Beach Today, Gone Tomorrow?
Unit 1 – Beach Today, Gone Tomorrow?
On Maui, coastal areas have been the focal point of human use since people first arrived here. The coastal ecosystem is the most altered of all native ecosystems on the island, in part due to the physical changes that people have brought to the coastal environment. This unit engages students in understanding the natural processes that shape the shorelines, as well as the effects of human use and development.
Length of Entire Unit
Activities in this unit
#1 - Sand Analysis Lab
Students analyze sand from two Haleakalā beaches to determine differences in composition and grain size.
Students use maps and other information to generate hypotheses that explain the differences in sand composition of the two beaches studied in Activity #1.
Students project coastal erosion along two sandy beaches and identify potentially hazardous areas for development.
Three class periods.
Unit Focus Questions
1. What factors account for differences in sand composition between beaches?
2. How are dunes, beaches, and reefs related in the process of maintaining beaches?
3. What factors cause shorelines to change over time?
4. What are the implications of shoreline changes over time for human activity in coastal areas?
Coastal geology and processes
The geologic features and processes of the coastal ecosystem are a strong influence on the dynamic environmental zones in which coastal plants and animals live.
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• In Activity #1 “Sand Analysis Lab,” use graduated geology sieves to obtain a more accurate measurement of sand grain sizes. If your school does not have a set of graduated geology sieves, make your own set of substitute strainers of different sizes. To construct sieves, use window screening with different mesh sizes mounted on simple wooden frames or on the bottoms of plastic containers such as those that margarine comes in. Measure and mark the grid size of each sieve, and you’re set!
• In Activity #1 “Sand Analysis Lab,” weigh out a small portion of sand (1/4 tsp.) and separate biotic and abiotic particles. Weigh each portion and record percentage composition.
• For a more detailed sand analysis lab, see E. Barbara Klemm, et al., The Fluid Earth: Physical Science and Technology of the Marine Environment, Curriculum Research and Development Group, University of Hawaiʻi, Honolulu, 1990, pp. 139-157.
• Analyze sand from other beaches around the island. Use the maps and information included in this unit, along with additional research to hypothesize about the origin of the sand on each beach. Sand collection guidelines are included in the teacher background, Activity #1 “Sand Analysis Lab” (p. 8).
• Compare sand samples taken from the same beach. Take one sample close to the back of the beach and one from the swash zone where water washes up onto the lower beach. There should be a difference in particle size from front to back, demonstrating differences in wave action on different parts of the beach.
• Visit one of the “coastal erosion hotspots or watchspots” identified in the Beach Management Plan for Maui. Observe the shoreline, looking for signs of erosion, structures that have been put in place to slow erosion, alterations that have been made to dunes, and buildings or other structures that look like they may be threatened by coastal erosion. Illustrate written reports with photos or sketches of the area.
• Research the pros and cons of different techniques for beach preservation. The Maui Beach Management Plan (see Whang and Fletcher in “Resources for Further Reading and Research” section) is a good place to start, as well as Internet research using some of the terms used in the Activity #3 “Causes and Consequences of Coastal Erosion” readings.
Resources for Further Reading
Clark, J. R. K., The Beaches of Maui County, University of Hawaiʻi Press, Honolulu, 1980.
Davis, Richard A. Jr., The Evolving Coast, Scientific American Library, New York, 1997.
Fletcher, C. H., R. A. Mullane, and B. M. Richmond, “Beach Loss Along Armoured Shorelines on Oahu, Hawaiian Islands,” Journal of Coastal Research, Vol. 13, No. 1, 1998, pp. 209-215.
Hawaiʻi Department of Land and Natural Resources, Coastal Lands Program, “Coastal Erosion and Beach Loss in Hawaiʻi”.
Macdonald, Gordon A., Agatin T. Abbott, and Frank L. Peterson, Volcanoes in the Sea: The Geology of Hawaiʻi, University of Hawaiʻi Press, Honolulu, 1983. (Chapter 8 provides detailed background about forces that weather rock and lead to soil formation.)
Whang, Dennis, and Charles Fletcher, Hawaiʻi Office of State Planning, Coastal Zone Management Program, “Beach Management Plan with Beach Management Districts” at <www.soest.hawaii.edu/SEAGRANT/bmpm/introduction.html>.