Flat Rock is a concrete dam located in Philadelphia County, Pennsylvania, built in 1977. It carries a Low hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 21 ft21 ft tall and 510 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Flat Rock
The primary purpose of Flat Rock is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Dep (state). It impounds the Schuylkill River.
The dam stands 21 feet tall and stretches 510 feet across, creates a reservoir covering 105 acres, has a maximum storage capacity of 1,500 acre-feet, and collects water from a drainage area of 1,809 square miles. Completed in 1977, the structure is 49 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 11/09/2017.
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Location
| State | Pennsylvania |
| County | Philadelphia |
| River/Stream | Schuylkill River |
| Coordinates | 40.03972, -75.24694 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 21 ft |
| Dam Height | 21 ft |
| Dam Length | 510 ft |
| Year Completed | 1977 (49 years old) |
Storage & Hydraulics
| NID Storage | 1,500 acre-ft |
| Max Storage | 1,500 acre-ft |
| Normal Storage | 788 acre-ft |
| Surface Area | 105 acres |
| Drainage Area | 1,809 sq mi |
Ownership & Safety
| Purpose | Recreation |
| Owner | Dep |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 11/09/2017 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | PA00896 |
| Federal ID | PA00896 |
| More Info | State Dam Safety Program |