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Date Permissions Signed

5-12-2018

Date of Award

Winter 1993

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Secondary Education

First Advisor

Schwartz, Maurice L.

Second Advisor

Easterbrook, Don J., 1935-

Third Advisor

Terich, Thomas

Abstract

Net shore-drift directions, representing the long-term, net result of littoral sediment transport on both the beachface and in nearshore waters, were determined in San Juan County, eastern Jefferson County, and southern Island and Snohomish Counties, Washington. Studies employing similar methods have been conducted in the state for the Washington State Department of Ecology, to update coastal drift information provided to area planners. This project completes net shore-drift mapping of the entire marine coast of Washington State. The Puget Lowland experiences prevailing and predominant southerly winds, but is also subjected to locally variable winds. The irregular coast of the islands and inland waters exhibits a wide range of fetch distances and wave regimes. The entire 820 km of coast in the study area was visited by boat or on foot to determine net shore-drift based on the occurrence of geomorphic and sedimentologic indicators of net shore-drift. Six site-specific indicators (spit growth, objects interrupting drift, stream diversion, identifiable sediment, plan view of river deltas and intertidal fans, and nearshore bars) and three drift-trend indicators (beach width, bluff morphology, and sediment size gradation) were utilized where they occurred. Net shore-drift cell location and net transport direction are presented on 25 reduced 7.5 minute quadrangles. The text includes descriptions of each of the 158 net shore-drift cells, with supporting field evidence. The crenulated coast of the San Juan Islands contains 119 net shore-drift cells, although the major portion of the county has a rocky coast where no appreciable net shore- drift occurs. Net shore-drift cells average 1.1-km-long in the San Juan Islands, and northward net shore-drift occurs most frequently (56 of 119 cells). The eastern Jefferson County coast north of Point Hannon has generally southward net shore-drift in 6 of 7 cells. The southeastern Jefferson County coast experiences northward or northeasterly net shore-drift in 16 of 23 cells. Southern Island and Snohomish counties consistently experience generally northward net shore-drift. Net shore-drift direction closely follows the direction of maximum fetch. Ten cuspate spits occur at the terminal ends of drift cells that originate in the study area. Cuspate spits form at the narrowest constriction within channels where opposing fetch directions, and net shore-drift cells, converge and deposit drift sediment.

Type

Text

Keywords

Net shore-drift, Littoral sediment transport, Jefferson County, Island County, Snohomish County

Publisher

Western Washington University

OCLC Number

1080643812

Subject – LCSH

Littoral drift--Washington (State); Littoral drift--Washington (State)--San Juan County; Coast changes--Washington (State); Coast changes--Washington (State)--San Juan County; Shorelines--Washington (State); Shorelines--Washington (State)--San Juan County

Geographic Coverage

Washington (State); San Juan County (Wash.)

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

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Geology Commons

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