DOCSLIB.ORG

Circulation and Sediment Transport at Headlands with Implications for Littoral Cell Boundaries by DOUGLAS ADAM GEORGE BS

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Circulation and Sediment Transport at Headlands with Implications for Littoral Cell Boundaries by DOUGLAS ADAM GEORGE BS Circulation and Sediment Transport at Headlands with Implications for Littoral Cell Boundaries By DOUGLAS ADAM GEORGE B.S. (Humboldt State University, Arcata) 1999 M.S. (Columbia University, New York City) 2001 M.Sc. (Dalhousie University, Halifax) 2003 DISSERTATION Submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in Hydrologic Sciences in the OFFICE OF GRADUATE STUDIES of the UNIVERSITY OF CALIFORNIA DAVIS Approved: _____________________________________ John L. Largier, PhD, Chair _____________________________________ Brian P. Gaylord, PhD _____________________________________ Gregory B. Pasternack, PhD Committee in Charge 2016 i Copyright © Douglas Adam George 2016 All rights reserved. Douglas Adam George September 2016 Hydrologic Sciences Circulation and Sediment Transport at Headlands with Implications for Littoral Cell Boundaries Abstract Coastal communities face the highest base sea level elevations in human history as the uncontrolled experiment of anthropogenic-driven climate change continues. Coastal engineering is expected to greatly expand as protection of infrastructure, property, and habitats becomes increasingly necessary. One of the most basic approaches in the protection toolbox is beach nourishment – the practice of placing large volumes of sand on existing beaches to shore up dunes and create a wider buffer from the ocean. The underlying assumption to beach nourishment projects is that they are temporary and will be repeated as the sand washes away over time. The clash between the natural coastal processes of littoral drift and the human efforts to build beaches leads to the framing question of this dissertation – where should sand be or not be placed to maximize the efficacy of a climate change adaptation strategy? The most exemplary coastal engineering projects dovetail with natural features to positively exploit fluid dynamic processes that are self-perpetuating and universal. For example, using a rocky headland as a protective anchor against erosion is prudent to optimize the longevity of a sand placement – yet most research has been conducted on beaches that are somewhat removed from the effects of ii headlands. Further, not all headlands are equal, though, and some may not provide any benefits to a nourishment project. This dissertation focuses on the knowledge gap about how sediment moves around headlands. Historically, studies on the hydrodynamics of headlands have emphasized tide- dominated systems through observations and numerical modeling. This yielded an opportunity to explore circulation and sediment transport around headlands located on wave-dominated coasts. Three studies were undertaken to conduct a deeper investigation on the geomorphic, oceanographic, and sedimentologic influences on sediment flux. The first used a GIS-based classification of headlands to identify morphological features common among 78 California headlands that may or may not perform as littoral cell boundaries. The second executed a field observation study at a large headland in southern California with the goal of understanding sediment pathways and patterns under different forcing conditions. The last study was a numerical modeling effort using Delft-3D and SWAN to identify how variable oceanographic and sedimentologic conditions affect sediment transport around four idealized headlands that were designed based on the first study. Through these three studies, headland size and shape coupled with incident wave angle emerged as the dominant factors influencing sediment pathways and sediment grain size determined the volume of sediment flux. The findings in each study were interpreted in the context of littoral cell boundaries, in particular to assess the “openness” of a headland-defined boundary. Assigning gradations of boundaries instead of the more commonly used “boundary” or “no boundary” monikers became apparent from the results that revealed sediment pathways varied by sediment grain size. The overarching conclusion from this dissertation is that a new set of parameters should be utilized to define littoral cell boundaries at