Lake John Annex
Key Takeaway
Lake John Annex is classified as low hazard in Colorado. It was completed in 1994 and is 32 years old. Its primary use is recreation.
Physical Details
| Dam Height | 4 ft |
| Dam Length | 32 ft |
| Dam Type | Gravity |
| Max Storage | 881 acre-ft |
| Normal Storage | 760 acre-ft |
| Surface Area | 221 acres |
| Drainage Area | 10 sq mi |
| Year Completed | 1994 (32 years old) |
| NID ID | CO03015 |
Safety Information
No probable loss of human life and low economic/environmental losses expected.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
COLORADO PARKS AND WILDLIFE
State Government
Nearby Dams
Lake John
Jackson, CO
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Low Hazard 16 ftFrequently Asked Questions
What is the hazard classification of Lake John Annex?
Lake John Annex is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Lake John Annex?
Lake John Annex is owned by COLORADO PARKS AND WILDLIFE (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Lake John Annex built?
Lake John Annex was completed in 1994, making it 32 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.
What is the primary purpose of Lake John Annex?
Lake John Annex serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Lake John Annex?
Lake John Annex has a dam height of 4 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.