Porter Reservoir Dam
Porter Reservoir Dam is a gravity dam located in New Castle County, Delaware, built in 1909. It carries a High hazard potential classification and has a fair condition assessment.
About Porter Reservoir Dam
The primary purpose of Porter Reservoir Dam 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 City Of Wilmington (local government). It impounds the Matson Run-os near Wilmington.
The dam stands 12 feet tall and stretches 2,160 feet across, creates a reservoir covering 6 acres, has a maximum storage capacity of 114 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1909, the structure is over a century 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. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 10/16/2000. That was 25 years ago — unusually long for a high-hazard dam, which typically requires more frequent inspections.
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 Delaware 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 | Delaware |
| County | New Castle |
| Nearest City | Wilmington |
| River/Stream | Matson Run-os |
| Coordinates | 39.77309, -75.54179 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 12 ft |
| Dam Height | 12 ft |
| Dam Length | 2,160 ft |
| Year Completed | 1909 (117 years old) |
Storage & Hydraulics
| NID Storage | 114 acre-ft |
| Max Storage | 114 acre-ft |
| Normal Storage | 103 acre-ft |
| Surface Area | 6 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 18 cfs |
| Spillway Type | None |
Ownership & Safety
| Purpose | Water Supply |
| Owner | CITY OF WILMINGTON |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 10/16/2000 |
| Emergency Action Plan | No |
Identifiers
| NID ID | DE00013 |
| Federal ID | DE00013 |
| More Info | State Dam Safety Program |