Biscayne Bay

Not to be confused with Bay of Biscay or Biscay Bay, Newfoundland and Labrador.

Biscayne Bay
View of northern Biscayne Bay from I-195, showing the Downtown Miami skyline in the background, May 2008.
Map: Biscayne Bay Biscayne Bay (Florida)
Coordinates	25°33′57″N 80°12′59″W
Ocean/sea sources	Atlantic Ocean
Countries	United States
Max. length	35 miles (56 km)
Max. width	8 miles (13 km)
Surface area	428 square miles (1,110 km2)
Settlements	Miami, Florida Miami Beach, Florida
References

Panoramic view of the bay from the Port of Miami

Southern Biscayne Bay makes up the bulk of Biscayne National Park.

Biscayne Bay (Bahía Vizcaína in Spanish) is a lagoon that is approximately 35 miles (56 km) long and up to 8 miles (13 km) wide located on the Atlantic coast of South Florida, United States. It is usually divided for purposes of discussion and analysis into three parts: North Bay, Central Bay, and South Bay. Its area is 428 square miles (1,110 km²). The drainage basin covers 938 square miles (2,430 km²).

North Bay lies between Miami Beach barrier island from Miami on the mainland. It has been severely affected over the last century by raw sewage releases, urban runoff, shoreline bulkheading, dredging, the creation of artificial islands and the loss of natural fresh water flow into the bay. However, water quality has steadily improved since regular monitoring began in 1979. North Bay accounts for only 10% of the water area of the bay.

Central Bay is the largest part of the bay. It is separated from the Atlantic Ocean by the Safety Valve. It has been adversely affected primarily by bulkheading, urban runoff discharged by canals, and the loss of natural fresh water flow.

South Bay is nearly as large as Central Bay, and is the least affected by human activities, although it also suffers from the loss of natural fresh water flow. South Bay is separated from the Straits of Florida by the northernmost of the Florida Keys, and includes Card sound and Barnes Sound. It is connected to Florida Bay through a few small channels.

The first bridge across Biscayne Bay was the 2.5 mile wooden Collins Bridge built by John S. Collins and Carl G. Fisher. The toll bridge was "the longest wooden bridge in the world" when it was completed in 1913 at the southern terminus of the Dixie Highway. The bridge was replaced in 1925 and renamed the Venetian Causeway. The MacArthur, Julia Tuttle, 79th Street and Broad causeways connect Miami to Miami Beach, and the Rickenbacker Causeway connects Miami to Key Biscayne. The Card Sound Bridge connects the mainland in the Homestead, Florida area to the northern part of Key Largo.

The bay makes up part of Biscayne National Park. Seven remaining houses of Biscayne Bay's Stiltsville settlement are now within the boundaries of this National Park which was established in 1980. Much of Biscayne National Park was designated as a National Monument in 1967. Card Sound and Barnes Sound lie within the Florida Keys National Marine Sanctuary. In regards to wildlife, Bottlenose Dolphins and Florida Manatees can be observed in the bay.

The bay has been known by several names. Juan Ponce de León called it Chequescha in 1513. Pedro Menéndez de Avilés called it Tequesta in 1565. The British, during their occupation of Florida, called the bay Cape River, Dartmouth Sound, and Sandwich gulph. Hernando de Escalante Fontaneda related that a sailor from the Bay of Biscay called the Viscayno or Biscayno had lived on the lower east coast of Florida for a while after being shipwrecked, and a 17th century map shows a Cayo de Biscainhos, the probable origin of Key Biscayne. The bay was known as Key Biscayne Bay in the 19th century, finally shrinking to Biscayne Bay late in the 19th century.

The bay is also home to the University of Miami Rosenstiel School of Marine and Atmospheric Science in Virginia Key (founded in 1947) and Florida International University's Biscayne Bay Campus (founded in 1977) in North Miami. It was seen in the music video for The Lonely Island's "I'm on a Boat".

Safety Valve

Aerial view of the Safety Valve from southern end of Key Biscayne (top) to Soldier Key

The Safety Valve is a series of shallow sand flats separated by tidal flow channels, stretching about 8 miles (13 km) from the south end of Key Biscayne to the Ragged Keys at the north end of the Florida Keys. The term "safety valve" was applied to the tidal flats by Ralph Munroe, who argued against building a causeway and bridges connecting Key Biscayne to the Ragged Keys and beyond on the grounds that such construction would block the free outflow of storm surges from the bay across the flats to the ocean. It is believed that it does moderate the effects of storm surges on the bay. The transportation of sand southward along the Atlantic Coast of Florida by longshore drift ends in the area of the Safety Valve. The structure of the Safety Valve has been stable for at least the last century.

Sources

• Biscayne Bay : A Bibliography of the Marine Environment
• South Florida Water Management District: Coastal Ecosystems: Biscayne Bay - retrieved via Wayback Machine September 12, 2007
• Florida Department of Environmental Protection: Biscayne Bay Aquatic Preserve
• History and Ecology of Biscayne Bay
• Biscayne Bay Watershed - Florida DEP