Full document / COSOC-W-86-002 - the National Sea Grant Library

only 45 acres before erosion overcomes delta building. This action is
mitigation for marsh loss caused by construction of a hurricane
protection levee system.
Innovative Uses of Dredged Haterlol. We remove about 30 million cubic
yards of dredged material every year in order to keep New Orleans
District navigation channels passible. There are many wayB to use this
material to help stop land loss. The Gulf Intercoastal Waterway runs
along the southern boundary of the Laccaslne National Wildlife Refuge.
A Refuge levee protected a large area of vegetated pond and marsh from
erosion and salinity Intrusion. The levee was In poor shape, so during
a maintenance dredging In 1982, we placed dredged material north of the
old levee. The Refuge used some of the material to make a new levee and
the remainder served to protect the new levee. Along the Baratarla Bay
Waterway, we have used dredged material to build up the bank of a pond
to prevent salinity intrusion which could endanger the trees where bald
eagles nest. Purther west along the GIWW, Grand Lake was threatening to
break through Its northern shoreline. If this had happened, the marsh
north of the GIWW would have been threatened by erosion due to a longer
wave fetch. We placed dredged material in the thinnest spots to rebuild
the shoreline.
Harsh nourishment Is a technique that we use where there is an upland
bank between the waterway and eroding marsh. We place the end of the
dredge pipe at the edge of the bank (See Figure 2) and start pumping.
FIGURE 2 - MARSH NOURISHMENT
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