12 Coastlines

Learning Objectives

By the end of this chapter, students should be able to:

  • Describe how waves occur, move, and carry energy.
  • Explain wave behavior approaching the .
  • Describe features and zones.
  • Describe and its contribution to and .
  • Explain how cause the of spits and baymouth bars.
  • Distinguish between and coasts and describe coastal features associated with each.
  • Describe the relationship between the natural of sand in the zone and human attempts to alter it for human convenience.
  • Describe the pattern of the main ocean currents and explain the different factors involved in surface currents and deep ocean currents.
  • Explain how ocean tides occur and distinguish among diurnal, semidiurnal, and patterns.

The Earth’s surface is 29% land and 71% water. Coastlines are the interfaces between, and as such, the longest visible boundaries on Earth. To understand the processes that occur at these boundaries, it is important to first understand wave energy.

12.1 Waves and Wave Processes

The particles move in roughly circular motion.
Figure 12.1: Particle motion within a wind-blown wave.

Wind blowing over the surface of water transfers energy to the water through friction. The energy transferred from wind to water causes waves to form. Waves move as individual oscillating particles of water. As the passes, the water is moving forward. As the passes, the water is moving backward. To see wave movement in action, watch a cork or some floating object as a wave passes.

Crest, trough, period, wavelength are labeled.
Figure 12.2: Aspects of water waves, labeled.

Important terms to understand in the operation of waves include: the is the highest point of the wave; the is the lowest point of the wave. is the vertical distance from the to the crest and is determined by wave energy. Wave is half the , or the distance from either the crest or trough to the still water line. is the horizontal distance between consecutive wave crests. is the speed at which a moves forward and is related to the wave’s energy. is the time interval it takes for adjacent wave crests to pass a given point.

The diagram shows that wavebase is 1/2 the wavelength of waves of water.
Figure 12.3: Diagram describing wavebase.

The circular motion of water particles diminishes with depth and is negligible at about one-half , an important dimension to remember in connection with waves. is the vertical depth at which water ceases to be disturbed by waves. In water shallower than , waves will disturb the bottom and sand. is measured at a depth of about one-half , where the water particles’ circular motion diminishes to zero. If waves approaching a beach have crests at about 6 m (~20 ft) intervals, this wave motion disturbs water to about 3 m (~10 ft) deep. This motion is known as fair- . In strong storms such as hurricanes, both and increase dramatically to a depth known as , which is approximately 91 m (~300 ft).

Waves are generated by wind blowing across the ocean surface. The amount of energy imparted to the water depends on wind velocity and the distance across which the wind is blowing. This distance is called . Waves striking a are typically generated by storms hundreds of miles from the and have been traveling across the ocean for days.

The wave moves across the image.
Figure 12.4: Wave train moving with dispersion.

Winds blowing in a relatively constant direction generate waves moving in that direction. Such a group of approximately parallel waves traveling together is called a . A coming from one can produce various wavelengths. Longer wavelengths travel at a faster velocity than shorter wavelengths, so they arrive first at a distant . Thus, there is a process that takes place during the ’s travel. This process is called wave dispersion.

12.1.1 Behavior of Waves Approaching Shore

There are four types of breakers
Figure 12.5: Types of breakers.

On the open sea, waves generally appear choppy because wave trains from many directions are interacting with each other, a process called wave interference. Constructive interference occurs where crests align with other crests. The aligned wave height is the sum of the individual , a process referred to as wave amplification. Constructive interference also produces hollows where troughs align with other troughs. Destructive interference occurs where crests align with troughs and cancel each other out. As waves approach and begin to make frictional contact with the sea floor at a depth of about one-half or less, they begin to slow down. However, the energy carried by the wave remains the same, so the waves build up higher. Remember that water moves in a circular motion as a wave passes, and each circle is fed from the in front of the advancing wave. As the wave encounters shallower water at the , there is eventually insufficient water in the in front of the wave to supply a complete circle, so the crest pours over creating a breaker.

The waves get taller in shallow water.
Figure 12.6: All waves, like tsunamis, slow down as they reach shallow water. This causes the wave to increase in hight.

