3.0 Coastal Processes
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Sediment Transport and the Genesis Flood — Case Studies Including the Hawkesbury Sandstone, Sydney
Sediment Transport and the Genesis Flood — Case Studies including the Hawkesbury Sandstone, Sydney DAVID ALLEN ABSTRACT The rates at which parts of the geological record have formed can be roughly determined using physical sedimentology independently from other dating methods if current understanding of the processes involved in sedimentology are accurate. Bedform and particle size observations are used here, along with sediment transport equations, to determine rates of transport and deposition in various geological sections. Calculations based on properties of some very extensive rock units suggest that those units have been deposited at rates faster than any observed today and orders of magnitude faster than suggested by radioisotopic dating. Settling velocity equations wrongly suggest that rapid fine particle deposition is impossible, since many experiments and observations (for example, Mt St Helens, mud- flows) demonstrate that the conditions which cause faster rates of deposition than those calculated here are not fully understood. For coarser particles the only parameters that, when varied through reasonable ranges, very significantly affect transport rates are flow velocity and grain diameter. Popular geological models that attempt to harmonize the Genesis Flood with stratigraphy require that, during the Flood, most deposition believed to have occurred during the Palaeozoic and Mesozoic eras would have actually been the result of about one year of geological activity. Flow regimes required for the Flood to have deposited various geological cross- sections have been proposed, but the most reliable estimate of water velocity required by the Flood was attained for a section through the Tasman Fold Belt of Eastern Australia and equalled very approximately 30 ms-1 (100 km h-1). -
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. -
Sediment Transport in the San Francisco Bay Coastal System: an Overview
Marine Geology 345 (2013) 3–17 Contents lists available at ScienceDirect Marine Geology journal homepage: www.elsevier.com/locate/margeo Sediment transport in the San Francisco Bay Coastal System: An overview Patrick L. Barnard a,⁎, David H. Schoellhamer b,c, Bruce E. Jaffe a, Lester J. McKee d a U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA, USA b U.S. Geological Survey, California Water Science Center, Sacramento, CA, USA c University of California, Davis, USA d San Francisco Estuary Institute, Richmond, CA, USA article info abstract Article history: The papers in this special issue feature state-of-the-art approaches to understanding the physical processes Received 29 March 2012 related to sediment transport and geomorphology of complex coastal–estuarine systems. Here we focus on Received in revised form 9 April 2013 the San Francisco Bay Coastal System, extending from the lower San Joaquin–Sacramento Delta, through the Accepted 13 April 2013 Bay, and along the adjacent outer Pacific Coast. San Francisco Bay is an urbanized estuary that is impacted by Available online 20 April 2013 numerous anthropogenic activities common to many large estuaries, including a mining legacy, channel dredging, aggregate mining, reservoirs, freshwater diversion, watershed modifications, urban run-off, ship traffic, exotic Keywords: sediment transport species introductions, land reclamation, and wetland restoration. The Golden Gate strait is the sole inlet 9 3 estuaries connecting the Bay to the Pacific Ocean, and serves as the conduit for a tidal flow of ~8 × 10 m /day, in addition circulation to the transport of mud, sand, biogenic material, nutrients, and pollutants. -
The Role of Geology in Sediment Supply and Bedload Transport Patterns in Coarse Grained Streams
The Role of Geology in Sediment Supply and Bedload Transport Patterns in Coarse Grained Streams Sandra E. Ryan USDA Forest Service, Rocky Mountain Research Station, Fort Collins, Colorado This paper compares gross differences in rates of bedload sediment moved at bankfull discharges in 19 channels on national forests in the Middle and Southern Rocky Mountains. Each stream has its own “bedload signal,” in that the rate and size of materials transported at bankfull discharge largely reflect the nature of flow and sediment particular to that system. However, when rates of bedload transport were normalized by dividing by the watershed area, the results were similar for many sites. Typically, streams exhibited normalized rates of bedload transport between 0.001 and 0.003 kg s-1 km-2 at bankfull discharges. Given the inherent difficulty of obtaining a reliable estimate of mean rates of bedload transport, the relatively narrow range of values observed for these systems is notable. While many of these sites are underlain by different geologic terrane, they appear to have comparable patterns of mass wasting contributing to sediment supply under current climatic conditions. There were, however, some sites where there was considerable departure from the normalized range of values. These sites typically had different patterns and qualitative rates of mass wasting, either higher or lower, than observed for other watersheds. The gross differences in sediment supply to the stream network have been used to account for departures in the normalized rates of bedload transport observed for these sites. The next phase of this work is to better quantify the contributions from hillslopes to help explain variability in the normalized rate of bedload transport. -
