Ferry Vessel Propeller Wash Effects on Scour at the Kingston Ferry Terminal, WA, USA

摘要

Vessel propeller wash has been shown to cause scour in the marine environment. We investigated the hydrodynamic causes of severe erosion at the Washington State Ferries ferry terminal in Kingston, WA, where a cliff-like bathymetric feature has shifted shoreward in recent years, forcing repairs on the slip's bridge pilings. High resolution measurements of velocity and estimates of turbulent bed stress were made during vessel arrivals and departures during two deployment periods in March and April 2018. Calculated bed stresses were found to be 100 times larger during vessel arrivals and departures than background levels. Bed stresses were higher during vessel departures than arrivals, corresponding to higher vessel acceleration during departures. Additionally, during departures, lower tidal stages correspond to higher bed stresses, because the propellers are closer to the seabed. During arrivals, larger vessels generated higher bed stresses.