Ottawa Upground Reservoir
Ottawa Upground Reservoir is an earth dam located in Putnam County, Ohio, built in 1972. It carries a High hazard potential classification and has a fair condition assessment.
About Ottawa Upground Reservoir
The primary purpose of Ottawa 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 Village Of Ottawa (local government). It impounds the Blanchard River - Offstream near Ottawa.
The dam stands 22 feet tall and stretches 3,800 feet across, creates a reservoir covering 19 acres, has a maximum storage capacity of 400 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1972, 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 12/12/2024.
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 | Putnam |
| Nearest City | Ottawa |
| River/Stream | Blanchard River - Offstream |
| Coordinates | 41.01333, -84.02306 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 3,800 ft |
| Year Completed | 1972 (54 years old) |
Storage & Hydraulics
| NID Storage | 400 acre-ft |
| Max Storage | 400 acre-ft |
| Normal Storage | 342 acre-ft |
| Surface Area | 19 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 25 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Village of Ottawa |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 12/12/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | OH01058 |
| Federal ID | OH01058 |
| More Info | State Dam Safety Program |