Greene Mill Dam is a gravity dam located in Butler County, Iowa, built in 1925. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 11 ft11 ft tall and 282 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 Greene Mill Dam
The primary purpose of Greene Mill Dam is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Butler County, Ia (private). It impounds the Shell Rock near Greene.
The dam stands 11 feet tall and stretches 282 feet across, creates a reservoir covering 85 acres, has a storage capacity of 385 acre-feet, and collects water from a drainage area of 1,357 square miles. Completed in 1925, 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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 09/08/2022.
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Location
| State | Iowa |
| County | Butler |
| Nearest City | Greene |
| River/Stream | Shell Rock |
| Coordinates | 42.89510, -92.80310 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 11 ft |
| Dam Height | 11 ft |
| Dam Length | 282 ft |
| Year Completed | 1925 (101 years old) |
Storage & Hydraulics
| NID Storage | 385 acre-ft |
| Normal Storage | 385 acre-ft |
| Surface Area | 85 acres |
| Drainage Area | 1,357 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Butler County, Ia |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/08/2022 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA01298 |
| Federal ID | IA01298 |
| More Info | State Dam Safety Program |