A special type of wave is called a , sometimes incorrectly called a “tidal wave.” are generated by energetic events affecting the sea floor, such as earthquakes, submarine , and eruptions (see chapter 9 and chapter 4). During earthquakes for example, can be produced when the moving crustal rocks below the sea abruptly elevate a portion of the seafloor. Water is suddenly lifted creating a bulge at the surface and a spreads out in all directions traveling at tremendous speeds [over 322 kph (200 mph)] and carrying enormous energy. may pass unnoticed in the open ocean because they move so fast, the is very long, and the is very low. But, as the approaches and each wave begins to interact with the shallow seafloor, friction increases and the wave slows down. Still carrying its enormous energy, wave height builds up and the wave strikes the shore as a wall of water that can be over 30 m (~100 ft) high. The wave, called a runup, may sweep inland well beyond the beach destroying structures far inland. can deliver a catastrophic blow to people at the beach. As the water in front of the wave is drawn back, the seafloor is exposed. Curious and unsuspecting people on the beach may run out to see exposed sea life only to be overwhelmed when the breaking crest hits.


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12.2 Shoreline Features

Coastlines are dynamic, high energy, and geologically complicated places where many different erosional and depositional features exist (see chapter 5). They include all parts of the land-sea boundary directly affected by the sea, including land far above high and seafloor well below normal . But, the itself is the direct interface between water and land that shifts with the tides. This shifting interface at the is called the zone. The combination of waves, currents, , coastal morphology, and gravity, all act on this land-sea boundary to create features.

12.2.1 Shoreline Zones

The image shows the many complexities of the shoreline described in the text.
Figure 12.7: Diagram of zones of the shoreline.

Shorelines are divided into five primary zones—, , surf, , and . The zone is below water, but it is still geologically active due to flows of that cascade over the and accumulate in the rise. The zone is the area of the affected by the waves where water depth is one-half wavelength or less. The width of this zone depends on the maximum of the approaching and the slope of the seafloor. The zone includes the , which is where sand is disturbed and deposited. The is broken into two segments: upper and lower . Upper is affected by everyday wave action and consists of finely-laminated and cross-bedded sand. The lower is the only area moved by storm waves and consists of hummocky cross-stratified sand. The is where the waves break.

The zone overlaps the and is periodically wet and dry due to waves and tides. The zone is where planer-laminated, well-sorted sand accumulates. The is the part of the zone where the breaking waves swash up and the backwash flows back down. Low ridges above the in the zone are called . During the summer in North America, when most people visit the beach, the zone where people spread their towels and beach umbrellas is the . Wave energy is typically lower in the summer, which allows sand to pile onto the beach. Behind the is a low ridge of sand called the . In winter, higher storm energy moves the sand off the beach and piles it in the zone. The next year, that sand is replaced on the beach and moved back onto the . The zone is the area always above sea level in normal conditions. In the zone, onshore winds may blow sand behind the beach and the , creating .

12.2.2 Refraction, Longshore Currents, and Longshore Drift

The waves move sand along the beach.
Figure 12.8: Longshore drift. 1=beach, 2=sea, 3=longshore current direction, 4=incoming waves, 5=swash, 6=backwash.

As waves enter shallower water less than one-half depth, they slow down. Waves usually approach the at an angle, with the end of the waves nearest the beach slowing down first. This causes the wave crests to bend, called . From the , this causes it to look like waves are approaching the beach straight on, parallel to the beach. However, as refracted waves actually approach the at a slight angle, they create a slight difference between the swash as it moves up the at a slight angle and the backwash as it flows straight back down under gravity. This slight angle between swash and backwash along the beach creates a current called the . Waves stir up sand in the and move it along the . This movement of sand is called . along both the west and east coasts of North America moves sand north to south on average.

The spit is a long ridge of sand
Figure 12.9: Farewell Spit, New Zealand.

can carry down a until it reaches a bay or inlet where it will deposit sand in the quieter water (see chapter 11). Here, a can form. As the grows, it may extend across the of the bay forming a barrier called a . Where the bay or inlet serves as boat anchorage, spits and baymouth bars are a severe inconvenience. Often, inconvenienced communities create methods to keep their bays and harbors open.

