Lake Mosier Upground Reservoir
Lake Mosier Upground Reservoir is an earth dam located in Hancock County, Ohio, built in 1941. It carries a High hazard potential classification and has a poor condition assessment.
About Lake Mosier Upground Reservoir
The primary purpose of Lake Mosier Upground Reservoir is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City Of Fostoria (local government). It impounds the East Branch Portage River - Offstream near Fostoria.
The dam stands 25 feet tall and stretches 8,125 feet across, creates a reservoir covering 90 acres, has a maximum storage capacity of 1,207 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1941, the structure is well-established, with more than 75 years 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 06/24/2021.
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 Ohio 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 | Ohio |
| County | Hancock |
| Nearest City | Fostoria |
| River/Stream | East Branch Portage River - Offstream |
| Coordinates | 41.13889, -83.42833 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 25 ft |
| Dam Height | 25 ft |
| Dam Length | 8,125 ft |
| Year Completed | 1941 (85 years old) |
Storage & Hydraulics
| NID Storage | 1,207 acre-ft |
| Max Storage | 1,207 acre-ft |
| Normal Storage | 740 acre-ft |
| Surface Area | 90 acres |
| Drainage Area | 0 sq mi |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Fostoria |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 06/24/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | OH00784 |
| Federal ID | OH00784 |
| More Info | State Dam Safety Program |