Cardinal Fly Ash No. 1 Dam
Cardinal Fly Ash No. 1 Dam is an earth dam located in Jefferson County, Ohio, built in 1974. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Cardinal Fly Ash No. 1 Dam
The primary purpose of Cardinal Fly Ash No. 1 Dam is tailings. Tailings dams contain waste material from mining operations — typically a slurry of finely ground rock left over after valuable minerals have been extracted. These structures require ongoing monitoring because tailings can contain heavy metals and other contaminants. The dam is owned by Cardinal Operating Company (public utility). It impounds the Blockhouse Run near Brilliant.
The dam stands 242 feet tall and stretches 1,300 feet across, creates a reservoir covering 80 acres, has a maximum storage capacity of 4,800 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1974, 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 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 11/07/2022.
At 242 feet, this dam is taller than 99% of all dams in the United States.
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 | Jefferson |
| Nearest City | Brilliant |
| River/Stream | Blockhouse Run |
| Coordinates | 40.26778, -80.64944 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 242 ft |
| Dam Height | 242 ft |
| Dam Length | 1,300 ft |
| Year Completed | 1974 (52 years old) |
Storage & Hydraulics
| NID Storage | 4,800 acre-ft |
| Max Storage | 4,800 acre-ft |
| Normal Storage | 3,870 acre-ft |
| Surface Area | 80 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 10,930 cfs |
Ownership & Safety
| Purpose | Tailings |
| Owner | Cardinal Operating Company |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/07/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | OH00920 |
| Federal ID | OH00920 |
| More Info | State Dam Safety Program |