Geography
Coastal Processes
Coastal processes refer to the natural forces and mechanisms that shape and change the coastline. These processes include erosion, transportation, and deposition of sediment by waves, tides, and currents. They play a crucial role in shaping coastal landforms and can have significant impacts on human activities and infrastructure in coastal areas.
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12 Key excerpts on "Coastal Processes"
eBook - PDF- Vijay K. Sharma(Author)
- 2010(Publication Date)
- CRC Press(Publisher)
307 11 Coastal Processes and Landforms A coast is up to a few kilometers wide tract of interacting terrestrial and marine pro-cesses between the shoreline and landward limit of the first major change in terrain, usually in the form of a cliff or coastal dunes. Coastal geomorphology explains the contemporary processes and their landforms, translates the effect of global sea level changes of the Pleistocene and Holocene periods and of the tectonic instability of land-mass on the evolution of coastal landscape, and interprets the chronology of Quaternary events for the present state of coastal development. In brief, coastal geomorphology is concerned essentially with the physics of wave motion, hydraulics, sediment transport mechanisms, and interpretation of the environmental change (Kidson, 1968). GRADATIONAL PROCESSES Coasts are areas of incessant motion of shallow seawater against the littoral tract that varies much in lithology, geologic structure, and resistance to erosion. The coastal water moves onshore and offshore by the effects of waves, tides, and currents—the three process domains of marine erosion and deposition. In a general term, waves are destructive in storm conditions, tides are known more for constructive than destruc-tive work, and currents possess much less erosive potential. Tsunamis are a type of destructive waves, which develop by sudden dislocation of the seabed. W AVES Transfer of the wind energy onto the surface of a deep water body generates surface waves, such that the wave size depends directly on the wind speed, duration of time the wind blows from one direction, and extent of the open water, called fetch of the water surface, over which the wind blows prior to reaching a given observation point. These deep water waves are sinusoidal in form with interdependent length, height, amplitude, and period attributes.
eBook - PDF- Alan F. Arbogast(Author)
- 2017(Publication Date)
- Wiley(Publisher)
437 CHAPTER 19 CHAPTER PREVIEW Oceans and Seas on Earth The Nature of Coastlines: Intersection of Earth’s Spheres Tides Coastal Landforms Waves and Coastal Erosion Longshore Processes and Depositional Coastlines Human Interactions with Coastlines Evolution of the Louisiana Coastline Coastal Processes and Landforms The previous three chapters investigated fluvial, glacial, and eolian processes and their distinctive landforms. Now we turn to the various processes and landforms that occur along coastlines. Although these processes affect a very small part of the Earth’s surface, they create some of the most distinctive and popular landscapes you see. Why should you be interested in Coastal Processes and landforms? One important reason is that you may very well live along or near a coast- line, as do a majority of people in the United States (and indeed, the world). People are attracted to coastlines for a variety of economic, recreational, and lifestyle reasons and are affected by the geomorphic processes that occur along these narrow strips of land. In turn, people influence the behavior of coastlines in dramatic ways through development. Thus, understanding the geomorphology of coastlines is important, not only for gaining a better appreciation of this landscape, but also for becoming a good steward for these areas. James Morgan/Robert Harding World Imagery/Getty Images Are you attracted to this landscape? If so, you are certainly not alone. Coastlines are perhaps the most exotic landscapes on Earth, and people love to live near or visit them. This chapter focuses on the oceans of the world and the way they shape the landscape along coastlines. 438 CHAPTER 19 Coastal Processes and Landforms Oceans and Seas on Earth Before we begin discussing various Coastal Processes, let’s take a closer look at the character of the world’s oceans and seas because it provides the context in which to view the shore.
eBook - PDFGeomorphological Processes
Studies in Physical Geography
- E Derbyshire, K. J. Gregory, J. R. Hails, K. J. Gregory(Authors)
- 2013(Publication Date)
- Butterworth-Heinemann(Publisher)
Yet many of these coastal engineering problems have provided a major impetus for research into nearshore sediment dynamics, and the rapid advance in the design and development of equipment for monitoring processes, in such a dynamic environment as the coastal zone, has already made a significant contribution to scientific and engineering interests at large. Competing interests within the coastal zone for residential, recreational, industrial, defence and other facilities are making it increas-ingly necessary to understand how beaches are regulated by nearshore processes. In the light of these comments, it is important that geomorphologists should be aware of their contribution to the study of Coastal Processes, by way of interdisciplinary research. The principal aim of this chapter is to summarize some of the more significant develop-ments and to suggest possible avenues for future research by highlighting the gaps in our current knowledge. Some topics are discussed in less detail than others because they have been evaluated fully elsewhere in basic texts. This slight imbalance in the treatment of subject material is redressed partly by recommending the reader to selected references and publications. As far as the coastal geomorphologist is concerned, there is a need to study, both quantitatively and qualitatively, those parameters and processes that fundamentally con-trol shoreline equilibrium. The more important of these include the degree to which a 108 Coastal Processes particular shoreline is exposed to ocean swell, as well as storm and locally-generated waves; tidal currents; oscillations in mean sea level; variations in the sediment budget; sediment transport by wave action as distinct from tidal and other currents; the morphol-ogy of the nearshore zone and the topography of the adjacent continental shelf; the coastline in plan; and the coastal climate.
