Transcript The Mobile-Tensaw River Delta is the second largest river delta in

MobileTensaw
River
Delta
MOBILE-TENSAW RIVER DELTA
Location
•
Mobile
The Mobile-Tensaw
River Delta is the
second largest river
delta in the U.S., second
only to the Mississippi
River Delta.
• It is characterized by
many distributary rivers,
streams, bayous and
creeks which form a
maze of waterways.
• The Delta itself covers
over 400 square miles
or 300,000 acres of
swamps, marshes, and
river bottomlands that
are among the most
impressive in the world,
so impressive that
Congress recently
named the Delta a
National Natural
Landmark.
Causeway/Bayway
Unique Shape
• The Mobile-Tensaw
is an elongated
delta formed, some
experts say, as a
result of a
depression or
sinking of the earth
between two
geological faults.
• Thus, the MobileTensaw Delta is
bounded on both
sides by relatively
high ground.
Wetland Habitat
 The
Mobile-Tensaw River Delta is one of
the largest intact wetland ecosystems in
the United States.
 Overall, it comprises approximately
260,000 acres of wetland habitats, ranging
from submersed grass beds to cypressgum swamps and seasonally flooded
bottomland hardwoods
Northern DeltaBottomland Hardwoods
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Over 36,000
acres of the
most extensive
area of
seasonally
flooded
bottomland
hardwoods in
Alabama.
swamp forests
of bald cypress
and tupelo gum
Moving South- River Swamp Forest

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River swamp forest, or
deepwater alluvial swamp,
which naturally supports bald
cypress and water tupelo in
equal numbers.
Common shrubs include
common alder, buttonbush,
swamp privet, fetterbush, and
black willow.
Typical herbs include golden
club, swamp lily, and fragrant
water lilies. Spanish moss is a
common epiphyte growing
among the crowns of trees.
These habitats can easily be
seen from the I-65 bridge that
dissects the Delta north of
Mobile.
Moving SouthLower Hardwood Swamp Forest

Lower hardwood swamp
forest, sometimes
referred to as the first
bottom, is characterized
by a greater diversity of
woody species.
 These include overcup
and laurel oak, water
hickory, river birch, red
maple, and green ash, as
well as cottonwood in
disturbed areas. Nonwoody plants include
lizard’s tail, jewelweed,
and several species of
ferns.
• Continuing further
downstream, a
maze of bayous,
creeks, distributary
channels and other
watercourses bisect
the Delta between
the Tensaw River
and Big Lizard
Creek adding to the
hydrologic and
ecologic diversity of
the system.
Moving South- Tidal Marsh
Tidal Freshwater
Marsh
• Tidal
freshwater
marshes occur
in the extreme
lower portion
of the Delta
near the mouth
of Mobile Bay.
Importance of the Delta

The Delta does things for us:
 It's a water filter, a sponge during hurricanes
and floods
 a nursery for redfish, menhaden, white shrimp
and numerous other species caught
commercially in the Gulf.
 Indeed, the Delta is an indispensable partner to
the Gulf, which accounts for more than 35
percent of the nation's commercial seafood
catch.
EstuaryWhere Freshwater and Saltwater
Meet
Mobile Bay
What is an Estuary?



Estuary (es-choo-er-ee) - a partially enclosed coastal
body of water, having an open connection with the
ocean, where freshwater from inland (MobileTensaw River Delta) is mixed with saltwater from
the Gulf of Mexico. Mix of salt and freshwater is
called BRACKISH water.
Estuaries represent some of the most sensitive and
ecologically important habitats on earth.
They provide sanctuary for many species of waterfowl,
store nutrients for larval and juvenile marine life, and
serve as breeding grounds for many desirable species
of ocean fish
Importance of an Estuary
 The
estuary is considered environmentally
and economically important because of its
exceptional biological diversity and
productivity.
 It
supports both fresh and saltwater
species and serves as nursery habitat for
many commercially and recreationally
important species.
Mobile Bay National Estuary
Program

The United States Environmental Protection
Agency's (EPA's) National Estuary Program
(NEP) was established by Congress in 1987 to
improve the quality of estuaries of national
importance.
 The mission of the MBNEP is to promote wise
stewardship of the water quality characteristics
and living resource base of the Mobile Bay
estuarine system.
The Mobile Bay NEP area of
study includes both Baldwin
and Mobile Counties which
surround Mobile Bay, the
Mississippi Sound westward to
the Alabama-Mississippi State
Line, and the Alabama State
marine waters in the north
central Gulf of Mexico,
extending three miles south of
Dauphin Island and the Fort
Morgan Peninsula.
.
Mobile Bay National Estuary
Program Priorities
 Water
Quality
 Living Resources
 Habitat Management
 Human Uses
 Education & Public Involvement.
Mobile Bay National Estuary
Program Monitoring Stations
Scientific Monitoring
 Atmospheric
Monitoring: Each of these
stations monitor temperature, humidity,
wind speed wind direction and
precipitation
 Hydrographic Monitoring (water): water
temperature, salinity (amount of salt in the
water), oxygen levels, tide height, nutrients
and other information on the water.
Human Impact
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Human impact on estuaries includes reclamation
of tidal land by:
filling
pollution from sewage
solid waste
increased sedimentation filling the estuary
alteration of the salinity of estuarine waters by
withdrawal or increased influx of freshwater.
Weeks Bay Estuary
• The Weeks Bay
Foundation was
incorporated in 1990 as a
to support the Weeks Bay
National Estuarine
Research Reserve in its
efforts to protect the
pristine coastal area of
Baldwin County , Alabama
.
• The Foundation supports
the Reserve through
donations of land and
educational exhibits,
public awareness and
education programs,
water quality monitoring
efforts, and volunteer
programs.
Location
The Weeks Bay Watershed has a drainage area of almost
126,000 acres (approximately 200 square miles) in Baldwin
County.
Weeks Bay in Pictures
Gaillard Island in Mobile Bay
• Gaillard Island is a dredge disposal island
located in Mobile Bay near Mobile, Alabama.
• The island is an important site for colonial
nesting seabirds and shore birds in coastal
Alabama and has been the only nesting site for
brown pelicans in Alabama - first discovered in
1983.
• Home to 16,000 shorebirds and seabirds
including the Brown Pelican which had
disappeared from Alabama in the late 1800's.