Conowingo
Conowingo is a concrete dam located in Cecil County, Maryland, built in 1928. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Conowingo
The primary purpose of Conowingo is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. It impounds the Susquehanna River near Port Deposit.
The dam stands 94 feet tall and stretches 4,648 feet across, creates a reservoir covering 8,563 acres, has a maximum storage capacity of 310,000 acre-feet, and collects water from a drainage area of 27,077 square miles. Completed in 1928, 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 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 08/08/2022.
At 94 feet, this dam is taller than 98% 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 Maryland 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 | Maryland |
| County | Cecil |
| Nearest City | Port Deposit |
| River/Stream | Susquehanna River |
| Coordinates | 39.66090, -76.17330 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 94 ft |
| Dam Height | 94 ft |
| Dam Length | 4,648 ft |
| Year Completed | 1928 (98 years old) |
Storage & Hydraulics
| NID Storage | 310,000 acre-ft |
| Max Storage | 310,000 acre-ft |
| Normal Storage | 301,400 acre-ft |
| Surface Area | 8,563 acres |
| Drainage Area | 27,077 sq mi |
| Max Discharge | 1,135,552 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner Type | Not Listed |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/08/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MD00097 |
| Federal ID | MD00097 |
| More Info | State Dam Safety Program |