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. -
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 ............... -
Modeling and Practice of Erosion and Sediment Transport Under Change
water Editorial Modeling and Practice of Erosion and Sediment Transport under Change Hafzullah Aksoy 1,* , Gil Mahe 2 and Mohamed Meddi 3 1 Department of Civil Engineering, Istanbul Technical University, 34469 Istanbul, Turkey 2 IRD, UMR HSM IRD/ CNRS/ University Montpellier, Place E. Bataillon, 34095 Montpellier, France 3 Ecole Nationale Supérieure d’Hydraulique, LGEE, Blida 9000, Algeria * Correspondence: [email protected] Received: 27 May 2019; Accepted: 9 August 2019; Published: 12 August 2019 Abstract: Climate and anthropogenic changes impact on the erosion and sediment transport processes in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes from natural areas to cultivated areas, and then from degraded areas to desertification. Such areas, under the effect of anthropogenic activities, are more sensitive to erosion, and are therefore prone to erosion. On the other hand, with an increase in the number of dams in watersheds, a great portion of sediment fluxes is trapped in the reservoirs, which do not reach the sea in the same amount nor at the same quality, and thus have consequences for coastal geomorphodynamics. The Special Issue “Modeling and Practice of Erosion and Sediment Transport under Change” is focused on a number of keywords: erosion and sediment transport, model and practice, and change. The keywords are briefly discussed with respect to the relevant literature. The papers in this Special Issue address observations and models based on laboratory and field data, allowing researchers to make use of such resources in practice under changing conditions. -
Progressive and Regressive Soil Evolution Phases in the Anthropocene
Progressive and regressive soil evolution phases in the Anthropocene Manon Bajard, Jérôme Poulenard, Pierre Sabatier, Anne-Lise Develle, Charline Giguet- Covex, Jeremy Jacob, Christian Crouzet, Fernand David, Cécile Pignol, Fabien Arnaud Highlights • Lake sediment archives are used to reconstruct past soil evolution. • Erosion is quantified and the sediment geochemistry is compared to current soils. • We observed phases of greater erosion rates than soil formation rates. • These negative soil balance phases are defined as regressive pedogenesis phases. • During the Middle Ages, the erosion of increasingly deep horizons rejuvenated pedogenesis. Abstract Soils have a substantial role in the environment because they provide several ecosystem services such as food supply or carbon storage. Agricultural practices can modify soil properties and soil evolution processes, hence threatening these services. These modifications are poorly studied, and the resilience/adaptation times of soils to disruptions are unknown. Here, we study the evolution of pedogenetic processes and soil evolution phases (progressive or regressive) in response to human-induced erosion from a 4000-year lake sediment sequence (Lake La Thuile, French Alps). Erosion in this small lake catchment in the montane area is quantified from the terrigenous sediments that were trapped in the lake and compared to the soil formation rate. To access this quantification, soil processes evolution are deciphered from soil and sediment geochemistry comparison. Over the last 4000 years, first impacts on soils are recorded at approximately 1600 yr cal. BP, with the erosion of surface horizons exceeding 10 t·km− 2·yr− 1. Increasingly deep horizons were eroded with erosion accentuation during the Higher Middle Ages (1400–850 yr cal. -
Sediment and Sedimentary Rocks
Sediment and sedimentary rocks • Sediment • From sediments to sedimentary rocks (transportation, deposition, preservation and lithification) • Types of sedimentary rocks (clastic, chemical and organic) • Sedimentary structures (bedding, cross-bedding, graded bedding, mud cracks, ripple marks) • Interpretation of sedimentary rocks Sediment • Sediment - loose, solid particles originating from: – Weathering and erosion of pre- existing rocks – Chemical precipitation from solution, including secretion by organisms in water Relationship to Earth’s Systems • Atmosphere – Most sediments produced by weathering in air – Sand and dust transported by wind • Hydrosphere – Water is a primary agent in sediment production, transportation, deposition, cementation, and formation of sedimentary rocks • Biosphere – Oil , the product of partial decay of organic materials , is found in sedimentary rocks Sediment • Classified by particle size – Boulder - >256 mm – Cobble - 64 to 256 mm – Pebble - 2 to 64 mm – Sand - 1/16 to 2 mm – Silt - 1/256 to 1/16 mm – Clay - <1/256 mm From Sediment to Sedimentary Rock • Transportation – Movement of sediment away from its source, typically by water, wind, or ice – Rounding of particles occurs due to abrasion during transport – Sorting occurs as sediment is separated according to grain size by transport agents, especially running water – Sediment size decreases with increased transport distance From Sediment to Sedimentary Rock • Deposition – Settling and coming to rest of transported material – Accumulation of chemical -