The two jetties led to a coastal waterway.
Figure 12.10: Jetties near Carlsbad, California. Notice the left jetty is loaded with sand, while the right jetty is lacking sand. This is due to the longshore drift going left to right.

One way to keep a harbor open is to build a , a long concrete or stone barrier constructed to deflect the sand away from a harbor or other ocean waterway. If the does not deflect the sand far enough out, sand may continue to flow along the , forming a around the end of the . A more expensive but effective method to keep a bay open is to dredge the sand from the growing spit, put it on barges, and deliver it back to the drift downstream of the harbor . An even more expensive but more effective option is to install large pumps and pipes to draw in the sand upstream of the harbor, pump it through pipes, and it back into the drift downstream of the harbor . Because natural processes work continuously, human efforts to mitigate inconvenient spits and baymouth bars require ongoing modifications. For example, the community of Santa Barbara, California, tried several methods to keep their harbor open before settling on pumps and piping.

Some water is rushing outwards while most water rushes in toward the shore.
Figure 12.11: Animation of rip currents.

are another coastal phenomenon related to . occur in the seafloor when wave trains come straight onto the . In areas where wave trains push water directly toward the or where the shape of the seafloor refracts waves toward a specific point on the beach, the water piles up on . But this water must find an outlet back to the sea. The outlet is relatively narrow, and carry the water directly away from the beach. Swimmers caught in are carried out to sea. Swimming back to directly against the strong current is fruitless. A for good swimmers is to ride out the current to where it dissipates, swim around it, and return to the beach. Another for average swimmers is to swim parallel to the beach until out of the current, then return to the beach. Where are known to exist, warning signs are often posted. The best is to understand the nature of , have a plan before entering the water, or watch the signs and avoid them all together.

Like , undertow is a current that moves away from the shore. However, unlike , undertow occurs underneath the approaching waves and is strongest in the where waves are high and water is shallow. Undertow is another return flow for water transported onshore by waves.

12.2.3 Emergent and Submergent Coasts

The arch is a rock in the water with a hole in the middle which allows water to pass through.
Figure 12.12: Island Arch, a sea arch in Victoria, Australia.

coasts occur where sea levels fall relative to land level. coasts occur where sea levels rise relative to land level. shifts and sea level changes cause the long-term rise and fall of sea level relative to land. Some features associated with coasts include high cliffs, headlands, exposed , steep slopes, rocky shores, arches, stacks, tombolos, wave-cut , and wave notches.

The rock in the ocean is connected by the sandy tombolo.
Figure 12.13: This tombolo, called “Angel Road,” connects the stack of Shodo Island, Japan.

In coasts, wave energy, wind, and gravity erode the . The erosional features are elevated relative to the wave zone. Sea cliffs are persistent features as waves cut away at their base and higher rocks calve off by . Refracted waves that attack at the base of headlands may erode or carve out a sea arch, which can extend below sea level in a sea cave. When a sea arch collapses, it leaves one or more rock columns called stacks.

Wave notches carved by Lake Bonneville, Antelope Island, Utah.
Figure 12.14: Wave notches carved by Lake Bonneville, Antelope Island, Utah.

A or near island creates a quiet water zone behind it. Sand moving in the accumulates in this quiet zone forming a : a sand strip that connects the island or to the . Where sand supply is low, wave energy may erode a wave-cut across the , exposed as bare rock with tidal pools at low . This bench-like extends to the cliff’s base. When wave energy cuts into the base of a sea cliff, it creates a .

The area is a filled-in river valleys.
Figure 12.15: Landsat image of Chesapeake Bay, eastern United States. Note the barrier islands parallel to the coastline.

coasts occur where sea levels rise relative to land. This may be due to —when the Earth’s sinks—or when sea levels rise due to melt. Features associated with coasts include flooded mouths, , , , , bays, , and tidal currents. In coastlines, mouths are flooded by the rising water, for example Chesapeake Bay. are valleys flooded by post- sea level rise (see chapter 14). are elongated bodies of sand that formed from old beach sands that used to parallel the . Often, lie behind . is controversial: some scientists believe that they formed when melted after the last , raising sea levels. Another is that formed from spits and bars accumulating far .

