The whole country around New Orleans, and indeed the entire region
adjacent to the Mississippi and its bayous, would be overflowed in
times of freshet were it not for the elaborate systems of levees,
which are a special feature of the whole lower Mississippi Valley. The
work of constructing these extensive embankments began at the
foundation of the infant city of New Orleans, when a dyke a mile long
was projected to protect the settlement from overflow, and it was
built soon afterwards. In 1770 the settlements extended thirty miles
above and twenty miles below the city, the plantations being
protected by levees. By 1828, the levees, though in many places
insufficient, had become continuous nearly to the mouth of Red River.
The methods of construction were various, and the authorities
conflicting, but the Government took hold of the work in 1850,
beginning by giving the States the swamplands to provide a fund for
reclamation. When the Civil War began, the levees extended a thousand
miles along the river, and as far north as the State of Missouri.
During the war the system fell into decay, and afterwards much work of
restoration was necessary. The Mississippi River Commission now has
charge, under comprehensive methods, and large sums are devoted to the
purpose, aggregating over $4,000,000 annually from the General
Government and the States, there being continuous lines of levees from
Memphis nearly to the delta below New Orleans. Were the river left to
itself, in most of this region during the spring floods it would
overflow the banks by several feet, this being, however, prevented by
these massive earth entrenchments, through which there nevertheless
often breaks a destructive crevasse. The sediment brought down by the
river has been deposited most abundantly upon the banks, making their
front the highest surface, so that there is a gradual descent inland
and back from the river of about four feet to the mile. During the
floods, an observer standing alongside the levee has the water in the
river running high above him, and when the levee breaks the
bottom-lands are soon extensively overflowed. The estimate is that
these lands, reclaimed and protected by the levees, embrace thirty
thousand square miles of the most fertile soil in the world, about
one-sixth of it being under cultivation; and that there are altogether
twenty-six hundred miles of levees along the great river, and the
adjunct tributary bayous, lakes and other water-courses. For nine
months the water stage is low, so that very little attention is given
it, but when the spring comes, the melted snows of the Rockies and the
torrential rains come down usually in conjunction, bringing an
enormous flood, that rushes along, filling the river to the tops of
the embankments. Processes of decay and weakening are always going
on--rats and mice have their burrows, and millions of crawfish, with
claws like chisels, riddle the levees with holes. Then in some
unexpected place the dreaded alarm is sounded that the bank is giving
way and a crevasse impends. The water-soaked bank shows fissures and
help is implored--bells are rung, fleet horsemen arouse the
neighborhood, the people assemble and try to stop the break. But the
crumbling levee soon gives way, and the swollen and muddy current
pours through with a roar like Niagara, the waters spreading afar over
the lowlands, and thus by reducing the stream-level bringing relief to
the river, but converting the adjacent region for many miles into a
turbid lake and ruining the crops.
Below New Orleans, as the river is descended, the thick forest
vegetation along the banks gradually disappears, giving place to vast
expanses of marsh and isolated patches of fast land bearing stunted
trees. The river banks grow less defined, and are finally lost in what
appears to be an interminable marsh with many waterways. This leads to
the delta, gradually built up from the sediment deposited by the
river, and demonstrating the eternal conflict and gradual encroachment
of the land upon the sea. Through the ages, this delta, steadily
constructed by the river, has been protruded into the Gulf of Mexico,
far beyond the general coast-line, and it is slowly advancing year
after year from the accumulated deposits. The delta divides into the
various channels or "passes" by which the waters seek the sea. These
are at first bordered by shore-lines of mud, which lower down dissolve
into consecutive lines of coarse grass growing from beneath the watery
surface, and then they are discernible only to the practiced eye of
the pilot by what appears to be a regular current flowing along in the
universal waste. This delta covers an area of fourteen thousand square
miles, and it divides into four separate passes, which are hardly much
more than outlet currents through the expanse of waters and marsh,
thus excavating deeper and navigable channels. There are lighthouses
at the entrances, and just inside the Northeast Pass is a spacious
mud-bank known as the Balize, where there once was a colony of
wreckers, but now are pleasant residences. Above the head of the
delta, and about seventy miles below New Orleans, located in eligible
positions at a bend, are Forts St. Philip and Jackson, the defensive
works of the river entrance, and below them the main ship channel goes
out to the Gulf through the South Pass, where the bar has been
deepened through the effective scouring produced by the famous Eads
Jetties on either side--one over two miles long and the other a mile
and a half. These jetties cost $5,000,000, and they maintain a channel
thirty feet deep. The twin lights marking their extremities can be
regarded as indicating as nearly as may be the mouth of the great
river, and beyond is the broad expanse of the Gulf of Mexico. Vast as
is the enormous outflow brought down by the Father of Waters, the
drainage of the whole broad centre of the Continent thus poured into
the Gulf, yet it has no appreciable effect upon the ocean into which
it flows. The Gulf easily swallows up all the Mississippi waters in a
way that reminds of Rossetti's dirge:
"Why does the sea moan evermore?
Shut out from heaven it makes its moan,
It frets against the boundary shore;
All earth's full rivers cannot fill
The sea, that drinking, thirsteth still"