a greater proportion of sand than in the case of the
neighboring channels mentioned.
The channel could therefore be more easily maintained.
Engineers estimate that a channel with a 300-foot bottom would be
needed. On the south shore of the lake, the side slopes should be on
the 1 to 3 ratio, with provision for a 1 to 5 ratio at the end of five
years. Dumped on shore, the material would reclaim considerable
frontage, and eliminate the re-deposit of this material in the channel.
Through the remainder of the route, the original excavation should be
made with side slopes on the 1 to 5 ratio, with provision made for a 1
to 10 ratio in five years.
The dredging of the 75 miles of the Pontchartrain Channel would amount
to 97,200,000 cubic yards, it is estimated by engineers. The cost would
be around $10,000,000. The annual maintenance, during the first five
years, would amount to 8,880,000 cubic yards--an estimate based on a
comparison with the other channels into the Gulf, and the character of
the material to be excavated. This estimate is considered large--but
even at that, it is only 118,400 cubic yards a mile a year, and the
cost would be about $750,000, according to Colonel Dent. After five
years, it would be less.
Another proposed route, investigated by Colonel Dent, is through Lake
Borgne. A canal some miles in length, through the marsh, would connect
the lake with the Industrial Canal. This route has considerable
maintenance advantages over the Pontchartrain route. The character of
the bottom in Borgne is more or less the same as in Pontchartrain.
Sooner or later, one of these channels will be built by the government.
That it has not already been begun is due to the fact that the Canal
has not yet been completed, and the expected development has not taken
place. But there is no doubt that it will.
[Illustration: TYPICAL BRIDGE ON CANAL]
[Illustration: EMERGENCY DAM CRANE]
WHY GOVERNMENT SHOULD OPERATE CANAL.
It is the function of the state to provide port facilities in the form
of docks, piers, warehouses, grain elevators, mechanical equipment,
etc. But it is the duty of the national government to improve harbors,
dredge streams, dig canals for navigation and irrigation, erect levees
to protect the back country, and build locks and dams when needed.
These are the premises from which the Hudson Dock Board reasons that
the cost of construction and maintenance of the New Orleans Navigation
|