The tidal flat it a network of channels.
Figure 12.16: General diagram of a tidal flat and associated features.

—or mudflats, form where tides alternately flood and expose low areas along the . Tidal currents create combinations of symmetrical and asymmetrical marks on mudflats, and drying mud creates mud cracks. In the central Wasatch Mountains of Utah, ancient deposits are exposed in the of the Big Cottonwood Formation. These ancient deposits provide an example of applying Hutton’s (see chapter 1). Sedimentary structures common on modern indicate that these ancient deposits were formed in a similar environment: there were , tides, and shoreline processes acting at that time, yet the ancient age indicates that there were no land plants to hold products of in place (see chapter 5), so rates would have been different.

Geologically, are broken into three different sections: barren zones, marshes, and salt pans. These zones may be present or absent in each individual . Barren zones are areas with strong flowing water, coarser , with marks and common. Marshes are vegetated with sand and mud. Salt pans or flats, less often submerged than the other zones, are the finest-grained parts of , with silty and mud cracks (see chapter 5).

The lagoon is just inside the coastline.
Figure 12.17: Kara-Bogaz Gol lagoon, Turkmenistan.

are locations where spits, , or other features partially cut off a body of water from the ocean. are a vegetated type of where fresh water flows into the area making the water —a salinity between salt and fresh water. However, terms like , , and even bay are often loosely used in place of one another. and are certainly transitional between land and water environments where , shallow shorelines; , lakes or ; and , or currents can overlap. For more information on and , see chapter 5.

12.2.4 Human Impact on Coastal Beaches

The sediment piled on one side and removed from the other.
Figure 12.18: Groins gathering sediment from longshore drift.

Humans impact coastal beaches when they build homes, condominiums, hotels, businesses, and harbors—and then again when they try to manage the natural processes of . Waves, currents, , and dams at mouths deplete sand from expensive beachfront property and expose once calm harbors to high-wave energy. To protect their investment, keep sand on their beach, and maintain calm harbors, cities and landowners find ways to mitigate the damage by building , , dams, and breakwaters.

Series of groins on a coast in Virginia
Figure 12.19: Groin system on a coast in Virginia.

are large manmade piles of boulders or concrete barriers built at mouths and harbors. A is designed to divert the current or , to keep a channel to the ocean open, and to protect a harbor or beach from wave action. are similar but smaller than . are fences of wire, wood or concrete built across the beach perpendicular to the and downstream of a property. Unlike , are used to preserve sand on a beach rather than to divert it. Sand erodes on the downstream side of the and collects against the upstream side. Every on one property thus creates a need for another one on the property downstream. A series of along a beach develops a scalloped appearance along the .

Inland and flow to the ocean carrying sand to the which distributes it to beaches. When dams are built, they sand and keep from reaching beaches. To replenish beaches, sand may be hauled in from other areas by trucks or barges and dumped on the depleted beach. Unfortunately, this can disrupt the ecosystem that exists along the by exposing native creatures to foreign ecosystems and microorganisms and by introducing foreign objects to humans. For example, visitors to one replenished east coast beach found munitions and metal shards in the sand, which had been dredged from abandoned military test ranges.

A tombolo formed behind the breakwater at Venice, CA
Figure 12.20: A tombolo formed behind the breakwater at Venice, CA.

An approach to protect harbors and moorings from high-energy wave action is to build a —an structure against which the waves break, leaving calmer waters behind it. Unfortunately, breakwaters keep waves from reaching the beach and stop sand moving with . When is interrupted, sand is deposited in quieter water, and the builds out forming a behind the . The eventually fill in behind the with sand. When the city of Venice, California built a to create a quiet water harbor, created a behind the , as seen in the image. The now acts as a large in the beach drift.

