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CHAPTER 1 COASTS Should Coastal Environments Matter?

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Presentation on theme: "CHAPTER 1 COASTS Should Coastal Environments Matter?"— Presentation transcript:

1 CHAPTER 1 COASTS Should Coastal Environments Matter?

2 CHECK-IN: Surfing a monster wave

3 CHECK-IN: Which photograph represents the coastline? Explain your choice

4 CHAPTER 1 COASTS Should Coastal Environments Matter? In this Chapter, you will explore three key questions: 1.How and why are coastal environments different and dynamic? 2.Why are coastal areas valuable? 3.How can we manage coastal areas in a sustainable manner?

5 CHAPTER 1 COASTS Should Coastal Environments Matter? KQ 1: How and why are coastal environments different and dynamic? a.What is a coastal environment? (zones) b.What are the differences within coastal environments? c.What factors lead to the difference and dynamism in coastal environments? d.How do coastal processes differ? e.How do coastal processes shape coastal landforms differently

6 a. What is a coastal environment? (zones)

7 CHAPTER 1 COASTS Should Coastal Environments Matter? KQ 1: How and why are coastal environments different and dynamic? a.What is a coastal environment? (zones) b.What are the differences within coastal environments? c.What factors lead to the difference and dynamism in coastal environments? d.How do coastal processes differ? e.How do coastal processes shape coastal landforms differently

8 What are the differences in the characteristics of the following coastal environments? Waikiki Beach, Hawaii Cape Kumukahi, Hawaii Lulworth Cove, Britain Bunaken, Indonesia b. What is the difference between coastal environment?

9 CHAPTER 1 COASTS Should Coastal Environments Matter? KQ 1: How and why are coastal environments different and dynamic? a.What is a coastal environment? (zones) b.What are the differences within coastal environments? c.What factors lead to the difference and dynamism in coastal environments? d.How do coastal processes differ? e.How do coastal processes shape coastal landforms differently

10 Waves Tides and sea level changes Currents Geology (rock composition) Types of ecosystems (e.g. mangroves and coral reefs) Human activities (e.g. trading, fishing, recreation) c. What factors lead to the differences and dynamism of coastal environments?

11 Tombolo c. What factors lead to the differences and dynamism of coastal environments?

12 Spit c. What factors lead to the differences and dynamism of coastal environments?

13 Beach c. What factors lead to the differences and dynamism of coastal environments?

14 Cliffs c. What factors lead to the differences and dynamism of coastal environments?

15 Waves -Wind energy transferred to water -Blowing across surface of seas and oceans Affects: the power of waves to erode landforms Tides and sea level changes -Rise/fall in sea level -Caused by gravitational pull of moon and Sun on Earth Affects: transportation of sediments (depositional landforms) and erosion c. What factors lead to the differences and dynamism of coastal environments?

16 Wave energyTide Low tide High tide c. What factors lead to the differences and dynamism of coastal environments?

17 Currents -Large scale continuous movement of water in seas and oceans -Driven by prevailing wind in one direction Affects: sediment distribution and erosion Geology (rock composition) -Composition: more/less resistant rocks; hard/soft rock -Composition: layered structure Affects: rate/speed of erosion c. What factors lead to the differences and dynamism of coastal environments?

18 Currents Geology c. What factors lead to the differences and dynamism of coastal environments?

19 Types of ecosystems -Natural barriers -Corals: Slow down speed of waves -Mangroves: trap sediments and reduce coastal erosion Affects: impact of waves on coasts Human activities -Built-up area along coastline -Pollution of coastal environment Affects: condition of coastal environment c. What factors lead to the differences and dynamism of coastal environments?

20 Mangroves Coral reefs c. What factors lead to the differences and dynamism of coastal environments?

21 Chapter 1 COASTS Should Coastal Environments Matter? KQ 1: How and why are coastal environments different and dynamic? a.What is a coastal environment? (zones) b.What are the differences within coastal environments? c.What factors lead to the difference and dynamism in coastal environments? d.How do coastal processes differ? e.How do coastal processes shape coastal landforms differently

22 How would you describe the waves? Wave action d. How do coastal processes differ?

23 Parts of a wave Wave action d. How do coastal processes differ?

24 Why do waves curl? Come up with a hypothesis to suggest how waves go from Photograph A to Photographs B1 & B2. Photograph B2 Photograph B1 Photograph A d. How do coastal processes differ?

