dustrial Canal to the development of New Orleans, and the commerce of
the nation, and has so expressed himself in public.
The Pontchartrain route has been laid off, by engineers, beginning at
the Canal, paralleling the south shore of the Lake Pontchartrain to the
south draw of the Southern Railway bridge, thence to the Rigolets to
Cat Island Pass, from there to Cat Island Channel and so to the deep
water of the Gulf, a total distance of 75 miles.
Soundings and surface probings have been taken at frequent intervals
over the entire route. These have shown the engineers the following:
Three-quarters of a mile from the south shore of the lake, and as far
as the railroad drawbridge, a hard bottom is found. The material is
principally packed sand, rather fine, with a small amount of clay, and
occasionally some broken shells. Beyond this distance from the shore,
the bottom is softer, consisting of mud mixed with sand. From the
bridge over the remainder of the route, the bottom, with the exception
of a few sand pockets, is soft--a blue mud with a large percentage of
sand. This soft material has so much tenacity, however, that current
and wave wash, which tend to fill up artificially dredged channels,
would affect only the surface.
The government is conducting large dredging operations in Mobile Bay,
Gulfport Channel, Atchafalaya Bay and the Houston Ship Channel. An
outline of the results there will show how feasible the dredging of the
Pontchartrain Channel would be, and how much cheaper in comparison.
The channel connecting Mobile Bay with the Gulf of Mexico has a bottom
very soft for the most part, and with a small percentage of sand.
Towards the outer end, the material is black mud, about equal in
consistency to the softest material found in the Pontchartrain route. A
sounding pole with a 4-inch disc on the end can be easily pushed three
or four feet into the mud and pulled out again. Wave and current action
cause the channel to shoal at the rate of 78,000 to 132,000 cubic yards
per mile per year, depending on the softness of the bottom and the
depth. Where the highest rate obtains, the surrounding material
consists of soft mud, without a trace of sand. Experience shows that
where there is a fair percentage of sand in the material adjacent to
the channel bed, the shoaling is lessened. In general, the material
along the Pontchartrain route contains a greater percentage of sand and
is far more tenacious than that alon
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