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Coastal Problems. A "coastal ecosystem" includes:. estuaries and coastal waters and lands located at the lower end of drainage basins, where stream and river systems meet the sea and are mixed by tides. . Coastal wetlands are commonly called: lagoons, salt marshes or tidelands.
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Coastal Problems Prepared by Prof. Rodriguez
A "coastal ecosystem" includes: • estuaries and coastal waters and lands located at the lower end of drainage basins, • where stream and river systems meet the sea and are mixed by tides. Prepared by Prof. Rodriguez
Coastal wetlands are commonly called: • lagoons, • salt marshes or • tidelands. • Coastal wetlands were among the first places to be converted and developed for human activities. Prepared by Prof. Rodriguez
The most common types of coastal problems are: • 1. erosion • 2. flooding • 3. salt intrusion • 4. pollution • 5. habitat degradation • 6. loss of biodiversity Prepared by Prof. Rodriguez
Coastal erosion increases the loss of sediments. Some of the process that affect the coastal areas are:1. Subsidence, the sinking of the sediments, reduces the coastal sediment. • 2. Currents, can increase or reduce the coastal sediment load. Prepared by Prof. Rodriguez
3. Riverine sediment flow, determines the amount of sediment available in the coastal areas. • 4. Seasonal changes in sea level, changes the coastal sediment budget. • 5. Seasonal storms, increase the offshore transport of coastal sediments. Prepared by Prof. Rodriguez
Human Activities • 1. Construction of dams reduces river sediment inflows. • 2. Extraction of sediments from rivers alters the sediment inflows. • 3. Extraction of fossil fuels and water causes subsidence. Prepared by Prof. Rodriguez
Consequences • 1. Loss of natural habitats and biodiversity • 2. Loss of beach areas and their recreational value. • 3. Potential loss of infrastructure and buildings.4. Reduction of natural protection against floods Prepared by Prof. Rodriguez
Hurricane Impact • In assessing hurricane effects to natural resources, increases in: • 1. habitat diversity, • 2. productivity, • 3. fisheries, etc. • are regarded as positive and decreases as negative. Prepared by Prof. Rodriguez
Storm waves caused extensive beach erosion in and around docks and results in theirs destruction. • On The French Bay all of the boards of the dock, the pilings, and part of the road were washed away. Prepared by Prof. Rodriguez
Surge deposits from the storm deposited sand in the roadway and flooded areas. • Rushing water resulted in the deposition of a large apron of sand. High-energy waves rip up bedrock and toss it onshore. Prepared by Prof. Rodriguez
Most beach erosion on the east coast of the United States can be correlated with human intervention with the natural migration pattern of barrier island inlets. • The channels migrate in the direction of the littoral transport under the influence of longshore transport of sand, and onshore under the influence of sea level rise. Prepared by Prof. Rodriguez
Humans attempt to stabilize the entrance position by : • 1. building long jetties, • 2. increase navigable depths by dredging straight channels offshore. Prepared by Prof. Rodriguez
Beach restoration has become the method of choice for alleviating threats to property arising from erosion, • this method is controversial due to economic and environmental concerns. Prepared by Prof. Rodriguez
The Santa Barbara, California, breakwater is a classic case study of the effects of shoreline engineering. • To create a harbor for small boats, an L-shaped breakwater was completed at Santa Barbara in 1929. Prepared by Prof. Rodriguez
The original design left a gap in the west side, • almost immediately sand began to pour through this opening to fill the harbor. Prepared by Prof. Rodriguez
The breakwater that protected the boats from waves also protected the beach from the wave and current action that are essential to maintaining the coastal sediment budget. • To halt the deposition within the harbor, the shoreward leg of the breakwater was completed in 1931. Prepared by Prof. Rodriguez
This literally "stop-gap" measure resulted in deposition along the seaward side of the breakwater which filled the area west of the shore leg in less than two years. • The University of California, Santa Barbara's athletic stadium is built on this "new" land. Prepared by Prof. Rodriguez
By 1934, sand had been deposited along the entire length of the seaward leg, had rounded the end of the breakwater, and was being deposited in the harbor again. • East of the harbor, the beaches were starved of sand. • Engineers estimated that about 98% of the sand transported by the longshore current was being deposited in the harbor. Prepared by Prof. Rodriguez
At Miramar Beach, four miles east of the harbor, erosion completely removed the 200 feet wide sandy beach by 1938, • leaving behind only the rubble that was too large to be moved. Prepared by Prof. Rodriguez
Six miles farther east at Sandyland, the beach was cut back 245 feet during 1940, • undermining and destroying the cottages built upon it. • Less severe erosion occurred as far along the coast as Rincon Point, about 20 miles east of the harbor. Prepared by Prof. Rodriguez
Dredging began in 1938 and has taken place at two- to three-year intervals ever since. • The beaches have been partially replenished and the harbor is still in use • The annual bill for dredging the harbor has varied from $350,000 to $1.7 million, depending on the amount of sand moved. Prepared by Prof. Rodriguez
Santa Barbara is only one example of the type of problem that has occurred repeatedly with artificial harbors in California and elsewhere along coastal areas. • Dredging to prevent the closure of these harbors was costing the Federal government $7 to $8 million annually in the early 1980's. Prepared by Prof. Rodriguez
Erosion In Florida • In Florida, during December of 1996, strong winds and pounding surf carved up to 28 feet off several Dania, Hollywood and Hallandale beaches, reducing some to narrow strips at the base of towering seawalls. • The state estimates that 21 of the 24 miles of Broward beaches are eroded Prepared by Prof. Rodriguez
Up to 875,000 tons of sand, enough to fill 35,000 dump trucks, were ripped from the county's coastline during a five-day storm. • Dredging sand back to Broward's shoreline would cost an estimated $4.5 million. • The county has engage in shore protection and restoration since 1960’s Prepared by Prof. Rodriguez
Almost 22 miles of Palm Beach County's coastline had been judged critically eroded before the storm removed another 20 to 30 feet in some areas. • If the beaches are not replenished, fewer visitors may come to South Florida. Prepared by Prof. Rodriguez
The projects or restoration are shared by: • the state, the county and the federal government • cost for the 10 years project: • $38 millions - $19 fed., $13 state, $6 county • County revenue from beach areas $600 millions annually • Beach area protects $4 billion in property Prepared by Prof. Rodriguez
Oceans Pollution • Most of the wastes and contaminants produced by human activities end up in the oceans. • Some are directly drained or dumped, either purposely or accidentally as in the case of oil spills. Prepared by Prof. Rodriguez
Rivers carry runoff from city streets, sewage, industrial wastes, raw sewage, pesticides and fertilizers from farms, and silt from land-clearing, construction projects, and dredging. • Some pollutants first enter the atmosphere and later settle in the ocean. Prepared by Prof. Rodriguez
Coastal Pollution • Most of the world's coastal areas are polluted. • Pollution and development are changing coastal habitats. • Feeding and nursery areas are being destroyed, reducing fish and wildlife populations. Prepared by Prof. Rodriguez
