HydrionisGlobal Water Intelligence

Reservoirs

Major reservoirs, their capacity and the systems they support — and, for reservoirs Hydrionis monitors, decades of storage history.

5 records
Lake Mead

The largest reservoir in the United States by capacity, impounded by the Hoover Dam. Its decline to record low levels in 2022 became the defining image of the Colorado River shortage.

Three Gorges Reservoir

The reservoir behind the Three Gorges Dam, the largest power station in the world by installed capacity and one of the largest engineering interventions ever made in a river system.

Lake Nasser

Formed by the Aswan High Dam, it gave Egypt multi-year storage on the Nile for the first time — ending the annual flood that had defined Egyptian agriculture for millennia, along with the …

Kielder Water

The largest artificial lake in the UK by capacity, built to supply industrial demand in north east England that never fully materialised — leaving the region with the most comfortable wate…

Rutland Water

One of the largest reservoirs in England by surface area, a pumped storage reservoir filled from the Rivers Nene and Welland rather than by its own catchment.

Monitored reservoirs (92)

Reservoirs for which Hydrionis holds a continuous storage record, the longest opening in 1914. Each has a monthly series, a seasonal profile and its position against its own history.

Monitored reservoirs
92 reservoirs with a held storage record
Monitored reservoirs92 locations, each labelled individually.Shasta Lk Nr Redding CA — 3,397.83 Mm³Lake Texoma Near Denison, TX — 3,202.78 Mm³Lake Mohave At Davis Dam, Az-NV — 2,089.25 Mm³Don Pedro Res Nr La Grange CA — 2,061.79 Mm³Lake O' The Cherokees At Langley, OK — 1,700.30 Mm³Navajo Reservoir Nr Archuleta, NM — 1,600.85 Mm³Brownlee Res At Brownlee Dam Id-Or State Line — 1,359.30 Mm³Lk Mcclure A Exchequer CA — 965.40 Mm³Lewisville Lk Nr Lewisville, TX — 793.10 Mm³Lake Havasu Near Parker Dam, Az-CA — 722.53 Mm³Cascade Res At Cascade ID — 692.92 Mm³Belton Lk Nr Belton, TX — 538.97 Mm³Milford Lake Nr Junction City, KS — 501.30 Mm³Millerton Lk A Friant CA — 356.57 Mm³Lake Hudson Near Locust Grove, OK — 263.01 Mm³Alder Reservoir At Alder, WA — 248.72 Mm³Harlan County Lake Near Republican City, Nebr. — 222.56 Mm³Ute Reservoir Near Logan, NM — 221.81 Mm³Arrowrock Res At Arrowrock Dam ID — 215.00 Mm³Jackson Lake Near Moran, WY — 199.12 Mm³Lk Brownwood Nr Brownwood, TX — 177.26 Mm³Lake Lowell Nr Caldwell ID — 167.30 Mm³Lk Kemp Nr Mabelle, TX — 165.95 Mm³Conchas Lake At Conchas Dam N. Mex. — 164.83 Mm³Bartlett Reservoir At Bartlett Dam, AZ — 164.74 Mm³Lahontan Res Nr Fallon, NV — 161.78 Mm³Sevier Bridge Reservoir Near Juab, UT — 153.60 Mm³Atoka Reservoir Near Stringtown, OK — 133.79 Mm³Red Bluff Res Nr Orla, TX — 121.88 Mm³Shaver Lk Nr Big C CA — 114.75 Mm³Stanley Draper Lake Near Oklahoma City, OK — 108.04 