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State · United States · USGS · BOR · USACE · CDEC

Wyoming

49.8% average fill

Measured

25

Data pending

2

Volume stored

4,964 hm³

Measured capacity

9,969 hm³

Critical

5

Low level

4

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Reservoirs

Sorted by capacity

Seminoe Reservoir Dam and Powerplant

low
31.4%394 hm³View →

Updated 2026-07-28

Pathfinder Reservoir and Dam

critical
19.7%248 hm³View →

Updated 2026-07-28

Jackson Lake and Jackson Lake Dam (JCK)

59.9%626 hm³View →

Updated 2026-07-28

Boysen Dam & Reservoir

76.2%659 hm³View →

Updated 2026-07-29

Boysen Reservoir Dam and Powerplant

76.2%659 hm³View →

Updated 2026-07-28

Buffalo Bill Reservoir Dam and Powerplant

91.8%732 hm³View →

Updated 2026-07-28

South Fork Dike at Buffalo Bill Reservoir

critical
0.4%3 hm³View →

Updated 2026-07-28

Glendo Dam & Reservoir

46.9%263 hm³View →

Updated 2026-07-29

Glendo Reservoir Dam and Powerplant

46.9%263 hm³View →

Updated 2026-07-28

Fontenelle Reservoir Dam and Powerplant

85.6%353 hm³View →

Updated 2026-07-28

Keyhole Dam & Reservoir

low
28.7%118 hm³View →

Updated 2026-07-29

Keyhole Reservoir and Dam

low
28.7%118 hm³View →

Updated 2026-07-28

Alcova Reservoir Dam and Powerplant

98.2%223 hm³View →

Updated 2026-07-28

Bull Lake Reservoir and Dam

82.9%156 hm³View →

Updated 2026-07-28

Guernsey Reservoir Dam and Powerplant

43.7%25 hm³View →

Updated 2026-07-28

Big Sandy Reservoir and Dam

48.0%24 hm³View →

Updated 2026-07-28

Pilot Butte Reservoir, WY

85.0%35 hm³View →

Updated 2026-07-29

Pilot Butte Reservoir and Dam

85.0%35 hm³View →

Updated 2026-07-28

Meeks Cabin Reservoir and Dam

critical
14.1%6 hm³View →

Updated 2026-07-28

Anchor Reservoir, SF Owl Cr, WY

critical
5.8%1 hm³View →

Updated 2026-07-29

Anchor Reservoir and Dam

critical
5.8%1 hm³View →

Updated 2026-07-28

Grassy Lake and Grassy Lake Dam (GRS)

45.7%9 hm³View →

Updated 2026-07-28

Eden Reservoir and Dam

low
25.7%5 hm³View →

Updated 2026-07-28

Kortes Dam & Reservoir

99.7%6 hm³View →

Updated 2026-07-29

Gray Reef Reservoir and Dam

80.7%2 hm³View →

Updated 2026-07-27

Storage from official US gauges (USGS, USACE, Bureau of Reclamation, CDEC). Fill % uses design capacity from the National Inventory of Dams where available; a few sites without a match fall back to the 5-year maximum.

Major reservoirs — data pending

2 major reservoirs — data sourcing in progress

Storage is monitored by the US Geological Survey (USGS NWIS) / the US Army Corps of Engineers (USACE CWMS), but the live feed is currently stale — we are working to restore it. Known capacities: BIG SANDY RESERVOIR NEAR FARSON, WY (0.0 km³), Seminoe Dam & Reservoir (1.3 km³).

About reservoirs in Wyoming

As of July 29, 2026, the reservoirs we track across Wyoming that report live levels hold roughly 4,964 hm³ of water — about 49.8% of their combined capacity. Taken together, Wyoming's reservoirs are within their normal operating range.

Across the region, 5 reservoirs are at critically low levels and 4 are low. Kortes Dam & Reservoir is the fullest at 99.7%, while South Fork Dike at Buffalo Bill Reservoir is the lowest at 0.4%.

Over the most recent week on record, 1 reservoir rose and 2 reservoirs fell across Wyoming.

Storage figures for Wyoming come from USGS · USACE · BOR · CDEC; the most recent reading is from July 29, 2026. Each reservoir below links to its own page with full history and seasonal context.

Wyoming at a glance

Reservoirs tracked
25
Average fill
49.8%
Water stored
4,964 hm³
Combined capacity
9,969 hm³
At critically low levels
5
Fullest
Kortes Dam & Reservoir (99.7%)
Lowest
South Fork Dike at Buffalo Bill Reservoir (0.4%)
Last updated
July 29, 2026

Frequently asked questions

How full are reservoirs in Wyoming right now?

As of July 29, 2026, the reservoirs tracked in Wyoming that report live levels are 49.8% full overall, holding about 4,964 hm³ of water.

How many reservoirs are there in Wyoming?

reservoirs.earth tracks 25 reservoirs in Wyoming, with a combined storage capacity of 9,969 hm³.

Which reservoir in Wyoming is the fullest?

Kortes Dam & Reservoir is currently the fullest reservoir in Wyoming, at 99.7% of capacity.

Which reservoir in Wyoming is the lowest?

South Fork Dike at Buffalo Bill Reservoir is currently the lowest in Wyoming, at 0.4% of capacity.

Where does the reservoir data for Wyoming come from?

All storage figures for Wyoming come from USGS · USACE · BOR · CDEC, an official source, last updated July 29, 2026.

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