Thompson is an earth dam located in Niobrara County, Wyoming, built in 1950. It carries a Low hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 37 ft37 ft tall and 365 ft long, taller than 83% 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 Thompson
The primary purpose of Thompson is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by J & R Christensen Land, LLC (private). It impounds the Cody Draw near Ardmore, Sd.
The dam stands 37 feet tall and stretches 365 feet across, creates a reservoir covering 10 acres, and has a maximum storage capacity of 173 acre-feet. Completed in 1950, the structure is well-established, with more than 75 years of service.
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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 07/26/2023.
At 37 feet, this dam is taller than 83% of dams nationwide.
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Location
| State | Wyoming |
| County | Niobrara |
| Nearest City | Ardmore, Sd |
| River/Stream | Cody Draw |
| Coordinates | 42.99639, -104.17639 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 37 ft |
| Dam Height | 37 ft |
| Dam Length | 365 ft |
| Year Completed | 1950 (76 years old) |
Storage & Hydraulics
| NID Storage | 173 acre-ft |
| Max Storage | 173 acre-ft |
| Normal Storage | 116 acre-ft |
| Surface Area | 10 acres |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | J & R Christensen Land, LLC |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 07/26/2023 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | WY00798 |
| Federal ID | WY00798 |
| More Info | State Dam Safety Program |