Oligarchy #1 is an earth dam located in Boulder County, Colorado, built in 1889. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 33 ft33 ft tall and 1,040 ft long, taller than 76% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Oligarchy #1
The primary purpose of Oligarchy #1 is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Oligarchy Reservoir Company (tipton, President, Ne (private). It impounds the St. Vrain Creek-os near Longmont.
The dam stands 33 feet tall and stretches 1,040 feet across, creates a reservoir covering 97 acres, and has a maximum storage capacity of 2,161 acre-feet. Completed in 1889, the structure is over a century old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 06/10/2022.
At 33 feet, this dam is taller than 76% of dams nationwide.
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Location
| State | Colorado |
| County | Boulder |
| Nearest City | Longmont |
| River/Stream | St. Vrain Creek-os |
| Coordinates | 40.19836, -105.19178 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 33 ft |
| Dam Height | 29 ft |
| Dam Length | 1,040 ft |
| Year Completed | 1889 (137 years old) |
Storage & Hydraulics
| NID Storage | 2,161 acre-ft |
| Max Storage | 2,161 acre-ft |
| Normal Storage | 1,737 acre-ft |
| Surface Area | 97 acres |
| Max Discharge | 1,580 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Oligarchy Reservoir Company (tipton, President, Ne |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/10/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CO01236 |
| Federal ID | CO01236 |
| More Info | State Dam Safety Program |