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
Texas High School Coastal
Monitoring Program
Funding for THSCMP is provided by the Texas Coastal
Coordination Council, The Meadows Foundation, the
National Science Foundation, Conoco, the Exxon
Foundation, and the Wray Family Trust.
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/
Study Area
Galveston Bay
TEXAS
Study Area
Ball High School
Galveston Island
Matagorda Bay
San Antonio Bay
Gulf of Mexico
Copano Bay
Corpus Christi Bay
Port Aransas High School
Mustang Island
N
Baffin Bay
Laguna M adre
50
0
Port Isabel High School
South Padre Island
50
100 Kilometers
Student Orientation
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
Hand sighting level
Sighting compass
Tape measure (at least 5m)
Survey flags
Data forms and clipboard
Topographic Profile
Determine vertical change
between front and back Emory
rods using siting level or horizon
Measure horizontal distance
between Emory rods
Relative height (m)
MUI01 (Mustang Island)
2
1999 Nov 4
2000 Sep 21
0
2000 Nov 9
2001 Feb 1
-2
-4
vertical exaggeration = 10:1
-50
-25
0
25
50
75
Distance
100
125
150
175
200
Relative height (m)
MUI01 (Mustang Island)
2
2001 Apr 9
2001 Oct 2
0
2002 Mar 19
2002 Oct 11
-2
-4
vertical exaggeration = 10:1
-50
-25
0
25
50
75
100
Distance (m)
125
150
175
200
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
wind gauge
Data forms and clipboard
Sighting compass
3 floats
Beach Observations
Observation of waves
Measuring Speed and Direction of Current
Observation of wind
Orientation of Dunes
and Shoreline
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
Mapping Shoreline and Vegetation Line
with GPS
2002-2003 Student Participants
Beach Features
Barrier Island System
Barrier Island Cross-Section
Tropical Storm Frances
Tropical Storm Frances

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


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 (>0.78 meters) lasted 64 hours
and extreme wave heights (>2.3 meters) lasted 73
hours.
Ball High School Monitoring Sites
BEG02 Pre-Tropical Storm Frances
BEG02 Post-Tropical Storm Frances
Coastal Processes
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.
Wave Diagram
Crest
Wave Length
Calm water
level
Wave
Height
Trough
Wave Period = time it takes 2 successive crests (or troughs)
to pass a fixed point
Frequency = number of waves per second (1/period)
Wave Motion
Direction of wave
Seafloor



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.
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, doesn’t actually break-wave rolls onto beach
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).
Galveston Pleasure Pier
Neap
Spring
Neap
Spring
Galveston Pleasure Pier-June 2003
Height Above Mean Lower Low Water (m)
1.2
Predicted
Observed
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
152
157
162
167
Julian Day
172
177
182
Hurricane Claudette Water Levels
Corpus Christi July 10-20, 2003
1.4
Bob Hall Pier
Texas State Aquarium
Height Above Mean Lower Low Water (m)
1.2
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
190
192
194
196
198
Julian Day
200
202
204