K-12 Teaching and Learning From the UNC School of Education

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Coastal processes and conflicts: North Carolina's Outer Banks
The lessons in this unit allow students to explore the processes affecting North Carolina's Outer Banks and the impact these processes have on daily life there.
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  • Human responses to eroding shorelines: This lesson is part of chapter one of the unit "Coastal processes and conflicts: North Carolina's Outer Banks." Students look at efforts that are taken to prevent shoreline erosion. These include building hardened structures along shorelines. Students examine the effects these efforts have on barrier islands.
  • Estuarine shorelines behind simple overwash barrier islands: This lesson is part of chapter one in the unit "Coastal processes and conflicts: North Carolina's Outer Banks." Students take another look at simple overwash and complex barrier islands. They examine more closely how overwash and inlet processes are crucial to the long-term maintenance of barrier islands and how these processes can affect human life.
  • The coastal dilemma: This lesson is part of chapter one of the unit "Coastal processes and conflicts: North Carolina's Outer Banks. Students look at examples of shoreline erosion. They reflect on the impact this erosion can have on human life on the Outer Banks.

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In this lesson, students examine the difference between simple overwash barrier islands and complex barrier islands. They also learn more about the island-building process and the effect this process can have on daily life on barrier islands.

Learning outcomes

Students will:

  • explain the difference between simple overwash barrier islands and complex barrier islands.
  • explain how storms are part of the island-building process.
  • explain the effects storms have on barrier islands, including the how these effects impact daily life on the islands.

Teacher planning

Materials

  • copy of figure 1-13 to project
  • copy of figure 1-2 to project
  • copy of figure 1-5 to project
  • copies of figure 1-14 — one per group
  • copies of figure 1-16 — one per group
  • multimedia projector or document camera

Figures and tables

Figure 1-13
Students use this diagram to compare simple overwash barrier islands to complex barrier islands.
Open as PDF (212 KB, 1 page)
Figure 1-2
Students view this satellite photograph again to identify examples of simple overwash barrier islands and complex barrier islands in the Outer Banks.
Open as PDF (214 KB, 1 page)
Figure 1-5
Students view this image of Isabel Inlet again to speculate about what happened to the sand that was once a part of the barrier island in the space where Isabel Inlet was formed.
Open as PDF (245 KB, 1 page)
Figure 1-14
Students use this image to see an example of overwash caused by Hurricane Isabel and to think about the effects it had on daily life on the Outer Banks.
Open as PDF (286 KB, 1 page)
Figure 1-16
Students use this image to see an example of a complex barrier island.
Open as PDF (238 KB, 1 page)

Teacher background information

Teacher background information: Barrier islands
This document contains background information for the teacher to read prior to implementing the lesson “Barrier islands.”
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Activities

Engage

Cross-sectional diagrams showing a simple overwash and a complex barrier island

Figure 1-13 Figure from Riggs and Ames (2003). Provided by North Carolina Sea Grant. About the diagram

  1. Project figure 1-13. Point out major differences between a simple overwash barrier island and a complex barrier island. Be sure to mention these points:
    1. A simple overwash barrier island occurs in a section of the coast where there is little sand available to form the island. These islands are “sediment-starved” and have relatively low elevations and narrow widths.
    2. A complex barrier island has abundant sand available (”sediment-rich”) to form a wide, high island, with tiers of beach ridges stretching a great distance from the ocean front.
  2. Have students discuss what differences might occur between the two types of islands when storm winds approach from the ocean side.
  3. Project figure 1-2. Ask students to identify a section of the Outer Banks that would be an example of a simple overwash barrier island. Ask them to identify a section that would be a complex barrier island.
  4. Project figure 1-5. Ask students to speculate on what happened to the sand that once formed the barrier island where Isabel Inlet was formed by Hurricane Isabel as it crossed the barrier island in the vicinity of Hatteras Island.

Explore

Isabel Inlet represents a classic conflict between natural dynamics and human economic utilization of the barrier islands. Put students in groups and give them copies of figure 1-14 and figure 1-6. Have student groups discuss and record responses to the following questions.

