Holly 9 is an earth dam located in Murray County, Minnesota, built in 2007. It carries a Low hazard potential classification.
Dam profile
NID height · 50 ft50 ft tall and 400 ft long, taller than 92% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Holly 9
The primary purpose of Holly 9 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 Knakmuhs, Darold & Loren (private). It impounds the Plum Creek-tr near Walnut Grove.
The dam stands 50 feet tall and stretches 400 feet across, has a maximum storage capacity of 186 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 2007, the structure is relatively new.
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 08/01/2024.
At 50 feet, this dam is taller than 92% of dams nationwide.
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Location
| State | Minnesota |
| County | Murray |
| Nearest City | Walnut Grove |
| River/Stream | Plum Creek-tr |
| Coordinates | 44.16801, -95.52569 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 50 ft |
| Dam Height | 40 ft |
| Dam Length | 400 ft |
| Year Completed | 2007 (19 years old) |
Storage & Hydraulics
| NID Storage | 186 acre-ft |
| Max Storage | 186 acre-ft |
| Normal Storage | 1 acre-ft |
| Drainage Area | 1 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Knakmuhs, Darold & Loren |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 08/01/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MN01427 |
| Federal ID | MN01427 |
| More Info | State Dam Safety Program |