Lone Tree
Lone Tree is an earth dam located in Larimer County, Colorado, built in 1882. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Lone Tree
The primary purpose of Lone Tree is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Consolidated Home Supply Ditch & Res. Co (dave Sch (private). It impounds the Big Thompson River-os near Johnstown.
The dam stands 29 feet tall and stretches 5,265 feet across, creates a reservoir covering 503 acres, has a maximum storage capacity of 10,973 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 1882, 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 09/02/2021.
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Location
| State | Colorado |
| County | Larimer |
| Nearest City | Johnstown |
| River/Stream | Big Thompson River-os |
| Coordinates | 40.34765, -105.11599 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 29 ft |
| Dam Height | 29 ft |
| Dam Length | 5,265 ft |
| Year Completed | 1882 (144 years old) |
Storage & Hydraulics
| NID Storage | 10,973 acre-ft |
| Max Storage | 10,973 acre-ft |
| Normal Storage | 9,268 acre-ft |
| Surface Area | 503 acres |
| Drainage Area | 5 sq mi |
| Max Discharge | 14,280 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | CONSOLIDATED HOME SUPPLY DITCH & RES. CO (DAVE SCH |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/02/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CO01734 |
| Federal ID | CO01734 |
| More Info | State Dam Safety Program |