DOCSLIB.ORG

Beach Topography and Beach Cusps

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Beach Topography and Beach Cusps Beach topography and beach cusps ROGER N. DUBOIS Department of Geography, University of Maryland Baltimore County, Baltimore, Maryland 21228 ABSTRACT The purpose of this paper is to investigate the influence of beach topography on the formation of beach cusps in a marine environ- The development of beach cusps was studied along the northern ment. The association between the breaching of a berm by the shore of Delaware from June 9 through June 30, and from July 28 backwash which cuts closely spaced channels through a berm and through August 10 of 1976. At the study site, the formation of the formation of beach cusps has been reported in the literature beach cusps was dependent upon the existence of a tidal berm in (Palmer, 1834; Jefferson, 1899; Otvos, 1964). Specifically, Sal- the developing stage and of a favorable backshore topography. lenger (1975) repeatedly observed the following conditions which Beach cusps developed as follows: after an erosional event on a led to the development of beach cusps along Parramore Island off sandy beach, a berm developed at low tide. The swash extended the eastern shore of Virginia: (a) following an erosional event on a over the berm and ponded between the berm and the backshore. beach, a berm developed on the foreshore at low tide. The swash The stream flow from the ponded water to the sea cut closely extended over the berm and ponded between the berm and the spaced channels through the berm. As the tide rose, the berm and backshore; stream flow from the ponded water cut closely spaced channels migrated landward. When the tide fell, the swash could no channels through the berm. The spacing of the channels was longer overtop the berm, and no water was ponded landward of the suggested to be controlled by subharmonic edge waves, (b) With a berm. Since no water was returning seaward through the channels, rising tide, the berm and channels migrated landward, (c) As the the channel form could not be maintained, and the swash flared the tide began to fall, the swash could no longer overtop the berm crest, channels into bays. A series of beach cusps appeared on the beach and no water was ponded landward of the berm. With no water as the tide continued to fall. The spacing between cusps was irregu- returning seaward through the channels, the swash reshaped the lar and was attributed to the irregular size of swash salients. At channels into bays, and a system of beach cusps was developed high tide, the horizontal distance from the berm crest to the along the beach. When beach cusps are formed by the backwash backshore (L) was less than 12 m. At high tide where L was greater breaching of a tidal berm, it is here suggested that two critical than 12 m, no beach cusps formed. Although a tidal berm de- beach elements be required: (1) a tidal berm, and (2) a favorable veloped, there was no effective bachwash to cut through the berm. backshore topography. The horizontal distance from the berm crest As the new tidal berm developed and as the swash overtopped the to the backshore should be as important to the formation of cusps berm crest, the swash continued landward and during a short as the presence of a berm. Consider Figure 1, which shows beach period of time flooded a portion of the backshore. No cusps were profiles with different types of beach topography. A tidal berm has observed to develop after a tidal berm had been constructed; berms developed at the foreshore of each of the four profiles. In Figure 1 A, and cusps developed together. the berm has formed near a relatively steep backshore; in IB, near a storm berm; and in 1C, near a beach scarp. The horizontal line INTRODUCTION from the top of the berm to a point intersecting the backshore (L) is Several hypotheses have been put forth to explain the origin of FOREDUNE beach cusps. All of these hypotheses can be classified into three broad groups. The first group of hypotheses associates some physi- cal characteristics of incident waves with the formation of beach cusps: intersecting wave trains (Branner, 1900; Dalrymple and La- TIDAL nan, 1976), swash length (Longuet-Higgins and Parkin, 1962), BERM wave energy (Russell and Mclntire, 1965), and wash salients (Gorycki, 1973). The second group, which deals with a single hypothesis, suggests that edge waves are the cause for the origin of some beach cusps (Galvin, 1965; Bowen and Inman, 1969, 1971; Komar, 1973; Guza and Inman, 1975). The third group of hypoth- eses states that cusps are a function of the interaction between inci- dent waves and beach topography: irregular depressions on a beach (Johnson, 1919; Otvos, 1964), irregular indentures along a foreshore (Kuenen, 1948), and breaching of a berm (beach ridge) (Jefferson, 1899; Evans, 1938; Williams, 1973; Sallenger, 1975). An analysis of all data reported by the cited authors shows that beach cusps can form under a variety of beach and wave condi- tions, and that no single process can account for the formation of Figure 1. Beach profiles with tidal berms. L is the horizontal distance beach cusps in all types of beach environments. from the berm crest to the backshore. Geological Society of America Bulletin, v. 89, p. 1133-1139, 10 figs., August 1978, Doc. no. 80802. