Net Shore-Drift Along the Strait of Juan De Fuca Coast of Clallam County, Washington
Total Page：16
File Type：pdf, Size：1020Kb
Western Washington University Western CEDAR WWU Graduate School Collection WWU Graduate and Undergraduate Scholarship Spring 1986 Net Shore-Drift Along the Strait of Juan de Fuca Coast of Clallam County, Washington Steven C. (Steven Craig) Bubnick Western Washington University Follow this and additional works at: https://cedar.wwu.edu/wwuet Part of the Geology Commons Recommended Citation Bubnick, Steven C. (Steven Craig), "Net Shore-Drift Along the Strait of Juan de Fuca Coast of Clallam County, Washington" (1986). WWU Graduate School Collection. 773. https://cedar.wwu.edu/wwuet/773 This Masters Thesis is brought to you for free and open access by the WWU Graduate and Undergraduate Scholarship at Western CEDAR. It has been accepted for inclusion in WWU Graduate School Collection by an authorized administrator of Western CEDAR. For more information, please contact [email protected]. WESTERN WASHINGTON UNIVERSITY Bellingham, Washington 98225 • [206] 676-3000 MASTER'S THESIS In presenting this thesis in partial fulfillment of the requirements for a N Master's degree at Western Washi¥>gton University, I agree that the Library tf shall make its copies freely available for inspection. I further agree that extensive cc^ying of this thesis is allowable only for scholarly purposes. It is understood, however, that any cc^ying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without ny written permission. Dated: Net Shore-Drift Along the Strait of Juan De Fuca Coast of Clallam County, Washington by Steven C. Bubnick Accepted in Partial Conpletion of the Requirements for the Degree Master of Science Dean of Graduate Sch^l Advisory Committee Chairman MASTER'S THESIS In presenting this thesis in partial fulfillment of the requirements for a master's degree at Western Washington University, I grant to Western Washington University the non-exclusive royalty-free rightto archive, reproduce, distribute, and display the thesis in any and all forms, including electronic format, via any digital library mechanisms maintained by WWU. I represent and warrant this is my original work and does not infringe or violate any rights of others. I warrant that I have obtained written permissions from the owner of any third party copyrighted material included in these files. I acknowledge that I retain ownership rights to the copyright of this work, including but not limited to the right to use all or part of this work in future works, such as articles or books. Library users are granted permission for individual, research and non-commercial reproduction of this work for educational purposes only. Any further digital posting of this document requires specific permission from the author. Any copying or publication of this thesis for commercial purposes, or for financial gain, is not allowed without my written permission. Net Shore-Drift Along the Strait of Jioan De Fuca Coast of Clallam County, Washington A Thesis Presented to The Faculty of Western Washington University In Partial Fulfillment of the Requirements for the Degree Master of Science by Steven C. Bubnick June, 1986 ABSTRACT Net shore-drift along the north coast of Clallam County, Washington, was determined by using geomorphic and sedimentologic indicators. These indicators include changes in bluff morphology, delta plan form, beach width and slope, sediment size gradation, direction of stream mouth diversion, spit growth, deposition and erosion at drift obstructions, identifiable sediment, relict beach ridges, and imbricated beach sediment. Irregularities in the coastline have caused the shore drift to become divided into drift cells, each displaying zones of supply, transportation, and accumulation. Drift direction determinations were made through field observations of the indicators, supplemented by the study of photographs, topographic maps, and literature. Winds from the west-northwest prevail (are the most frequent) and predominate (are the most effective sediment movers) over the Strait of Juan De Fuca. The result is a dominant easterly direction of net shore- drift in the study area. However, other directions of net shore-drift were observed along parts of the Clallam County north coast. These shore drift variations occurred in the wave shadow of headlands, vdiere waves are refracted around spits and jetties, or vAiere the coastline differs significantly from the general trend. Thirty-two drift cells, ranging from 0.4 km to 31.4 km in length, have been identified and their net shore-drift directions determined along the 210 km Juan De Fuca coast of Clallam County. Areas of no appreciable net shore-drift were found over 43.5 km of the study area. This condition exists because of artificial modification of the coastline, the wave energy is too low, or deep water offshore impedes the shore drift. 