  1. Why was Isabel Inlet closed and N.C. Highway 12 rebuilt within five weeks after the storm opened it?
  2. Why are inlets important to the health of a simple overwash barrier island?
  3. How are these two functions (1 and 2 above) in conflict with each other?
  4. Oysters live in the estuary on the back side of the barrier island. However, they are the most common shell on the ocean beach in front of simple barrier islands. Explain how the estuarine oyster shells get onto the ocean beach (figure 1-13A).
  5. Aerial photographs of a simple overwash barrier island

    Figure 1-14 Photos from NOAA and provided by North Carolina Sea Grant. About the photograph

  6. Identify a major conflict and human inconvenience caused by storm overwash in the aerial photographs in Figure 1-14. How do you think the N.C. Department of Transportation deals with this problem?
  7. Why does the N.C. Department of Transportation move overwash sand from the sound side of the highway back to the ocean side? What are the long-term consequences of this for a simple barrier island that continues to erode on the ocean side?
  8. What alternatives might be considered to accommodate the transportation needs of island residents and visitors without disrupting the natural evolution of the island?
  9. Using the scale on both photographs (1-14 and 1-16), measure the island width at the widest part of the Pea Island and the Kitty Hawk barrier island segments.
  10. From what you know about simple overwash barrier islands and complex barrier islands, describe the differences between the Kitty Hawk barrier island segment (figure 1-16) and the Pea Island barrier island segment (figure 1-14).
Infrared aerial photograph of Kitty Hawk, NC

Figure 1-16 Photo found in Riggs and Ames (2003). Provided by North Carolina Sea Grant. About the photograph

Explain

Use student responses to the “explore” phase as a basis for classroom discussion. Reiterate the differences between the two types of barrier islands with an emphasis on the differences in how they respond to storm events. A major concept in this section is the importance of storms in island building — the natural process of washing sand to the sound side and building up the island in that direction. Islands gradually role over themselves toward the mainland. This is the reason for finding oyster shells on the ocean side. This is a good place to introduce the idea of conflicting interests in any environment — and the importance of making decisions — including scientific evidence, but also economic and cultural realities. Decision-making will be a major emphasis in chapter two.

Extend

  • Have students discuss this question: If you were planning to buy a lot for a house on the Outer Banks, how would your knowledge of barrier islands help to inform your decision?
  • Have student groups choose a community along the Outer Banks where they might like to buy a property. Have them do research to determine the history of that community in terms of storm damage and shoreline erosion. There are Internet sites that provide that information. Have students weigh the pros and cons for their proposed site and make a decision about the purchase.

Assessment

Evaluate

Have students answer the following questions:

  1. What are differences between complex barrier islands and simple overwash barrier islands?
  2. Explain this statement: Storms are very important to the process of island building.
  3. What is the short-term advantage of moving sand that has washed across a simple overwash island back to the ocean side?
  4. What is the long-term disadvantage?

  • North Carolina Essential Standards
    • Science (2010)
      • Earth and Environmental Science

        • EEn.2.1 Explain how processes and forces affect the lithosphere. EEn.2.1.1 Explain how the rock cycle, plate tectonics, volcanoes, and earthquakes impact the lithosphere. EEn.2.1.2 Predict the locations of volcanoes, earthquakes, and faults based on information...

    • Social Studies (2010)
      • Grade 8

        • 8.G.1 Understand the geographic factors that influenced North Carolina and the United States. 8.G.1.1 Explain how location and place have presented opportunities and challenges for the movement of people, goods, and ideas in North Carolina and the United States....

North Carolina curriculum alignment

Science (2005)

Grade 8

  • Goal 5: The learner will conduct investigations and utilize appropriate technologies and information systems to build an understanding of evidence of evolution in organisms and landforms.
    • Objective 5.05: Use maps, ground truthing and remote sensing to make predictions regarding:
      • Changes over time.
      • Land use.
      • Urban sprawl.
      • Resource management.

Grade 9–12 — Earth/Environmental Science

  • Goal 2: The learner will build an understanding of lithospheric materials, tectonic processes, and the human and environmental impacts of natural and human-induced changes in the lithosphere.
    • Objective 2.05: Create and interpret topographic, soil and geologic maps using scale and legends.
  • Goal 4: The learner will build an understanding of the hydrosphere and its interactions and influences on the lithosphere, the atmosphere, and environmental quality.
    • Objective 4.01: Evaluate erosion and depositional processes:
      • Formation of stream channels with respect to the work being done by the stream (i.e. down-cutting, lateral erosion, and transportation).
      • Nature and characteristics of sediments.
      • Effects on water quality.
      • Effect of human choices on the rate of erosion.