OAK HARBOR MARINA REDEVELOPMENT SEDIMENTATION ANALYSIS AND DREDGING PRIORITIZATION
Whidbey Island, Washington

Coast & Harbor Engineering (CHE) evaluated rates of sedimentation and volumes of required maintenance dredging for the existing marina, developed recommendations to minimize future dredging needs and dredging costs, and developed and recommended the preferred dredging scenario.

To determine sedimentation rates, data from historical bathymetric surveys were compiled, processed and analyzed. Dredging scenarios were developed based on minimal cost, compliance with the existing dredging permit, depth limitation, and 10- and 20-year maintenance dredging frequency. CHE then computed the advanced maintenance dredging clearance for each of the scenarios and sites by multiplying the recommended rates of sedimentation by a period of time between maintenance dredging (10 or 20 years). The selected preferred alternative satisfied the design criteria and provided the minimum maintenance dredging requirement which was once every 20 years.

Oak Harbor Dredging, January 2011