Page:Popular Science Monthly Volume 80.djvu/249

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245
TEE MISSISSIPPI DELTA

future of deep-sea navigation to New Orleans, I think it desirable to call attention to it at the present time, in order that, if possible, measures may be taken to prevent a still farther obstruction from mudlump upheaval, by persistent cutting-away of the present lump as it rises; so as to relieve the pressure at the point already upheaved, and thus, perhaps, prevent the rising of additional obstructions by giving vent to the mud column at the initial point. How far this is practicable I will not venture to discuss. It is an engineering problem of no mean difficulty, considering that, in past experience, the utmost efforts of specially constructed dredges have failed to maintain a proper depth for more than a few hours or days, where mudlump upheavals had occurred in the Southwest Pass. In the South Pass there has thus far been only a single upheaval to deal with, whereas in the Southwest Pass a succession of these upheavals rendered the maintenance of the main channel extremely difficult. When we consider that in many cases the shock of the grounding of a vessel on a mudlump was sufficient to cause a quick upward movement (in one instance lifting the bow of the vessel above the water over-night), showing a state of very unstable equilibrium, it is not at all inconceivable that in a comparatively narrow channel, as is the South Pass at the present time, diligent and effective dredging might serve to cause the upheaving force to continue to spend itself on the one point where it has now acted, and so to prevent, or at least retard, the formation of new upheavals.

It is to be noted that at the present time the dredges maintain, in the seaward channel, a depth of as much as thirty-seven feet. "Whether this depth, apparently excessive for the present requirements of navigation, will prove an incitement to new upheavals of the bottom is, perhaps, a question worth considering. In any case, the mudlump now lying across the mouth of the main channel of the Mississippi has doubtless come to stay, and no amount of dredging will suffice to do away with it.