Hershey Mill is an earth dam located in Chester County, Pennsylvania, built in 1748. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 14 ft14 ft tall and 450 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Hershey Mill
The primary purpose of Hershey Mill is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by East Goshen Township (local government). It impounds the Ridley Creek.
The dam stands 14 feet tall and stretches 450 feet across, creates a reservoir covering 7 acres, has a maximum storage capacity of 18 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1748, the structure is one of the older dams in the region, with over a century and a half of service.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in 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. An emergency action plan is in place for this dam. The most recent inspection on record was 05/19/2015. That was over 11 years ago.
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Location
| State | Pennsylvania |
| County | Chester |
| River/Stream | Ridley Creek |
| Coordinates | 40.01306, -75.55722 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 14 ft |
| Dam Height | 14 ft |
| Dam Length | 450 ft |
| Year Completed | 1748 (278 years old) |
Storage & Hydraulics
| NID Storage | 18 acre-ft |
| Max Storage | 18 acre-ft |
| Normal Storage | 13 acre-ft |
| Surface Area | 7 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Recreation |
| Owner | East Goshen Township |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 05/19/2015 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PA01868 |
| Federal ID | PA01868 |
| More Info | State Dam Safety Program |