REMOTE SENSING OF A MARSH ENVIRONMNET: JAMAICA BAY

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REMOTE SENSING OF A MARSH ENVIRONMNET JAMAICA BAY

• Siu Chan, Mary Forrester, and Pauline Lo
• City University of New York, Hunter College,
  Geography Department

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LOCATION OF JAMAICA BAY, NY

• Jamaica Bay is an 18,000-acre estuary surrounded
  by the Rockaway Peninsula, Brooklyn, and Queens
• Decreasing in salt marshes due to modifying
  coastal regime, landfill, sewage discharge

Queens
Jamaica Bay
Brooklyn
Rockaway Peninsula
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DEVELOPMENT OF JAMAICA BAY

• JFK International Airport
• Wildlife Refuge
• Spring Creek
• Floyd Bennett
• Marine Park
• Breezy Point
• Fort Tilden
• Riis Park.

4
WILDLIFE REFUGE

• Wildlife refuge site is the most essential
  feature in Jamaica Bay. It is a home to over 300
  bird species, over one hundred thousand migrating
  shorebirds, and to various fish species. This
  site has a very complex ecosystem
• In the past, Jamaica Bay used to have a wider
  area. Its size has been reduced as the result of
  growing urban land use.

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JAMAICA BAY IN THE PAST

• Before intervention of men, Jamaica Bay was a
  roughly circular marshland of 25,000 acres
• In 1907 the marsh area of Jamaica Bay was 16000
  acres
• In 1970, only 4000 acres remain
• Major construction works were done to develop
  Jamaica Bay as a commercial seaport

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JAMAICA BAY IN 1917
NY Rockaway Beach R R
Canarise Landing
JFK
Bulkhead Line
Duck Point Marsh
Floyed Bennett Field
Barren Island
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JAMAICA BAY IN DEVELOPMENT

• The Jamaica Bay Improvement Scheme created of two
  large and entirely bulkheaded islands, West
  Island and East Island
• 15 basins were created
• 16 or 18 piers were constructed between Barren
  Island and Mill Basin
• A platform was constructed at Barren Island for
  the Street Cleaning Department to unload ashes
  and other refuse for filling the marshlands

8
JAMAICA BAY IN 1934
The Dredged Channel
Canarsie Upland
Flatland Bay
Island Channel

• In 1912, financed by Congressional funds, the
  city started work on the main ship channel
• Totally of about 1500 feet wide channel was
  constructed until 1930s

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MONITORING OF JAMAICA BAY
East/West Island
Duck Point Marsh

• False Color Image Showing the Vegetation Growth
  Around Jamaica Bay
• Jamaica Bay Bands 4R, 2G, 1B

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LOSS OF INTERTIDAL MARSH Duck Point Marsh

• Scanning historic US Coast and Geodetic Survey
  Maps and aerial photography
• 64 acres / 68 of tidal wetlands were lost on
  Duck Point Marsh

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HISTORICAL MARSH LOSS IN JAMAICA BAY

• From 1924 to 1974, 780 acres of marsh islands
  were lost due to direct dredging and drilling,
  and 510 acres were lost due to other reasons.
• Between 1974 and 1994, 526 acres of marsh islands
  were lost
• Average rate of 26 acres per year.
• Between 1994 and 1999, 220 acres were lost at an
  average rate of 44 acres per year.
• The vegetated intertidal marsh is being converted
  to nonvegetated underwater lands.

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Jamaica Bay Salt Marsh Is No Longer A
Self-Sustaining Ecosystem

• Environmental impacts have altered processes for
  water and sediment movement.
• Dredging of the channels prior to the 70s has
  increased the average water depth from 1 to 3 m
• Strengthening the tidal currents, enhancing
  erosion, and trapping sediments deposits
• Greater nutrient inputs have led to changes in
  primary and secondary producers in the Bay.
• 900,000 gallons of leachate flows daily from
  landfills
• Since 1993, 20 rise in nitrogen due to sewage
  sludge dewatering
• High populations of ribbed mussels that appear to
  block marsh drainage patterns, causing pounding
  and Spartina death.
• Nutrients stimulate macroalgae production and
  increases sea lettuce density

These changes have taken the ability of the Bay
to sustain marsh habitats in the face of sea
level rise
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ACTION PLANS FOR JAMAICA BAY

• Some areas placed under Parks jurisdiction since
  1938
• In 1950, the Park commissioner approved for five
  new parks of totally 17.9 square miles / 0.028
  acres
• In 1951, the Jamaica Bay Wildlife Refuge was
  established
• In 1974, over 9,000 acres were transferred to the
  newly created Gateway National Recreation Area
• 1993, Parks acquired an additional 2 acres

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CONCLUSIONS

• Salt marsh islands are disappearing into the bay,
  transforming grassy green meadows into submerged
  mud flats
• Land area had decreased by around 12 between
  1959 and 1998, roughly 0.3 /yr or 40 - 60 acres
  per years
• Unusual to see marshes disappearing so
  dramatically
• Further research and studies are needed and we
  will use remote sensing as a tool for the future
  management.

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ACKNOWLEDGEMENT

• Prof. Karl Szekielda
• Miss Mary Forrester
• Miss Pauline Lo