headlands that take into account size, shape, and sediment. The headlands most iii likely to be candidates for absolute boundaries are large, pointed ones for most common beach- sized sand while large, broad-faced ones are barriers for coarser sand but not finer sand; smaller headlands are less likely to be absolute boundaries in general but can be barriers for coarser sand under certain conditions. The discoveries presented herein expand knowledge of headland dynamics as it relates to particle transport and delineation of dynamic littoral cell boundaries, both of which lead to the prospect of improved coastal management decisions in an era of profound coastal change. iv Acknowledgements My dissertation is the product of the support and guidance from a slew of people including my advisor, John Largier, my UCD committee, Greg Pasternack and Brian Gaylord, and my USGS committee, Curt Storlazzi and Patrick Barnard. John was open to me being a part- time student trying to sustain my career and myriad of challenges associated with conducting my research from afar; this product came about from his collegial style with me that respected my background and prompted growth in new areas. Greg also greatly assisted me in navigating the UCD realm and battled on my behalf many times, including unexpectedly providing student funding more than once. Curt and Patrick were stalwarts who encouraged me to grow and keep my eye on the prize. Numerous others provided intelligent conversations, tutoring, and thoughtful discourse during these past four years: Rocko Brown, Justin Vandever, Matt Robart, my sugar mama Phyllis Grifman, members of the Coastal Sediment Management Workgroup, colleagues at the USGS including Li Erikson, Guy Gelfenbaum, Andrew Stevens, and Jon Warrick, and my labmate Kate Hewett. The backing of my friends through this experience was grounding and invaluable and so I thank Liz Pittinos, Joe Toland, Lori Kelly, Amy East, Steve Grimes, Nena Vandebroek, Ken and Laura Krueger, Conor and Joél Flannery, Amy Foxgrover, Paul Melvin, Sean Corcoran, Kathi Koontz, my ETC family, and many others. Covering the geography from Bodega Marine Laboratory to Davis to Santa Cruz was only possible with the generosity of guest rooms and couch space from more than a dozen friends and family, and my trusty set of wheels, Digdoug. I was also fortunate to garner the support of my employers at ESA and AMS who allowed me the space to balance two worlds. I thank my siblings, Amber and Peter, my cousin Danielle, my Aunt Georgette and Uncle Joe, and my nephews, Daniel and Gabriel, for celebrating the highs and enduring the lows with me. Finally, I thank my parents who have stood behind me for more than a decade to help me realize this dream – there’s no doubt in my mind that without their love and encouragement from this earthly place (Mom) and from beyond (Dad), I would not have accomplished this PhD. To understand the heart and mind of a person, look not at what he has already achieved, but at what he aspires to. -Khalil Gibran v Chapter Specific Acknowledgments In addition to the individuals named above, the following provided further assistance that was greatly appreciated for the three studies. Chapter 2 Elena Vandebroek, Dennis Hall (NOAA), and Joshua Novac and Erin Musgrave (Dewberry) provided geospatial technical assistance and data and Li Erikson (USGS) provided wave data. Discussions regarding geomorphology with Rocko Brown and cluster analysis with Christie Hegermiller helped guide this research. The published manuscript from Chapter 2, which was co-authored with John, Curt, and Patrick, was improved upon by review from Bruce Jaffe (USGS), Edward Thornton (NPS), and an anonymous review. The methodological appendix, published under a co-authorship with Elena, benefitted from review by Clif Davenport (CGS), John Dingler (USACE), and Nancy Ferris (BAAMA). The Hydrologic Sciences Graduate Group at the University of California Davis and the US Geological Survey’s Coastal and Marine Geology program supported this work. Chapter 3 The field observational component of this dissertation was completed in Malibu with extensive assistance from the following individuals: Matt Robart, David Dann, and Brian Gaylord (all BML), Tom Ford (The Bay Foundation), and Dan Hoover, Tim Elfers, Andrew Stevens, and Jackson Curry (all USGS). Instruments came from John, Brian, Curt, and Patrick. Jon