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/89/8/1133/3444126/i0016-7606-89-8-1133.pdf by guest on 28 September 2021 1134 R. N. DUBOIS BACKSHORE The methodology of this study was relatively simple but time consuming. The beaches in the study area, especially at Key Box Road and at Half Way Road (Fig. 3), were monitored from June 9 through June 30, and from July 28 through August 10 of 1976; the total study time was five weeks. At Key Box Road and at Half Way Road, four beach profiles at intervals of 61 m were surveyed, and photographs of the beach were taken as foreshore conditions changed. BACKSHORE RESULTS The results of this study are chronologically presented as beach conditions changed. Beach profiles and photographs are presented as evidence in support of the qualitative description of how beach cusps formed at the study area. Throughout the study period when cusps were present, the spac- B. BACKWASH ing of beach cusps was irregular; for example, the spacing within a Figure 2. (A) Swash in the form of salients advancing over a developing set of cusps ranged from 26.5 to 39.6 m. The average angle of the tidal berm. "Hie dotted area is the tidal berm in the developing stage. (B) seaward slope of horns (8.3° of arc) was steeper than the average Water from adjacent salients merge and cut channels in the tidal berm. angle of bays (5.7°). Also, the angle of the slope immediately shoreward of the crest of the beach cusps varied from a 1.0° of arc relatively short in Figures 1A through 1C. As a berm develops and seaward dip to a 1.0° landward dip; when no cusps were present, as the swash overtops the berm crest, the water collects in the nar- the shoreward angle from the berm crest was dipping landward at row zone between the berm crest and the backshore; the ponded about 2.4° of arc. As cusps developed, waves approached the water returns seaward and cuts closely spaced channels through the shoreline at an oblique angle. berm (Fig. 2). Note that in Figure ID, in contrast, L is relatively long. Except for the foredune, the tidal berm is the highest eleva- tional feature on the beach. Consequently, as the swash overtops the developing tidal berm in Figure ID, the swash energy dies out in the backshore, and the swash percolates into the beach. Once the voids in the backshore sediments are saturated with water, a por- tion of the backshore becomes flooded. To release the ponded water in the backshore, a few widely spaced channels are cut through the developing tidal berm; no beach cusps consisting of closely spaced bays or troughs are formed on the foreshore. If the assumptions about the behavior of the swash and backwash are correct in Figure 1, then the formation of beach cusps by backwash breaching of a tidal berm is dependent upon the presence of a tidal berm and a relatively short horizontal distance from the tidal berm crest to the backshore (L). The development of a tidal berm depends upon the immediate wave condition; however, the distance of L not only depends upon the immediate wave condition but also upon the beach topography prior to the formation of the tidal berm and consequently of beach cusps. Even if a tidal berm forms and water is ponded between the berm and the backshore, it does not necessarily follow that beach cusps will develop. The as- sumption that an initial beach topography can influence the forma- tion of beach cusps was tested in the field. STUDY AREA AND METHODOLOGY The study was conducted along the northern shore of Delaware from the Indian River Inlet to Cape Henlopen (Fig. 3). This study area was selected because beach cusps frequently exist along the shore. The coast of Delaware is composed of a barrier system which includes baymouth barriers and barriers against pre-Holocene highlands (Kraft, 1971). At the study area, the average width of the backshore ranged from about 15 m just north of the Indian River Inlet and of Rehoboth Beach to about 75 m in the area of Key Box Road (Fig. 3).
