Bayou Lafourche

elow the marsh. When the oil was extracted, yet more canals were dug to lay the
pipeline used to transport the goods for storage and refining. Millions of cubic yards of
sediment were removed and deposited adjacent to each canal. These spoil banks and
canals permanently altered the hydrology of the region by blocking the natural flow of
water and providing a conduit for salt water intrusion.
Though each channel may vary in size and purpose, they all share common
characteristics. When a channel is excavated through Louisiana’s fragile wetlands, the
adjacent landscape becomes exposed to the erosive potential of the water that fills it.
Flowing water driven by runoff, wind, or tides, can quickly erode canal banks. A
channel as small as the trapper’s traĩnasse, can grow over time to be as wide as a
petroleum access canal.
Manmade channels also provide a conduit that allows saltwater to infiltrate inland
brackish and fresh marshes. The diverse floras of the Barataria Basin are specialized
for survival in each unique environment. Salt water carried though manmade channels
by wind or tides, quickly decimates fresh marsh grasses that cannot tolerate higher
salinity. As these plants die, their roots no longer provide stability to the underlying
sediment and once gone, the marsh grasses can no longer produce the organic
material that balanced the subsiding earth. The loss of root structure and productivity
accelerates bank erosion and can turn a once productive wetland into open water.
Channels may also transport pollution-laden runoff that would have once been naturally
filtered as it flowed through the wetland. Nutrients are transported to lakes or carried to
the Gulf where they promote eutrophication that consumes oxygen vital to aquatic life.
The Damming of Bayou Lafourche
The single largest impact to Bayou Lafourche came at the turn of the twentieth century.
By that time rail lines connected the bayou residents to trading posts in New Orleans
and beyond. The bayou was no longer critical to transportation and growing frustration
with spring flooding had come to a head. In
February of 1904 a damn was completed on
the banks of the Mississippi River at
Donaldsonville, severing Bayou Lafourche
from its lifeline and forever changed the
physical, chemical, biological, and social
characteristics of the region.
The residents of Bayou Lafourche had initially
requested the installation of a set of locks at
Walter Lemann Sr. Pumping Station in Donaldsonville
Donaldsonville, but the locks were never
constructed. Navigation and flow from the
Mississippi River was completely obstructed. The swamps and marshes of the Bayou
Lafourche region were cut off from the flow of fresh water that sustained them. The
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