ATCHAFALAYA
Atchafalaya refers to both
a river and a large wetlands region; the name derives from the
Choctaw hacha falaia, meaning "Long River." The river
itself serves as a major distributary of the Mississippi and Red
rivers, and runs through a swampy wetlands called the Atchafalaya
Basin, which is about twenty miles in width and one hundred and
fifty in length. Since the eighteenth century, a small number of
Cajun fishermen and trappers have depended on the basin and river
for their livelihoods. During the Civil War, the region provided a
hiding place for Cajun conscript evaders. Although a misconception
holds that Cajuns primarily inhabit swamps like the Atchafalaya,
the basin remains largely unpopulated, except by wildlife,
including three hundred bird species, as well as crawfish, shrimp,
crabs, frogs, snakes, nutrias, beavers, raccoons, foxes,
alligators, and black bears. It is used, however, by weekend
sportsmen, Cajun and non-Cajun alike, whose camps line its fringes
and elevated enclaves. Tourists flock to the basin’s "swamp
tours" and seafood restaurants. Spanned by an 18-mile elevated
section of Interstate 10, the basin is enclosed by artificial
levees on its eastern and western sides. During major floods, the
region serves as a containment area for rising waters.
The Atchafalaya Basin is
unique among the basins because it has a growing delta system with
nearly stable wetlands. Wetland loss is minor in the areas north of
Atchafalaya Bay when compared to the other basins. The total
wetland loss in the area is approximately 3,760 acres between 1932
and 1990. The average loss from 1974 through 1990 is 87 acres per
year. Wetland loss in this area is site dependent; loss is
primarily due to erosion, human activities, and natural conversion.
Storms and hurricanes cause shoreline erosion between Wax Lake
Outlet and Point Chevreuil. Oil and gas pipelines disrupt the
natural movement of flow and sediment within the wetlands. The
development of the Lower Atchafalaya River, from a tidal to a
riverine system, has created natural levees along the banks of the
river, disrupting the movement of flow and sediment into the
wetlands.
In Atchafalaya Bay, wetland
gain, rather than loss, is taking place. However, natural processes
and human activity are limiting the effectiveness of flow and
sediment resources in creating new wetlands by affecting sediment
delivery, deposition, and retention. Winter storm fronts, waves,
and currents refine and reshape the deltas in the bay by eroding
and reworking sediments. MR&T project features such as the Wax
Lake Outlet Control Structure affect the location and quantity of
flow and sediment entering the bay. Sediments available for delta
building in the Lower Atchafalaya River delta deposit in the
channel above Atchafalaya Bay. These sediments reach the delta only
during significant high water events. The Chene, Boeuf, and Black
navigation channel affects deposition and retention of sediments
within the Lower Atchafalaya River delta. The majority of sediments
conveyed by the Lower Atchafalaya River do not reach the delta;
sands fall out in the navigation channel where they are dredged to
maintain navigation; silts and clays are conveyed out of the bay.
The lack of sediments available for delta growth in the Lower
Atchafalaya River delta is evident when the growth rate of this
delta is compared to that of the Wax Lake Outlet delta. The Wax
Lake Outlet delta receives approximately one-third the amount of
flow and sediment of the Lower Atchafalaya River delta, and yet
grows at a rate three times as great.
About halfway across the 18
mile span of I-10 is a rest stop/welcome center. This is the
neatest stop I have ever been to in all my travels! If you stop
during the welcome center's day time operating hours be sure to
take in the presentation on Atchafalya. Kids, as well as the
young-at-heart will enjoy this free Disney-like presentation that
is both entertaining and educational. :)
To view a powerpoint of the layout and progress/completion of the
Atchafalya Project go to
http://dnr.louisiana.gov/sec/atchafalaya/projects/054.htm