Anything that causes water to move can cause a wave: earthquakes, underwater landslides, changes in atmospheric pressure, underwater volcanic eruptions, the movement of ships, or even a fish jumping. The most common cause of surface waves in the ocean, however, is the wind blowing across the water. Once set in motion by the wind, as long as the wave is in deep water, the energy of the waves is passed from water particle to water particle without the water actually moving. The size of a wave depends on how long the wind blows, the strength of the wind, and the distance the wind blows, known as the fetch.


Scientists define sand as unconsolidated (loose) grains of minerals and rock that are less than 2.1 mm (1/2 inch) but more than .06 mm (1/400 inch) in diameter. Aeronologists, scientists who = study sand, can "read" the history of sand and tell it's source, the climate of the area where it originated, the distance and environments it traveled through, and what the environment was like where it was found.

Sand Dunes

Sand dunes form between the shrub zone and the beach. Older stabilized dunes called secondary dunes usually exist between the shrub zone and the newer, usually higher, less stable primary dunes. A sand dune forms wherever sand blown by the wind can be trapped by plants and debris. Wind velocities of 12 miles per hour or greater are capable of moving fine, dried beach sand. The formation of dunes is dependent upon the direction of the prevailing winds and fair-weather winds move more sand, subsequently producing more dunes than do storm winds. Storm winds, because they are accompanied by strong waves and rain, generally erode dunes.

Sea Grapes

You’ve probably seen them. Nestled among mats of seaweed-looking animals like bryozoans and hydroids, these plump little creatures evoke an irresistible urge to poke at them and make them squirt. But be careful! If you poke them too hard the animal itself might explode and so will end your fun and its existence. The animal in question is Molgula manhattensis, or the Sea Grape. The sea grape is a common constituent of the thriving communities found growing on floating docks, piers and boat bottoms throughout the creeks and rivers of coastal Georgia.

Sea Oats

Sea oats are the most important and widespread grass on southern coastal dunes. Sea oats get their name from the large plumes produced during summer which resemble oats grown for food. This tough perrenial grows to a height of 1-2 meters (3-6 feet) and may be recognized by its oat-like flowers or panicles. The seed heads mature in autumn. They are compressed spikelets borne at the end of stiff stems 1 meter (3 feet) long or more. Its pale green leaves are long and narrow, measuring less than 1/5 centimeters (0.5 inches) in width.

The Beach

The beach forms at the edge of an island between the ocean and the sand dunes. The sand is deposited by waves and currents and is then blown around by the wind to create dunes. The beaches of Georgia’s undeveloped islands are made mostly of fine-grain sand. The beaches are fairly wide and slope gently toward the ocean. This harsh environment is a moderate energy area because the waves from distant storms release their energy as they roll up onto the beach. Winds keep sand in constant motion. In the summer the prevailing winds along the east coast blow from the southwest and in the winter from the northwest. The profile of the beach changes from a broad flat beach in the summer to a narrower and steeper beach in the winter.

Mission Statement

The Coastal Resources Division of Georgia DNR is the state agency entrusted to manage Georgia’s marshes, beaches, Marine waters and marine fisheries for the benefit of present and future generations.

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