25 Why do waves curl? 1.What do the photographs definitely tell me? 2.What can I infer from the photographs? 3.What do the photographs not tell me? What further questions do I need to ask? Photograph A Photograph B1 Photograph B2 d. How do coastal processes differ?

26 Why do waves curl? d. How do coastal processes differ?

27 Match the diagrams to the factors affecting wave energy Factors Fetch (distance the wave travels) Duration of wind Wind speed Wind strength 1 A B C D d. How do coastal processes differ?

28 Wave Action Swash Backwash 2 wave types: Constructive & Destructive Erosion Transportation Deposition Wave refraction d. How do coastal processes differ?

29 Constructive – dominant process: swash carries sediments onto beach at an oblique angle) Destructive – dominant process: backwash carries sediments away from beach into ocean at a right angle due to gravity) NOTE: A Swash and Backwash occurs for every wave that comes onto the shore) Wave Type d. How do coastal processes differ?

30 Constructive WavesDestructive Waves GradientLowHigh Energy environmentLowHigh Wave heightLowHigh Wave lengthLongShort Wave frequency6–8 per minute10–14 per minute Swash vs backwashSwash more powerful than backwash Backwash more powerful than swash BreakersSwells and spilling breakersPlunging and surging breakers Occurs onGentle coastal slope and sheltered coast Steep coastal slope and open coast Prominent processDepositionErosion Wave Type d. How do coastal processes differ?

31 Wave Refraction Wave Action d. How do coastal processes differ?

32 Wave Refraction (approaching a coast) -The process by which waves change direction when they approach a coast -Occurs only when there is friction between water and seabed -Change in wave speed -Waves converge on headlands and diverge on bays -When waves converge – increased wave height and greater erosive energy -When waves diverge – decreased wave height and lower erosive energy -Uneven impact on shoreline Wave Action d. How do coastal processes differ?

33 Coastal Erosion Focus on: Cause (wave action, rock particle movement) & Effect (outcome of wave action with rock particles) a.Hydraulic action b.Abrasion or corrasion c.Attrition d.Solution or corrosion Wave Action d. How do coastal processes differ?

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36 Coastal Erosion Focus on: Cause (wave action, rock particle movement) & Effect (outcome of wave action with rock particles) a. Hydraulic action Waves striking against a rock surface trap air in its joints. This air is compressed by the oncoming waves, exerting pressure on the joints. Over time, these joints weaken and the rocks shatter. 1d. How do coastal Processes differ? – Wave Action

37 Coastal Erosion Focus on: Cause (wave action, rock particle movement) & Effect (outcome of wave action with rock particles) b. Abrasion As waves break, sediments carried by waves such as sand and rocks are hurled against the coast. These loosened sediments knock and scrape against the coastal cliffs. This weakens the surface, resulting in the breaking down of the coast. Over time, the impact from abrasion is powerful enough to undercut a cliff. 1d. How do coastal Processes differ? – Wave Action

38 Cliff undercut by coastal abrasion d. How do coastal processes differ?

39 Coastal Erosion Focus on: Cause (wave action, rock particle movement) & Effect (outcome of wave action with rock particles) c. Attrition When rock particles carried by waves rub or hit against one another, they break down into smaller pieces and become smoother and more rounded over time. 1d. How do coastal Processes differ? – Wave Action

40 Rocks rounded by attrition d. How do coastal processes differ?

41 Coastal Erosion Focus on: Cause (wave action, rock particle movement) & Effect (outcome of wave action with rock particles) d. Solution Sea water reacts chemically with water-soluble minerals in coastal rocks and dissolves them. For example, limestone rocks are easily eroded by carbonic acid in solution. When solution of minerals occurs, rocks are weakened and will eventually disintegrate 1d. How do coastal Processes differ? – Wave Action

42 Sediment Transport – Longshore drift and longshore currents Recap: Currents -Large scale movement of water in oceans -Driven by prevailing wind in one direction Affects: sediment distribution and erosion Wave Action d. How do coastal processes differ?