eBook - PDFWater Quality Modeling
Rivers, Streams and Estuaries
- R. Manivanan(Author)
- 2021(Publication Date)
It is therefore necessary to study this valuable region so as to prevent that competing activities are gradually causing depletion of the resources in the coastline. The following figures (Fig. 7.1and 7.2) show the typical coastal area of rocky coast and sandy coast. Fig. 7.2 Sandy Shore Coastal geography is the study of the dynamic interface between the ocean and the land, incorporating both the physical geography (i.e coastal geomorphology, geology and oceanography) and the human geography (sociology and history) of the coast. It involves an understanding of coastal weathering processes, particularly wave Fig. 7.1: Rocky Shore 95 MODELING - COASTAL AND ESTUARIES action, sediment movement and weather, and also the ways in which humans interact with the coast. 7.2 Coastal Processes The waves of different strengths that constantly hit against the shoreline are the primary movers and shapers of the coastline. Despite the simplicity of this process, the differences between waves and the rocks they hit result in hugely varying shapes. The effect that waves have depends on their strength. Strong, also called destructive waves occur on high energy beaches and are typical of Winter. They reduce the quantity of sediment present on the beach by carrying it out to bars under the sea. Constructive, weak waves are typical of low energy beaches and occur most during summer. They do the opposite to destructive waves and increase the size of the beach by piling sediment up onto the berm. One of the most important transport mechanisms results from wave refraction. Since waves rarely break onto a shore at right angles, the upward movement of water onto the beach occurs at an oblique angle. However, the return of water is at right angles to the beach, resulting in the net movement of beach material laterally.
eBook - PDFEnvironmental Sciences
A Student′s Companion
- K J Gregory, Ian Simmons, Anthony Brazel, John W Day, Edward A Keller, Alejandro Yanez-Arancibia, Arthur G Sylvester(Authors)
- 2008(Publication Date)
- SAGE Publications Ltd(Publisher)
(Cont'd) 236 Processes and Dynamics as karst processes exclusive to limestone terrain, and some processes such as subsidence can occur in periglacial environments or be the result of tectonic processes. All processes can be envisaged as involving expenditure of energy acting on materials (rock and solids, water, air, organic materials) to produce products which can include landforms, soil profiles or vegeta-tion types. Several processes may be grouped together, especially when studying them in terms of basic laws, so that the principles of fluid flow and fluid mechanics apply to fluvial, coastal, aeolian and glacial processes. Throughout environmental sciences, data is required on Earth surface processes and some is collected by national and international organizations such as hydrological and oceanographic data. In addition data is obtained in the course of national surveys for example of soil types or from vegetation surveys. However if data is not already available it can be obtained empirically by field measurements often through carefully designed experiments such as experimental areas or by remote sensing; by laboratory investigations which include scaled down environ-mental models, of a section of coast for example; and by historical techniques, which use a method of deducing change over time from records or archive materials, such as historical maps of the position of a glacier margin at different dates. Earth surface processes are combined in particular ways in different environments and so process domains are zones in which particular processes operate. Some processes such as glacial processes are confined to particular zones whereas others such as fluvial, aeolian and mass wasting can occur in most regions of the world.