Mm³Pineview Reservoir Near Ogden, UT — 104.20 Mm³Fern Ridge Lake Near Elmira, OR — 102.77 Mm³Benbrook Lk Nr Benbrook, TX — 101.67 Mm³Bucks Lk Nr Bucks Lodge CA — 98.40 Mm³Swanson Lake Near Trenton, Nebr. — 96.85 Mm³Ridgway Reservoir Near Ridgway, CO — 92.09 Mm³Huntington Lk Nr Big Creek CA — 85.29 Mm³Lake Eucha Near Eucha, OK — 81.06 Mm³Lake Hefner At Oklahoma City, OK — 76.95 Mm³Lk Kickapoo Nr Archer City, TX — 67.07 Mm³B. A. Steinhagen Lk At Town Bluff, TX — 62.75 Mm³Cochiti Lake Near Cochiti Pueblo, NM — 58.94 Mm³Dorena Lake Near Cottage Grove, OR — 57.73 Mm³Lake Lawtonka Near Lawton, OK — 55.65 Mm³Lake Altus At Lugert, OK — 42.22 Mm³Horseshoe Reservoir At Horseshoe Dam, AZ — 41.41 Mm³John Martin Reservoir At Caddoa, CO — 39.10 Mm³Hugh Butler Lake Near Mc Cook, Nebr. — 38.18 Mm³Lk Pillsbury Nr Potter Valley CA — 36.42 Mm³Lake Sumner Nr Fort Sumner, NM — 35.35 Mm³Wolford Mtn Reservoir Nr Kremmling, CO — 33.48 Mm³Rockport Reservoir Near Wanship, UT — 32.92 Mm³Florence Lk Nr Big C CA — 31.75 Mm³Wild Horse Res Nr Gold Cr, NV — 30.75 Mm³Big Sandy Reservoir Near Farson, WY — 29.13 Mm³Eagle Nest Lake Nr Eagle Nest, NM — 27.79 Mm³Topaz Lake Nr Topaz, CA — 26.77 Mm³Harry Strunk Lake Near Cambridge, Nebr. — 23.79 Mm³Lake Ellsworth Near Elgin, OK — 23.39 Mm³Trinidad Lake Near Trinidad, Co. — 23.02 Mm³Lk Arlington At Arlington, TX — 22.65 Mm³Cottage Grove Lake Nr Cottage Grove, OR — 21.13 Mm³Lk Colorado City Nr Colorado City, TX — 20.79 Mm³Lemon Reservoir Near Durango CO — 17.18 Mm³Echo Reservoir At Echo, UT — 14.84 Mm³Lake Overholser Near Oklahoma City, OK — 14.09 Mm³Rye Patch Res Nr Rye Patch, NV — 13.25 Mm³Enders Reservoir Near Enders, Nebr. — 13.23 Mm³Lk Nasworthy Nr San Angelo, TX — 10.73 Mm³Cragin Dam Reservoir Near Pine, Az (Blue Ridge) — 9.37 Mm³Piute Reservoir Near Marysvale, UT — 7.49 Mm³Weber Res Nr Schurz, NV — 7.30 Mm³Marlette Lake Nr Carson City, NV — 6.33 Mm³Lake Maloya Nr Raton NM — 4.31 Mm³Lake Avalon Nr Carlsbad N Mex — 3.39 Mm³Hords Ck Lk Nr Valera, TX — 3.22 Mm³Silver Jack Reservoir Near Cimarron, CO — 2.03 Mm³San Carlos Reservoir At Coolidge Dam, AZ — 1.19 Mm³Nambe Falls Reservoir Near Nambe, NM — 1.06 Mm³Nichols Reservoir Near Santa Fe N Mex — 0.54 Mm³Mcclure Reservoir Near Santa Fe N Mex — 0.54 Mm³Mackay Res Nr Mackay ID — 0.43 Mm³Paonia Reservoir Near Bardine, CO — 0.33 Mm³Teller Reservoir Near Stone City, Co. — 0.04 Mm³Mud Mountain Lake Near Buckley, WA — 0.03 Mm³Jemez Canyon Res Nr Bernalillo N M — 0.00 Mm³Scofield Reservoir Near Scofield, UT — 0.00 Mm³Deer Creek Reservoir Near Charleston, Utah — 0.00 Mm³Hetch Hetchy Res A Hetch Hetchy CA — 0.00 Mm³Lk Eleanor Nr Hetch Hetchy CA — 0.00 Mm³Milner Lake At Milner Dam ID — 0.00 Mm³
Coverage follows the United States Geological Survey reservoir network, which is concentrated in the western and plains states. It is a monitoring network, not a national inventory.

