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

⏳

9 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), Alcova Dam nr Casper, WY (0.2 km³), Buffalo Bill Dam & Reservoir (0.8 km³), Bull Lake Dam, Bull Lake Cr, WY (0.2 km³), Gray Reef Dam & Reservoir (0.0 km³), Grayrocks Dam and Reservoir (0.1 km³), Guernsey Dam & Reservoir (0.1 km³), North Platte R at Pathfinder Dam (1.3 km³), Seminoe Dam & Reservoir (1.3 km³).

BIG SANDY RESERVOIR NEAR FARSON, WY

Sourcing

Capacity: 49 hm³⏳ Pending

Alcova Dam nr Casper, WY

Sourcing

Capacity: 227 hm³⏳ Pending

Buffalo Bill Dam & Reservoir

Sourcing

Capacity: 798 hm³⏳ Pending

Bull Lake Dam, Bull Lake Cr, WY

Sourcing

Capacity: 188 hm³⏳ Pending

Gray Reef Dam & Reservoir

Sourcing

Capacity: 2 hm³⏳ Pending

Grayrocks Dam and Reservoir

Sourcing

Capacity: 128 hm³⏳ Pending

Guernsey Dam & Reservoir

Sourcing

Capacity: 56 hm³⏳ Pending

North Platte R at Pathfinder Dam

Sourcing

Capacity: 1,254 hm³⏳ Pending

Seminoe Dam & Reservoir

Sourcing

Capacity: 1,255 hm³⏳ Pending

About reservoirs in Wyoming

As of June 11, 2026, the reservoirs we track across Wyoming that report live levels hold roughly 5,865 hm³ of water — about 58.8% of their combined capacity. Taken together, Wyoming's reservoirs are within their normal operating range.

Across the region, 3 reservoirs are at critically low levels and 5 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 1 reservoir fell across Wyoming.

Storage figures for Wyoming come from USGS · USACE · BOR · CDEC; the most recent reading is from June 11, 2026. Each reservoir below links to its own page with full history and seasonal context.

Wyoming at a glance

Reservoirs tracked: 25
Average fill: 58.8%
Water stored: 5,865 hm³
Combined capacity: 9,969 hm³
At critically low levels: 3
Fullest: Kortes Dam & Reservoir (99.7%)
Lowest: South Fork Dike at Buffalo Bill Reservoir (0.4%)
Last updated: June 11, 2026

Frequently asked questions

How full are reservoirs in Wyoming right now?

As of June 11, 2026, the reservoirs tracked in Wyoming that report live levels are 58.8% full overall, holding about 5,865 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 June 11, 2026.

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