 1981249
April 1981265
May 1981281
June 1981282
July 1981273
August 1981250
September 1981224
October 1981228
November 1981220
December 1981255
January 1982232
February 1982259
March 1982255
April 1982245
May 1982261
June 1982269
July 1982266
August 1982246
September 1982230
October 1982202
November 1982211
December 1982247
January 1983247
February 1983247
March 1983249
April 1983241
May 1983241
June 1983258
July 1983277
August 1983277
September 1983259
October 1983221
November 1983239
December 1983222
January 1984244
February 1984244
March 1984245
April 1984256
May 1984267
June 1984269
July 1984277
August 1984264
September 1984244
October 1984216
November 1984237
December 1984205
January 1985157
February 1985135
March 1985137
April 1985184
May 1985246
June 1985278
July 1985264
August 1985232
September 1985204
October 1985183
November 1985229
December 1985161
January 1986185
February 1986241
March 1986264
April 1986254
May 1986261
June 1986270
July 1986242
August 1986219
September 1986192
October 1986162
November 1986169
December 1986233
January 1987191
February 1987217
March 1987239
April 1987245
May 1987263
June 1987260
July 1987237
August 1987215
September 1987201
October 1987179
November 1987150
December 1987212
January 1988197
February 1988208
March 1988217
April 1988276
May 1988283
June 1988279
July 1988266
August 1988244
September 1988224
October 1988204
November 1988245
December 1988234
January 1989245
February 1989198
March 1989192
April 1989232
May 1989273
June 1989277
July 1989258
August 1989231
September 1989208
October 1989177
November 1989170
December 1989211
January 1990238
February 1990237
March 1990221
April 1990257
May 1990267
June 1990278
July 1990273
August 1990248
September 1990217
October 1990192
November 1990228
December 1990238
January 1991232
February 1991270
March 1991259
April 1991260
May 1991269
June 1991276
July 1991279
August 1991263
September 1991233
October 1991194
November 1991179
December 1991238
January 1992207
February 1992252
March 1992248
April 1992229
May 1992238
June 1992207
July 1992181
August 1992166
September 1992147
October 1992119
November 1992134
December 1992161
January 1993138
February 1993151
March 1993159
April 1993233
May 1993251
June 1993259
July 1993248
August 1993242
September 1993218
October 1993181
November 1993132
December 1993135
January 1994171
February 1994174
March 1994228
April 1994236
May 1994222
June 1994208
July 1994192
August 1994168
September 1994151
October 1994129
November 1994169
December 1994221
January 1995216
February 1995227
March 1995221
April 1995229
May 1995237
June 1995233
July 1995220
August 1995200
September 1995185
October 1995179
November 1995220
December 1995220
January 1996224
February 1996225
March 1996212
April 1996225
May 1996237
June 1996246
July 1996229
August 1996204
September 1996170
October 1996141
November 1996157
December 1996190
January 1997204
February 1997213
March 1997199
April 1997209
May 1997231
June 1997259
July 1997262
August 1997253
September 1997225
October 1997217
November 1997224
December 1997215
January 1998213
February 1998213
March 1998217
April 1998209
May 1998231
June 1998257
July 1998253
August 1998237
September 1998202
October 1998144
November 1998132
December 1998229
January 1999223
February 1999213
March 1999214
April 1999182
May 1999231
June 1999252
July 1999239
August 1999242
September 1999227
October 1999181
November 1999180
December 1999229
January 2000196
February 2000192
March 2000198
April 2000219
May 2000237
June 2000246
July 2000254
August 2000226
September 2000179
October 2000144
November 2000102
December 200098.0
January 2001110
February 2001121
March 2001125
April 2001159
May 2001216
June 2001254
July 2001251
August 2001218
September 2001183
October 2001141
November 2001160
December 2001218
January 2002226
February 2002198
March 2002211
April 2002228
May 2002223
June 2002253
July 2002252
August 2002228
September 2002195
October 2002154
November 2002121
December 2002121
January 2003193
February 2003236
March 2003239
April 2003236
May 2003229
June 2003226
July 2003202
August 2003180
September 2003158
October 2003143
November 2003156
December 2003197
January 2004168
February 2004204
March 2004204
April 2004207
May 2004197
June 2004228
July 2004223
August 2004205
September 2004221
October 2004215
November 2004192
December 2004187
January 2005186
February 2005189
March 2005161
April 2005222
May 2005251
June 2005246
July 2005233
August 2005213
September 2005192
October 2005163
November 2005163
December 2005166
January 2006240
February 2006231
March 2006188
April 2006192
May 2006231
June 2006253
July 2006243
August 2006212
September 2006180
October 2006144
November 2006205
December 2006228
January 2007231
February 2007209
March 2007236
April 2007221
May 2007206
June 2007205
July 2007187
August 2007166
September 2007143
October 2007134
November 2007145
December 2007203
January 2008196
February 2008160
March 2008177
April 2008170
May 2008218
June 2008253
July 2008258
August 2008244
September 2008220
October 2008178
November 2008175
December 2008161
January 2009226
February 2009195
March 2009185
April 2009213
May 2009236
June 2009251
July 2009233
August 2009207
September 2009182
October 2009144
November 2009174
December 2009191
January 2010208
February 2010194
March 2010194
April 2010214
May 2010228
June 2010256
July 2010255
August 2010239
September 2010213
October 2010184
November 2010215
December 2010227
January 2011236
February 2011232
March 2011203
April 2011229
May 2011215
June 2011230
July 2011236
August 2011225
September 2011203
October 2011166
November 2011144
December 2011170
January 2012206
February 2012213
March 2012215
April 2012237
May 2012248
June 2012252
July 2012256
August 2012243
September 2012208
October 2012164
November 2012193
December 2012219
January 2013165
February 2013175
March 2013190
April 2013237
May 2013234
June 2013251
July 2013257
August 2013234
September 2013216
October 2013220
November 2013191
December 2013181
January 2014176
February 2014197
March 2014245
April 2014233
May 2014239
June 2014248
July 2014248
August 2014231
September 2014200
October 2014167
November 2014194
December 2014224
January 2015233
February 2015233
March 2015229
April 2015243
May 2015224
June 2015197
July 2015170
August 2015156
September 2015142
October 2015108
November 2015189
December 2015240
January 2016220
February 2016253
March 2016254
April 2016231
May 2016214
June 2016199
July 2016189
August 2016183
September 2016162
October 2016182
November 2016219
December 2016180
January 2017166
February 2017225
March 2017246
April 2017246
May 2017249
June 2017255
July 2017246
August 2017220
September 2017189
October 2017155
November 2017188
December 2017216
January 2018229
February 2018240
March 2018181
April 2018223
May 2018249
June 2018242
July 2018216
August 2018185
September 2018147
October 2018100
November 2018115
December 2018163
January 2019181
February 2019179
March 2019147
April 2019209
May 2019234
June 2019220
July 2019202
August 2019185
September 2019165
October 2019139
November 2019120
December 2019133
January 2020222
February 2020243
March 2020208
April 2020221
May 2020246
June 2020259
July 2020255
August 2020238
September 2020218
October 2020209
November 2020176
December 2020167
January 2021237
February 2021192
March 2021176
April 2021185
May 2021213
June 2021252
July 2021252
August 2021229
September 2021206
October 2021178
November 2021220
December 2021214
January 2022235
February 2022210
March 2022234
April 2022221
May 2022238
June 2022251
July 2022252
August 2022236
September 2022215
October 2022183
November 2022177
December 2022165
January 2023187
February 2023161
March 2023143
April 2023168
May 2023232
June 2023241
July 2023217
August 2023195
September 2023171
October 2023142
November 2023148
December 2023209
January 2024190
February 2024222
March 2024230
April 2024229
May 2024233
June 2024255
July 2024251
August 2024231
September 2024208
October 2024180
November 2024174
December 2024180
January 2025207
February 2025184
March 2025220
April 2025229
May 2025214
June 2025212
July 2025200
August 2025179
September 2025156
October 2025121
November 2025157
December 2025209
January 2026214
June 2026249

