SHONE LUMBER - WHITE CLAY CREEK FLOODPLAIN/
FLOODWAY EVALUATION AND MITIGATION
NEW CASTLE COUNTY, DELAWARE
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The Shone Lumber property is situated in a flood prone area along White Clay Creek in Stanton, just downstream of its confluence with Red Clay Creek. The property has been subjected to repeated flooding and the owner worked with local agencies to obtain a FEMA grant to floodproof the showroom building. Flood height estimation at the site is complex due to flooding from both the White Clay Creek and an Amtrak railroad underpass adjacent to the site.

Using HEC-RAS models of White Clay Creek and analysis of ancillary flooding sources completed for prior projects, as well as analysis of high water mark data, Duffield Associates worked with Shone Lumber to establish a target flood-proofing height that balanced construction cost and flood risk. Additionally, Duffield Associates obtained a New Castle County floodplain development permit for the project.

Once Duffield Associates had helped the owner evaluate the costs and benefits of flood protection, in consultation with the New Castle Conservation District, Duffield Associates designed highly customized flood protection for the owner's expansive showroom. Flood protection improvements consisted of reinforced masonry and concrete floodwalls and a variety of floodgates, including easy-to-deploy hinged gates and large, single-panel gates for many overhead doors. In addition, in association with the flood protection improvements, Duffield Associates designed enhancements to the main entrance and the receiving area, plus many modifications that "cleaned up" the perimeter of the facility, which had been constructed and altered over many years.

Following the design stage, Duffield Associates provided full-phase construction review services and performed testing required by New Castle County. Additionally, during the implementation of the flood protection, several conditions were discovered that were different than indicated by historical records and drawings. Duffield Associates responded quickly and modified several of the design details while also accommodating many changes requested by the client and the construction contractor to allow construction to continue with minimal delays.