The Coast

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The Coast

• temporary junctions between land and sea
• are subject to change
• waves, currents, tides, biological processes,
  tectonic activity
• position changes as sea-level does

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Sea level 18,000 years ago during last ice age
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If sea level rises 60cm (20ft)
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• Red areas will flood in about 100-200 years
• Blue areas may flood over several centuries

• http//www.epa.gov/climatechange/effects/coastal/s
  lrmaps_sealevelmap.html

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• Over the next century, sea level is most likely
  to rise 55-60 cm along most of the U.S. Atlantic
• Red areas would flood during spring high tides
• http//www.epa.gov/climatechange/effects/coastal/s
  lrmaps_ne_liny.html

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Sea Level Rise Does Matter

• Superstorm Sandy produced record storm surge
  levels for locations in and around the NY City
  metropolitan region
• Sea levels have risen more than a foot in the New
  York City region since the Industrial Revolution.
  
• So what difference did this extra foot make for
  the citizens of New York City? Quite a lot. 6,000
  more people impacted for each inch of rise!
• 70,929 more people and 30,551 more homes flooded.
• According to Dr. Ben Strauss, Chief Operating
  Officer and Director of the Program on Sea Level
  Rise at Climate Central

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Beaches

• a zone of loose particles that covers part of the
  shore
• extends from a landward limit
• cliff, permanent dunes, seawall
• extends to the seaward limit where movement of
  sediment on and offshore ceases

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• Figure 10.1

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Beach Profiles

• Steepness of beaches change with seasons and
  storms
• Summer and calm periods build up beaches
• Swash dominates (soaks into beach), less backwash
• Winter and storms erode and flatten beaches
• Backwash dominates, very little swash soaks in
  because beach is saturated)

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• Figure 10.2a

• Wide berm
• Steep beach face

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• Figure 10.2d

• Narrow berm
• Flatter beach face
• longshore bar

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• Seasonal Changes on a beach in California

• Fig. 11-13c, p. 254

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Before and After Sandy

• Mantoloking, NJ

• Long Branch, NJ

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Before and After Sandy

• Cupsogue Beach, Westhampton, NY

• Fire Island Natl Seashore

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Beaches

• exist in a delicate balance between accumulation
  and destruction
• Waves can transport sand onshore or offshore
• Longshore currents transport sand along the
  coastline

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• Figure 10.3b

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Barrier Islands

• Are essentially large sand bars
• Protect the coast behind them
• Very unstable themselves

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• Figure 10.9

• Toms River, NJ

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Heavily developed barrier island Ocean City, MD
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Barrier Island Migration

• Figure 10.10

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• Fig. 11-19, p. 258

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Human Impact on Beaches

• Attempts to save beaches or property often fail
  or make matters worse

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• Figure 10.18 Groins

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• Figure 10.19

• Shipbottom, NJ

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Groin Field Cape May, NJ
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• Figure 10.20 Jetties

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• Figure 10.21

• Santa Cruz Harbor, CA

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Break water
Santa Monica, CA
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• Designed to protect harbors from waves
• Can cause excessive erosion, requiring dredging
  to keep area stable

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• Figure 10.24 Seawalls

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Alternative Beach Replenishment
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• Figure 10.26

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• Figure 10.B Relocation