Fact Sheet Article View

Delaware Bay Coastline, Port Mahon, DE

USACE Philadelphia District
Published April 15, 2026
The plan proposed in the final feasibility report for the purpose of flood and coastal storm damage reduction and ecosystem restoration at Port Mahon consists of a 5,200 foot long beachfill with periodic nourishment to provide for horseshoe crab and shorebird habitat.  It also includes raising State Road 89 for a distance of 7,500 feet and placing riprap along a 1,200 foot length of the road to protect wetlands, and restoring 21.4 acres of degraded wetland habitat west of the road.

The plan proposed in the final feasibility report for the purpose of flood and coastal storm damage reduction and ecosystem restoration at Port Mahon consists of a 5,200 foot long beachfill with periodic nourishment to provide for horseshoe crab and shorebird habitat. It also includes raising State Road 89 for a distance of 7,500 feet and placing riprap along a 1,200 foot length of the road to protect wetlands, and restoring 21.4 acres of degraded wetland habitat west of the road.

CONGRESSIONAL DISTRICTS: DE-AL

APPROPRIATION / PHASE: Construction, General

BUSINESS PROGRAM: Flood and Coastal Storm Damage Reduction, Ecosystem Restoration

AUTHORITY:  The Delaware Bay Coastline, DE & NJ – Port Mahon, DE project was authorized for construction by Title I, Section 101 (a) (12) of WRDA 1999.

LOCATION:  The project area is located on Delaware Bay at Port Mahon, Kent County, Delaware.

DESCRIPTION: The plan proposed in the final feasibility report for the purpose of flood and coastal storm damage reduction and ecosystem restoration at Port Mahon consists of a 5,200 foot long beach fill with periodic nourishment to provide for horseshoe crab and shorebird habitat. It also includes raising State Road 89 for a distance of 7,500 feet and placing riprap along a 1,200 foot length of the road to protect wetlands, and restoring 21.4 acres of degraded wetland habitat west of the road. The estimated initial project cost is $13.1 million. The Planning, Engineering and Design phase was completed in FY 2001 with finishing detailed plans and specifications for those features recommended in the feasibility report.

STATUS: Funds have not been received for this project since Fiscal Year 2007. The next steps toward initial construction once adequate funding is received is to update the Limited Reevaluation Report; develop, approve and execute the Project Partnership Agreement; acquire the necessary real estate; complete plans and specifications; and advertise and award the construction contract. 

PROJECT GOALS: The purpose of this project provides hurricane and coastal storm damage reduction and ecosystem restoration at Port Mahon, with a beach fill and periodic nourishment to provide for horseshoe crab and shorebird habitat.

NON-FEDERAL SPONSOR:  Delaware Department of Natural Resources and Environmental Control.

DATE OF PROJECT PARTNERSHIP AGREEMENT:  TBD