Load more

Recommended publications
  • Management of Coastal Erosion by Creating Large-Scale and Small-Scale Sediment Cells
    COASTAL EROSION CONTROL BASED ON THE CONCEPT OF SEDIMENT CELLS by L. C. van Rijn, www.leovanrijn-sediment.com, March 2013 1. Introduction Nearly all coastal states have to deal with the problem of coastal erosion. Coastal erosion and accretion has always existed and these processes have contributed to the shaping of the present coastlines. However, coastal erosion now is largely intensified due to human activities. Presently, the total coastal area (including houses and buildings) lost in Europe due to marine erosion is estimated to be about 15 km2 per year. The annual cost of mitigation measures is estimated to be about 3 billion euros per year (EUROSION Study, European Commission, 2004), which is not acceptable. Although engineering projects are aimed at solving the erosion problems, it has long been known that these projects can also contribute to creating problems at other nearby locations (side effects). Dramatic examples of side effects are presented by Douglas et al. (The amount of sand removed from America’s beaches by engineering works, Coastal Sediments, 2003), who state that about 1 billion m3 (109 m3) of sand are removed from the beaches of America by engineering works during the past century. The EUROSION study (2004) recommends to deal with coastal erosion by restoring the overall sediment balance on the scale of coastal cells, which are defined as coastal compartments containing the complete cycle of erosion, deposition, sediment sources and sinks and the transport paths involved. Each cell should have sufficient sediment reservoirs (sources of sediment) in the form of buffer zones between the land and the sea and sediment stocks in the nearshore and offshore coastal zones to compensate by natural or artificial processes (nourishment) for sea level rise effects and human-induced erosional effects leading to an overall favourable sediment status.
    [Show full text]
  • Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel Beaches Tiffany Roberts University of South Florida, [email protected]
    University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School January 2012 Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel Beaches Tiffany Roberts University of South Florida, [email protected] Follow this and additional works at: http://scholarcommons.usf.edu/etd Part of the American Studies Commons, Geology Commons, and the Geomorphology Commons Scholar Commons Citation Roberts, Tiffany, "Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel Beaches" (2012). Graduate Theses and Dissertations. http://scholarcommons.usf.edu/etd/4216 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel Beaches by Tiffany M. Roberts A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Geology College of Arts and Sciences University of South Florida Major Professor: Ping Wang, Ph.D. Bogdan P. Onac, Ph.D. Nathaniel Plant, Ph.D. Jack A. Puleo, Ph.D. Julie D. Rosati, Ph.D. Date of Approval: July 12, 2012 Keywords: barrier island beaches, beach morphodynamics, beach nourishment, longshore sediment transport, cross-shore sediment transport. Copyright © 2012, Tiffany M. Roberts Dedication To my eternally supportive mother, Darlene, my brother and sister, Trey and Amber, my aunt Pat, and the friends who have been by my side through every challenge and triumph.
    [Show full text]
  • Part III-2 Longshore Sediment Transport
    Chapter 2 EM 1110-2-1100 LONGSHORE SEDIMENT TRANSPORT (Part III) 30 April 2002 Table of Contents Page III-2-1. Introduction ............................................................ III-2-1 a. Overview ............................................................. III-2-1 b. Scope of chapter ....................................................... III-2-1 III-2-2. Longshore Sediment Transport Processes ............................... III-2-1 a. Definitions ............................................................ III-2-1 b. Modes of sediment transport .............................................. III-2-3 c. Field identification of longshore sediment transport ........................... III-2-3 (1) Experimental measurement ............................................ III-2-3 (2) Qualitative indicators of longshore transport magnitude and direction ......................................................... III-2-5 (3) Quantitative indicators of longshore transport magnitude ..................... III-2-6 (4) Longshore sediment transport estimations in the United States ................. III-2-7 III-2-3. Predicting Potential Longshore Sediment Transport ...................... III-2-7 a. Energy flux method .................................................... III-2-10 (1) Historical background ............................................... III-2-10 (2) Description ........................................................ III-2-10 (3) Variation of K with median grain size................................... III-2-13 (4) Variation of K with
    [Show full text]
  • The Relationship Between Wave Action and Beach Profile Characteristics
    CHAPTER 14 THE RELATIONSHIP BETWEEN WAVE ACTION AND BEACH PROFILE CHARACTERISTICS P. H. Kemp Department of GivH Engineering. University College London, England. ABSTRACT. The rational design of coast protection works requires a knowledge of the behaviour of the beach under natural conditions. The understanding of the relationship between the waves acting on the beach and the characteristics of the beach profile produced, is thus a necessary preliminary to the analysis of the causes of beach erosion and the evaluation of the effect of projected remedial measures. The present paper describes the results of a series of prelimin- ary hydraulic model experiments carried out by the author prior to a model study of the behaviour of groynes in stabilising beaches. Most of the beach materials used represented coarse sand or shingle in nature. The results demonstrate the fundamental importance of the "phase- difference" in terms of wave period between the break-point and the limit of uprush, in relation to flow conditions, cusp formation, and the change from "step" to "bar" type profiles. Within the limits of the experiments an expression connecting the breaker height, beach profile length, and grain diameter is developed, and its implications examined in relation to beach slope, and to the previous "wave steepness" criterion for the change from step to bar type profiles. Observations are included on the rate of recession of a shore- line due to the onset of more severe wave conditions. INTRODUCTION. BEACH CHANGES. Changes in the coastline may be classified as:- (1) Progressive changes resulting in prograding or recession of the shoreline over a long period of time.
