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 capacitySeminoe Reservoir Dam and Powerplant
lowUpdated 2026-07-28
Pathfinder Reservoir and Dam
criticalUpdated 2026-07-28
Jackson Lake and Jackson Lake Dam (JCK)
Updated 2026-07-28
Boysen Dam & Reservoir
Updated 2026-07-29
Boysen Reservoir Dam and Powerplant
Updated 2026-07-28
Buffalo Bill Reservoir Dam and Powerplant
Updated 2026-07-28
South Fork Dike at Buffalo Bill Reservoir
criticalUpdated 2026-07-28
Glendo Dam & Reservoir
Updated 2026-07-29
Glendo Reservoir Dam and Powerplant
Updated 2026-07-28
Fontenelle Reservoir Dam and Powerplant
Updated 2026-07-28
Keyhole Dam & Reservoir
lowUpdated 2026-07-29
Keyhole Reservoir and Dam
lowUpdated 2026-07-28
Alcova Reservoir Dam and Powerplant
Updated 2026-07-28
Bull Lake Reservoir and Dam
Updated 2026-07-28
Guernsey Reservoir Dam and Powerplant
Updated 2026-07-28
Big Sandy Reservoir and Dam
Updated 2026-07-28
Pilot Butte Reservoir, WY
Updated 2026-07-29
Pilot Butte Reservoir and Dam
Updated 2026-07-28
Meeks Cabin Reservoir and Dam
criticalUpdated 2026-07-28
Anchor Reservoir, SF Owl Cr, WY
criticalUpdated 2026-07-29
Anchor Reservoir and Dam
criticalUpdated 2026-07-28
Grassy Lake and Grassy Lake Dam (GRS)
Updated 2026-07-28
Eden Reservoir and Dam
lowUpdated 2026-07-28
Kortes Dam & Reservoir
Updated 2026-07-29
Gray Reef Reservoir and Dam
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.