The existing Reedsport Levee is an approximately 2.6-mile-long system made up of earthen levees, concrete and sheet-pile floodwalls, interior drainage structures, and pump stations. The City of Reedsport is seeking to have their levee system evaluated and ultimately certified to meet Federal Emergency Management Agency (FEMA) requirements for levee certification in accordance with the National Flood Insurance Program. For levees to be recognized by FEMA, the Code of Federal Regulations requires a statement from a registered professional engineer that the flood protection system was designed in accordance with standard engineering practices and that analyses have been performed correctly to assess whether the levee will provide protection from the base flood. 

Shannon & Wilson is providing geotechnical services, including a review and compilation of existing subsurface information in the site vicinity. We are also performing a site reconnaissance; field explorations consisting of borings and Cone Penetrometer Tests with pore pressure dissipation tests; laboratory testing; and engineering analyses, and we will provide geotechnical design recommendations for the project.  

Our analyses included levee stability studies; settlement; development of underseepage protection measures; special considerations for new multi-use paths and a concrete T-wall; and identification of potential adverse impacts of a tsunami on the levee system. We also provided the characterization of borrow areas. Shannon & Wilson is currently performing additional field explorations and engineering analysis for mitigation design.