11 Chapters
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1. Coastal Processes

Richard A. Davis Texas A&M University Press ePub

Coastal Processes

WHEN we hear the word beach, the first thing that comes to mind is sand; the next is probably waves. Actually there are multiple processes that impact beaches and control their existence and appearance (figure 1.1). It is appropriate to begin with the most fundamental of these coastal processes: the weather. Then it is important to consider how the waves, which are a result of the weather, impact the beach. These waves also generate currents that are a major element of beach dynamics. Storms, especially hurricanes, are a significant factor in Gulf of Mexico beaches. A process that is always present but is not weather related is the ebb and flow of tides, but tides do not play a major role in Gulf Coast beaches.

Weather

The Gulf Coast is positioned in the latitudes that range from about 18° to 30° north of the equator. This range of latitudes experiences a fairly wide variation in weather patterns. As the seasons change, so do the weather patterns. During the summer the Gulf is within the Trade Winds belt, with the prevailing direction from the southeast. This is the time when tropical storms can impact this coast. In the winter the westerlies prevail as weather systems are moving from the northwest to the southeast. The changes from one pattern to another influence the way beaches respond to the wind and the waves produced by it.

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8. Beaches of Mississippi

Richard A. Davis Texas A&M University Press ePub

Beaches of Mississippi

THE beaches of Mississippi are found on two distinctly different coasts: the mainland and four barrier islands that are several kilometers from the mainland (figure 8.1). None of the barrier islands is accessible by vehicle. For this reason and because they are mostly public land, the islands are pristine. A regular ferry schedule in spring and summer conveys people to West Ship Island, a federal park. The mainland beaches are among the most beautiful and best cared for along the entire Gulf of Mexico.

Beach nourishment has been common on the mainland of Mississippi. The first such major projects were after Hurricanes Ivan (2004) and Katrina (2005), which hit this coast very hard. A volume of 280,000 m3 of sediment was placed on the eroded beach at Pascagoula with the help of the federal government (figure 8.2). Farther to the west at Ocean Springs the beach is very well maintained. This area is dominated by fine sand with few shells. Wave energy is limited along this coast due to the offshore barrier islands that provide a level of protection. This low wave energy is evidenced by the vegetation near the strand line (figure 8.3). The Ocean Springs beaches also have groins to help maintain beach sediment.

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5. Common Animals and Plants of the Gulf Beaches and Surf Zone

Richard A. Davis Texas A&M University Press ePub

Common Animals and Plants of the Gulf Beaches and Surf Zone

ALTHOUGH the beach and surf zone are very dynamic, they do have a community of organisms that is pretty similar throughout the Gulf Coast. Both the plants and animals must be adapted to fairly rigorous conditions: tidal fluctuations, wave attack, wind, little available freshwater, and predators. These conditions limit the diversity of organisms. This discussion does not consider the extremely mobile animals such as birds or fish. The emphasis is on the few common benthic organisms of the beach and surf zone, both mobile and sessile (permanently attached). Others not mentioned here are described in the many books on beach fauna and flora.

Nearshore / Surf Zone

The shallow nearshore zone where waves break and currents can be strong presents a difficult set of conditions for bottom-dwelling organisms. The occasional bivalve or snail may find a place to burrow here to be protected from the typical waves. Epifaunal organisms, which live on the sand surface, are not common due to the wave energy and the mobile substrate. It is important for the wader to be careful of burrowing snails such as Turritella and Oliva, both of which can put a hole in your heel if you step on them. The other creature that can cause injury is the sting ray (figure 5.1). This animal has a stinging barb that can penetrate the foot or heel. The so-called sting ray shuffle is the way to avoid the problem. When walking through the surf zone, it is best to shuffle your feet, thus warning the ray of your approach and sending it on its way.

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11. Beaches of Mexico and Cuba

Richard A. Davis Texas A&M University Press ePub

Beaches of Mexico and Cuba

OVERALL, the Gulf Coast of Mexico is relatively unpopulated and therefore rather pristine. Areas around population centers of Veracruz and Tampico are exceptions. This chapter considers some of the major places where people will visit. The discussion of the Mexican coast of the Gulf terminates in the Cancún vicinity.

The Cuban shoreline is not well known and is frequented only by non-US citizens at this time. The northern coast just east of Havana is the most popular place to visit and has excellent beaches. There are two styles to the shoreline zone in Cuba, and each is discussed.

Mexico

The beaches are much the same in northern Mexico as they are in South Texas. The back-barrier lagoon here is also called Laguna Madre. Overall, the beaches of Mexico are fine sand and are terrigenous except for the area of Campeche Bay and the Yucatán Peninsula, where carbonate skeletal debris dominates beach sediment. This material is coarser than that on the terrigenous beaches. In the area between the two distinct sediment types the beaches are dominated by a mixture of quartz and carbonate debris, giving the sediment a bimodal texture.

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6. Beaches of Florida

Richard A. Davis Texas A&M University Press ePub

Beaches of Florida

FLORIDA beaches can be easily subdivided into three distinct regions: the Keys, the Gulf peninsula, and the Panhandle. Each of these regions has its own characteristics and its own types of beaches. The three sections are also each oriented quite differently to the primary weather patterns, they have different offshore regions, and they experience hurricanes differently. It should also be noted that these regions are separated by extensive coastal reaches where beaches are rare and poorly developed: the Ten Thousand Islands mangrove system and the Big Bend coastal marsh system (figure 6.1).

Florida Keys

Although not a part of the Florida Keys, the islands of the Dry Tortugas are a part of Florida and have beaches. These islands are associated with extensive reef development on Quaternary carbonates and are occupied only by Fort Jefferson, a national monument, and a Coast Guard station. The beaches there are accumulations of reef debris that is coarse sand and all calcium carbonate (figure 6.2).

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