Baton Rouge tri-weekly gazette & comet. [volume] (Baton Rouge, La.) 1865-18??, 1868-01-16

Such pockets would act upon the rivers
automatically, and greatly assist in re
straining their floods, 50 that u less height
Of leyees would answer.
This plan applied to Spanish Lake, Lake
Bistlneau, the Buioau, and the Cnddo
Lakes, so as 10 ralse the water few feet
on each, would probably restrain all The
floods Of Red River; but it would not ma
terially benefl IT'D navigation, rs tho sur
plus wnter would drain off too quickly to
answer that end. sH
| think that have proved all that
asserted III regard 10 tho lakes above and
near Shreveport, but it will be said that
they, as well rs many others fill now with
every considerable rise In the water, aud
hat they ulI act reservoirs in their
present condition.
Tins IL true in QUO sense, but while they
now act ~ reservoirs, they fill with the
very water which the channel Of the river
could easily carry oh ! mean by this,
thlt while they are filing, the river is Mt
bunk iull, winch it would be it thev did
not receive the water, and thus Il large
| volume OF water Ii retained in them which
| Tho river could he nude to carry Oft, before
lhe food commenced.
In u word these reservoirs now fill pre-
| matureiy, the food sweep. through them,
the river below becomes golgcd, aud up
| stream currents arc Produced. Thus a. no
| aJl &c Of The overflow, Is tho river perform
ing well its functions.
Nearly, II not all VI the lakes in the val
ley of Red River appear to have been
| merely low rwuInps through which the
creeks or bayous which drain the border
ing hills, found their way to he main
stream. Most Of them deliver nearly all
! their water TO the river, ut It's low stage,
through outlets at their lower, end, and re-
celve water from the river above, us 1t
Rises, through various channels, and di-
lechy over the river banks. The tall in
the water surfaces of the bayous leading
W the lakes from tho river above, as well
as the tall III the surface OF the land IL very
rapid, and the outlets from them into the
RIVER below, exhibits the Same feature of
rapid descent.
The effect Of these lak,s upon the river,
iB Of II threefold character. Their first
Effect is TO delay the rise Of the river; tor,
ncting rs reservoirs when they are not
wanted, they receive water through the
bayous leaJiug to them, and thus prevent
the river from rising rapidly in their i'm
mediate vicinity.
Thor second effect, Us will be explained |
presently, Is 10 accelerate the passage OF !
the floods through the swamps and down |
the valley; furnishing the influx below,
which as already shown, chokes the river
channel and produces the undesirable up
stream currents.
Their third influence upon the river, is
to Proiong the overflow on the lands be-
low them. This is evident; for having
caused, at the outlet, IA material delay in
the rise Of the food there must result a
corresponding delay in its subsistence, es
pecInily as The river channel is choked at 7
the tIme the lakes are draining
Ihe!r second effect, as ntimated, needs
SPECIAL explanation. To make it clearly
understood bow the lakes accelerate the
passage q the Hood down the valley, we
viii, suppose That the riyer divides into
two equal parts, forming OF en- bracpg an
island, suy ten miles long, with channels
On each side al he head aud foot of the
island, Of equal capacity, and that the
general fall Is one foot TO the mile, or ten
feet in the ten miles. In ono Of the chan
ucls tie fail is regular, aud tho dimen-
SONS are the same Jhroug bout its length;
uui the other has 4 lake in its route, say
eight ml - Tong and one hundred times as
wld" Us the channel. This lake is sup
posed to DO Of sufficient capacity to main
tain Il noarly level surface. uotwithstund-
Ing the entrance Of tho water above, and
It's exit below. Thus nearly the whole fall
OF The water from the head Of the island
to it, foot, is TO bc effected by the two re-
naming miles of channels; one mile of
channel lending from the head of the
island into the lake with nearly five feet of
tail, and Tie other mile leading from the
lake To the foot OF the island with five
feet Of fall.
Now, is clear, that the channel on the
Iuko eide OF the island will carry down
much more water than the other; for its
upper ard lower miles, with the given
section, have each % fall of five feet, while
the other'chnnnels of like section has on
corresponding lengths, a fall Of only one
foot.
II, now, we crook the latter channel in
such n manner that it will traverse three
times the distance Of the lake route, thus
producing in the tortuous channel a more
gradual fall, and therefore less rapid cur
roHt, we shall make our case sufficiently
analogous to the condition of Red River
with its lakes. We have only to reverse
the consideration and we SEQ that the lake
route, compared with the tortuous main
stream, must convey food with acceler-
ated speed. The same threefold effect is
produced by the swamps along the Red
and Mississippi rivers. They first act as ,
reservoirs, when they are not wanted rs
such; then they accelerate the passage OF
lhe water. changing the local slope of the
river 10y preventing its rise above, while
they raise it below, and finally, continue
the overflow below them. The local slope
Of the Mississippi was at one time changed
between the head Of the Yazoo swamp,
ana its outlet heipw, over two feet, by
this means. he local slope of Red Riyer
from the head ~ he raft to Shreveport,
Is chang itJcru feet, and between
ohrereF atd Grand Ecore, not far from
twenty by he same cause. 1t is a
faijae} rI4n, o." ~oppose that these lakes
t''d s"amP- produce 0 sensible effect upon
stt a4T2 of tho river below them.
therefore, conclude that i'll their natu-
-hi .""snll"h. The lakes and swamps ad-
o'"l"g our 'lFers not only do not coun-
eNact their floods, but that they exert a
Injurious Influence. Neverthe-
eSa by the adoption of proper measures,
hey may be made to restrain overfows
= Jogether, at least IN Rod river, if not in & &
'thers; while in the others, they can GER
ain y pc made to render much assistance
q the attainment of the great deslderatum
by the adoption Of the plans which |
m ,iaa rf,rit, -. ma 1T /.