How is a coastline different from a beach




















They are a mechanism for returning the water back out to sea, and a conduit to transport seaward eroded beach sediment Figure 9b during high seas. They are also a major hazard to beach goers and responsible for most beach rescues and drowning Short Figure 9 a Low waves breaking on a shallow bar and flowing shoreward into a rip feeder channel. The dye highlights the rip feeder current flowing along the base of the beach face, then turning to flow seaward in the deeper rip channel.

When the broken wave reaches the base of the wet beach it collapses and runs up the beach face as swash or uprush in the swash zone Figure The uprush stops toward the top of the slope, some percolates into the beach, the remainder flows back down the beach as backwash. As sediment is deposited in the swash zone it can build a berm , a near horizontal to slightly landward-dipping sand surface, the area where most people sit when they go to the beach. The swash zone may also contain beach cusps , spaced about every 20 to 30 m and produced by another form of edge wave Figure Figure 10 Wave runup on the steep beach face at Ke lli Beach, Hawaii.

Figure 11 A steep reflective beach with well developed high tide beach cusps at Hammer Head, Western Australia. Wave-dominated beaches have an RTR tide range less than three times the average wave height RTR Reflective beaches are produced by lower waves H Figure 12 A plot of breaker wave height versus sand size, together with wave period, that can be used to determine the approximate beach state for wave-dominated beaches. To use the chart, determine the breaker wave height, period and grain size mm.

They are characterized by a surf zone with one or two bars up to m wide. The bar is usually cut by regular rip channels and currents Figure Figure 13 Well-developed intermediate beach containing transverse bars and rip channels along Lighthouse Beach, Australia. Note the waves breaking on the bars, with no waves breaking in the deeper darker rip channels.

Also note the rhythmic shoreline protruding in lee of the bars and forming an embayment in lee of the rips. Waves break on the outer then inner bar s , thereby dissipating their energy as the move across the surf zone Figure The swell breaks over the wide outer bar, reforms in the central trough, then breaks across the inner bar, resulting up to 10 lines of breakers and a m wide dissipative beach and surf zone. They usually have a steep, coarser-grained, cusped, reflective, high tide beach.

This is fronted by a wide, finer-grained, low gradient, often featureless, intertidal zone, up to m wide, then a low tide surf zone which may contain bars and rip channels Figure Figure 15 A steep reflective high tide beach face fronted by a m wide tide-modified low tide terrace crossed by shallow drainage channels at North Harbour Beach, Australia. An additional beach type consists of a high tide reflective beach face fronted by intertidal rocks flats, and in the tropics a high tide beach fronted by a fringing coral reef flat Figure Furthermore any beach located in the high latitudes will be seasonally exposed to freezing air and water temperatures leading to the development of sea ice, shoreface ice, and a frozen snow covered beach Figure Figure 18 The beach at Pingok Island, north Alaska, shown a during summer, with floating ice against the shore; b during freeze-up, with snow and sea ice accumulating; and c the frozen winter beach and ocean.

Beach systems are an essential component of a larger scale coastal landform called barriers , which are long-term accumulation of wave, tide, and wind deposited marine sediment usually sand at the shore. When separated from the mainland by lagoons and marshes Figure 19 they are called barrier islands Figure 20 , which occur along the US East and Gulf coasts.

Some are backed by large dune systems as along the Oregon coast. Figure 19 A coastal sand barrier consisting of a beach and vegetated dunes, backed by a lagoon, at Big Beach, Queensland, Australia. Figure 20 A series of low barrier islands separated by tidal inlets, at Corner Inlet, Victoria, Australia. Davis, R. Davis, Jr. Komar, P. Beach Processes and Sedimentation , 2nd ed. Masselink, G. Introduction to Coastal Processes and Geomorphology.

Short, A. Handbook of Beach and Shoreface Morphodynamics. Australian beach systems — Nature and distribution. Journal of Coastal Research 22 , 11—27 The Coast of Australia. Melbourne, Australia: Cambridge University Press, Woodroffe, C. Coasts — Form and processes. Global Change: An Overview.

Conservation of Biodiversity. Introduction to the Basic Drivers of Climate. Tropical Weather. Terrestrial Biomes. Causes and Consequences of Dispersal in Plants and Animals. Causes and Consequences of Biodiversity Declines. Disease Ecology. Coastal Dunes: Geomorphology.

Coastal Processes and Beaches. Drip Water Hydrology and Speleothems. Earth's Earliest Climate. El Nino's Grip on Climate. Large-Scale Ecology Introduction. Methane Hydrates and Contemporary Climate Change. Modeling Sea Level Rise. Ocean Acidification. Rivers and Streams - Water and Sediment in Motion.

Principles of Landscape Ecology. Spatial Ecology and Conservation. Restoration Ecology. Energy Economics in Ecosystems. Earth's Ferrous Wheel. The Ecology of Fire. Citation: Short, A. Nature Education Knowledge 3 10 Waves, tide, and wind dominate coastal processes and landforms.

Rivers deliver sediment to the coast, where it can be reworked to form deltas, beaches, dunes, and barrier islands. Some beaches do not have any restaurants or resorts beside them, which are said to be wild beaches. This is because they are not developed. There are various kinds of beaches, and two interesting types are said to be the coral and the volcanic beach.

The volcanic beaches are present neat volcanoes which are fully made up of lava which makes it down to the path of the ocean, while the coral beach is really beautiful with having white powder-type sand along with them. An island comes under the category of a coast, which is surrounded by water on all four sides with trees, sand, and rocks in between them.

In short, the area of the island which is the nearest to the ocean or any kind of water available is known as the coast. A coast in any region is usually segregated as the West Coast or east coast.

The two main coast types are said to be sheltered coast that coast which are shelters and the pelagic coast. In a bay or a gulf , a person will be able to see a sheltered coast, and on the other hand, a pelagic coast is usually seen at the start point of an ocean. Residents of the Gulf Coast, for instance, are more familiar with food made from shrimp, a seafood native to the warm waters of the Gulf of Mexico.

Maine, on the northern East Coast, is famous for its lobster. Photograph by Mark Makowski , My Shot. The Most Coast. Canada has , kilometers , miles of coastline. Short But Sweet. Monaco has 4 kilometers 2. Banks and Shores Technically, the land next to rivers and lakes is coastal.

But river coasts are called banks and lake coasts are called shores. Sea level is determined by measurements taken over a year cycle. Seaweed can be composed of brown, green, or red algae, as well as "blue-green algae," which is actually bacteria. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Caryl-Sue, National Geographic Society. Dunn, Margery G. For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

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Physical boundaries include oceans, cliffs, or valleys. Select from these educational resources to teach middle school students more about physical boundaries. A jetty is a long, narrow structure that protects a coastline from the currents and tides. Watch this brief, video picture of practice that captures everyday classroom life and provides real-life examples of how students learn and think about ocean topics. The gravitational pull of the moon and the rotational force of the Earth cause tides to rise and fall across the planet.

The species living in coastal areas most affected by changing tides have unique ways of surviving. Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content.



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