Daily Davenport Democrat. [volume] (Davenport, Iowa) 1864-1874, 1867-02-22

not be built on either aide FOR less than at
two and half million to three and nalf
million liars.
The third plan, viz, by improving the
stural chinnvl Of the river. vii recon-
mend itself to all on accoun, Of he obvious
Advantages Of having an improvement, Of
'u's Kind free frnm all TO Il and sources ~
de'ly have already d serted the dill,
- ties ~ the way of nayi CATION on the zap
ii-. Between the chains there ere long
raches of navicahlv r ve-. VARYING 10 der'h /
rom feet ppNa-ds, the j faculties BEN,
ca.tiacd - tie cii,in- almost entirely. a lev
builders ana patches OF rock VIII cl can
ensiiy b. r rroved Occurring here and there
between them.
A. have 1lready remarked. th.aS tia.
D., tune has tot yet come when a CANA is
necessary in order 10 overcome the diff
cultles Of navigation on the rapids, nor is il
d iAcult to sec that even canal improve
ment would fail 10 confer all the benefits on
commerce that perfect improvement ofihe
river Itself would. have eosvsrsed with
. number Of persons INTERESTED in the nav.
iga,ion Of the Upper Mississippi, and they
oil admit that four feet Of water on the
rapids is al that is required. In fact, in
low stages, boats cannot carry more than
from three or four feet above and below,
and hence more than four feet on the rapids
is Unnecessary. As this depth can be had
more economically and quickly b. the plan
Of improving the channel thai in s-y other
way, and, moreover, as it gives all the facil
tiles that the present commerce demand. ]
am of the opinion that this il the plan that
should he adopted.
II, however, al any future time, the nav.>
CATION Of the river should be Improved SO
as to produce more than four feet above and
and below the rapids at low water, and con
sequentiy to require more than four feet on
rapids, | woulu recommend the adopt ion Of
some other plan, AS the amount Of excava
ton it that case Composing the river was so
improved a. to secure SIX ieelj would prob.
ably be so great rs to render its cost far
more than the construction OF canal. Bot
let me add that, whatever may be the ulti-
mate demands of commerce, OF the ultimate
plan that may be adopted to satisfy those
dcrnsOds, this improvement win not be
thrown away. 1t w.ilalways be useful, and
should, in my opinion. be made, even though
canal were 10 10 built 70 morrow.
There are many boats navigating the Up.
per Mississippi that never require more
than four feet, and for such this improve
ment Will, ut all times be ample besides, il
is probable that when more than four feet
has been obtained. in low water, on the bars
above, and below the rapids. the commerce
Of this river will he hey nd the capacity Of
any one canal 10 accommodate.
There are many advantages connected
wi h the CT annel improvement that do not
exist in connection With other plans, and
these must Ill have weight in deciding this
question.
II will be free. It will not require an an
nual appropriation from the General Gov
eminent to keep it in repair, and when com
peted will be permanent. 1t will not intcr>
ferr with canal improvement in case that
should, at some future time, become advise
able or necessary and, moreover, the ben,
cit arising from this plan will be fe,t - the
work progresses. Every patch Of rock rex
moved is tina. much benefit to navigation;
whereas a canal improvement can be Of no
benefit until completed The latter, howev
err, has one advantage, viz, in atfording safe
navigation in the darkest and atormiest
nights.
The principal objection urged against the
application OF the channel improvement ut
I uItSC IhpiuS - Wlt'iout SuOstautInt IUuUuu>
ton. II is feared by deepening tho channel
| TO four feet in low water, and widening it to
two hundred feet, will increase the capacity
Of the water way 10 such an extent as to
draw off from the pools above such m
amount Ct water Ms TO develop new dangers
where ttcy heretofore did not exist. But
/ by careful examination, one can scarcely
fail 10 see tina; this objection is ground.
/ less.
a, the upper or Smiths ch,in, besides
removing te. patches of rock that are
source Of difficulty, there will be a few
points Of the projecting lodges cut off, as
indicated on the accompanying map
The excaya,ed material can be deposited
below tie last cut in order TO check the ve>
locty ~ the current aud make il
conform more to the direction OF the chan.
mel AT this turn. Certainly this can
have no prejn4ica eject; the chan
mel is already deep enough, the difficulty be-
ing in making the sharp turns.
At Sycamore the cutting will be almost
entirely from the projecting lodes, and the
material can be used in closing the deep
pocket that runs off towards Mechanics
Rock, which produces strong cross current
and carries off an immense volume of water
from tie main channel. The amount Of
water cut I'll iTop tbs pocket viii more
than compensate for the Increased capacity
OF the new channel. he other cuts between
this chain and Campheli's arc so 81 ght as 10
render This consideration Unnecessary.
At Canpbel's chain there will be a long
cut, and the capacity of the new channel
here will Doubtless be increased, but the
current is not rapid, and by closing the
slough behind Campbelps Island (Which, as
+ have already remarked, is not used for
navIgstion) with the excavatei material. a
much larger volume OF water can be thrown
/ into Il THAI its increased ca ,acity can carry
off.
should have mentioned that by closing
/ the slough behind fuion's isla.d, some
! benefit would doubtless be felt on the raft
channel and ON st Louis chain.
At Duck Creek Chain We cannot com
pensate for the increased capacity Of the
nsw channel by closing up sloughs in its
vicinity, and we can accomplish the same
end by depositing the excavated material in
the river in the form Of a dam. and thus
throw .nto it any amount Of water that may
be necessary.
Al Moline Chain, the slough behind
Rock Island has already been practically
closed by the Moline dam, and. according
TO the testimony Of pilots, the depth Of
water on the chain has been increasing at
least ten inches. T. ere is no doubt but
that the removal OF a portion Of this reef,
AS it extends entirely across the river, will
affect. in slight degree. the level Of the
water for short distance above, aud may
necessitate tho removal Of few rocks
But the upper edge Of the reef where the
channel crosses il, slopes OF into deep
water, as may be seen by referring to the
accompanying profile Of the channel. In
making this cut the slope Of the water
surface will be lessened, and the area 81
the cross section increased. These are
variable elements that enter into the
problem OF discharge, and would prob
ably neutralixc each otter SO that the
velocity disch ,rged would remain SEM
sibly what they were before. BY
means Of . dam made Of the ex-avated
material, sufficient water can be thrown
into tho new channel TO more than com.
penstale for its increased capacity Of dis.
charge. The water way across this reel
~iil be increased in cross sectional area
some 800 square feet; but the material
taken out would make. il desired, . dsm
4