Abstract:
Strong tidal currents experienced at Keystone Harbor, WA, have caused
navigational hazards and disrupted ferry service in the area. This thesis presents
details of the design, construction and implementation of a large scale physical model
of Keystone Harbor used to evaluate the effectiveness of proposed jetty design
alternatives to improve navigation at the Keystone Ferry Terminal.
A fixed bed, 1:40 Froude scaled model was built in the Tsunami Wave Basin at
the 0. H. Hinsdale Wave Research Laboratory using a bathymetric survey of
Keystone Harbor. A recirculating pump system simulated the peak ebb tidal current
and a wavemaker simulated 50 year storm conditions. A series of five tests were
conducted to (1) evaluate the performance of existing and proposed jetty extensions
and (2) determine whether these changes would have an adverse affect on the
neighboring cobble beach. Analysis revealed large velocity gradients for all 4
proposed alternatives at the harbor channel entrance which may have significant
impacts on navigational safety. No adverse impacts were observed on the adjacent
beaches.
