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4. Human Impact on Gulf Beaches

Richard A. Davis Texas A&M University Press ePub

Human Impact on Gulf Beaches

MOST of the world population lives within an hour’s drive of a beach. The influence of humans on the coast has been extensive and intensive, and it will continue in the future. The entire coastal system has been impacted by various human activities: the dunes, estuaries, tidal inlets, and most certainly, the beaches. This discussion includes the spectrum of human influence on the beaches going back to some of the early efforts to protect and/or control coastal change. Since the 1960s we have made changes in how we manage the coast, including the beaches. These changes have been aimed at being less intrusive into coastal dynamics and have provided more aesthetic methods for beach management.

Human efforts to control some of the changes that beaches experience focus on coastal erosion and inlet management. There have been numerous approaches to these efforts, some that work pretty well and others that definitely do not. The US Army Corps of Engineers has led the way in the effort to eliminate or moderate beach erosion problems. They have taken considerable criticism over the years because of their approaches to coastal management. Most recently the Corps, as it is commonly known, has moderated its approach and the public has been appreciative of their efforts. Now all Gulf Coast states also have agencies that are responsible for coastal management and for regulating various activities there, especially construction. Typically it is necessary to obtain permits for any type of coastal modification from both the federal (Corps) and state government agencies. The current system is not perfect, but it works much better than in the past, and the coast has benefited greatly from this cooperation.

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7. Beaches of Alabama

Richard A. Davis Texas A&M University Press ePub

Beaches of Alabama

THE coast of Alabama is not very long, but its beaches are almost all well developed. It extends from a portion of Perdido Key on the east through Dauphin Island across the mouth of Mobile Bay (figure 7.1). Like most of the northern Gulf Coast, the Alabama beaches have been severely eroded by tropical storms and hurricanes. Two recent hurricanes have resulted in major erosion of the beaches and destruction of built property: Ivan in 2004 and Katrina in 2005. These took place on a coast that was experiencing tremendous growth and development for the tourist industry. Obviously, good beaches are an integral part of this development, and these storms caused considerable loss of beach sand and tourism dollars.

Hurricanes are very destructive to beaches as well as the built environment. Nourishment is the primary way that beaches can recover from these storms. On the Alabama coast, nourishment took place along both Gulf Shores and Orange Beach in 2001 to mitigate the erosion of Hurricane Danny in 1997. The erosion from Hurricane Katrina required considerable nourishment to bring the beaches back for tourism. In 2006, what is one of the largest nourishment projects on the Gulf Coast was constructed with more than 7 million cubic meters of sand distributed along about 22 km of beach at a cost of $28 million.

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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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9. Beaches of Louisiana

Richard A. Davis Texas A&M University Press ePub

Beaches of Louisiana

THE beaches of Louisiana are probably the least attractive and least visited on the entire Gulf Coast. This is primarily the result of the Mississippi River and delta dominating the coast of this state, and the fact that only one barrier island, Grand Isle, is accessible by vehicle. There are several kilometers of mainland beaches that are fairly popular.

The river system produces a huge volume of fine sediment that dominates the coast. Much of this fine sediment remains suspended as it leaves its distributary channels, producing muddy water that is not attractive to tourists but is very important for the community of organisms that lives along this coast. The bulk of the sediment discharged by this fluvial system either remains in the Louisiana coastal zone or is transported westward. Some moves offshore and is deposited on the Mississippi Fan in deep water.

The beaches in Louisiana are limited to narrow, low barrier islands formed by reworking of abandoned lobes of the delta and to the low-lying chenier plain of the western portion of the state. In both settings the sand that composes the barriers and their contained beaches is perched on thick mud. As a result, the sand is sinking. The rapid rate of sea-level rise along this coast is causing a problem for the long-term existence of the barriers, and the size and elevation of the barriers make them very vulnerable. In fact, they are eroding rapidly and are regularly washed over by storms that spread the sand landward. Several attempts have been made to halt or reduce this erosion. Unfortunately, the future of these barriers, and therefore the beaches, is not very promising.

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10. Beaches of Texas

Richard A. Davis Texas A&M University Press ePub

Beaches of Texas

THE Texas coast is essentially a continuum of beaches with tidal inlets scattered throughout (figure 10.1). With few exceptions, these beaches are on barrier islands that are no more than 7000 years old. Mainland beaches are present between Follets Island and Matagorda Peninsula. This is a distinctly wave-dominated coast with low to moderate energy and a mean annual wave height of about 0.5 m. Because the prevailing wind is from the southeast, much of the coast experiences a northeast-to-southwest longshore transport of sediment. In contrast, from the Rio Grande mouth north to an area known as “Big Shell” in central Padre Island, the longshore transport is in the opposite direction. The passage of cold fronts between October and March produces strong wind from the north that blows generally offshore and dissipates wave energy for a few days each year. This process and the relatively strong prevailing wind have resulted in this coast being considered wind dominated, a more specific category of wave-dominated coasts.

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