Green Valley Lake Dam is an earth dam located in Union County, Iowa, built in 1953. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 41 ft41 ft tall and 1,020 ft long, taller than 87% 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 Green Valley Lake Dam
The primary purpose of Green Valley Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Iowa Department of Natural Resources (state). It impounds the Platte River near Creston.
The dam stands 41 feet tall and stretches 1,020 feet across, creates a reservoir covering 336 acres, has a maximum storage capacity of 6,830 acre-feet, and collects water from a drainage area of 8 square miles. Completed in 1953, the structure is well into its service life at over 50 years 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 07/26/2021.
At 41 feet, this dam is taller than 87% of dams nationwide.
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Location
| State | Iowa |
| County | Union |
| Nearest City | Creston |
| River/Stream | Platte River |
| Coordinates | 41.09680, -94.38380 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 41 ft |
| Dam Height | 41 ft |
| Dam Length | 1,020 ft |
| Year Completed | 1953 (73 years old) |
Storage & Hydraulics
| NID Storage | 6,830 acre-ft |
| Max Storage | 6,830 acre-ft |
| Normal Storage | 3,990 acre-ft |
| Surface Area | 336 acres |
| Drainage Area | 8 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Iowa Department of Natural Resources |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 07/26/2021 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA01097 |
| Federal ID | IA01097 |
| More Info | State Dam Safety Program |