12.2.5 Submarine Canyons

The canyons are carved into the slope.
Figure 12.21: Submarine canyons off of Los Angeles. A=San Gabriel Canyon, B=Newport Canyon. At point C, the canyon is 815 m wide and 25 m deep.

are narrow, deep underwater canyons located on shelves. typically form at the mouths of large landward systems. They form when cut down into the during low sea level and when material continually slumps or flows down from the of a or a . Underwater currents rich in and more dense than sea water, can flow down the canyons, even erode and deepen them, then drain onto the . Underwater , called , occur when steep faces and underwater flows are released down the . in submarine canyons can continue to erode the canyon, and eventually, fan-shaped deposits develop at the of the canyon on the rise. See chapter 5 for more information on .


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12.3 Currents and Tides

Ocean water moves as waves, currents, and tides. Ocean currents are driven by persistent global winds blowing over the water’s surface and by water density. Ocean currents are part of Earth’s heat engine in which solar energy is absorbed by ocean water and distributed by ocean currents. Water has another unique property, high specific heat, that relates to ocean currents. Specific heat is the amount of heat necessary to raise a unit volume of a substance one degree. For water it takes one calorie per cubic centimeter to raise its one degree Celsius. This means the oceans, covering 71% of the Earth’s surface, soak up solar heat with little change and distribute that heat around the Earth by ocean currents.

Warm currents are red, blue currents are blue.
Figure 12.22: World ocean currents.

12.3.1 Surface Currents

The Earth’s rotation and the Coriolis effect exert significant influence on ocean currents (see chapter 13). In the figure, the black arrows show global surface currents. Notice the large circular currents in the northern and southern hemispheres in the Atlantic, Pacific, and Indian Oceans. These currents are called and are driven by atmospheric circulation—air movement. rotate clockwise in the northern hemisphere and counterclockwise in the southern hemisphere because of the Coriolis Effect. Western boundary currents flow from the equator toward the poles carrying warm water. They are key contributors to local . Western boundary currents are narrow and move poleward along the east coasts of adjacent continents. The Gulf Stream and the Kuroshio currents in the northern hemisphere and the Brazil, Mozambique, and Australian currents in the southern hemisphere are western boundary currents. Currents returning cold water toward the equator are broad and diffuse along the western coasts of adjacent land masses. These warm western boundary and cold eastern boundary currents affect of nearby lands making them warmer or colder than other areas at equivalent latitudes. For example, the warm Gulf Stream makes Northern Europe much milder than similar latitudes in northeastern Canada and Greenland. Another example is the cool Humboldt Current, also called the Peru Current, flowing north along the west coast of South America. Cold currents limit evaporation in the ocean, which is one reason the in Chile is cool and arid.

12.3.2 Deep Currents

In certain areas, the current sinks or rises.
Figure 12.23: Global thermohaline circulation. PSS=practical salinity units.

Whether an ocean current moves horizontally or vertically depends on its density. The density of seawater is determined by and salinity.

Evaporation and freshwater influx from affect salinity and, therefore, the density of seawater. As the western boundary currents cool at high latitudes and salinity increases due to evaporation and ice (recall that ice floats; water is densest just above its freezing point). So the cold, denser water sinks to become the ocean’s deep waters. Deep-water movement is called thermo refers to , and haline refers to salinity. This circulation connects the world’s deep ocean waters. Movement of the Gulf Stream illustrates the beginning of . Heat in the warm poleward moving Gulf Stream promotes evaporation which takes heat from the water and as heat thus dissipates, the water cools. The resulting water is much colder, saltier, and denser. As the denser water reaches the North Atlantic and Greenland, it begins to sink and becomes a deep-water current. As shown in the illustration above, this worldwide connection between shallow and deep-ocean circulation overturns and mixes the entire world ocean, bringing nutrients to life, and is sometimes referred to as the .

12.3.3 Tides

are the rising and lowering of sea level during the day and are caused by the gravitational effects of the Sun and Moon on the oceans. The Earth rotates daily within the Moon and Sun’s gravity fields. Although the Sun is much larger and its gravitational pull is more powerful, the Moon is closer to Earth; hence, the Moon’s gravitational influence on tides is dominant. The of the at a given location and the difference between high and low —the tidal range, depends primarily on the configuration of the Moon and Sun with respect to the Earth orbit and rotation. occurs when the Sun, Moon, and Earth line up with each other at the full or new Moon, and the tidal range is at a maximum. occurs approximately two weeks later when the Moon and Sun are at right angles with the Earth, and the tidal range is lowest.