    [Show full text]
  • Pocket Beach Hydrodynamics: the Example of Four Macrotidal Beaches, Brittany, France
    Marine Geology 266 (2009) 1–17 Contents lists available at ScienceDirect Marine Geology journal homepage: www.elsevier.com/locate/margeo Pocket beach hydrodynamics: The example of four macrotidal beaches, Brittany, France A. Dehouck a,⁎, H. Dupuis b, N. Sénéchal b a Géomer, UMR 6554 LETG CNRS, Université de Bretagne Occidentale, Institut Universitaire Européen de la Mer, Technopôle Brest Iroise, 29280 Plouzané, France b UMR 5805 EPOC CNRS, Université de Bordeaux, avenue des facultés, 33405 Talence cedex, France article info abstract Article history: During several field experiments, measurements of waves and currents as well as topographic surveys were Received 24 February 2009 conducted on four morphologically-contrasted macrotidal beaches along the rocky Iroise coastline in Brittany Received in revised form 6 July 2009 (France). These datasets provide new insight on the hydrodynamics of pocket beaches, which are rather poorly Accepted 10 July 2009 documented compared to wide and open beaches. The results notably highlight a cross-shore gradient in the Available online 18 July 2009 magnitude of tidal currents which are relatively strong offshore of the beaches but are insignificant inshore. Communicated by J.T. Wells Despite the macrotidal setting, the hydrodynamics of these beaches are thus totally wave-driven in the intertidal zone. The crucial role of wind forcing is emphasized for both moderately and highly protected beaches, as this Keywords: mechanism drives mean currents two to three times stronger than those due to more energetic swells when beach morphodynamics winds blow nearly parallel to the shoreline. Moreover, the mean alongshore current appears to be essentially embayed beach wind-driven, wind waves being superimposed on shore-normal oceanic swells during storms, and variations in beach cusps their magnitude being coherent with those of the wind direction.
    [Show full text]
  • Lecture 12: Coasts
    Ediz Hook, Port Angeles ESCI 321 announcements • Problem set 2 due tonight at midnight • Exam 2 in one week • We will have a major review session next Thursday. Come with questions. • Study guide posted. Bring to class on Thursday Coasts, beaches and estuaries I. Coast formation II. Beaches: Rivers of sand III. Estuaries http://www.nps.gov/olym/naturescience/damremovalblog.htm 1 Processes determining coastal morphology and formation Beach morphology Plate tectonics Sea level changes (eustatic and relative sea level change) Glaciers Weathering Wave action and storms Maine N.C. General scheme of coastline development (primary → secondary) Seasonal changes in beach morphology Longshore sediment transport How do waves affect beaches? (Beach movie) 2 Tombolo on the shore of Lake Erie, Erie, Pennsylvania Formation of rip currents and beach cusps Sediment composing barrier Islands along the east coast of the U.S. is continuously eroding and depositing toward the continent and toward the south. Swash on beach cusps at Propriano, Corsica. (Photo: Sogreah, France) Rip currents on a New Zealand beach 3 Dune Ridge Beach Open Ocean Puget Sound coastlines Lagoon Marsh Flat Lagoonal Peat Common types of shorelines in Puget Sound Natural shoreline with development •Sand and gravel •Sandy beach/dunes •Sediment-starved beach •Mudflats •Deltas •Beach w/ bulkheads 4 Shoreline with bulkhead Effects of beach armoring on amphipod habitat, Paihia, New Zealand Forage fish spawning grounds in Bellingham Bay • Surf smelt spawn in upper intertidal zone • In Bellingham
    [Show full text]
  • RICHARD J. RUSSELL WILLIAM G. Mcintire Coastal Studies Institute, Louisiana State University, Baton Rouge, La. Beach Cusps Abstr
