Coastal Zone Module

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Coastal Zone Module

• Tiffany L. Hepner
• Bureau of Economic Geology
• John A. and Katherine Jackson School of
  Geosciences
• The University of Texas at Austin
• Development of this module has been funded by
  National Science Foundation Geoscience Education
  GEO-0224501

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Texas High School Coastal Monitoring Program

• Funding for THSCMP is provided by the Texas
  Coastal Coordination Council, Conoco, the Exxon
  Foundation, and the Wray Family Trust.

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Texas High School Coastal Monitoring Program

• Provide high school students with an
  inquiry-based learning experience.
• Increase public awareness and understanding of
  coastal processes and hazards.
• Obtain a better understanding of the relationship
  between coastal processes, beach morphology, and
  shoreline change, and make data and findings
  available for solving coastal management
  problems.
• http//txcoast.beg.utexas.edu/thscmp/

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Study Area
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Student Orientation
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Beach Measurements

• Topographic transect oriented perpendicular to
  the shoreline. For comparison through time,
  profiles are measured from the same starting
  point landward of the beach and oriented in the
  same direction.
• Purpose
• Provide quantitative morphological data and
  shoreline and vegetation line positions
• Method
• Measure relative changes in beach topography
  using Emery rods and tape measure
• Equipment
• Emery rods Tape measure (at least 5m)
• Hand sighting level Survey flags
• Sighting compass Data forms and clipboard

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Topographic Profile
Determine vertical change between front and back
Emory rods using siting level or horizon
Measure horizontal distance between Emory rods
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Processes measurements

• Estimates of processes acting on the beach wind
  direction and speed wave breaker type surf zone
  width wave direction, height, and period number
  of apparent longshore bars longshore current
• Purpose
• Explore relationship between processes and beach
  changes. Over time these data may be used to
  calibrate, for a specific beach location, data
  acquired by weather and wave stations in the
  area. Encourage students to systematically
  observe processes that surround them
• Method
• Visual observations averaged among three
  observers. Float and stopwatch for longshore
  current. Hand-held wind gauge
• Equipment
• Tape measure Sighting compass
• wind gauge 3 floats
• Data forms and clipboard

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Beach Observations
Observation of waves
Observation of wind
Orientation of Dunes and Shoreline
Measuring Speed and Direction of Current
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Shoreline Measurements

• Horizontal (no elevation) survey of the
  vegetation line and shoreline. Shoreline and
  foredune trends. Measurement of beach cusps
• Purpose
• Provide quantitative data on the position and
  trend of the shoreline and the longshore spacing
  and relief of beach cusps
• Method
• Differential Global Positioning System walking
  survey
• Equipment
• Differential Global Positioning System (GPS)
  receiver
• Emery rods Digital camera
• Sighting level Sighting Compass
• Tape measure Data forms and clipboard

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Mapping Shoreline and Vegetation Line with GPS
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2002-2003 Student Participants
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Beach Features
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Barrier Island System
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Barrier Island Cross-Section
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Tropical Storm Frances
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Tropical Storm Frances

• September 7-13, 1998
• Extensive beach and dune erosion and damage to
  structures.
• Storm surge peaked at 1.4 meters above mean sea
  level.
• Peak wave height 4.09 meters
• Extreme water levels (gt0.78 meters) lasted 64
  hours and extreme wave heights (gt2.3 meters)
  lasted 73 hours.

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Ball High School Monitoring Sites
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BEG02 Pre-Tropical Storm Frances
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BEG02 Post-Tropical Storm Frances
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Coastal Processes
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Waves

• There are 3 forces that form waves wind,
  earthquakes, and gravitational attractions
  between Earth, Sun, and Moon.
• Ocean waves are typically formed by the wind
  (friction between the wind and the waters
  surface).
• The size of a wave depends upon the wind speed,
  length of time wind blows in the same direction,
  and the fetch (distance over which the wind
  blows).
• Wind waves will continue as long as the wind is
  blowing. Once the wind stops the waves will
  continue until all of their energy is dissipated.

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Wave Diagram
Wave Period time it takes 2 successive crests
(or troughs) to pass a fixed point Frequency
number of waves per second (1/period)
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Wave Motion

• Water particles in waves move in a nearly
  stationary circular motion.
• At the surface, the orbit is equal to the wave
  height. The orbits decreases in size downward
  through water column to a depth of L/2.
• Breaking occurs when crest angle is less than
  120º or a steepness (H/L) greater than 1/7.

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Breaker Types

• Spilling Breaker-gentle beach slope, waves break
  far from shore and surf gently rolls over the
  front of the wave
• Plunging Breaker-moderately steep beach slope,
  less steep wave, slightly longer period, wave
  curls over forming a tunnel until wave breaks
• Surging Breaker-steep beach slope, low wave of
  long period, doesnt actually break-wave rolls
  onto beach

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Tides

• Tides are actually waves. They are caused by the
  gravitational forces of the Earth, Moon, and Sun.
• Tides are caused by a relationship between mass
  of the above celestial objects as well as their
  distance from Earth.
• The moon orbits the Earth once every 27 days and
  8 hours. Therefore, the tides move up 50 minutes
  every day.
• High tide is generated by the pull of the moon
  upon global waters. There is an equal pull on the
  opposite side of the Earth from the moon.
• Spring tides occur when the Earth, sun, and moon
  line up (new and full moon-2x during the lunar
  month). Spring tides have the largest tidal
  ranges.
• Neap tides occur when the moon is in the first
  and third quarter (tidal range smallest).

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Galveston Pleasure Pier
Neap
Spring
Neap
Spring
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Galveston Pleasure Pier-June 2003
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Hurricane Claudette Water Levels Corpus Christi
July 10-20, 2003