Clockwise with Earth in the center: first quarter moon, spring tide, new moon, neap tide, third quarter moon, spring tide, full moon, neap tide. Sun is to the right.
Figure 12.24: The types of tides.
Each tide has a different curve.
Figure 12.25: Different tide types.

The Earth rotates within a tidal envelope, so tides rise and ebb daily. Tides are measured at coastal locations. These measurements and the tidal predictions based on them are published on the NOAA website. Tides rising and falling create tidal patterns at any given location. The three types of tidal patterns are diurnal, semidiurnal, and mixed.

The map shows locations of the different tide types.
Figure 12.26: Global tide types.

go through one complete cycle each . A is the amount of time for the Moon to align with a point on the Earth as the Earth rotates, which is slightly longer than 24 hours. Semidiurnal tides go through two complete cycles in each —approximately 12 hours and 50 minutes, with the tidal range typically varying in each cycle. Mixed tides are a combination of diurnal and semidiurnal patterns and show two tidal cycles per , but the relative amplitudes of each cycle and their highs and lows vary during the tidal month. For example, there is a high, high and a high, low . The next day, there is a low, high and a low, low . Forecasting the tidal pattern and the times tidal phases arrive at a given location

GIF animation showing Earth rotating and tides fluctuating as a result of lunar gravitational forces.
Figure 12.27: A tidal day lasts slightly longer than 24 hours.

is complicated and can be done for only a few days at a time. Tidal phases are determined by bathymetry: the depth of ocean basins and the obstacles that are in the way of the tidal envelope within which the Earth rotates. Local tidal experts make 48-hour tidal forecasts using tidal charts based on daily observations, as can be seen in the chart of different types. A typical tidal range is approximately 1 m (3 ft). Extreme tidal ranges occur where the tidal wave enters a narrow restrictive zone that funnels the tidal energy. An example is the English Channel between Great Britain and the European where the tidal range is 7 to 9.75 m (23 to 32 ft). The Earth’s highest tidal ranges occur at the Bay of Fundy, the funnel-like bay between Nova Scotia and New Brunswick, Canada, where the average range is nearly 12 m (40 ft) and the extreme range is around 18 m (60 ft). At extreme tidal range locations, a person who ventures out onto the seafloor exposed during ebb may not be able to outrun the advancing water during flood . NOAA has additional information on tides.


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Summary

processes are complex, but important for understanding coastal processes. Waves, currents, and tides are the main agents that shape shorelines. Most coastal landforms can be attributed to moving sand via , and long-term rising or falling sea levels.

The is the interface between water and land and is divided into five zones. Processes at the are called processes. Waves approach the beach at an angle, which cause the waves to bend towards the beach. This bending action is called and is responsible for creating the and —the process that moves sand along the coasts. When the deposits sand along the into quieter waters, the sand can accumulate, creating a or barrier called a , which often blocks bays and harbors. Inconvenienced humans create methods to keep their harbors open and preserve sand on their beaches by creating and , which negatively affect natural beach processes.

coasts are created by sea levels falling, while coasts are caused by sea levels rising. Oceans absorb solar energy, which is distributed by currents throughout the world. Circular surface currents, called , rotate clockwise in the northern hemisphere and counterclockwise in the southern hemisphere. Thermohaline deep circulation connects the world’s deep ocean waters: when shallow poleward moving warm water evaporates, the colder, saltier, and denser water sinks and becomes deep-water currents. The connection between shallow and deep-ocean circulation is called the .

Tides are the rising and lowering of sea level during the day and are caused by the gravitational effects of the Sun and Moon on the oceans. There are three types of tidal patterns: diurnal, semidiurnal, and mixed. Typical tidal ranges are approximately 1 m (3 ft). Extreme tidal ranges are around 18 m (60 ft).