    RICHARD J. RUSSELL Coastal Studies Institute, Louisiana State University, Baton Rouge, La. WILLIAM G. McINTIRE Beach Cusps Abstract: Beach cusps develop along seaward faces posure and state of the sea. Conditions under which of growing berms. They appear early in the transi- cusps disappear are described. Although most steps tional period of decreasing wave energy from in the depositional development and erosional winter- to summer-beach conditions. Growth stages removal of cusps are understood, the theory of their are described and related to currents within the origin will remain incomplete until the reasons for swash zone. Cusp spacing depends on coastal ex- their spacing are known in quantitative terms. CONTENTS Introduction and acknowledgments 307 3. Number of examples in spacing of cusp apices . 311 Field observations 308 4. Beach changes related to increasing and decreas- Juvenile cusps 311 ing wave energy 315 Well-developed cusps 312 5. Sequential stages of turbidity distribution and Cusp disappearance 312 current flow associated with growing cusps 316 Toward a theory of cusp origin 313 References cited 318 Plate Following Appendix 1. Relationship between apex and bay 1. Cusps on firm beaches slopes 319 2. Juvenile cusps Appendix 2. Relationship of cusp length to de- 3. Well-developed cusps gree of exposure 319 4. Cusp erosion, Preston Beach, south of Perth, Western Australia r-316 Figure 5. Asymmetrical erosion of cusps, Dominica . 1. Section across three series of cusps: Cluny, Basse 6. Cusp-originating processes Terre, Guadeloupe 309 7. Current flow into bays, Warnbro Sound, south 2. Comparison between bay and apex slopes . 310 of Safety Bay, Western Australia ment and formulating opinions about their INTRODUCTION AND histories, we turned to the literature, usually ACKNOWLEDGMENTS finding confusion at least as great as our own Our beach-cusp observations started in the during initial stages of investigation.
    [Show full text]
  • EMERITA TALPOIDA and DONAX VARIABILIS DISTRIBUTION THROUGHOUT CRESCENTIC FORMATIONS; PEA ISLAND NATIONAL WILDLIFE REFUGE a Thesi
    EMERITA TALPOIDA AND DONAX VARIABILIS DISTRIBUTION THROUGHOUT CRESCENTIC FORMATIONS; PEA ISLAND NATIONAL WILDLIFE REFUGE A thesis submitted in partial fulfillment of the requirements for the degree MASTER OF SCIENCE in ENVIRONMENTAL STUDIES by BLAIK PULLEY AUGUST 2008 at THE GRADUATE SCHOOL OF THE COLLEGE OF CHARLESTON Approved by: Dennis Stewart, Thesis Advisor Dr. Robert Dolan Dr. Scott Harris Dr. Lindeke Mills Dr. Amy T. McCandless, Dean of the Graduate School 1454471 1454471 2008 ABSTRACT EMERITA TALPOIDA AND DONAX VARIABILIS DISTRIBUTION THROUGHOUT CRESCENTIC FORMATIONS; PEA ISLAND NATIONAL WILDLIFE REFUGE A thesis submitted in partial fulfillment of the requirements for the degree MASTER OF SCIENCE in ENVIRONMENTAL STUDIES by BLAIK PULLEY JULY 2008 at THE GRADUATE SCHOOL OF THE COLLEGE OF CHARLESTON Pea Island National Wildlife Refuge is a 13-mile stretch of shoreline located on the Outer Banks of North Carolina, 40 miles north of Cape Hatteras and directly south of Oregon Inlet. This Federal Navigation Channel is periodically dredged and sand is placed on the north end of the Pea Island beach. While the sediment nourishes the beach in a particularly sand-starved environment, it also alters the physical and ecological conditions. Most affected are invertebrates living in the swash, the most dominant being the mole crab (Emerita talpoida) and the coquina clam (Donax variabilis). These two species serve as a major food source for shorebirds on the island. It is especially important to protect this food resource on the federal Wildlife Refuge, which operates under a mandate to protect resources for migratory birds. For this research, beach cusps of various sizes were sampled to determine whether there is a correlation between invertebrate populations and the physical characteristics associated with these crescentic features.
