Green Mountain Reservoir
Green Mountain Reservoir is managed by U.S. Bureau of Reclamation.
Lake Status
We don't have enough recent gauge readings to summarize Green Mountain Reservoir's status yet. View the water level page for the latest published data.
Watershed drought conditions
Summit County, CO · surrounding county from lake location
Exceptional Drought
Exceptional drought conditions are present.
Severity
Weekly trend
Stable
Compared with last week
Official drought
Yes
100% of the watershed is currently classified as official drought (D1+).
Expected impacts
- Significantly reduced stream inflows
- Lake levels may fall quickly without heavy rain
- Dry vegetation and elevated wildfire risk
- Water use restrictions may apply nearby
U.S. Drought Monitor · map date Sep 8, 2026. Updated weekly. droughtmonitor.unl.eduView drought map for Summit County, CO
Key Facts
Managing authority
Waterbody / project type
Official purposes
Project / NID identifier
Dam / watershed (NID design values)
Static design values from a confidently matched National Inventory of Dams record — not live gage readings.
- Normal storage
- 153,640 acre-ft
- Max storage
- 161,850 acre-ft
- Surface area at normal pool
- 2,125 acres
- Drainage area
- 582 sq mi
- Spillway capacity (design)
- 25,000 cfs
- Dam structure
- Earth · 309 ft high · completed 1943
- Hazard classification
- High
- Safety & inspection
- last inspection Jan 9, 2024
National Inventory of Dams · matched record: Green Mountain Dam (CO01658)
How this lake is operated
- Documented project purposes (National Inventory of Dams): Hydroelectric, Irrigation, Recreation.
Why the level can change
General factors for reservoirs like this
These are common influences for this type of lake. They do not identify the cause of a specific current change unless an operator update confirms it.
Rainfall & inflows
Rain and upstream river inflows can raise reservoir levels, especially after storms.
Downstream releases
When an operator releases water through a dam, reservoir storage can fall and downstream flows can rise.
Flood-risk operations
Some projects store or release water under flood-risk rules when conditions require it.
Water supply
Some reservoirs support municipal, industrial, irrigation, or regional water-supply needs.
Hydropower
Hydropower projects may pass water through turbines when generating electricity.
Seasonal weather
Dry periods, heat, evaporation, and seasonal rainfall patterns can affect storage over weeks and months.
Current data source
Managing authority: U.S. Bureau of Reclamation
Observation source used by Lake Insights: Not published
Who manages the lake and who publishes the reading Lake Insights displays can differ. Lake Insights does not invent a source label from the managing authority alone.
General education
Shared background — not lake-specific facts
Lake Insights aggregates water level information from authoritative public sources such as the U.S. Army Corps of Engineers, NOAA, TVA, Bureau of Reclamation, power utilities, and other official lake operators. We preserve historical observations, calculate trends, and present lake conditions in a consistent format. Lake Insights does not predict future lake levels unless an official forecast has been published by the managing authority.
Common questions about Green Mountain Reservoir
- Who manages Green Mountain Reservoir?
- Green Mountain Reservoir is managed by U.S. Bureau of Reclamation. Lake Insights reports published gauge readings; it does not operate the waterbody.
- What are the documented purposes of Green Mountain Reservoir?
- Documented purposes for Green Mountain Reservoir (National Inventory of Dams): Hydroelectric, Irrigation, Recreation.