Latest storage held

ReservoirStoredAs ofRecordMonths held
Shasta Lk Nr Redding CA3,397.83 Mm³September 20251944–2025972
Lake Texoma Near Denison, TX3,202.78 Mm³September 19931943–1993600
Lake Mohave At Davis Dam, Az-NV2,089.25 Mm³August 20261950–2026919
Don Pedro Res Nr La Grange CA2,061.79 Mm³August 20261930–20261,151
Lake O' The Cherokees At Langley, OK1,700.30 Mm³August 20261940–20261,013
Navajo Reservoir Nr Archuleta, NM1,600.85 Mm³September 20171965–2017624
Brownlee Res At Brownlee Dam Id-Or State Line1,359.30 Mm³September 20051958–2005566
Lk Mcclure A Exchequer CA965.40 Mm³September 20231930–20231,107
Lewisville Lk Nr Lewisville, TX793.10 Mm³June 20011954–2001560
Lake Havasu Near Parker Dam, Az-CA722.53 Mm³August 20261938–20261,058
Cascade Res At Cascade ID692.92 Mm³September 19961959–1996441
Belton Lk Nr Belton, TX538.97 Mm³January 20041954–2004599
Milford Lake Nr Junction City, KS501.30 Mm³August 20262002–2026253
Millerton Lk A Friant CA356.57 Mm³September 20221941–2022968
Lake Hudson Near Locust Grove, OK263.01 Mm³August 20261989–2026394
Alder Reservoir At Alder, WA248.72 Mm³June 20261965–2026724
Harlan County Lake Near Republican City, Nebr.222.56 Mm³August 20261965–2026624
Ute Reservoir Near Logan, NM221.81 Mm³August 20261974–2026540
Arrowrock Res At Arrowrock Dam ID215.00 Mm³September 19861917–1986828
Jackson Lake Near Moran, WY199.12 Mm³September 19851937–1985516
Lk Brownwood Nr Brownwood, TX177.26 Mm³September 19861933–1986581
Lake Lowell Nr Caldwell ID167.30 Mm³September 19651917–1965576
Lk Kemp Nr Mabelle, TX165.95 Mm³February 20021949–2002605
Conchas Lake At Conchas Dam N. Mex.164.83 Mm³May 20171965–2017620
Bartlett Reservoir At Bartlett Dam, AZ164.74 Mm³August 20261974–2026623
Lahontan Res Nr Fallon, NV161.78 Mm³August 20261960–2026749
Sevier Bridge Reservoir Near Juab, UT153.60 Mm³April 19921920–1992812
Atoka Reservoir Near Stringtown, OK133.79 Mm³August 20261999–2026323
Red Bluff Res Nr Orla, TX121.88 Mm³September 19931937–1993668
Shaver Lk Nr Big C CA114.75 Mm³September 20251927–20251,185
Stanley Draper Lake Near Oklahoma City, OK108.04 Mm³August 20261999–2026323
Pineview Reservoir Near Ogden, UT104.20 Mm³September 19651936–1965345
Fern Ridge Lake Near Elmira, OR102.77 Mm³September 19741941–1974393
Benbrook Lk Nr Benbrook, TX101.67 Mm³June 20011952–2001585
Bucks Lk Nr Bucks Lodge CA98.40 Mm³September 20251928–20251,164
Swanson Lake Near Trenton, Nebr.96.85 Mm³September 19941965–1994348
Ridgway Reservoir Near Ridgway, CO92.09 Mm³July 20261990–2026262
Huntington Lk Nr Big Creek CA85.29 Mm³September 20251926–20251,188
Lake Eucha Near Eucha, OK81.06 Mm³August 20262001–2026299
Lake Hefner At Oklahoma City, OK76.95 Mm³August 20261999–2026321
Lk Kickapoo Nr Archer City, TX67.07 Mm³September 19981946–1998620
B. A. Steinhagen Lk At Town Bluff, TX62.75 Mm³February 20021951–2002607
Cochiti Lake Near Cochiti Pueblo, NM58.94 Mm³September 20171973–2017537
Dorena Lake Near Cottage Grove, OR57.73 Mm³September 19741949–1974300
Lake Lawtonka Near Lawton, OK55.65 Mm³August 20261994–2026275
Lake Altus At Lugert, OK42.22 Mm³August 20261988–2026442