Warrick (USGS) provided guidance for sediment photogrammetry. This work was produced with support from the USC Sea Grant Program, National Oceanic and Atmospheric vi Administration, U.S. Department of Commerce, under grant number NA14OAR4170089, and the USGS Coastal and Marine Geology program. Unpublished work off Bodega Head utilized the assistance of Matt Robart and David Dann (both BML), and Sam Johnson (USGS), with funding from the PADI Foundation and the UC Natural Reserve System. Chapter 4 The monumental modeling task could not have been attempted nor completed without the deep involvement of Edwin Elias, Andrew Stevens, Li Erikson, and Andrea O’Neill (all USGS). Patrick provided a much-needed modern computer that accelerated the process many times over. The USC Sea Grant Program, National Oceanic and Atmospheric Administration, U.S. Department of Commerce, financially supported the modeling under grant number NA14OAR4170089, with substantial computer and software support from the USGS Coastal
Load more

Recommended publications
  • Ocean Trench
    R E S O U R C E L I B R A R Y E N C Y C L O P E D I C E N T RY Ocean trench Ocean trenches are long, narrow depressions on the seafloor. These chasms are the deepest parts of the ocean—and some of the deepest natural spots on Earth. G R A D E S 5 - 12+ S U B J E C T S Earth Science, Geology, Geography, Physical Geography C O N T E N T S 11 Images, 1 Video, 2 Links For the complete encyclopedic entry with media resources, visit: http://www.nationalgeographic.org/encyclopedia/ocean-trench/ Ocean trenches are long, narrow depressions on the seafloor. These chasms are the deepest parts of the ocean—and some of the deepest natural spots on Earth. Ocean trenches are found in every ocean basin on the planet, although the deepest ocean trenches ring the Pacific as part of the so-called “Ring of Fire” that also includes active volcanoes and earthquake zones. Ocean trenches are a result of tectonic activity, which describes the movement of the Earth’s lithosphere. In particular, ocean trenches are a feature of convergent plate boundaries, where two or more tectonic plates meet. At many convergent plate boundaries, dense lithosphere melts or slides beneath less-dense lithosphere in a process called subduction, creating a trench. Ocean trenches occupy the deepest layer of the ocean, the hadalpelagic zone. The intense pressure, lack of sunlight, and frigid temperatures of the hadalpelagic zone make ocean trenches some of the most unique habitats on Earth.
    [Show full text]
  • Bedrock Geology Glossary from the Roadside Geology of Minnesota, Richard W
    Minnesota Bedrock Geology Glossary From the Roadside Geology of Minnesota, Richard W. Ojakangas Sedimentary Rock Types in Minnesota Rocks that formed from the consolidation of loose sediment Conglomerate: A coarse-grained sedimentary rock composed of pebbles, cobbles, or boul- ders set in a fine-grained matrix of silt and sand. Dolostone: A sedimentary rock composed of the mineral dolomite, a calcium magnesium car- bonate. Graywacke: A sedimentary rock made primarily of mud and sand, often deposited by turbidi- ty currents. Iron-formation: A thinly bedded sedimentary rock containing more than 15 percent iron. Limestone: A sedimentary rock composed of calcium carbonate. Mudstone: A sedimentary rock composed of mud. Sandstone: A sedimentary rock made primarily of sand. Shale: A deposit of clay, silt, or mud solidified into more or less a solid rock. Siltstone: A sedimentary rock made primarily of sand. Igneous and Volcanic Rock Types in Minnesota Rocks that solidified from cooling of molten magma Basalt: A black or dark grey volcanic rock that consists mainly of microscopic crystals of pla- gioclase feldspar, pyroxene, and perhaps olivine. Diorite: A plutonic igneous rock intermediate in composition between granite and gabbro. Gabbro: A dark igneous rock consisting mainly of plagioclase and pyroxene in crystals large enough to see with a simple magnifier. Gabbro has the same composition as basalt but contains much larger mineral grains because it cooled at depth over a longer period of time. Granite: An igneous rock composed mostly of orthoclase feldspar and quartz in grains large enough to see without using a magnifier. Most granites also contain mica and amphibole Rhyolite: A felsic (light-colored) volcanic rock, the extrusive equivalent of granite.
