Client: Diamond State Port Corporation
Date: February 1, 2017
A large portion of the Port of Wilmington, Delaware is up to four feet below the 100 year floodplain. Flood control at the Port is primarily provided by tide gates on their stormwater drain outfalls, in combination with bank-top berms. However, after years of use and poor upkeep many of the tide gates were in poor condition and were failing. Metal flap gates were clogged with debris and duckbill gates were UV degraded. Some tide gates were even missing entirely. In addition, sections of the bank-top berm were being overtopped or infiltrated on a regular basis.
VanDemark & Lynch was selected to provide the planning, surveying, and civil engineering for this project. We provided a comprehensive survey of the status of the existing tide gates and berms, and developed a number of optional concepts for protecting the Port from tidal flooding and storm surges. The final solution included replacing many of the existing pipe outlet tide gates, which were vulnerable to damage by river debris, with new in-pipe, rubber flap-gate style tide gates. These tide gates are protected from river debris, and UV light, and easily accessed from structures conveniently located on the landside of the river bank. We also designed a new impervious berm, armored with concrete revetment mattresses, a concrete capped bulkhead, and raised the floating berth access ramp landside hinge points, along the vulnerable portion of the river bank.