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Coastal Problems

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Title: Coastal Problems


1
Coastal Problems
2
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.

3
  • All these water and land forms interact as
    integrated ecological units.
  • The definition of "coastal ecosystem" also
    applies to the Great Lakes, where enormous bodies
    of freshwater play an ecological role similar to
    oceans.

4
  • 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.

5
The most common types of coastal problems are
  • 1. erosion
  • 2. flooding
  • 3. salt intrusion
  • 4. pollution
  • 5. habitat degradation
  • 6. loss of biodiversity

6
  • Coastal erosion increases the loss of sediments.
    Some of the process that affect the coastal areas
    are1. Subsidence, the sinking of the sediments,
    reduces the coastal sediment.
  • 2. Currents, can increase or reduce the coastal
    sediment load.

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  • 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.

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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.

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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

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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.

17
  • During hurricane Lili on The French Bay some of
    the more branching forms of coral were damaged,
    especially Acropora palmata.
  • On the reef flat and the reef crest, sea fans
    (Gorgonia sp.) were ripped up and washed into the
    backreef lagoon and on the beaches.
  • The damage to the reef was most apparent where A.
    palmata could be found completely flipped over.

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  • 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.

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  • 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.

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  • 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.

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  • Humans attempt to stabilize the entrance
    position by
  • 1. building long jetties,
  • 2. increase navigable depths by dredging straight
    channels offshore.

28
  • 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.

29
  • 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.

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  • The original design left a gap in the west side,
  • almost immediately sand began to pour through
    this opening to fill the harbor.

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  • 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.

33
  • 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.

34
  • 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.

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  • 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.

37
  • 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.

38
  • By constructing the Santa Barbara breakwater,
    several problems have been created
  • 1. Sand was being deposited in the harbor eroding
    other areas.
  • 2.To everyone concerned, it was obvious that the
    harbor would soon become useless for anything but
    sun bathing and building sand castles unless
    something was done.

39
  • 3. The lack of sufficient sand on the downdrift
    shoreline where valuable beaches and waterfront
    property had been destroyed.
  • 4. The only solution was to move the sand from
    the harbor to the beaches, to artificially
    recreate the longshore drift with dredges and
    pumps.

40
  • 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.

41
  • 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.

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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

44
  • 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 1960s

45
  • 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.

46
  • 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

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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.

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  • 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.

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  • Chemical contamination and litter exist from the
    poles to the tropics, from beaches to ocean
    depths.
  • The open ocean is relatively clean because most
    pollutants come from land and remain in water
    near coastal areas.

55
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.

56
  • Along some coasts, runoff enriches the water with
    too many nutrients, leading to oxygen-depleted
    water and fish kills.
  • The two most widespread and serious sources of
    coastal pollution are
  • 1. sewage disposal
  • 2. sedimentation from land-clearing and erosion.

57
Types of Pollution
  • SEWAGE Contaminates the water with organisms
    that cause diseases such as hepatitis, cholera,
    and typhoid fever.
  • Humans can become infected by eating contaminated
    shellfish and by swimming.
  • Most of the world's sewage is not treated.

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  • MARINE LITTER Human activities on land are a
    major source of plastic debris.
  • Plastic items such as, lighters, tampon
    applicators, six-pack-container rings wash down
    rivers and enter the ocean.

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Plastic
  • Found even in remote Antarctica, plastics harm
    porpoises, seals, turtles, birds, fish, and other
    marine life, and degrade beaches.
  • Equipment from the fishing industry (nets, lines,
    buoys, etc.) that has been lost or discarded
    another source of litter.

63
PETROLEUM
  • Kills birds, fish, and animals, causes
    long-lasting problems for marine organisms, and
    fouls beaches.
  • Most oil spills occur in coastal waters where oil
    is being drilled or transported.
  • Petroleum also enters the sea in the form of
    municipal and industrial wastes.

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SYNTHETIC ORGANIC CHEMICALS
  • Pesticides and industrial chemicals inhibit
    photosynthesis and movement in plankton
  • cause tumors,
  • birth defects,
  • and other damage in vulnerable organisms.

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  • These substances are widely distributed in the
    oceans,
  • some accumulate in the food chain.
  • In areas of heavy pollution, fish and shellfish
    can become unfit for human consumption.

68
  • TOXIC METALS These are a minor hazard because
    they occur in low concentrations, aside from a
    few isolated hot spots.
  • RADIOACTIVE SUBSTANCES Natural radioactive
    substances are present everywhere along with a
    very small amount caused by fallout from nuclear
    weapons testing.
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