eBook - PDF- James Petersen, Dorothy Sack, Robert Gabler, , James Petersen, James Petersen, Dorothy Sack, Robert Gabler(Authors)
- 2021(Publication Date)
- Cengage Learning EMEA(Publisher)
LEARNING OBJECTIVES WHEN YOU COMPLETE THIS CHAPTER YOU SHOULD BE ABLE TO: 20.1 Sketch the coastal zone, including labels for its principal subdivisions. 20.2 Explain how waves are formed and characterized. 20.3 Discuss how wind waves transfer and deliver energy to the coastal zone. 20.4 Explain why coastlines tend to straighten over time. 20.5 Recount how sediment moves along a beach. 20.6 Identify the three coastal erosion processes and five principal landforms found on erosion-dominated coastlines. 20.7 Describe the types and sources of sediment found in coastal depositional landforms. 20.8 Distinguish between beaches and spits. 20.9 Summarize a global-scale and a regional-scale classification of coasts. 20.10 Differentiate among the three types of coral reef. Coastal Processes AND LANDFORMS The shorelines of the world are extensive, complex, and often spectacular environments. David Crosbie/Alamy Stock Photo Copyright 2022 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 574 C H A P T E R 2 0 • C O A S T A L P R O C E S S E S A N D L A N D F O R M S 20-1 The Coastal Zone Most of the processes and landforms of the marine coastal zone are also found along the coastlines of large lakes. All are consid- ered standing bodies of water because the water in each occupies a basin and has an approximately uniform still-water level around the basin. This contrasts with the sloping, channelized flow toward lower elevations that constitutes streams. The shoreline of a standing body of water is the exact and constantly changing contact between the ocean or lake surface and dry land.
eBook - PDF- Tom Garrison, Robert Ellis(Authors)
- 2017(Publication Date)
- Cengage Learning EMEA(Publisher)
Generally, the finer the particles on the beach, the flatter Chapter in Perspective its slope. Beaches change shape and volume as a function of wave energy and the balance of sediment input and removal. Deltas and estuaries form where freshwater meets the ocean. Coral reefs and mangroves are among the most complex and biologically productive coasts. Human interference with Coastal Processes has generally accelerated the erosion of coasts near inhabited areas. In the next chapter you’ll learn that the study of oceanogra-phy includes a marvelous variety of living things. The next chapter’s discussion of the general nature and characteristics of marine life will launch us into the biological part of our journey. Post-Glacial Sea Level Rise 20 18 0 12 6 0 14 8 4 16 10 2 Thousands of years ago 00 50 50 25 75 75 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-300 COASTS 175 STUDY QUESTIONS 1. How is an erosional coast different from a depositional coast? 2. What features would you expect to see along an erosional coast? A depositional coast? What determines how long the features will last? 3. What two processes contribute to longshore drift? What powers longshore drift? What is the predominant direction of drift on U.S. coasts? Why? 4. What are some of the features of a sandy beach? Are they temporary or permanent? What is the relationship between wave energy on a coast and the size (or slope, or grain size) of beaches found there? 5. What is a coastal cell? Where does sand in a coastal cell come from? Where does it go and how does it get there? 6. How are deltas classified? Why are there deltas at the mouths of the Mississippi and Nile rivers, but not at the mouth of the Columbia River? 7. How are estuaries classified? Upon what does the classifica-tion depend? Why are estuaries important? 8. What kinds of organisms can have significant influence on a coast? How do they do this? 9.
eBook - PDF- Tom Freeman(Author)
- 2012(Publication Date)
- Wiley(Publisher)
Coastal Processes and Problems 203 12 Coastal Processes and Problems The 1990 Census reported that the greatest percent increases in U.S. population during the 1980s were in coastal regions. At present 50% of our population lives within an hour’s drive of a coast, and that number is expected to grow to 75% by the year 2025. • The problem: Exponential growth along our coasts is accompanied by building in high-risk localities. • The solution: A better understanding of Coastal Processes. We attempt to protect our coastal facilities with installations of stone and concrete—but such projects commonly either produce unexpected results, or fail entirely in the wake of incessant waves and currents and devastating weather. Q12.1 Before going further, (A) can you name a natural process that seasonally presents big problems for coastal residents—namely the Gulf and Atlantic coasts? Try naming a notable 2005 example of that process. (B) In this context, can you name a human activity along coasts that commonly meets with this kind of disaster? Try naming a specific occurrence of such human activity. Hint: Think about a particular Texas ‘island city’ in 1900. Q12.2 Can you name a kind of inland waterway management effort that also commonly meets with disaster? A. Are we loving our coasts to death? Topics A. What percent of the U.S. population is expected to live within an hour’s drive of a sea coast by the year 2025? B. What physiographic coastal features occur along an active continental margin? What physiographic coastal features occur along a passive continental margin? C. In what way does the profile of an ideal surface sea wave differ from that of a sine wave? What three variables determine the size of wind-generated waves? D.
