Mendota Locks
Mendota Locks is an other dam located in Dane County, Wisconsin, built in 1849. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Mendota Locks
The primary purpose of Mendota Locks is navigation. The dam maintains water levels sufficient for boat and barge traffic, supporting commercial or recreational navigation on the waterway. The dam is owned by Dane County (local government). It impounds the Yahara River near Madison.
The dam stands 16 feet tall and stretches 100 feet across, creates a reservoir covering 9,730 acres, has a maximum storage capacity of 160,000 acre-feet, and collects water from a drainage area of 254 square miles. Completed in 1849, the structure is one of the older dams in the region, with over a century and a half of service.
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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 06/19/2020.
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 | Dane |
| Nearest City | Madison |
| River/Stream | Yahara River |
| Coordinates | 43.09489, -89.37025 |
Physical Characteristics
| Dam Type | Other |
| NID Height | 16 ft |
| Dam Height | 16 ft |
| Dam Length | 100 ft |
| Year Completed | 1849 (177 years old) |
Storage & Hydraulics
| NID Storage | 160,000 acre-ft |
| Max Storage | 160,000 acre-ft |
| Normal Storage | 132,000 acre-ft |
| Surface Area | 9,730 acres |
| Drainage Area | 254 sq mi |
| Max Discharge | 1,860 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Navigation |
| Owner | Dane County |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/19/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WI00621 |
| Federal ID | WI00621 |
| More Info | State Dam Safety Program |