    [Show full text]
  • 25. PELAGIC Sedimentsi
    ^ 25. PELAGIC SEDIMENTSi G. Arrhenius 1. Concept of Pelagic Sedimentation The term pelagic sediment is often rather loosely defined. It is generally applied to marine sediments in which the fraction derived from the continents indicates deposition from a dilute mineral suspension distributed throughout deep-ocean water. It appears logical to base a precise definition of pelagic sediments on some limiting property of this suspension, such as concentration or rate of removal. Further, the property chosen should, if possible, be reflected in the ensuing deposit, so that the criterion in question can be applied to ancient sediments. Extensive measurements of the concentration of particulate matter in sea- water have been carried out by Jerlov (1953); however, these measurements reflect the sum of both the terrigenous mineral sol and particles of organic (biotic) origin. Aluminosilicates form a major part of the inorganic mineral suspension; aluminum is useful as an indicator of these, since this element forms 7 to 9% of the total inorganic component, 2 and can be quantitatively determined at concentration levels down to 3 x lO^i^ (Sackett and Arrhenius, 1962). Measurements of the amount of particulate aluminum in North Pacific deep water indicate an average concentration of 23 [xg/1. of mineral suspensoid, or 10 mg in a vertical sea-water column with a 1 cm^ cross-section at oceanic depth. The mass of mineral particles larger than 0.5 [x constitutes 60%, or less, of the total. From the concentration of the suspensoid and the rate of fallout of terrigenous minerals on the ocean floor, an average passage time (Barth, 1952) of less than 100 years is obtained for the fraction of particles larger than 0.5 [i.
    [Show full text]
  • Littoral Cells, Sand Budgets, and Beaches: Understanding California S
    LITTORAL CELLS, SAND BUDGETS, AND BEACHES: UNDERSTANDING CALIFORNIA’ S SHORELINE KIKI PATSCH GARY GRIGGS OCTOBER 2006 INSTITUTE OF MARINE SCIENCES UNIVERSITY OF CALIFORNIA, SANTA CRUZ CALIFORNIA DEPARTMENT OF BOATING AND WATERWAYS CALIFORNIA COASTAL SEDIMENT MANAGEMENT WORKGROUP Littoral Cells, Sand Budgets, and Beaches: Understanding California’s Shoreline By Kiki Patch Gary Griggs Institute of Marine Sciences University of California, Santa Cruz California Department of Boating and Waterways California Coastal Sediment Management WorkGroup October 2006 Cover Image: Santa Barbara Harbor © 2002 Kenneth & Gabrielle Adelman, California Coastal Records Project www.californiacoastline.org Brochure Design & Layout Laura Beach www.LauraBeach.net Littoral Cells, Sand Budgets, and Beaches: Understanding California’s Shoreline Kiki Patsch Gary Griggs Institute of Marine Sciences University of California, Santa Cruz TABLE OF CONTENTS Executive Summary 7 Chapter 1: Introduction 9 Chapter 2: An Overview of Littoral Cells and Littoral Drift 11 Chapter 3: Elements Involved in Developing Sand Budgets for Littoral Cells 17 Chapter 4: Sand Budgets for California’s Major Littoral Cells and Changes in Sand Supply 23 Chapter 5: Discussion of Beach Nourishment in California 27 Chapter 6: Conclusions 33 References Cited and Other Useful References 35 EXECUTIVE SUMMARY he coastline of California can be divided into a set of dis- Beach nourishment or beach restoration is the placement of Ttinct, essentially self-contained littoral cells or beach com- sand on the shoreline with the intent of widening a beach that partments. These compartments are geographically limited and is naturally narrow or where the natural supply of sand has consist of a series of sand sources (such as rivers, streams and been signifi cantly reduced through human activities.
    [Show full text]
  • Coastal and Marine Ecological Classification Standard (2012)
    FGDC-STD-018-2012 Coastal and Marine Ecological Classification Standard Marine and Coastal Spatial Data Subcommittee Federal Geographic Data Committee June, 2012 Federal Geographic Data Committee FGDC-STD-018-2012 Coastal and Marine Ecological Classification Standard, June 2012 ______________________________________________________________________________________ CONTENTS PAGE 1. Introduction ..................................................................................................................... 1 1.1 Objectives ................................................................................................................ 1 1.2 Need ......................................................................................................................... 2 1.3 Scope ........................................................................................................................ 2 1.4 Application ............................................................................................................... 3 1.5 Relationship to Previous FGDC Standards .............................................................. 4 1.6 Development Procedures ......................................................................................... 5 1.7 Guiding Principles ................................................................................................... 7 1.7.1 Build a Scientifically Sound Ecological Classification .................................... 7 1.7.2 Meet the Needs of a Wide Range of Users ......................................................
