Study for Flushing of Salt Lagoon and Small-Boat Harbor Improvements at St. PaulHarbor, St. Paul Island, Alaska. Coastal Model Investigation

摘要

A 1:10-scale (undistorted) three-dimensional coastal hydraulic model wasinitially used to investigate the design of proposed harbor improvements at St Paul Harbor, St Paul Island, Alaska, with respect to wave and current conditions in the harbor and sediment patterns at the site. Wave-induced circulation and sediment patterns seaward of the main breakwater as a result of a submerged reef were investigated. Proposed improvements consisted of deepening the entrance channel, constructing a maneuvering area and installing a wave dissipating spending beach inside the existing harbor, and constructing a submerged reef seaward of the main breakwater. In this study, the model was reactivated to optimize flushing of Salt Lagoon and small-boat harbor improvements in St. Paul Harbor. The model reproduced approximately 2,865 m (9,400 ft) of the St Paul Island shoreline, the existing harbor, the surface area of Salt Lagoon with its connecting channels to the harbor, and sufficient offshore area in the Bering Sea to permit generation of the required test waves. An 18.3m-long (60ft-long) unidirectional, spectral wave generator, an automated data acquisition and control system, and a crushed coal tracer material were used in model operation.