The Rock Island Argus. (Rock Island, Ill.) 1877-1885, 1881-01-05
OUTLETS VS., LEvEEs.
(Memphis Avalanche.)


sippi, by the plan proposed by 1ohn
Cowdon, the engineer whose memorials 70
che 45th congress attracted wide attention
at the time. Mr.. Fl. B. Herr OF the U.
8. Engineers Office. evidently one OF the
;ettvgadyocates, replied to Cowdon's letter,
cndeavoring to show cause why the plans
of Cowdon were not practicable at the
time proposed. In the Avalanche OF Dec
% Mr.. Cowdon replies to U. s, Eogineer
Herr, and fully answers the objections
As the matter of improving the ..Missis,
sippi is vital one to everyone we give
below the letter in full:
EDITOR AyALANCHE-Mr. I'll. b. Herr,
who I understand is in the United States
engineers office, stationed in this city, IN
an article published in the Avalanche OF
the 18th inst, after admitting that the
table compiled from Mr.. Begaurd's re-
port was correct, tries to explain away the
effect as shown by said table on the high
waters by and above the outlets named,
because sat such places the river was
higher than IN 1873.
I was fully aware Of the fact that Bon
net Care outlet did not make until 1874.
but in order to leave gap down for some
one to enter, as we used to catch deer l
compiled in the table the year OF 1878 and
as Mr., Herr has stepped in, will just
lay up the rails behind him by stating that
in 1873 the Red river was low. and backed
up several miles by the Mississippi, which
enabled the Atchafalaya to discharge
great volumes of water from the Missis-
sippi? The discharge OF the Atchafalaya
il 120, 900 cubic feet per second. or one
ninth the volume of the Mississippi river
below that point, when the greatest dis
charge at Bonnet Care was little over
81 900 cubic feet per second, or one-twslfth
the discharge Of the Mississippi river at
that point, This, taken in connection
with the fact that in 1878 the river, as
shown In the table referred to, at the
mouth of White river, lacked feet and 9
inches of being to high water marx;
when, as shown by the same table, in
1874, at the same place the river rose to
high water mark. This shows the reason
why the water from Vicksburg down to
the mouth of Red river was not high in
the Mississippi in 1878.
Now, let me ask, if, as was the case. the
Bonnet Care in 1874 lessened the high
water mark three to four feet at New
Orleans, and for $50 miles above, with a
discharge of 81, 900 cubic feet per second,
why should not the Atchafalaya. With
discharge of 100, 600 cubic feet per second
lower it in the same proportion TO Eicks
burg, distant $50 miles, aided as it was by
the outlet at Ashton. in Carroll parish,
1880 feet wide by 4 feet deep, and
another outlet, Diamond Island bend, in
Madison parish, SO, 600 feet wide by feet
deep.
l think that if the gentleman will con-
slider all these things, he will see that he
jumped into print little too quick, and
tor his further information, will refer
him and the many readers of theAUdlanche
to what was the opinion OF Gen.
Humphreys, the chief engineer of
the United States army, as to the
efficiency of the Atchafalaya outlet,
On page TIA of his report he says: In
the great food of 1914 the country below
Red river escaped, Tor the reason that
Red river was low, which enabled the
Atchafayala river to carry off the greater
part OF the surplus discharge of the Mis-
sissippi river This is just what happen
ed in 1878. In speaking of the high
water of 1850, showing the opposite eft
feet, on bage 176, be says: The St.
Francis and YazoO bottoms were badly
overlooked. owing to the heavy rains which
fell there before the Mississippi river rose,
which filed the swamps so that the water
could not escape through the crevasses to
relieve the river" For the same reason,
on page III. he says: The lower bot
tom lands were Ioverhowed. Below tie
mouth of Red river, the country Jared no
better, as the water pouring in from the
Red river exceeded the capacity of the
Atchafayala to discharge it. This ad
ditionai flow of water kept the creVasses
below discharging for four months"
Precisely as was the case in 1874. when
Red river rose high. oyerfowed the coast
below until relieved By the great crevasse
at Bonnet Care and the lesser one at
Monganza.
Now, after this clear Acknowledgement
by the chief engineer as to the great
efficiency aud benefit OF not only the |
Atchafayala, but other outlets. we fnd |
these government engineers asking money |
to close all outlets.
| can only discuss this subject 10 the |
light OF a great system; its underlying |
principles are these.
LET US MAKE THE CAPACITY FOR OUT- |
FLOW GREATER THAT THAN ACTUAL
INFLOW. THEN THERE CAN BE NO OVER
FLOW.
10 do this we most open outlets so as
TO enable the food of the river to reach
the gull level sooner than by the rivers
mouth. This will drain the country.
When, on the other hand, the Ievee and
jetty jobbers would dam the water up and
overflow the eountry,as all past experience
has shown.
The opening of outlets direct to the
gulf, as shown at Bonnet Care, increases
the angle of fall and the current in the
lower river. which draws the water off
from above so much faster that it cannot
rise as high as before the outlets were
made; when, on the other hand, TO close
outlets, and. as a necessary consequence
build levess. raises the water, decreasing
the angle sof fall, and thus slackens the
current, causing overhows.
Now Ter ns take some statistics: The an
nual rainfall of the entire Mississippi val.
ley is 85 trillien cubic feet, of which the
Red river shed is. say, ons.ninth. Wei
are told by the engineers that the maxi
mum volume poured into the great basin
at Cairo during such high water as 1858.
Or perhaps 1874, was ATS, 900 cubic feet
per second, and that the discharge of the c
at Carrollton in 1874 was :
100000 cubic per second. Here the inflow
than tho