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Portsmouth New Boston Flood Protection System

Owner: City of Portsmouth
Client: Howerton Engineering & Surveying
Services: Geotechnical 

The project involved a geotechnical exploration along the entire 41,713 foot long flood protection system, which consists of a combination of cantilevered reinforced concrete floodwalls and earthen levees. The geotechnical study, involving eighty-eight (88) test borings, was performed as required by FEMA to determine if the flood protection system was providing appropriate protection from the base flood on National Flood Insurance Program Maps. The evaluations of the subject system with respect to uncontrolled seepage, slope stability and the seismic stability were presented in accordance with FEMA and USACE protocol.


Work performed by Thelen Associates, Inc.