Sedimentation in a 'Half-Tide' Harbor. Part 1. Sedimentation under Ice-Free Conditions. Part 2. Sedimentation during Periods of Ice-Cover.

摘要

Harbor shoaling becomes a significant problem when coastal waters are laden with suspended solids and the tidal range is high. Because of currents resulting from the tides and severe ice conditions which exist along much of the Alaskan coast, some small-craft harbors are constructed as enclosed basins sited adjacent to, rather than within, navigable estuaries. Determination of the shoaling rate and relative importance of factors involved in the shoaling process is essential to the effective design of these harbors. The unique feature of the 'half-tide' harbor is a sill placed in the navigation channel at an elevation greater than that of the basin. Flotation for vessels is provided during low-tide stages, but the sill restricts navigation into and out of the harbor to times of higher tidal elevations. This report describes the history and processes of shoaling observed during the ice-free season at an enclosed small-craft harbor at Dillingham, Alaska, since its construction in 1961. Results of a study of the shoaling process during the winter ice-cover season at Dillingham Harbor are presented in Part 2. (Author)