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URLs Linked Within This Chapter

Tide measurements and predictions: https://tidesandcurrents.noaa.gov/tide_predictions.html

NOAA: https://tidesandcurrents.noaa.gov/

Text References

  1. Colling, Angela. 2001. Ocean Circulation. Edited by Open University Course Team. Butterworth-Heinemann.
  2. Davis, Richard A., Jr., and Duncan M. Fitzgerald. 2009. Beaches and Coasts. John Wiley & Sons.
  3. Davis, Richard Albert. 1997. The Evolving Coast. Scientific American Library New York.
  4. Greene, Paul, George Follett, and Clint Henker. 2009. “Munitions and Dredging Experience on the United States Coast.” Marine Technology Society Journal 43 (4): 127–31.
  5. Jackson, Nancy L., Mitchell D. Harley, Clara Armaroli, and Karl F. Nordstrom. 2015. “Beach Morphologies Induced by Breakwaters with Different Orientations.” Geomorphology 239 (June). Elsevier: 48–57.
  6. “Littoral Bypassing and Beach Restoration in the Vicinity of Port Hueneme, California.” n.d. In Coastal Engineering 1966.
  7. Munk, Walter H. 1950. “On the Wind-Driven Ocean Circulation.” Journal of Meteorology 7 (2): 80–93.
  8. Normark, William R., and Paul R. Carlson. 2003. “Giant Submarine Canyons: Is Size Any Clue to Their Importance in the Rock Record?” Geological Society of America Special Papers 370 (January): 175–90.
  9. Reineck, H-E, and Indra Bir Singh. 2012. Depositional Sedimentary Environments: With Reference to Terrigenous Clastics. Springer Science & Business Media.
  10. Rich, John Lyon. 1951. “Three Critical Environments of Deposition, and Criteria for Recognition of Rocks Deposited In Each of Them.” Geological Society of America Bulletin 62 (1). gsabulletin.gsapubs.org: 1–20.
  11. Runyan, Kiki, and Gary Griggs. 2005. “Implications of Harbor Dredging for the Santa Barbara Littoral Cell.” In California and the World Ocean ’02, 121–35. Reston, VA: American Society of Civil Engineers.
  12. Schwiderski, Ernst W. 1980. “On Charting Global Ocean Tides.” Reviews of Geophysics 18 (1): 243–68.
  13. Stewart, Robert H. 2008. Introduction to Physical Oceanography. Texas A & M University Texas.
  14. Stommel, Henry, and A. B. Arons. 2017. “On the Abyssal Circulation of the World ocean—I. Stationary Planetary Flow Patterns on a Sphere – ScienceDirect.” Accessed February 26. http://www.sciencedirect.com/science/article/pii/0146631359900656.
  15. Stommel, Henry, and A. B. Arons. 2017. “On the Abyssal Circulation of the World ocean—I. Stationary Planetary Flow Patterns on a Sphere – ScienceDirect.” Accessed February 26. http://www.sciencedirect.com/science/article/pii/0146631359900656.

Figure References

Figure 12.1: Particle motion within a wind-blown wave. Kraaiennest. 2008. CC BY-SA 4.0. https://commons.wikimedia.org/wiki/File:Deep_water_wave.gif

Figure 12.2: Aspects of water waves, labeled. NOAA. Unknown date. Public domain. https://oceanservice.noaa.gov/education/tutorial_currents/media/supp_cur03a.html

Figure 12.3: Diagram describing wavebase. GregBenson. 2004. CC BY-SA 3.0. https://en.wikipedia.org/wiki/File:Wavebase.jpg

Figure 12.4: Wave train moving with dispersion. Fffred~commonswiki. 2006. Public domain. https://commons.wikimedia.org/wiki/File:Wave_packet_(dispersion).gif

Figure 12.5: Types of breakers. Kraaiennest. 2015. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Breaking_wave_types.svg

Figure 12.6: All waves, like tsunamis, slow down as they reach shallow water. Régis Lachaume. 2005. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Propagation_du_tsunami_en_profondeur_variable.gif

