HydrionisGlobal Water Intelligence
Monitored reservoir

Bartlett Reservoir At Bartlett Dam, AZ

United States Geological Survey reservoir gauge 09509502 in AZ, with published storage from 1974.

Storage record09509502

Storage now, against this reservoir's own record

164.74 Mm³
Stored, August 2026
55th
Percentile among 52 Augs on record
+4.7%
Against the Aug 1991–2020 average
+82.2%
Change over the 12 months to 2026-08

Storage in August 2026 was around the middle of the Aug record, ranked against 52 other Augs held for this reservoir.

Storage, 1974–2026

Monthly mean storage
623 monthly values, 1974 to 2026
Monthly mean storageMonthly mean storage: Bartlett Reservoir At Bartlett Dam, AZ in Mm³, from 1974.75 to 2026.5833333333333.0100200Mm³1974.751981.251987.751994.252000.752007.252013.752020.25Year

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
PeriodBartlett Reservoir At Bartlett Dam, AZ (Mm³)
October 197478.0
November 197477.1
December 197470.2
January 197555.6
February 197557.1
March 197564.4
April 197595.0
May 1975112
June 1975117
July 1975111
August 197589.6
September 197577.2
October 197576.4
November 197559.4
December 197547.0
January 197629.9
February 197664.2
March 1976116
April 1976148
May 1976174
June 1976164
July 1976114
August 197697.0
September 197685.3
October 197696.7
November 197687.8
December 197674.8
January 197764.6
February 197748.9
March 19779.64
April 19770
May 19770
June 19770
July 19770
August 19770
September 19770
October 197736.3
November 197749.9
December 197750.8
January 197853.0
February 197884.9
March 1978211
April 1978217
May 1978216
June 1978206
July 1978200
August 1978188
September 1978191
October 1978209
November 1978213
December 1978197
January 1979200
February 1979196
March 1979204
April 1979212
May 1979217
June 1979213
July 1979206
August 1979209
September 1979192
October 1979197
November 1979188
December 1979158
January 1980152
February 1980185
March 1980194
April 1980211
May 1980217
June 1980191
July 1980198
August 1980176
September 1980147
October 1980134
November 1980101
December 198072.2
January 198152.5
February 198174.8
March 1981101
April 1981138
May 1981146
June 1981132
July 198189.0
August 198172.3
September 198172.9
October 198196.2
November 198190.9
December 1981101
January 1982114
February 1982156
March 1982200
April 1982208
May 1982209
June 1982202
July 1982182
August 1982140
September 1982132
October 1982130
November 1982120
December 1982150
January 1983170
February 1983156
March 1983195
April 1983217
May 1983218
June 1983207
July 1983195
August 1983202
September 1983183
October 1983181
November 1983195
December 1983190
January 1984188
February 1984187
March 1984195
April 1984196
May 1984203
June 1984192
July 1984172
August 1984175
September 1984182
October 1984185
November 1984161
December 1984162
January 1985181
February 1985201
March 1985208
April 1985218
May 1985214
June 1985200
July 1985204
August 1985207
September 1985208
October 1985207
November 1985207
December 1985206
January 1986205
February 1986206
March 1986206
April 1986215
May 1986213
June 1986208
July 1986208
August 1986207
September 1986206
October 1986206
November 1986202
December 1986201
January 1987199
February 1987202
March 1987210
April 1987218
May 1987215
June 1987207
July 1987202
August 1987205
September 1987205
October 1987195
November 1987186
December 1987167
January 1988152
February 1988189
March 1988205
April 1988212
May 1988206
June 1988202
July 1988206
August 1988199
September 1988206
October 1988209
November 1988196
December 1988191
January 1989183
February 1989170
March 1989147
April 1989157
May 1989161
June 1989155
July 1989136
August 1989121
September 1989107
October 198980.4
November 198941.7
December 198938.2
January 199042.5
February 199043.3
March 199024.5
April 199027.1
May 199038.5
June 199043.2
July 199049.6
August 199064.1
September 199075.8
October 199091.7
November 199081.8
December 199068.3
January 199172.8
February 199174.4
March 1991179
April 1991218
May 1991216
June 1991211
July 1991201
August 1991200
September 1991203
October 1991201
November 1991204
December 1991208
January 1992210
February 1992207
March 1992211
April 1992218
May 1992219
June 1992214
July 1992207
August 1992206
September 1992210
October 1992203
November 1992206
December 1992208
January 1993173
February 1993187
March 1993196
April 1993214
May 1993217
June 1993206
July 1993199
August 1993170
September 1993174
October 1993193
November 1993203
December 1993183
January 1994186
February 1994204
March 1994206
April 1994208
May 1994183
June 1994188
July 1994171
August 1994160
September 1994163
October 1994168
November 1994148
December 1994139
January 1995151
February 1995153
March 1995163
April 1995158
May 1995161
June 1995147
July 1995146
August 1995143
September 1995152
October 1995156
November 1995146
December 1995132
January 1996117
February 1996132
March 1996131
April 1996113
May 199698.8
June 199679.5
July 199669.1
August 199658.8
September 199651.4
October 199638.4
November 199625.5
December 199633.7
January 199749.2
February 199796.6
March 1997144
April 1997153
May 1997153
June 1997151
July 1997151
August 1997153
September 1997146
October 1997139
November 1997114
December 1997103
January 1998112
February 1998131