    [Show full text]
  • On Beach Cusp Formation
    J. Fluid Mech. (2008), vol. 597, pp. 145–169. c 2008 Cambridge University Press 145 doi:10.1017/S002211200700972X Printed in the United Kingdom On beach cusp formation NICHOLAS DODD1, ADAM M. STOKER1, DANIEL CALVETE2 AND ANURAK SRIARIYAWAT1 1School of Civil Engineering, University of Nottingham, Nottingham, NG7 2RD, UK 2Dept. de Fisica Aplicada, Univeristat Politecnica de Catalunya, Barcelona, Spain (Received 29 September 2005 and in revised form 6 October 2007) A system of shallow water equations and a bed evolution equation are used to examine the evolution of perturbations on an erodible, initially plane beach subject to normal wave incidence. Both a permeable (under Darcy’s law) and an impermeable beach are considered. It is found that alongshore-periodic morphological features reminiscent of swash beach cusps form after a number of incident wave periods on both beaches. On the permeable (impermeable) beach these patterns are accretional (erosional). In both cases flow is ‘horn divergent’. Spacings of the cusps are consistent with observations, and are close to those provided by a standing synchronous linear edge wave. An analysis of the processes leading to bed change is presented. Two physical mechanisms are identified: concentration gradient and flow divergence, which are dominant in the lower and upper swash respectively, and their difference over a wave cycle leads to erosion or deposition on an impermeable beach. Infiltration enters this balance in the upper swash. A bed wave of elevation is shown to advance up the beach at the tip of the uprush, with a smaller wave of depression on the backwash. It is found that cusp horns can grow by a positive feedback mechanism stemming from decreased (increased) backwash on positive (negative) bed perturbations.
    [Show full text]
  • Morphology and Morphodynamics of Gravel Beaches - J
    COASTAL ZONES AND ESTUARIES – Morphology and Morphodynamics of Gravel Beaches - J. Shulmeister and R. Jennings MORPHOLOGY AND MORPHODYNAMICS OF GRAVEL BEACHES J. Shulmeister and R. Jennings School of Earth Sciences, Victoria University Wellington, New Zealand Keywords: Gravel beaches, morphology, morphodynamics, morphosedimentology, hydrodynamics, stratigraphy, sea-level responses. Contents 1. Introduction 2. Gravelly Beach Morphology 2.1. Gravelly beach profiles 2.2. Berms and the beach step 2.3. Cusps 3. Hydrodynamics of gravel beaches 3.1. Waves 3.2. Swash phase and percolation effects 3.3. Hydrodynamic effects of the beach step 4. Morphosedimentology of Gravel Beaches 4.1. Size and shape sorting 4.2. Measuring gravel size and shape. 4.3. Bluck models of gravel beach size and shape facies 4.3.1 The Sker type 4.3.2 The Newton type. 5. Stratigraphy of Gravel Beaches 6. Gravelly beach responses to external forcing 6.1. Coastal erosion on gravel coasts 6.2. Responses to sea-level rise 7. Future directions Acknowledgments Glossary Bibliography Biographical Sketches UNESCO – EOLSS Summary SAMPLE CHAPTERS Gravelly beaches are at least partly composed of coarse grained material. They have steep and typically concave profiles with slope increasing up the beach face. Gravelly beaches often contain multiple steps or berms and are invariably associated with a beach step, at or about, low tide mark. Beach cusps are a characteristic feature and are associated with the berms. Beach width is narrow, ranging from less than 20 m on some gravel barriers to about 200 m on some mixed sand and gravel beaches. Slopes are inversely related to beach width.