    [Show full text]
  • INTERTIDAL ZONATION Introduction to Oceanography Spring 2017 The
    INTERTIDAL ZONATION Introduction to Oceanography Spring 2017 The Intertidal Zone is the narrow belt along the shoreline lying between the lowest and highest tide marks. The intertidal or littoral zone is subdivided broadly into four vertical zones based on the amount of time the zone is submerged. From highest to lowest, they are Supratidal or Spray Zone Upper Intertidal submergence time Middle Intertidal Littoral Zone influenced by tides Lower Intertidal Subtidal Sublittoral Zone permanently submerged The intertidal zone may also be subdivided on the basis of the vertical distribution of the species that dominate a particular zone. However, zone divisions should, in most cases, be regarded as approximate! No single system of subdivision gives perfectly consistent results everywhere. Please refer to the intertidal zonation scheme given in the attached table (last page). Zonal Distribution of organisms is controlled by PHYSICAL factors (which set the UPPER limit of each zone): 1) tidal range 2) wave exposure or the degree of sheltering from surf 3) type of substrate, e.g., sand, cobble, rock 4) relative time exposed to air (controls overheating, desiccation, and salinity changes). BIOLOGICAL factors (which set the LOWER limit of each zone): 1) predation 2) competition for space 3) adaptation to biological or physical factors of the environment Species dominance patterns change abruptly in response to physical and/or biological factors. For example, tide pools provide permanently submerged areas in higher tidal zones; overhangs provide shaded areas of lower temperature; protected crevices provide permanently moist areas. Such subhabitats within a zone can contain quite different organisms from those typical for the zone.
    [Show full text]
  • Beach Nourishment: Massdep's Guide to Best Management Practices for Projects in Massachusetts
    BBEACHEACH NNOURISHMEOURISHMENNTT MassDEP’sMassDEP’s GuideGuide toto BestBest ManagementManagement PracticesPractices forfor ProjectsProjects inin MassachusettsMassachusetts March 2007 acknowledgements LEAD AUTHORS: Rebecca Haney (Coastal Zone Management), Liz Kouloheras, (MassDEP), Vin Malkoski (Mass. Division of Marine Fisheries), Jim Mahala (MassDEP) and Yvonne Unger (MassDEP) CONTRIBUTORS: From MassDEP: Fred Civian, Jen D’Urso, Glenn Haas, Lealdon Langley, Hilary Schwarzenbach and Jim Sprague. From Coastal Zone Management: Bob Boeri, Mark Borrelli, David Janik, Julia Knisel and Wendolyn Quigley. Engineering consultants from Applied Coastal Research and Engineering Inc. also reviewed the document for technical accuracy. Lead Editor: David Noonan (MassDEP) Design and Layout: Sandra Rabb (MassDEP) Photography: Sandra Rabb (MassDEP) unless otherwise noted. Massachusetts Massachusetts Office Department of of Coastal Zone Environmental Protection Management 1 Winter Street 251 Causeway Street Boston, MA Boston, MA table of contents I. Glossary of Terms 1 II. Summary 3 II. Overview 6 • Purpose 6 • Beach Nourishment 6 • Specifications and Best Management Practices 7 • Permit Requirements and Timelines 8 III. Technical Attachments A. Beach Stability Determination 13 B. Receiving Beach Characterization 17 C. Source Material Characterization 21 D. Sample Problem: Beach and Borrow Site Sediment Analysis to Determine Stability of Nourishment Material for Shore Protection 22 E. Generic Beach Monitoring Plan 27 F. Sample Easement 29 G. References 31 GLOSSARY Accretion - the gradual addition of land by deposition of water-borne sediment. Beach Fill – also called “artificial nourishment”, “beach nourishment”, “replenishment”, and “restoration,” comprises the placement of sediment within the nearshore sediment transport system (see littoral zone). (paraphrased from Dean, 2002) Beach Profile – the cross-sectional shape of a beach plotted perpendicular to the shoreline.
