The New Orleans Democrat. (New Orleans, La.) 1875-1876, 1876-04-12
THE CITY LEVEES.
LETTER FROM THE CITY SURVEYOR.
bonnet Carre crevasse shoaiing Lake
POntcIIartraIn.
SURVEYORS OFFICE,
New Orleans, April 10, 1876.

J
Hon. f. A. Burke. Administrator of Improve
Dedr Sir-In your communication OF
the 8th inst. am asked my opinion with
regard to the present peculiar condition
OF Lake Pontchartrain in connection with
the Bonnet Carre crevasse and the
waters Of the Gulf; and to submit the
probable damaging results Of heavy
| gale in OverflOwing the rear Of the city.
| l consider the situation serious one,
and in the present condition Of many Of
the back levees no time should be lost in
raising and strengthening them.
! The effect of the Bonnet Carre Gre
vase is clearly proven to raise con
siderably the normal level OF Lake
| Pontchartrian, because the capacity Of
the RigOlets is not equal to discharge
the Mississippi water as fast rs it comes
| in, when the river is at anything like
food height. And these difficulties
must increase in proportion to the rise
Of the river and the consequent increase
Of the volume Of water to be discharged.
| This Is the third successive season
that the Bonnet Carrc crevasse water has
poured into Lake Pontchartrain, besides
the crevasse Of 1871, and it is contended
with good reason that the deposits from
muddy water is tending to shoal the
lake IF this be true it follows that the
sened each year that the crevasse water
is received into it, and of course, the
same volume passing through the lake
this year in given time will cause the
water to raise cOrrespondingly to q
higher level than the years preceding.
The notes in this office snow that the
average level OF water in Lake Pontch-
artrain during the crevasse period Of
1874, when not disturbed by winds, was
r. RI ho tf,l, e,t al
ard height Of Metairie Ridge, in 1875
four feet and one-tenth, and up to the
present time Of this year. three feet and
four tenths, proving that the theory Of
shoaling is not without some founda-
ton for correctness.
OF course the same bulk Of water did
not pass through the crevasse each Of
the above mentioned years, but near
enough 50 to enable some idea to be
formed Of the enlarging effects Of the
crevasse upon Lake POntchartrain in
elevating the water line. And to sus-
tain the fear that each year that the
crevasse remains unclosed, adds to the
danger OF q disastrous overflow in the
rear Of the city, whenever the winds
should so combine as to produce it.
In the present situation Of Lake Pont-
chartrain, with the water nearly two
feet above the usual level, and already
hll1nS all the swamp basins contiguous
to it, it can be easily conceived that
furious gale, similar to the one Of June,
1871, would so hold in check the accu-
mulating waters Of the crevasse, that it
would only be question of the dura-
ton Of the storm to carry the water
bodily over the natural barrier Of Me-
tairie Ridge, and thus mundate almost
the entire city.
1 would, therefore, earnestly recon-
mend that all Of the back levees, which
are now too low and weak, should be
siren gthened and raised at least to the
standard level Of Metairie Ridge.
/ herewith have the honor to transmit
memorandum showing the points
where work is required, and the nature
and probable cost of the same.
Respectfully submitted,
.Signed) THOMAS S. HARDEE,
City Surveyor.