Chesapeake Bay
The Chesapeake Bay is the largest estuary in the
United States. It lies off the Atlantic Ocean, surrounded by
Virginia and Maryland. The Chesapeake Bay's watershed covers 64,299
mi² (166,534 km²) in the District of Columbia and parts of six
states: New York, Pennsylvania, Delaware, Maryland, Virginia, and
West Virginia. More than 150 rivers and streams drain into the
Bay.
Chesapeake Bay -
satellite Landsat photo, circa 2000.
The main stem of the Bay itself is about 189 miles (304 km) long,
from the Susquehanna River in the north to the Atlantic Ocean in
the south. At its narrowest point (near Annapolis, Maryland, the
Bay is 4 miles (6.4 km) wide; at its widest point, near the mouth
of the Potomac River, it is 30 miles (48.3 km) wide. Total
shoreline for the Bay is 11,684 miles (18,804 km), and the surface
area of the Bay and its major tributaries is 4,479 mi² (11,600
km²).
The narrowest point of the Bay is spanned by the Chesapeake Bay
Bridge, and the Chesapeake Bay Bridge-Tunnel spans a 23 mile (37
km) section of the Bay at near its mouth.
Geology
The Bay is the drowned valley of the Susquehanna, meaning that was
where the river flowed when sea level was lower, but the Bay's
geology and its present form and its very location have also been
affected by a bolide impact event at the end of the Eocene (about
35.5 million years ago), forming the recently discovered submerged
Chesapeake Bay impact crater.
Parts of the Bay, especially the coast line of Calvert County, are
lined by cliffs as the result of receding waters millions of years
ago. These cliffs, generally known as Calvert Cliffs, are famous
for their fossils, especially fossilized shark teeth. Fossilized
shark teeth are commonly found washed up on the beaches next to the
cliffs. Scientist's Cliffs is a beach community in Calvert County,
named so because of the cliffs' propensity for geological finds and
numerous fossils.
Much of the bay is quite shallow. A person 6'7" (2 m) tall could
not only walk across the mouth of the Susquehanna at the upper bay,
but could also traverse some 700,000 acres (2,800 km²) of the bay
without being entirely submerged. On average, the depth of the Bay
is less than 5 fathoms (30 feet or 9 meters).
History
The Chesapeake Bay was the site of the Battle of the Chesapeake in
1781, during which the French fleet defeated the Royal Navy in the
decisive naval battle of the American Revolutionary War.
Today, the Calvert Cliffs Nuclear Generating Station uses water
from the Bay to cool its reactor.
The bay is also known for the Chesapeake Bay Retriever, a dog breed
developed in this area.
Watershed
The largest rivers flowing into the Bay are:
* Susquehanna River
* Potomac River
* James River
* Appomattox River
* Rappahannock River
* Patuxent River
* Choptank River
* York River formed by:
° Mattaponi River
° Pamunkey River
Fishing Industry
The word Chesepiooc is an
Algonquian word meaning "Great Shellfish Bay." The Bay was once
known for its great seafood production, especially blue crabs,
clams and oysters. The plentiful oyster harvests led to the
development of the Skipjack, the State Boat of Maryland, which is
the only remaining working boat type in the United States still
under sail power. Today, the body of water is less productive than
it used to be, because of runoff from development throughout the
watershed, urbanization, particularly on its western shore,
overharvesting, and invasion of foreign species. The bay though,
still yields more fish and shellfish (about 45,000 short tons or
40,000 metric tons yearly) than any other estuary in the United
States.
The Bay is famous for its Rockfish, otherwise known as Striped
bass. Once on the verge of extinction, Rockfish have made a
significant comeback and are now able to be fished in strictly
controlled and limited quantities.
The Bay serves as the predominate source of eel in the United
States.
In 2005, local governments began debate on the introduction to
certain parts of the Bay of a species of asian oyster, to revive
the lagging shellfish industry.
The Chesapeake Bay
Bridge.
Deteriorating environment conditions
In the 1970s, the Chesapeake Bay contained one of the planet's
first identified marine dead zones, where hypoxic waters were so
depleted in oxygen they were unable to support life, identified
when massive fish kills resulted. Chesapeake Bay's oyster industry
has also suffered from two diseases: MSX and dermo. Harmful algae
blooms such as Pfiesteria
which can effect both fish and humans is also a problem. The
depletion of oysters due to overharvesting has had a particularly
harmful effect on the quality of the Bay. The reduction of oysters,
which serve as natural water filters for the Bay, has led to
reduced water quality of the Bay: water that was formerly clear for
fathoms is now so turbid that a wader may lose sight of his feet
before his knees are wet.
Issue #150