    [Show full text]
  • NPP) A) Global Patterns B) Fate of NPP
    OCN 401 Biogeochemical Systems (11.1.11) (Schlesinger: Chapter 9) Oceanic Production, Carbon Regeneration, Sediment Carbon Burial Lecture Outline 1. Net Primary Production (NPP) a) Global Patterns b) Fate of NPP 2. Sediment Diagenesis a) Diagenesis of Organic Matter (OM) b) Biogenic Carbonates Net Primary Production: Global Patterns • Oceanic photosynthesis is ≈ 50% of total photosynthesis on Earth - mostly as phytoplankton (microscopic plants) in surface mixed layer - seaweed accounts for only ≈ 0.1%. • NPP ranges from 130 - 420 gC/m2/yr, lowest in open ocean, highest in coastal zones • Terrestrial forests range from 400-800 gC/m2/yr, while deserts average 80 gC/m2/yr. Net Primary Production: Global Patterns (cont’d.) • O2 distribution is an indirect measure of photosynthesis: CO2 + H2O = CH2O + O2 14 • NPP is usually measured using O2-bottle or C-uptake techniques. 14 • O2 bottle measurements tend to exceed C-uptake rates in the same waters. Net Primary Production: Global Patterns (cont’d.) • Controversy over magnitude of global NPP arises from discrepancies in methods for measuring NPP: estimates range from 27 to 51 x 1015 gC/yr. 14 • O2 bottle measurements tend to exceed C-uptake rates because: - large biomass of picoplankton, only recently observed, which pass through the filters used in the 14C technique. - picoplankton may account for up to 50% of oceanic production. - DOC produced by phytoplankton, a component of NPP, passes through filters. - Problems with contamination of 14C-incubated samples with toxic trace elements depress NPP. Net Primary Production: Global Patterns (cont’d.) Despite disagreement on absolute magnitude of global NPP, there is consensus on the global distribution of NPP.
    [Show full text]
  • Feasibility Study of an Artifical Sandy Beach at Batumi, Georgia
    FEASIBILITY STUDY OF AN ARTIFICAL SANDY BEACH AT BATUMI, GEORGIA ARCADIS/TU DELFT : MSc Report FEASIBILITY STUDY OF AN ARTIFICAL SANDY BEACH AT BATUMI, GEORGIA Date May 2012 Graduate C. Pepping Educational Institution Delft University of Technology, Faculty Civil Engineering & Geosciences Section Hydraulic Engineering, Chair of Coastal Engineering MSc Thesis committee Prof. dr. ir. M.J.F. Stive Delft University of Technology Dr. ir. M. Zijlema Delft University of Technology Ir. J. van Overeem Delft University of Technology Ir. M.C. Onderwater ARCADIS Nederland BV Company ARCADIS Nederland BV, Division Water PREFACE Preface This Master thesis is the final part of the Master program Hydraulic Engineering of the chair Coastal Engineering at the faculty Civil Engineering & Geosciences of the Delft University of Technology. This research is done in cooperation with ARCADIS Nederland BV. The report represents the work done from July 2011 until May 2012. I would like to thank Jan van Overeem and Martijn Onderwater for the opportunity to perform this research at ARCADIS and the opportunity to graduate on such an interesting subject with many different aspects. I would also like to thank Robbin van Santen for all his help and assistance for the XBeach model. Furthermore I owe a special thanks to my graduation committee for the valuable input and feedback: Prof. dr. ir. M.J.F. Stive (Delft University of Technology) for his support and interest in my graduation work; Dr. ir. M. Zijlema (Delft University of Technology) for his support and reviewing the report; ir. J. van Overeem (Delft University of Technology ) for his supervisions, useful feedback and help, support and for reviewing the report; and ir.
