The evening star and Newark advertiser. [volume] (Newark, N.J.) 1907-1908, 1907-12-23
Big CHANNEL FEAT.
ONE OF DEEPEST HARBoRS
IN WORLD.
Mississippi's Great River Improvement
Is Very Near Compile
ton.

NEW ORLEANS. Dec. a3.-One of the
greatest channel-making undertak kings
in the history of American i've inn
provement will be brought nearly to
completion this week. when the jetties
at the mouth of the Southwest Pass
of the Mississippi River are finished.
These %Jetties. after some dredging be-
tween them is completed, will give the
South one of the deepest harbors in
the world. by opening to the access OF
the largest steamships ahoat the 100
and 200-foot depths of the lower aSS@
sissippi River.
The harbor thus made accessible has
%navieable water connection with at
least a dozen States bordering the
Mississippi and its tributaries. tho
Ohio, Missouri. Arkansas and Red riv-
ers. Abou $4,000. 900 is being spent on
this improvement by the United States
Government, which has the work in
charge.
The new ~1etties were begun four
years ago. They are on q larger scale
and more substantial than the famous
| jetties at the Mississippis South Pass,
an outlet which for over thirty years
has been the rivers commercial en-
trance. They are nearly parallel walls.
one about three and the other about
four miles long, lying over half a mile
apart and built in the shoaI water at
the juncture of the pass with the Gulf
Of Mexico. Their purpose Is to con-
fine and thus accelerate the rivers
current across a mud harbor about
three miles broad, so as to produce a
channel at least 1000 feet wide, with
a minimum depth of thirty-dve feet
The swift current which they have pro-
duced, aided by dredging, even before their
completion, has caused a tremendous
scour and has already made 50 to SIS feet
of water in some places where at the
beginning of the work the depth
was but a little over a mans head. To
make the uniform contract depth there
is still in several spots about 10 feet Of
mud to be removed. 1t Is expected that
the high water due within a few weeks
will sweep the remaining mud deposits
out to sea.
Probably few walls have ever been con-
structed under greater difficulties than
these %jetties. They are made of willow.
scantling, stone and concrete. Although
In some places they are not six feet deep,
and, although their greatest depth Is barely
10 feet, they will have cost s., 10000. Every
material entering into their construction
has been brought from distances of 100 to
500 miles. The jetties have no foundation,
but rely for stability upon their extremely
broad bases, being from 100 to $50 feet wide
at the bottom. In contrast to this great
width of base. the concrete Gaping which
forms the top of the jetties and which Is
the work receiving its finishing touches
this week is but a few feet Wide. The
| Gaping is n sea wall AZ feet wide and is
the only portion of the jetties not SUBJ
merged.
The wall weighs between two and three
tons per lineal foot. The submerged struc-
ture supporting this mass Of concrete IS
made almost entirely Of willow poles ana
brush. with the aid Of frameworks OF
scantling the willows were formed into
so-called mattresses; broad, Nat structures
resembling bed mattresses in form, each
about 2 feet thick, 200 feet long and vary
ing In width from IS to 100 feet. The
mattresses were sunk one above the other.
with the widest at the bottom and those
above uniformly diminishing in width as
they approached the surface. The top
most mattresses were uniformly IS feet
wide and on a level with the surface OF
the water. Heavy broken stone was
spread evenly over the mattresses to sink
them, so that a layer of stone rests be-
tween each Of these willow structures.
The greatest number of s-uperimpoeed matt
treSses was FIVE.