eBook - PDFOceanography
An Invitation to Marine Science
- Tom Garrison(Author)
- 2015(Publication Date)
- Cengage Learning EMEA(Publisher)
Coasts are classified as erosional coasts (on which erosion dominates) or deposi-tional coasts (on which deposition dominates). Natural rock bridges, tall stacks, and sea caves are found on erosional coasts. Depositional coasts often support beaches, accumulations of loose particles. Generally, the finer the particles on the beach, the flatter its slope. Beaches change shape and volume as a function of wave energy and the balance of sediment input and removal. Coral reefs and estuaries are among the most complex and biologically productive coasts. Hu-man interference with Coastal Processes has generally accelerated the erosion of coasts near inhabited areas. In the next chapter you’ll learn that the study of oceanogra-phy includes a marvelous variety of living things. The next chapter’s discussion of the general nature and characteristics of marine life will launch us into the biological part of our journey. Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. CHAPTER 12 366 1. I have seen photos of the massive coastal modifications being made in Dubai. What happens when humans modify a coast-line so extensively? The Persian Gulf Emirate of Dubai has embarked on the most extensive human-made coastal developments in the world (Fig-ure 12.38) . Most of the additions were islands shaped like palm trees to maximize waterfront footage. Construction of the first island, Palm Jumeirah, began in June 2001. Shortly after, the Palm Jebel Ali was announced and reclamation work began.
eBook - PDF- Andrew S. Goudie, Heather A. Viles(Authors)
- 2016(Publication Date)
- Cambridge University Press(Publisher)
9.6 Conclusions During historical times, humans have become the dominant control on coastal change, primarily by altering river discharge and sediment supply to the coast, increasing rates of subsidence through fluid withdrawal, and through global cli- mate change and associated accelerated SLR (Anderson et al., 2014). Many coastal landforms are essentially fragile (e.g. beaches, barriers, marshes, etc.) and many humans live in close proximity to the seas. Thus they are particularly likely to show major changes in the face of a range of human pressures. 222 Coastal Processes and Forms in the Anthropocene
No longer available |Learn more- James Petersen, Dorothy Sack, Robert Gabler(Authors)
- 2016(Publication Date)
- Cengage Learning EMEA(Publisher)
USGS Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. C O A S T A L G E O M O R P H I C P R O C E S S E S 581 Weathering is an important factor in the breakdown of rocks in the coastal zone, as in other environments, preparing pieces for removal by wave erosion. Water is a key element in most weathering processes, and in addition to normal precipitation, rocks near the shoreline are subjected to spray from breaking waves, high relative humidities, and condensation. Salt weath- ering is particularly significant in preparing rocks for removal through chemical and physical weathering along the marine coast and coasts of salt lakes. Coasts of high relief are dominated by erosion (● Fig. 20.15). Sea cliffs (or lake cliffs) are carved where waves pound directly against steep land. If a steep coastal slope continues deep beneath the water, it may reflect much of the incoming wave energy until corrosion and hydraulic action eventually take their toll on the rock. The tides present along marine coasts allow these processes to attack a range of shoreline elevations. Once a recess, or notch, has been carved out along the base of a cliff (● Fig. 20.16a), weathering and rockfall within the shaded overhang supply clasts that can collect on the notch floor and be used by the water as tools for more efficient erosion by abrasion. Abrasion extending the notch landward leaves the cliff above subject to rockfall and other forms of mass wasting. Stones used as tools in abrasion quickly become rounded and may accumu- late at the base of the cliff as a cobble beach.
eBook - PDF- James Petersen, Dorothy Sack, Robert Gabler, , James Petersen, Dorothy Sack, Robert Gabler(Authors)
- 2014(Publication Date)
- Cengage Learning EMEA(Publisher)
Like water in streams, water that has accumulated in basins erodes some rock material chemically through corro-sion. Corrosion is the removal of the ions that have been sep-arated from rock-forming minerals by solution and other chemical weathering processes. Likewise, the power of hydraulic action from the sheer physical force of the water alone pounds against and removes coastal rock material, sometimes compressing air or water into cracks, augmenting the process. The power of storm waves, combined with the buoyancy of water, enables them at times to dislodge and move even large boulders. Once clastic particles are in motion, the waves have solid tools to perform even more erosive work through the grinding process of abrasion . Abra-sion is the most effective form of erosion by each of the geo-morphic agents, including waves. Weathering is an important factor in the breakdown of rocks in the coastal zone, as in other environments, providing sediment to be removed by wave erosion. Water is a key ele-ment in most weathering processes, and in addition to normal precipitation, rocks near the shoreline are subjected to spray from breaking waves, high relative humidity, and condensa-tion. Salt is particularly significant in breaking down rocks through chemical and physical weathering along the marine coast and coasts of salt lakes. Coastal Erosional Landforms Coasts of high relief are dominated by erosion ( ■ Fig. 17.13). Sea cliffs (or lake cliffs ) are carved where waves pound directly against steep land. If a steep coastal slope continues deep beneath the water, the slope can reflect much of the incoming wave energy until corro-sion and hydraulic action eventually take their toll on the rock. Tides present along marine coasts allow these pro-cesses to attack a range of shoreline ele-vations.
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