    [Show full text]
  • 1 the Influence of Groyne Fields and Other Hard Defences on the Shoreline Configuration
    1 The Influence of Groyne Fields and Other Hard Defences on the Shoreline Configuration 2 of Soft Cliff Coastlines 3 4 Sally Brown1*, Max Barton1, Robert J Nicholls1 5 6 1. Faculty of Engineering and the Environment, University of Southampton, 7 University Road, Highfield, Southampton, UK. S017 1BJ. 8 9 * Sally Brown ([email protected], Telephone: +44(0)2380 594796). 10 11 Abstract: Building defences, such as groynes, on eroding soft cliff coastlines alters the 12 sediment budget, changing the shoreline configuration adjacent to defences. On the 13 down-drift side, the coastline is set-back. This is often believed to be caused by increased 14 erosion via the ‘terminal groyne effect’, resulting in rapid land loss. This paper examines 15 whether the terminal groyne effect always occurs down-drift post defence construction 16 (i.e. whether or not the retreat rate increases down-drift) through case study analysis. 17 18 Nine cases were analysed at Holderness and Christchurch Bay, England. Seven out of 19 nine sites experienced an increase in down-drift retreat rates. For the two remaining sites, 20 retreat rates remained constant after construction, probably as a sediment deficit already 21 existed prior to construction or as sediment movement was restricted further down-drift. 22 For these two sites, a set-back still evolved, leading to the erroneous perception that a 23 terminal groyne effect had developed. Additionally, seven of the nine sites developed a 24 set back up-drift of the initial groyne, leading to the defended sections of coast acting as 1 25 a hard headland, inhabiting long-shore drift.
    [Show full text]
  • Recent Sediments of the Monterey Deep-Sea Fan
    UC Berkeley Hydraulic Engineering Laboratory Reports Title Recent Sediments of the Monterey Deep-Sea Fan Permalink https://escholarship.org/uc/item/5f440431 Author Wilde, Pat Publication Date 1965-05-01 Peer reviewed eScholarship.org Powered by the California Digital Library University of California RECENT SEDIMENTS OF THE MONTEREY DEEP-SEA FAN A thesis presented by Pat Wilde to The Department of Geological Sciences in partial fulfillment of the requirements for the degree of Doc tor of Philosophy in the subject of Geology Harvard Univer sity Cambridge, Massachusetts May 1965 Copyright reserved by the author University of California Hydraulic Engineering Laboratory Submitted under Contract DA- 49- 055-CIV-ENG- 63-4 with the Coastal Engineering Research Center, U. S. Army Technical Report No. HEL-2-13 RECENT SEDIMENTS OF THE MONTEREY DEEP-SEA FAN by Pat Wilde Berkeley, California May, 1965 CONTENTS Page Abstract ................... 1 Introduction ...................... 5 Definition ..................... 5 Location ..................... 5 Regional Setting .............. 8 Subjects of Investigation ............... 9 Sources of Data .................. 10 Acknowledgements ................ 10 Geomorphology ..................11 Major Features ..............'11 FanSlope ................... 11 Under sea Positive Relief ............15 Submarine Canyon-Channel Systems . 16 Hydraulic Geometry ................ 19 Calculations ............... 19 Comparison with other Channel Systems ..30 Lithology ........................32 Sampling Techniques ...............
    [Show full text]
  • Baja California Sur, Mexico)
    Journal of Marine Science and Engineering Article Geomorphology of a Holocene Hurricane Deposit Eroded from Rhyolite Sea Cliffs on Ensenada Almeja (Baja California Sur, Mexico) Markes E. Johnson 1,* , Rigoberto Guardado-France 2, Erlend M. Johnson 3 and Jorge Ledesma-Vázquez 2 1 Geosciences Department, Williams College, Williamstown, MA 01267, USA 2 Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada 22800, Baja California, Mexico; [email protected] (R.G.-F.); [email protected] (J.L.-V.) 3 Anthropology Department, Tulane University, New Orleans, LA 70018, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-413-597-2329 Received: 22 May 2019; Accepted: 20 June 2019; Published: 22 June 2019 Abstract: This work advances research on the role of hurricanes in degrading the rocky coastline within Mexico’s Gulf of California, most commonly formed by widespread igneous rocks. Under evaluation is a distinct coastal boulder bed (CBB) derived from banded rhyolite with boulders arrayed in a partial-ring configuration against one side of the headland on Ensenada Almeja (Clam Bay) north of Loreto. Preconditions related to the thickness of rhyolite flows and vertical fissures that intersect the flows at right angles along with the specific gravity of banded rhyolite delimit the size, shape and weight of boulders in the Almeja CBB. Mathematical formulae are applied to calculate the wave height generated by storm surge impacting the headland. The average weight of the 25 largest boulders from a transect nearest the bedrock source amounts to 1200 kg but only 30% of the sample is estimated to exceed a full metric ton in weight.
    [Show full text]