March 1998162
April 1998216
May 1998210
June 1998202
July 1998191
August 1998187
September 1998187
October 1998154
November 1998130
December 1998125
January 1999109
February 199982.5
March 199961.7
April 199971.8
May 199982.2
June 199985.0
July 199985.7
August 199985.4
September 199985.7
October 199987.3
November 199995.7
December 199990.1
January 200077.6
February 200073.8
March 200081.3
April 200092.5
May 200095.0
June 200089.5
July 200080.2
August 200074.8
September 200092.1
October 200095.8
November 200088.6
December 200087.1
January 2001116
February 2001132
March 2001164
April 2001184
May 2001196
June 2001195
July 2001191
August 2001195
September 2001197
October 2001185
November 2001126
December 200187.5
January 200281.5
February 200292.7
March 2002100.0
April 2002105
May 2002106
June 2002100
July 200290.7
August 200287.0
September 200289.7
October 200292.6
November 200280.5
December 200276.6
January 200377.2
February 200381.3
March 2003146
April 2003201
May 2003189
June 2003194
July 2003182
August 2003164
September 2003168
October 2003159
November 2003140
December 2003129
January 2004124
February 2004116
March 2004118
April 2004123
May 2004122
June 2004123
July 2004139
August 2004152
September 2004154
October 2004168
November 2004186
December 2004196
January 2005196
February 2005203
March 2005219
April 2005219
May 2005216
June 2005202
July 2005192
August 2005214
September 2005209
October 2005196
November 2005189
December 2005189
January 2006187
February 2006171
March 2006149
April 2006157
May 2006159
June 2006156
July 2006153
August 2006165
September 2006175
October 2006168
November 2006135
December 2006107
January 200791.6
February 200786.3
March 200791.5
April 200790.4
May 200785.4
June 200793.0
July 200789.8
August 200796.2
September 2007105
October 2007107
November 200791.3
December 2007136
January 2008203
February 2008218
March 2008218
April 2008218
May 2008202
June 2008202
July 2008189
August 2008207
September 2008217
October 2008167
November 2008112
December 2008108
January 2009133
February 2009161
March 2009199
April 2009218
May 2009205
June 2009216
July 2009212
August 2009205
September 2009201
October 2009155
November 200995.1
December 200991.0
January 2010110
February 2010200
March 2010207
April 2010219
May 2010219
June 2010209
July 2010200
August 2010213
September 2010205
October 2010190
November 2010156
December 2010135
January 2011171
February 2011186
March 2011165
April 2011125
May 2011116
June 2011120
July 2011115
August 2011110
September 2011107
October 2011106
November 2011107
December 201199.3
January 201297.1
February 201281.6
March 201285.3
April 2012100
May 2012104
June 2012100
July 201295.6
August 201297.9
September 2012109
October 2012111
November 2012114
December 2012118
January 2013132
February 2013157
March 2013193
April 2013211
May 2013209
June 2013217
July 2013213
August 2013215
September 2013216
October 2013209
November 2013181
December 2013165
January 2014148
February 2014128
March 2014108
April 201483.0
May 2014100
June 2014129
July 2014157
August 2014162
September 2014179
October 2014175
November 2014148
December 2014138
January 2015132
February 2015116
March 2015149
April 2015178
May 2015179
June 2015167
July 2015155
August 2015145
September 2015134
October 2015121
November 201592.6
December 201591.4
January 2016100
February 201696.7
March 201697.2
April 201699.1
May 2016108
June 2016129
July 2016146
August 2016153
September 2016157
October 2016155
November 2016125
December 2016114
January 2017141
February 2017196
March 2017216
April 2017216
May 2017205
June 2017198
July 2017209
August 2017202
September 2017194
October 2017182
November 2017154
December 2017135
January 2018126
February 2018109
March 2018102
April 201899.0
May 201897.8
June 201897.3
July 201895.8
August 201897.9
September 201899.2
October 2018102
November 2018101
December 2018103
January 201997.9
February 2019133
March 2019213
April 2019213
May 2019216
June 2019215
July 2019201
August 2019193
September 2019183
October 2019164
November 2019118
December 2019133
January 2020166
February 2020175
March 2020198
April 2020219
May 2020218
June 2020214
July 2020214
August 2020211
September 2020200
October 2020172
November 2020124
December 2020111
January 2021105
February 2021103
March 2021103
April 2021109
May 2021113
June 2021108
July 2021102
August 2021114
September 2021146
October 2021171
November 2021150
December 2021118
January 2022119
February 2022122
March 2022115
April 2022109
May 2022111
June 2022106
July 202299.6
August 2022100
September 2022111
October 2022112
November 2022118
December 2022121
January 2023138
February 2023185
March 2023194
April 2023212
May 2023217
June 2023209
July 2023181
August 2023147
September 2023132
October 2023117
November 2023130
December 2023106
January 2024101
February 2024110
March 2024113
April 2024142
May 2024134
June 2024146
July 2024145
August 2024134
September 2024127
October 2024143
November 2024128
December 2024110
January 2025114
February 2025116
March 2025115
April 2025106
May 2025112
June 2025108
July 202597.3
August 202590.4
September 202593.3
October 2025111
November 2025128
December 2025177
January 2026162
February 2026172
March 2026138
April 2026153
May 2026145
June 2026148
July 2026159
August 2026165

