Markham is an earth dam located in Park County, Wyoming, built in 1929. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 11 ft11 ft tall and 2,500 ft long. 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 Markham
The primary purpose of Markham is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City of Cody (local government). It impounds the S Fork Shoshone Offstream near Cody.
The dam stands 11 feet tall and stretches 2,500 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 730 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1929, the structure is well-established, with more than 75 years of service.
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. An emergency action plan is in place for this dam. The most recent inspection on record was 05/13/2024.
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Location
| State | Wyoming |
| County | Park |
| Nearest City | Cody |
| River/Stream | S Fork Shoshone Offstream |
| Coordinates | 44.51000, -109.05417 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 11 ft |
| Dam Height | 11 ft |
| Dam Length | 2,500 ft |
| Year Completed | 1929 (97 years old) |
Storage & Hydraulics
| NID Storage | 730 acre-ft |
| Max Storage | 730 acre-ft |
| Normal Storage | 67 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 0 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Cody |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 05/13/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WY01101 |
| Federal ID | WY01101 |
| More Info | State Dam Safety Program |