1 ACKNOWLEDGEMENTS I thank the members of my advisory committee, Drs. M.L. Schwartz, D.J. Easterbrook, T.A. Terich, and J.B. Phipps, v^o gave graciously of their time and suggestions in improving this manuscript. Dr Schwartz, the comnittee chairman, is to be especially thanked for the expertise he lent and the patience he showed during the preparation of this document. For Dr. Phipps, vdio gave me the initial spark and encouragement, I have a deep, heartfelt appreciation. Special recognition is given to Coastal Consultants, Inc., of Bellingham, Washington, v^o provided financial assistance through a contract with the Washington State Department of Ecology. A1 Mullen deserves special gratitude for assisting me through the piques and valleys encountered in the field. I also thank the people of the Makah Indian Nation viio gave me permission for access to coastal sectors within the boundaries of the Makah Reservation. And finally, a loving sublime acknowledgement is merited by Sharon, Aaron, and Bryan, v^o gave me the familial support and understanding needed through all phases of this investigation and manuscript preparation. 11 TABLE OF CONTENTS Abstract i Ackncwledgements ii Table of Contents iii List of Figures iv List of Tables v Introduction 1 Regional Setting 3 Geography 3 Climate 5 Geology 8 Oceanography 12 Waves 13 Tides 15 Bathymetry 16 Principles of Shore Drift 18 Field Methods 22 Whole-cell indicators 22 Site-specific indicators 25 Preface to Net Shore-Drift Discussion 32 Net Shore-Drift Discussion 35 Summary 63 Bibliography 64 111 LIST OF FIGURES Figure Page 1 Regional map of western Washington. Study area is 4 along the north shoreline of Clallam County. 2 Mean atmospheric pressure systems in the Northeast 6 Pacific. 3 Schematic diagram illustrating the shore-drift 21 process. 4 A series of photographs displaying mean sediment grain 24 size dimunition (in drift cell 21): a) Primarily pebbles near the cell origin; b) Mixed sand and pebbles midway through the cell; c) Primarily sand near the terminus of the drift cell. 5 Driftwood obstructs the movement of sediment (from 27 right to left in photo). 6 Imbrication of beach cobble depicting the net shore- 31 drift (to the upper right in photo). Map case dimensions are 35 cm x 23 cm x 2 cm. 7 Diagrammatic beach cross-section with major geomorphic 33 features. IV LIST OF TABLES Table Page 1 Coastal zone stratigraphy. 10 2 Tides along the north coast of Clallam County. 16 V INTPDDUCTION As a result of the U.S. Coastal Zone Management Act of 1972, the Washington State Department of Ecology began a series of studies of the marine coast of Washington. In 1977, the Washington State D.O.E. published the Coastal Zone Atlas of Washington, viiich consists of twelve volumes. The net shore-drift of Washington's coastal zone is delineated along with the biologic, geologic, coastal flooding, slope stability, and land-use information in the atlas. The shore drift investigation consisted solely of hindcasting from the available wind data and the application of empirical formulae to that data. About this time, a group of graduate students fran Western Washington University , working under the supervision of Dr. M.L. Schwartz, began studying the net shore-drift along the marine coast of Washington. Ralph Keuler completed the first net shore-drift study under Dr. Schwartz in 1979. Keuler (1979) studied the coastal processes and coastal zone geomorphology of Skagit County, Washington. During the study, Schwartz and Keuler began to recognize long-term geotrarphic indicators of net shore- drift. These indicators were found to be more reliable in indicating the net shore-drift of a particular coastal stretch than the hindcasting of wind data and the application of empirical formulae. In 1980, as an employee of the U.S. Geological Survey, Keuler used the geomorphic indicators in a study of the net shore-drift of Island and San Juan Counties, Washington. Also in 1980, another W.W.U. graduate student, Edmund Jacobsen (1980), began to refine the geomorphic indicators vAiile studying the net shore-drift of Whatcom County, Washington. Inspired by their findings and 1 the results of others (e.g. Sunamura and Horikawa, 1972; Hunter et al, 1979), Jacobsen and Schwartz published an article in the October 1981 issue of Shore and Beach entitled "The Use of Geomorphic Indicators to Determine the Direction of Net Shore-Drift". Recognizing the need to update the coastal zone atlas, the Washington State D.O.E. began issuing grants, individually, to a succession of W.W.U. graduate students. In 1982, Michael Clirzastowski studied the net shore- drift of King County, Washington, using the geomorphic indicators as presented by Jacobsen and Schwartz (1981). Chrzastowski's study was succeeded by net shore-drift studies of: Dana G. Blankenship, Mason County, Washington (1983); D.M. Hatfield, Thurston County, Washington (1983); Brad D. Harp, Pierce County, Washington (1983); Bruce Taggart, Kitsap County, Washington (1984); Hiram Bronson III, Pacific and Grays Harbor Counties, Washington, in 1985; and, James Mahala, the Pacific Coast of Jefferson and Clallam Counties, Washington (1985), (Schwartz et al, 1985).