Allyn Dam
Allyn Dam is an earth dam located in Holt County, Nebraska, built in 1968. It carries a Low hazard potential classification and has a poor condition assessment.
About Allyn Dam
The primary purpose of Allyn Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Holt County (private). It impounds the Tr-niobrara River near Redbird.
The dam stands 30 feet tall and stretches 1,042 feet across, creates a reservoir covering 8 acres, has a maximum storage capacity of 138 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1968, the structure is well into its service life at over 50 years 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 05/18/2023.
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Location
| State | Nebraska |
| County | Holt |
| Nearest City | Redbird |
| River/Stream | Tr-niobrara River |
| Coordinates | 42.84467, -99.10074 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 25 ft |
| Dam Length | 1,042 ft |
| Year Completed | 1968 (58 years old) |
Storage & Hydraulics
| NID Storage | 138 acre-ft |
| Max Storage | 138 acre-ft |
| Normal Storage | 37 acre-ft |
| Surface Area | 8 acres |
| Drainage Area | 4 sq mi |
| Max Discharge | 826 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Holt County |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Poor |
| Last Inspection | 05/18/2023 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NE00420 |
| Federal ID | NE00420 |
| More Info | State Dam Safety Program |