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 12.0100200Mm³123456789101112Month1991–2020 average 1: 201 Mm³1991–2020 average 2: 209 Mm³1991–2020 average 3: 206 Mm³1991–2020 average 4: 220 Mm³1991–2020 average 5: 232 Mm³1991–2020 average 6: 241 Mm³1991–2020 average 7: 232 Mm³1991–2020 average 8: 214 Mm³1991–2020 average 9: 189 Mm³1991–2020 average 10: 161 Mm³1991–2020 average 11: 169 Mm³1991–2020 average 12: 191 Mm³Most recent 12 months 1: 214 Mm³Most recent 12 months 3: 220 Mm³Most recent 12 months 4: 229 Mm³Most recent 12 months 5: 214 Mm³Most recent 12 months 6: 249 Mm³Most recent 12 months 7: 200 Mm³Most recent 12 months 8: 179 Mm³Most recent 12 months 9: 156 Mm³Most recent 12 months 10: 121 Mm³Most recent 12 months 11: 157 Mm³Most recent 12 months 12: 209 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)
Jan201214
Feb209—
Mar206220
Apr220229
May232214
Jun241249
Jul232200
Aug214179
Sep189156
Oct161121
Nov169157
Dec191209

Rate and persistence

6 of 24
Months in the last two years 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

Alder Reservoir At Alder, WA
Gauge location
Alder Reservoir At Alder, WAAlder Reservoir At Alder, WA — 248.72 Mm³Alder Reservoir At Alder, WA — 248.72 Mm³

Where this comes from

724 monthly observations 1965–2026 Mm³
Spatially aggregatedHigh confidenceJune 2026

Source: USGS — National Water Information System, 12085000. 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 25 August 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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