Marble Rock Milldam is a gravity dam located in Floyd County, Iowa, built in 1913. It carries a Low hazard potential classification.
Dam profile
NID height · 15 ft15 ft tall and 187 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Marble Rock Milldam
The primary purpose of Marble Rock Milldam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by City of Marble Rock (local government). It impounds the Shell Rock River near Marble Rock.
The dam stands 15 feet tall and stretches 187 feet across, creates a reservoir covering 110 acres, has a maximum storage capacity of 836 acre-feet, and collects water from a drainage area of 1,318 square miles. Completed in 1913, the structure is over a century old.
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. The most recent inspection on record was 12/12/1989. That was over 36 years ago.
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Location
| State | Iowa |
| County | Floyd |
| Nearest City | Marble Rock |
| River/Stream | Shell Rock River |
| Coordinates | 42.96530, -92.87090 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 187 ft |
| Year Completed | 1913 (113 years old) |
Storage & Hydraulics
| NID Storage | 836 acre-ft |
| Max Storage | 836 acre-ft |
| Normal Storage | 836 acre-ft |
| Surface Area | 110 acres |
| Drainage Area | 1,318 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | City of Marble Rock |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 12/12/1989 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA01309 |
| Federal ID | IA01309 |
| More Info | State Dam Safety Program |