Bedload Equation for Ripples and Dunes
Bedload Equation for Ripples and Dunes GEOLOGICAL SURVEY PROFESSIONAL PAPER 462-H Bedload Equation for Ripples and Dunes By D. B. SIMONS, E. V. RICHARDSON, and C. F. NORDIN, JR. SEDIMENT TRANSPORT IN ALLUVIAL CHANNELS GEOLOGICAL SURVEY PROFESSIONAL PAPER 462-H An examination of conditions under which bed- load transport rates may be determined from the dimensions and speed of shifting bed forms UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 20 cents (paper cover) CONTENTS Page Page Symbols. _______________________ ___________________ IV Bedload Transport __ ______________ . _____ ___ __ HI Abstract __ __________ ___ ___ .__._--_____._..___ HI Conclusions_______________ ________ _________ _ ____ 7 Introduction ____________________ _______ _ 1 References cited. ___________________ _ __ ___________ 9 ILLUSTRATIONS Page FIGURES 4-7. Relation of Page FIGURE 1. Definition sketch of dunes. H2 4. V.to(V-V H5 . Vs 2. Comparison of computed bedload with 5. 6 observed bed-material load__________ 3 V-VQ g 6. h to 3. Comparison of computed and observed (V V\ bedload.___________________________ 7. qriOToV[~y~ )______ _______ 8 TABLE Page TABLE 1. Variables considered. H2 m LIST OF SYMBOLS C Chezy coefficient Ci A constant D Mean depth g Accleration due to gravity h Average ripple or dune amplitude KI, K2) Ka, KI, K5 Constants q_b Bedload, by volume or weight qr Bed material load S Slope of the energy gradient t Time V Mean velocity VQ Noneroding mean velocity Vs Average velocity of ripples or dunes in the direction of flow x Distance parallel to the direction of flow y Elevation of the bed above an arbitrary horizontal datum 7 Unit weight of the fluid 5 A transformation, 5=x Vst TO The shear stress at the bed X Porosity of the sand bed d Partial derivative SEDIMENT TRANSPORT IN ALLUVIAL CHANNELS BEDLOAD EQUATION FOR RIPPLES AND DUNES By D. -
Measuring Currents in Submarine Canyons: Technological and Scientifi C Progress in the Past 30 Years
Exploring the Deep Sea and Beyond themed issue Measuring currents in submarine canyons: Technological and scientifi c progress in the past 30 years J.P. Xu U.S. Geological Survey, 345 Middlefi eld Road, MS-999, Menlo Park, California 94025, USA ABSTRACT 1. INTRODUCTION processes, and summarize and discuss several future research challenges constructed primar- The development and application of The publication of the American Association ily for submarine canyons in temperate climate, acoustic and optical technologies and of of Petroleum Geologists Studies in Geology 8: such as the California coast. accurate positioning systems in the past Currents in Submarine Canyons and Other Sea 30 years have opened new frontiers in the Valleys (Shepard et al., 1979) marked a signifi - 2. TECHNOLOGICAL ADVANCES submarine canyon research communities. cant milestone in submarine canyon research. IN CURRENT OBSERVATION IN This paper reviews several key advance- Although there had been studies on the topics of SUBMARINE CANYONS ments in both technology and science in the submarine canyon hydrodynamics and sediment fi eld of currents in submarine canyons since processes in various journals since the 1930s 2.1. Instrumentation the1979 publication of Currents in Subma- (Shepard et al., 1939; Emory and Hulsemann, rine Canyons and Other Sea Valleys by Fran- 1963; Ryan and Heezen 1965; Inman, 1970; Instrument development has come a long way cis Shepard and colleagues. Precise place- Drake and Gorsline, 1973; Shepard, 1975), this in the past 30 yr. The greatest leap in the tech- ments of high-resolution, high-frequency book was the fi rst of its kind to provide descrip- nology of fl ow measurements was the transition instruments have not only allowed research- tion and discussion on the various phenomena from mechanical to acoustic current meters. -
Dynamics of Beach Sand Made Easy
Dynamics of Beaches Made Easy Page 1 Dynamics Of Beaches Made Easy San Diego County Chapter of the Surfrider Foundation 1. Introduction Beaches are made up of more than just sand. In California beaches are generally formed by erosion of uplifted plates resulting in cliff backed beaches or in the delta areas of rivers or watersheds. Beach sand is an important element of beaches but not the only element. Wavecut platforms or tidal terraces are equally important in many areas of San Diego. The movement of beach sand is governed by many complex processes and variables. However, there are a few very basic elements that tend to control not only how much sand ends up on our beaches, but also how much sand exists near enough to the shore to be deposited on the beach under favorable conditions. The following is a brief description of the most important issues influencing the current condition of our local beaches with respect to sand. Dynamics of Beaches Made Easy Page 2 2. Geology The geology of San Diego County varies from sea cliffs to sandy beaches. Beaches are generally found at the mouths of lagoons or in the lagoon or river outfalls. Cliffs formed by tectonic activity and the erosion via marine forces deserve special mention. Much of San Diego’s coastline consists of a wavecut platform sometimes referred to as a tidal terrace. A wavecut platform is formed where a seacliff is eroded by marine action, meaning waves, resulting in the deposition of cliff material and formation of a bedrock area where erosion occurred.