43 Wave Action Sediment Transport – Longshore drift and longshore currents d. How do coastal processes differ?

44 Sediment Transport -Longshore currents and longshore drift Longshore currents: Flows parallel to coast, forms when waves approach coasts at an angle Resultant zigzag movement of sediments known as beach drift: 1.Carried up the beach at an oblique angle through swash due to wind direction 2.Carried perpendicularly down the beach through backwash due to gravity Wave Action d. How do coastal processes differ?

45 Longshore drift: A result of both longshore currents and beach drift Sediments are deposited when they meet an obstruction. These sediments are transported by both longshore current and beach drift, which produces longshore drift. Determined by direction of wind Wave Action d. How do coastal processes differ?

46 Sediment Deposition -What are some reasons for the man being unable to carry the boxes properly? -What should the man do if the boxes are too much and too heavy? Wave Action d. How do coastal processes differ?

47 Sediment Deposition -What are some reasons for the wave being unable to carry the sediments? -What should the wave ‘do’ if the sediments are too much and too heavy/large? Wave Action d. How do coastal processes differ?

48 Sediment Deposition Sediment textureSediment typeSediment size VERY FINE Clayless than mm Coarse / fine? Silt mm to mm Coarse / medium? Fine sand0.125 mm to 0.25 mm Medium sand0.25 mm to 0.5 mm Coarse sand0.5 mm to 1 mm Very coarse sand1 mm to 2 mm Fine / coarse? Pebble2 mm to 64 mm Cobble64 mm to 256 mm Bouldermore than 256 mm Wave Action d. How do coastal processes differ?

49 Chapter 1 COASTS Should Coastal Environments Matter? KQ 1: How and why are coastal environments different and dynamic? a.What is a coastal environment? (zones) b.What are the differences within coastal environments? c.What factors lead to the difference and dynamism in coastal environments? d.How do coastal processes differ? e.How do coastal processes shape coastal landforms differently

50 Coastal features/landforms: Process leads to an outcome/characteristic of landform Cliffs and shore platforms Headlands and bays Caves, arches and stacks Beaches Spits and tombolos

51 Coastal features/landforms: process leads to an outcome/characteristic of landform Cliffs and shore platforms -Hydraulic action -Erosion by waves -Enlarged joints -Notch -Cliff collapse and cliff retreat -Gently-sloping platform at cliff base e. How do coastal processes shape coastal landforms differently

52 Coastal features/landforms: process leads to an outcome/characteristic of landform Headlands and bays -Different rates of erosion on rocks of different resistance -Bays (wide indented inlets in the coastline) -Headlands (rocks which extend into sea) e. How do coastal processes shape coastal landforms differently

53 Coastal features/landforms: process leads to an outcome/characteristic of landform Arches, stacks and stumps -Further erosion of headlands (abrasion and hydraulic action) -‘Hollowing’ by wave action -Roof of cave collapses -Lines of weaknesses -Cave -Stack (pillar of rock) e. How do coastal processes shape coastal landforms differently

54 Coastal features/landforms: process leads to an outcome/characteristic of landform Beaches -Deposition of different sized particles -Erosion by strong waves -Zone of deposition -Made of loose sand, gravel and pebbles -Gentle gradient (fine grains) -Steep gradient (coarse grains) e. How do coastal processes shape coastal landforms differently

55 Coastal features/landforms: process leads to an outcome/characteristic of landform Spits and Tombolos -Longshore drift -Deposition and transportation -Continued longshore drift even though coastline changes abruptly -Accumulated materials -Spits/tombolos e. How do coastal processes shape coastal landforms differently

56 CHAPTER 1 COASTS Should Coastal Environments Matter? KQ 1: How and why are coastal environments different and dynamic? a.What is a coastal environment? (zones) b.What are the differences within coastal environments? c.What factors lead to the difference and dynamism in coastal environments? d.How do coastal processes differ? e.How do coastal processes shape coastal landforms differently


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