Learning Objectives
After reading and studying this chapter, students should:
• Know the basic terminology of waves, and processes of waves.
• Be able to define the basic components of a beach.
• Understand the process of littoral transport of sediment.
Chapter Summary
This chapter focuses on coastline processes and their hazards to life and property. The chapter opens with
a discussion of oceanic and coastal processes, including wave generation and behavior, beach processes,
Chapter Outline
I. Introduction to coastal hazards
A. Coastal areas are dynamic environments
2. coastal landscapes are capable of rapid change
3. impact of coastal processes is considerable
B. Most United States population will eventually be concentrated along the coastlines
1. today approximately 75% of population lives in coastal states
2. coastal problems have and will increase as population grows in coastal areas
C. Global warming and sea level rise
1. coastal erosion problems increase
D. Most serious coastal hazards
2. coastal erosion
4. tropical cyclones
II. Coastal processes
A. Waves
1. size of waves depends on wind velocity, duration, and fetch
3. wave characteristics: wave height, wavelength, wave period
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Coastal Processes
5. waves expend most of their energy at the coastline
7. wave refraction: wave convergence at headland, wave divergence in embayments
9. types of breakers: plunging, spilling
B. Beach form and beach processes
2. beach landform terminology
a. berms
b. beach face
C. Transport of sand
1. longshore sediment transport
D. Rip currents
1. water returning seaward in narrow zones
2. serious coastal hazard
III. Coastal erosion
A. Beach budget (see A Closer Look: Beach Budget)
B. Erosion factors
1. sand supply, affected by damming of rivers
3. rise in sea level
C. Seacliff erosion
2. mantle of sand covers beach during summer
4. human activities can induce seacliff erosion
6. seacliff erosion is a natural process that cannot be completely controlled
IV. Coastal hazards and engineering structures
A. Hard stabilization
1. improve navigation or retard erosion
2. often cause undesirable deposition and erosion
3. Seawalls
4. Groins
5. Breakwaters
a. designed to intercept waves and provide protected area
6. jetties
7. see A Closer Look: Coastal Erosion at Pointe du Hoc, France
B. Soft stabilization
1. Beach nourishment: an alternative to engineering structures
a. artificially adding sand to beach
e. complications include sufficient sand sources, cost, and possible disruption of ecosystems
V. Human activity and coastal erosion: some examples
A. Human interference with shore processes has caused considerable erosion
B. The Atlantic Coast
2. Maryland: dune removal has resulted in serious erosion on Fenwick Island and left it prone to
C. The Gulf Coast
1. coastal erosion a serious problem
3. causes: coastal engineering structures, groundwater/petroleum withdrawal subsidence, damming
D. The Great Lakes
1. coastal erosion a periodic problem, especially on Lake Michigan shoreline
3. during periods of below-average lake level, wide beaches develop
5. severity of erosion at a site depends on many factors
6. beach nourishment has been attempted
VI. Tropical cyclones
A. Typhoons in most of Pacific, hurricanes in the Atlantic
1. generated as tropical disturbances
B. Hurricane forma and process
1. defined as a hurricane if sustained winds exceed 119 km/hr (74 mi/hr)
3. hurricanes are very high energy storms with bands of spinning storms around eye
5. categorized upon size and intensity, categories 1–5
7. three likely storm tracks
C. Hazards
2. flooding from rain and waves
3. storm surges
D. Property damage can be staggering
1. Hurricane Andrew, 1992: $25 billion damage
Coastal Processes
E. Hurricanes ranked from category 1–5 on Saffir-Simpson scale
VII. Perception of and adjustment to coastal hazards
A. Perception of coastal erosion
1. an individual’s past experience
3. probability of suffering property damage
B. Adjustment to coastal hazards
2. coastal erosion: adjustments include beach nourishment, shoreline stabilization, and land-use
change
3. preliminary process in managing coastal erosion is estimating rates of erosion (see A Closer Look:
E-Lines and E-Zones)
C. We are at a crossroads with respect to coastal erosion, with two possibilities
2. learning to live with coastal erosion through flexible environmental planning and land use
D. Five principles of coastal zone development
2. any shoreline construction causes change
4. engineering structures designed to protect a beach may eventually destroy it
5. shoreline engineering structures produce a trend in coastal development that is difficult to reverse
Answers to Review Questions and Critical Thinking Questions
Review Questions
2. Plunging breakers rise quickly on steep beach faces and plunge forward, while spilling breakers spill
forward gently on gently sloping beaches.
4. Human activities that increase seacliff erosion include damming of rivers, urbanization, and construction
that increases the weight on seacliffs.
5. Important differences between beach erosion on the East and West Coasts include the dominance of
6. Major alternatives to coastal stabilization include hard stabilization with engineered structures such as
seawalls and groins, and soft stabilization through beach nourishment. Soft stabilization is generally
7. Seawalls and groins are shore-parallel and shore-perpendicular structures, respectively. Seawalls are
8. Processes important in the formation of a hurricane include the formation of a tropical depression (e.g.,
9. Beach nourishment is the artificial addition of sand to a beach, intended to fight coastal erosion without
11. A storm surge is a local rise in sea level caused through hurricane winds pushing water toward the
coast.
13. Five general principles that should be accepted if we choose to live with coastal erosion are: 1. coastal
4. engineering structures designed to protect a beach may eventually destroy it; and 5. shoreline
engineering structures produce a trend in coastal development that is difficult to reverse.
Critical Thinking Questions
1. Such a research program should include an examination of statistics regarding human activity in the
2. An answer to this question will be value-laden, but should address the benefits and drawbacks of
“permanent” development in the coastal zone and of erosion prevention structures. A student could
3. This question will require the student to understand fully the processes of hard and soft stabilization and
the benefits and drawbacks of each. The student will need to determine whether the two approaches