Willow Slough Dam is an earth dam located in Mills County, Iowa, built in 1959. It carries a Low hazard potential classification.
Dam profile
NID height · 8 ft8 ft tall and 11,100 ft long. 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 Willow Slough Dam
The primary purpose of Willow Slough 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 Tr-west Nishnabotna River near Hastings.
The dam stands 8 feet tall and stretches 11,100 feet across, creates a reservoir covering 2,100 acres, has a maximum storage capacity of 1,600 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1959, 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. The most recent inspection on record was 10/30/1963. That was over 62 years ago.
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Location
| State | Iowa |
| County | Mills |
| Nearest City | Hastings |
| River/Stream | Tr-west Nishnabotna River |
| Coordinates | 41.10120, -95.45310 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 8 ft |
| Dam Height | 8 ft |
| Dam Length | 11,100 ft |
| Year Completed | 1959 (67 years old) |
Storage & Hydraulics
| NID Storage | 1,600 acre-ft |
| Max Storage | 1,600 acre-ft |
| Normal Storage | 600 acre-ft |
| Surface Area | 2,100 acres |
| Drainage Area | 2 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Iowa Department of Natural Resources |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 10/30/1963 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | IA00696 |
| Federal ID | IA00696 |
| More Info | State Dam Safety Program |