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SAN FRANISCO BAY. By: Randall Alcorn. Golden Gate Bridge. History of the Bridge. Took over 4yrs to construct Costs $35 million dollars 1.7 miles long in length Opened May 28,1937. Alcatraz. History of Alcatraz “Rock”. Converted to Federal prison in 1934
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SAN FRANISCO BAY By: Randall Alcorn
History of the Bridge • Took over 4yrs to construct • Costs $35 million dollars • 1.7 miles long in length • Opened May 28,1937
History of Alcatraz “Rock” • Converted to Federal prison in 1934 • Thought had the perfect area for a prison • 34 people tried to escape • Closed March 21, 1963
About the Bay • 55,572 acres • 16,000 sq. miles • 50mi. Long and 3-13mi. wide • 40% fresh water drains into bay • Extends from California’s San Pablo Bay to South San Francisco Bay • 4 areas of the bay the north, central, and south San Francisco Bay, and San Pablo Bay
About the bay (cont.) • 400ft is deepest area • Relatively shallow, channel on 50 ft exists • One of the most important coastal wintering and migratory habitats for Pacific flyway waterfowl
SAN FRANCISCO BAY The development
Development (cont.) • The bay was formed 10,000 yrs ago during the last ice age. • Sea levels rose and inland through the “golden gate” • Levels were rising at 1” per year, along with rivers and creeks coming into the area • Sedimentation occurred
San Pablo Bay (cont.) • Shallow tidal estuary • 10mi. Across and covers app. 90 sq miles • Mostly fresh water but contains salt marshes and also mudflats • Sacramento and San Joaquin Rivers empty
Estuary • Nation’s second largest/most biologically significant estuary on the Pacific Coast • Made up of San Francisco Bay (north, south, and central) and the San Pablo Bay • Interconnecting wetlands (sloughs, marshes, channels, rivers) • Some areas are mixed salt/fresh water
Habitats • Tidal Flats- Areas that are flooded during high tide and lose most the water during low tide • Tidal Marsh- Areas flooded by high tide but retain some water during low tide. • Seasonal Wetlands- Moist grassland and vernal pools. • Riparian Habitat- Boards creek, rivers, lakes • Non-tidal diked wetlands- Tidal marshes that are isolated from tidal influence and maintain wetland features. • Salt ponds- Large man-made ponds that are flooded with Bay water.
Tidal Marshes • 190,000 acres now only 16,000 • The “kidneys” of Bays, purifying pollutants • Produce large amounts of plant material
Tidal Marshes (cont.) • Important for fish and waterfowl • Vegetation consists of algae, sea lettuce, and eel grass • High tide fish use the area for forage • Low tide fish eating birds consume fish, that didn’t make it out
Salt Ponds • San Francisco Bay offers good area for salt production (Cargill Salt Company) • Water is brought in from the bay into man-made ponds • Provides food and habitat for more than 70 species of waterfowl and shorebirds • San Francisco Bay Wildlife Refuge bought 16,500 acres of salt ponds (one of largest restoration attempts in America)
Salt Pond (cont.) • 300 million dollars • Take five years to fully restore but hope to: • Increase bays tidal wetland by 50% • Preserve open space • Improve water quality • Act as natural flood control • Prevent shoreline erosion • Provide habitat for endangered species
Importance of Wetlands in Bay • San Francisco is heavily polluted, wetlands help filter pollutants. • Soak up excess water, that could flood the bay • Provides home for endangered species • 70% of commercial fishing
Wetlands destroyed • (Human influence) They are cheap, provide go location for business and are easy to build on. • Exotic species brought in from ships • They push out native species of plants and animals. • 100 exotic species
Programs to help restore wetland habitats • Ducks Unlimited • San Pablo Bay National Wildlife Refuge • San Francisco Bay Joint Venture
Ducks Unlimited 20,000 acres of habitat Help to directly benefit endangered species and sensitive species Habitat improvement for waterfowl: lesser scaup, canvasback, northern pintail, and redhead. San Pablo Bay NWR Open bay, tidal marshes, mudflats, and seasonal and managed wetlands Marches have been greatly impacted; agriculture, draining, industrial use and water diversions 85% wetlands been altered. Refuge provides area for migratory waterfowl species. Programs (cont.)