New Castle County, DE Delaware Department of Transportation

Stormwater Management Design and Environmental Compliance for US 301

Straughan designed 18 stormwater management ponds, using low impact development techniques, for this multi-lane highway.


Our Approach

The US 301 project was approximately 17.5 miles of new and reconstructed roadway located primarily in southern New Castle County, Delaware, and included a new four-lane limited access roadway from the Maryland/Delaware state line to State Route 1, south of the Chesapeake and Delaware (C&D) Canal. Section 3 is approximately 2.8 mi. of the overall project length, and is located from 0.38 mi. (2000 ft.) south of the Maryland/Delaware boundary to the Levels Road Interchange. The focus of the Straughan design effort was to minimize environmental impacts while accommodating the planned development of the roadway.

Straughan designed fourteen (14) stormwater management ponds in Delaware and four (4) ponds in Maryland. The ponds in Maryland were designed using MDE standards and the Delaware ponds were sized using design guidelines developed by DelDOT and DNREC. The design effort included the preparation of the preliminary design, semi-final plan, final and PS&E stormwater plans and report. Straughan sized the ponds to develop the footprint so that the right-of-way could be determined for the road. Adhering to project schedules required our water resource engineering team to maintain close coordination with all project disciplines, attend frequent project meetings, and meet aggressive design milestone submittal dates. Straughan integrated low impact development techniques into the overall design where practical including filter strips, bioswales, water quality swales, and bioretention areas.

Straughan also provided support for wetland permitting and environmental compliance. The emphasis of the environmental compliance task was to help the design team avoid impacts to wetland preservation sites and secure multi-jurisdictional approval for unavoidable impacts to wetlands. Construction of the project broke ground in 2016. During construction, Straughan attended the pre-construction and monthly status meetings, responded to contractor RFIs, and conducted shop drawing review. The US301 Mainline opened to traffic on January 10, 2019.

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