Horseshoe Reservoir At Horseshoe Dam, AZ41.41 Mm³August 20261974–2026623
John Martin Reservoir At Caddoa, CO39.10 Mm³October 20201977–2020517
Hugh Butler Lake Near Mc Cook, Nebr.38.18 Mm³September 19941965–1994348
Lk Pillsbury Nr Potter Valley CA36.42 Mm³September 20251928–20251,100
Lake Sumner Nr Fort Sumner, NM35.35 Mm³January 20171965–2017615
Wolford Mtn Reservoir Nr Kremmling, CO33.48 Mm³August 20261998–2026260
Rockport Reservoir Near Wanship, UT32.92 Mm³September 19901960–1990360
Florence Lk Nr Big C CA31.75 Mm³September 20251925–20251,197
Wild Horse Res Nr Gold Cr, NV30.75 Mm³August 20261980–2026344
Big Sandy Reservoir Near Farson, WY29.13 Mm³November 20241987–2024447
Eagle Nest Lake Nr Eagle Nest, NM27.79 Mm³August 20261987–2026469
Topaz Lake Nr Topaz, CA26.77 Mm³September 19701931–1970316
Harry Strunk Lake Near Cambridge, Nebr.23.79 Mm³September 19941965–1994348
Lake Ellsworth Near Elgin, OK23.39 Mm³August 20261995–2026371
Trinidad Lake Near Trinidad, Co.23.02 Mm³October 20191989–2019361
Lk Arlington At Arlington, TX22.65 Mm³September 19981957–1998498
Cottage Grove Lake Nr Cottage Grove, OR21.13 Mm³September 19741942–1974384
Lk Colorado City Nr Colorado City, TX20.79 Mm³November 20021949–2002632
Lemon Reservoir Near Durango CO17.18 Mm³August 20261990–2026206
Echo Reservoir At Echo, UT14.84 Mm³September 19901930–1990719
Lake Overholser Near Oklahoma City, OK14.09 Mm³August 20261999–2026321
Rye Patch Res Nr Rye Patch, NV13.25 Mm³August 20211936–2021819
Enders Reservoir Near Enders, Nebr.13.23 Mm³September 20061960–2006553
Lk Nasworthy Nr San Angelo, TX10.73 Mm³September 20011930–2001855
Cragin Dam Reservoir Near Pine, Az (Blue Ridge)9.37 Mm³August 20261965–2026648
Piute Reservoir Near Marysvale, UT7.49 Mm³September 19751914–1975703
Weber Res Nr Schurz, NV7.30 Mm³August 20261995–2026360
Marlette Lake Nr Carson City, NV6.33 Mm³August 20261974–2026622
Lake Maloya Nr Raton NM4.31 Mm³August 20261987–2026466
Lake Avalon Nr Carlsbad N Mex3.39 Mm³March 20171965–2017602
Hords Ck Lk Nr Valera, TX3.22 Mm³November 20021948–2002644
Silver Jack Reservoir Near Cimarron, CO2.03 Mm³August 20261987–2026231
San Carlos Reservoir At Coolidge Dam, AZ1.19 Mm³August 20261987–2026467
Nambe Falls Reservoir Near Nambe, NM1.06 Mm³August 20261984–2026512
Nichols Reservoir Near Santa Fe N Mex0.54 Mm³August 20261965–2026551
Mcclure Reservoir Near Santa Fe N Mex0.54 Mm³August 20261965–2026731
Mackay Res Nr Mackay ID0.43 Mm³September 19591930–1959348
Paonia Reservoir Near Bardine, CO0.33 Mm³August 20261987–2026234
Teller Reservoir Near Stone City, Co.0.04 Mm³July 20181978–2018416
Mud Mountain Lake Near Buckley, WA0.03 Mm³August 20261982–2026518
Jemez Canyon Res Nr Bernalillo N M0.00 Mm³August 20151965–2015599
Scofield Reservoir Near Scofield, UT0.00 Mm³September 20031942–2003692
Deer Creek Reservoir Near Charleston, Utah0.00 Mm³September 19651941–1965293
Hetch Hetchy Res A Hetch Hetchy CA0.00 Mm³August 20261930–20261,148
Lk Eleanor Nr Hetch Hetchy CA0.00 Mm³August 20261918–20261,144
Milner Lake At Milner Dam ID0.00 Mm³February 20171978–2017460

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