Nicolaysen
Nicolaysen is an earth dam located in Natrona County, Wyoming, built in 1899. It carries a Significant hazard potential classification and has a fair condition assessment.
About Nicolaysen
The primary purpose of Nicolaysen is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Kro Ventures, Llc (private). It impounds the Dry Muddy Creek near Big Muddy Oil Field.
The dam stands 22 feet tall and stretches 1,500 feet across, creates a reservoir covering 30 acres, has a maximum storage capacity of 475 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 1899, 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 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 05/18/2022.
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Location
| State | Wyoming |
| County | Natrona |
| Nearest City | Big Muddy Oil Field |
| River/Stream | Dry Muddy Creek |
| Coordinates | 42.81060, -106.19660 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 1,500 ft |
| Year Completed | 1899 (127 years old) |
Storage & Hydraulics
| NID Storage | 475 acre-ft |
| Max Storage | 475 acre-ft |
| Normal Storage | 330 acre-ft |
| Surface Area | 30 acres |
| Drainage Area | 5 sq mi |
| Max Discharge | 3,120 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | KRO VENTURES, LLC |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 05/18/2022 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | WY00233 |
| Federal ID | WY00233 |
| More Info | State Dam Safety Program |