Lake John Annex is a gravity dam located in Jackson County, Colorado, built in 1994. It carries a Low hazard potential classification.
Dam profile
NID height · 7 ft7 ft tall and 32 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Lake John Annex
The primary purpose of Lake John Annex is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Colorado Parks and Wildlife (state). It impounds the Lake Creek.
The dam stands 7 feet tall and stretches 32 feet across, creates a reservoir covering 221 acres, has a maximum storage capacity of 881 acre-feet, and collects water from a drainage area of 10 square miles. Completed in 1994, the structure is 32 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life.
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Location
| State | Colorado |
| County | Jackson |
| River/Stream | Lake Creek |
| Coordinates | 40.77350, -106.45691 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 7 ft |
| Dam Height | 4 ft |
| Dam Length | 32 ft |
| Year Completed | 1994 (32 years old) |
Storage & Hydraulics
| NID Storage | 881 acre-ft |
| Max Storage | 881 acre-ft |
| Normal Storage | 760 acre-ft |
| Surface Area | 221 acres |
| Drainage Area | 10 sq mi |
| Spillway Type | None |
Ownership & Safety
| Purpose | Recreation |
| Owner | Colorado Parks and Wildlife |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | CO03015 |
| Federal ID | CO03015 |
| More Info | State Dam Safety Program |