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Hydrological modifications typically refers to
man-made changes in surface water flow. These changes mainly affect the
quantity of water delivered through a system, which in turn, can affect
the water quality. The best example of a man-made modification affecting
Mobile Bay is the Battleship Parkway. In 1926, improving travel between
Mobile and Baldwin Counties was accomplished by the building of the
"Causeway" and realizing the impact that project would have on the health
of Mobile Bay was many years away.
An Estuary depends on freshwater and saltwater inflow of water to create
the brackish water conditions needed to support this kind of habitat. The
Causeway has restricted the natural exchange of water between the delta
and the bay since 1927. How that modification has affected the Mobile Bay
Delta habitats and inhabitants is becoming more of a concern. In addition,
shoreline modifications (i.e., bulkheads, jetties), filling in of
wetlands, locks and dams along Alabama's rivers all have an impact on the
hydrology of Mobile Bay. Lining streams with concrete or gabien
baskets, burying them in stormwater pipes, and filling them with riprap
also has a major effect on water quality and quantity within the estuarine
system.
As a deep water shipping port, modifications within the Bay are seen in
dredging activities. Mobile Bay has an average depth of 9 to 10 feet. This
can give you some idea of how deep a shipping channel must be dredged in
order to accommodate the large vessels we see in the Port of Mobile. These
dredging activities may alter the natural flow of water and may affect
water quality.
Population growth, and the land development that comes with population
growth, has created storm water management and sedimentation/erosion
problems. Pollutants from storm water runoff jeopardizes an estuary's
flora and fauna. The sedimentation caused by storm water runoff increases
the turbidity and reduces the sunlight necessary for submerged aquatic
vegetation thereby affecting aquatic animal life.
Mobile Bay and the Delta are a delicate balance of conditions that create
a perfect hydrological environment for our estuary. The long-term impacts
of modifications need to be well thought out and well planned. If you
would like more information or you would like to get involved, please call
our office, (251)431-6409 or e-mail us.
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