    [Show full text]
  • Coastal Impressions
    CoastalA Photographic Journey Impressions along Alaska’s Gulf Coast i Exhibit compiled by Susan Saupe, Mandy Lindeberg, and Dr. G. Carl Schoch Photographs selected by Mandy Lindeberg and Susan Saupe Photo editing and printing by Mandy Lindeberg Photo annotations by Dr. G. Carl Schoch Booklet prepared by Susan Saupe with design services by Fathom Graphics, Anchorage Photo mounting and laminating by Digital Blueprint, Anchorage Digital Maps for Exhibit and Booklet prepared by GRS, Anchorage January 2012 Second Printing November 2012 Exhibit sponsored by Cook Inlet RCAC and developed in partnership with NMFS AFSC Auke Bay Laboratories, and Alaska ShoreZone Program. ii Acknowledgements This exhibit would not exist without the vision of Dr. John Harper of Coastal and Ocean Resources, Inc. (CORI), whose role in the development and continued refinement of ShoreZone has directly led to habitat data and imagery acquisition for every inch of coastline between Oregon and the Alaska Peninsula. Equally important, Mary Morris of Archipelago Marine Research, Inc. (ARCHI) developed the biological component to ShoreZone, participated in many of the Alaskan surveys, and leads the biological habitat mapping efforts. CORI and ARCHI have provided experienced team members for aerial survey navigation, imaging, geomorphic and biological narration, and habitat mapping, each of whom contributed significantly to the overall success of the program. We gratefully acknowledge the support of organizations working in partnership for the Alaska ShoreZone effort, including over 40 local, state, and federal agencies and organizations. A full list of partners can be seen at www.shorezone.org. Several organizations stand out as being the earliest or staunchest supporters of a comprehensive Alaskan ShoreZone program.
    [Show full text]
  • Sedimentology of the Outer Texas Coast
    " ."' / i \t-anjllWi.£^/2i?^^1 7 Sedimentology of the Outer Texas Coast W William Dave Blankenship, B. A. prasaatad It the Pmmltg of the Ctra&*«t* School ©f fto Hmi¥#r»it^ of f©i«i» la partial Aslflllaant of tha Beciulr^aeiits For t3a® B^re® if mmm of AMM fhe osrrafisxn of tmub Vi w» wl£ t illappreelativn ilMil mm «Beoarts«Mie»t Abstract H§ ftatant a* ap#f»3*#»ei*t#& ®& the f#n«s ©oast saqr &c a#p&rstad atoonolngijsslii into tha Xaglealcte, &l&is®£, mm PoaVAlasan or tmmmt times ♥ Each aubaivlsion is associated aUjmti^ with a n&Jor fXmotn&tiaaf th« Xngl«»id« ftud F0»%» Hassan yltfe tte oflr«t0flr«t aM s^oßd oXlaMitl6 I', % rtsp«6tlvely # eai t Altaaa with tbt» "Little Xc« %# » Clsari«st@Fisti^ if th# Xaglealde «»5 ?r#s®at time®, and an& lagoon ayfttema. file ptesmlvgmp&X& teaturaa of the preseist coastal banker ssrst^ foml«ig th# o«t#r f«»» e^mst, «aiilf«at a <Hr«et MAittM to tte ©liaatlci ItJtlftfilllltiil ®f th# Fr4HMHOt# Jtav&rlag onalK>r# aoT«&ant of »«dl®aat®. fhm »«4im€ott sa-rrle4. b> laainland streams to the b®% ayataßMi^ th#a »ov«(l tte©a.gh the fesrri#r passes b^ tidal o^rr#sta, ar# oostrlbated t® a sauttoestwara «^vJ4ag lon^J^^^e enrrtiit. Way® transport aM «<!% aotl©u trajsuit#f th« s^dia#nta to mm %m&mr® Orift oU2^*#atf utoleh it r^ersifel# In dir©etiun with tha loagals&ra c^eponeat of tli€ |OM| wii^# 9ha tl^ittlO if taie IMHi 4rlft mirrant iffflMlli Olraatly th# orlantatipft of f&?aate*a f^tor^st MMMIg Kpi b#tw#tn cmtps, a^ the atsoclat^di ba©k»#^i ahisanelt ®M rlppla Biarks.
    [Show full text]