Cox Hollow Number Two
Cox Hollow Number Two is an earth dam located in Iowa County, Wisconsin, built in 1965. It carries a High hazard potential classification and has a fair condition assessment.
About Cox Hollow Number Two
The primary purpose of Cox Hollow Number Two is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Wisconsin Department Of Natural Resources (state). It impounds the Mill Creek.
The dam stands 55 feet tall and stretches 630 feet across, creates a reservoir covering 152 acres, has a maximum storage capacity of 5,370 acre-feet, and collects water from a drainage area of 13 square miles. Completed in 1965, the structure is well into its service life at over 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 11/09/2021.
At 55 feet, this dam is taller than 94% of dams nationwide.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Wisconsin dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Wisconsin |
| County | Iowa |
| Nearest City | None |
| River/Stream | Mill Creek |
| Coordinates | 43.02528, -90.08360 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 55 ft |
| Dam Height | 55 ft |
| Dam Length | 630 ft |
| Year Completed | 1965 (61 years old) |
Storage & Hydraulics
| NID Storage | 5,370 acre-ft |
| Max Storage | 5,370 acre-ft |
| Normal Storage | 1,850 acre-ft |
| Surface Area | 152 acres |
| Drainage Area | 13 sq mi |
| Max Discharge | 606 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Wisconsin Department of Natural Resources |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 11/09/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WI00013 |
| Federal ID | WI00013 |
| More Info | State Dam Safety Program |