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 12.050100150200Mm³123456789101112Month1991–2020 average 1: 130 Mm³1991–2020 average 2: 139 Mm³1991–2020 average 3: 156 Mm³1991–2020 average 4: 165 Mm³1991–2020 average 5: 163 Mm³1991–2020 average 6: 162 Mm³1991–2020 average 7: 158 Mm³1991–2020 average 8: 157 Mm³1991–2020 average 9: 159 Mm³1991–2020 average 10: 151 Mm³1991–2020 average 11: 131 Mm³1991–2020 average 12: 126 Mm³Most recent 12 months 1: 162 Mm³Most recent 12 months 2: 172 Mm³Most recent 12 months 3: 138 Mm³Most recent 12 months 4: 153 Mm³Most recent 12 months 5: 145 Mm³Most recent 12 months 6: 148 Mm³Most recent 12 months 7: 159 Mm³Most recent 12 months 8: 165 Mm³Most recent 12 months 9: 93.3 Mm³Most recent 12 months 10: 111 Mm³Most recent 12 months 11: 128 Mm³Most recent 12 months 12: 177 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)
Jan130162
Feb139172
Mar156138
Apr165153
May163145
Jun162148
Jul158159
Aug157165
Sep15993.3
Oct151111
Nov131128
Dec126177

Rate and persistence

+6.19 Mm³
Mean change per month over 12 months
3 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

Bartlett Reservoir At Bartlett Dam, AZ
Gauge location
Bartlett Reservoir At Bartlett Dam, AZBartlett Reservoir At Bartlett Dam, AZ — 164.74 Mm³Bartlett Reservoir At Bartlett Dam, AZ — 164.74 Mm³

Where this comes from

623 monthly observations 1974–2026 Mm³
Spatially aggregatedHigh confidenceAugust 2026

Source: USGS — National Water Information System, 09509502. 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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