Figure 12.7: Diagram of zones of the shoreline. U.S. Navy. 2006. Public domain. https://commons.wikimedia.org/wiki/File:Littoral_Zones.jpg

Figure 12.8: Longshore drift. 1=beach, 2=sea, 3=longshore current direction, 4=incoming waves, 5=swash, 6=backwash. USGS. 2006. Public domain. https://commons.wikimedia.org/wiki/File:Longshore_i18n.png

Figure 12.9: Farewell Spit, New Zealand. NASA. 2006. Public domain. https://commons.wikimedia.org/wiki/File:Farewell_spit.jpg

Figure 12.10: Jetties near Carlsbad, California. USGS. 2005. Public domain. https://commons.wikimedia.org/wiki/File:Jetty_break2_new(USGS).jpg

Figure 12.11: Animation of rip currents. NOAA. 2008. Public domain. https://www.nws.noaa.gov/mdl/rip_current/

Figure 12.12: Island Arch, a sea arch in Victoria, Australia. Diliff. 2008. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Island_Archway,_Great_Ocean_Rd,_Victoria,_Australia_-_Nov_08.jpg

Figure 12.13: This tombolo, called “Angel Road,” connects the stack of Shodo Island, Japan. 663highland. 2012. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Angel_Road_Shodo_Island_Japan01s3.jpg

Figure 12.14: Wave notches carved by Lake Bonneville, Antelope Island, Utah. Wilson44691. 2008. Public domain. https://commons.wikimedia.org/wiki/File:WaveCutPlatformsAntelopeIslandUT.jpg

Figure 12.15: Landsat image of Chesapeake Bay, eastern United States. USGS, NASA. 2009. Public domain. https://www.usgs.gov/media/images/chesapeake-bay-landsat

Figure 12.16: General diagram of a tidal flat and associated features. Foxbat deinos. 2009. Public domain. https://en.m.wikipedia.org/wiki/File:Tidal_flat_general_sketch.png

Figure 12.17: Kara-Bogaz Gol lagoon, Turkmenistan. NASA. 1995. Public domain. https://commons.wikimedia.org/wiki/File:Kara-Bogaz_Gol_from_space,_September_1995.jpg

Figure 12.18: Groins gathering sediment from longshore drift. Archer0630. 2013. CC BY-SA 3.0. https://commons.wikimedia.org/wiki/File:Groin_effect-3.JPG

Figure 12.19: Groin system on a coast in Virginia. Internet Archive Book Images. 1958. Public domain. https://commons.wikimedia.org/wiki/File%3AThe_Annual_bulletin_of_the_Beach_Erosion_Board_(1958)_(18396945096).jpg

Figure 12.20: A tombolo formed behind the breakwater at Venice, CA. Internet Archive Book Images. 1948. Public domain. https://flic.kr/p/wRSfxb

Figure 12.21: Submarine canyons off of Los Angeles. A=San Gabriel Canyon, B=Newport Canyon. At point C, the canyon is 815 m wide and 25 m deep. USGS. 2012. Public domain. https://commons.wikimedia.org/wiki/File:Canyons_off_LA.jpg

Figure 12.22: World ocean currents. Dr. Michael Pidwirny. 2007. Public domain. https://commons.wikimedia.org/wiki/File:Corrientes-oceanicas.png

Figure 12.23: Global thermohaline circulation. NASA. 2008. Public domain. https://commons.wikimedia.org/wiki/File:Thermohaline_Circulation_2.png

Figure 12.24: The types of tides. KVDP. 2009. Public domain. https://commons.wikimedia.org/wiki/File:Tide_schematic.svg

Figure 12.25: Different tide types. Snubcube. 2013. Public domain. https://commons.wikimedia.org/wiki/File:Tide_type.svg

Figure 12.26: Global tide types. KVDP. 2009. Public domain. https://commons.wikimedia.org/wiki/File:Diurnal_tide_types_map.jpg

Figure 12.27: A tidal day lasts slightly longer than 24 hours. NOAA. Unknown date. Public domain. https://oceanservice.noaa.gov/education/tutorial_tides/tides05_lunarday.html

 

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