The New Orleans daily Democrat. [volume] (New Orleans, La.) 1877-1880, 1877-11-22

aluvion deposit which would ir.evitably occur be-
tween the breastwork and tne land, and which
would force out the breastw ork in spite of all the
braces that could be placed to secure 1t to the
shore.
They 10 on to say thst the footing for perma-
nent work cannot be attained, on account of the
great depth, which in places exceeds 15O feet. To
reach that depth gradual process is necessary,
by lining the edge Of the bank with materials
that are not susceptible of being washed away by
under currents, and nothing they believe can pct
ter serve this purpose than fascnes In connection
with cribwork. Where caves occur, like at Bora-
puru street, the entire curve should be dredged
al low water as deep az possible Round piles
should then be driven every ten feet, in line. in
every direction; willow mattresses should he laid
at right angles to one another, should be sunken
into the hole formed by the dredging, and should
be continued until the top mattresses shall have
reached the height Of Che high water mark.
The piles are to be driven at an inward incline
of from fifteen to twenty degrees to syoid, as
much as possible the tendency which piles
driven vertically have of leaning outward. The
piling should also be made secure by means of
crib work composed OF round timber laid longitu-
dinally and crosswise; two pieces to be used, one
within square. At each intersection the longi-
tudinal PIECES should be made fast to the cross
pieces by means OF rack bolts.
THE Orb WORK.
thus built, being perfectly independent Of the
piles, would be at liberty to slide down with Che
fascines, for the sinking Of which ballast can be
used. Within the space between high and low
water marks two rows OF cribbing should be
placed, one about midway aud the other on top
Of the last course Of mattresses. In this man
ner the whole space of the cave shall be filed
with substance much lighter than the alluyion
and liable to be washed away.
They say, further, that this system has the
double advantage Of securing both temporary
and permanent protection temporary, mas
much as 1t offers q quick protection, and perma-
mar W shan hn huI hay VIC
undermined the bank at q greater depth than
that reached by the lowest course OF mattresses,
and the whole Of the fascines and crib work shall
have suuk out of sight, and the same process
applied year after year. with the exception OF the
| dredging, until the uppermost layer OF fascines
| shall have reached the very bottom Of the river
| or passed the layer undermined by the current,
| then the bank presenting nothing but sub.
| ton will have become permanent and no more
caving or land slides will oconr. II will take only
| a few years to reach the bottom.
THIS THEORY
| the signers OF the document say they have drawn
from observations for the last thirty-five years
on oaving banks. That these observations have
been principally made at a csving point opposite
the French Beef Market. This point, they add,
situated midway in the bend Of the river, would
have long ago been washed away but for the tenn
porary protection given 1t at high water bya
triple row Of ships lying along the wharf. Be-
tween these ships and the bank there was
hardly any current, so that the water coming in
there overchargedwith sedimentary matter depos-
tied . sort Of artificial batture which was being
continually undermined by the current Of the
river flowing at depth below the keel Of the
ship; that the water at its high stage
ACTED AZ A SUPPORT
to this over hanging bstture, but when the
water receded the artificial batture went down
with it, and 80 did everything to which the bat
ture itself was support, that is the wharves,
etc. At this point the piles, stringers, eto., OF
the wharves were left in their sunken condition
The garbage Of the city and ballast were then
thrown into the hole and new wharves have been
built from year to year.
GEN. BLANCHARD
also visited the commission and gave his expert
ence. Gen. Blanchard said also that in his opin~
ion no cheap method should be adopted to &C.
cure the banks Of the river. His proposition
would be to revet the banks OF the river with will
low mattresses or fascines, secured by galvanized
wire gauze. He estimated that the cost OF such
a work would be 100000 per mile.