Quantification of Net Shore-Drift Rates in Puget Sound and the Strait of Juan de Fuca, Washington
Keywords:Beaches, littoral drift rates, littoral zone, longshore sediment transport, Puget Sound, Georgia Strait, sediment budget, Strait of Juan de Fuca, Washington State
Quantitative analysis of net shore-drift has been carried out at 26 sites in Puget Sound and the Strait of Juan de Fuca, Washington, USA. Three methods were used to obtain net shore-drift rates: (1) field measurement of sediment accumulation at drift obstructions; (2) extrapolation of spit growth using aerial photographs and historical maps; and (3) evaluation of maintenance dredging volumes at navigation channels. The study area was divided into four regions based on physiography and the effect of wind patterns on the area. The largest volumes of sediment were transported in the west-central region, along the southern coast of the Strait of Juan de Fuca. The smallest transport volumes were recorded along the southern coast of Puget Sound, whereas east-central and northern Puget Sound were intermediate with regard to sediment transport volumes. The factors influencing net shore-drift rates are fetch distance, availability of sediment, and drift cell length.