The Rock Island Argus. (Rock Island, Ill.) 1877-1885, 1881-04-23
IMPROVEMENT.
The Recommendation of the
River Commission.
Their opinion as to what
should he done.
snacial mention CT the Rock Island
Rapids.

The report of the Mississippi river com
mission to congress the present year has
been completed. 1t is very important
document and of especial interest to Rock
Island and vicinity, as it deals with the
Improvement of the river at this point.
II was the intention of tie members
forming the commission to inspect the river
below St. Louis, but so far the examination
extends only to the mouth of the Illinois
river
The report is as follows:
I'm pursuance of this amended project
the commission visited the river between
CT Paul and the mouth of the Illinois
river in the early part of the year, but the
water was too high to afford proper oppor-
tunities of observation. Subsequently in
October, during an exceedingly favorable
period, this tour Of inspection was repeated.
THE DRAINAGE BASIN
comprises 80, 719 square miles above St.
Paul, and SO, 800 square miles on the right
and 4S. 1876 square miles on the left bank
from that point to the mouth of the Illi-
nois, 25 miles above the mouth of the Mis-
sour. The immediate valley has an aver
age width of about three miles, often, how
ever, of double this, as below Muscatine
and again crowded by the hills on both
sides, as below Rock river.
The rocky limits of this valley have been
filled in some places 100 feet deep with
sand and gravel in which the present river
excavates and shapes its bed in curves to
which the bluff are tangent, but never
reaching the bedrock below. To these
general characteristics there are two cXcep-
tons. one at Rock Island and one at Keo-
kuk. Here the line of least resistance
seems to have been through gorges in the
adjacent hills instead of the glacial drift
obstructing the main valley. In these To-
calities are, therefore, found rocky beds,
forming rapids which obstruct low-water
Similar formations exist at
Fountain Bluff and at the Chain-o Rocks
below St. Louis
AT ROCK ISLAND.
A channel four feet deep and two hun
dred feet wide at extreme low water has
been cut in the rock, while at Keokuk has
been built a canal, affOrding a minimum of
eight feet.
The entire valley, except the sand ter
races, is subject to flood inundation. The
river courses from side to side, bed of
shifting sands and gravel which leaves its
water nearly free from suspended matter
The changes occurring in the channel are
constant, although not so rapid as in the
lower river. They are produced and
measured by the force directly applied to
the material of the bed by the motion of
the water.
The complications and uncertainties at
tending the Improvement of sedimentary
streams, from the prolonged and even in
definite suspension and transportation of
solid matter and from the instability of the
banks constructed thereby are not found
here. On either side of the main stream
are sloughs, open at both ends, and also
lakes, which are without outlets, except
during floods. These lakes are sometimes
of great depth. The sloughs give favor
able opportunity for improvement, as they
enable the engineer to control the force
which he proposes to use in
DEEPENING THE MAIN CHANNEL.
Some of the tributaries sweep in large
quantities of sand, forming a lake-like
and depth above, with slight fall,
and a steep, uncertain and difficult channel
below
The following factors enter into the
regimen Of the stream. The length from
St. Paul to the mouth of the Illinois river is
645 miles, and the fall $50 feet, giving a
mean slope of 432 foot per mile. The
minimum is above the tributaries and
rapids as 1872 foot at Waconter, aboue the
Chippewa river; 1913 foot at Prairie du
CHEN, above the Wisconsin river; 1877 foot
at LIE Claire, at the head of the Rock
Island rapids; 1856 foot at New Boston, above
the Iowa river, and 256 foot at Montrose,
ut the head of the Des Moines rapids, and
the maximum below the tributaries, as
$50 foot, 500 foot and 663 foot, between
Chippewa and Winona, and 533 foot at
Cquawka, below the Iowa river
From this statement Lake Pepin and
the Rock Island and Des Moines rapids are
omitted, being considered extreme cases.
The low water velocity may be stated
ut mean at one mile per hour. In floods
it increases to about three miles per hour.
The conditions, briefly described, are
of river well adapted to the
abors of an engineer
The present condition of the river
loes not afford a navigable depth over five
,eet for sufficient part of the year to jus
ify the construction of boats of greater
lraught. Even this depth for long part
IF each wear is not found above Keokuk;
md during such times boats of sufficient
dimensions to be economical as freight
,arriers are laid up and replaced by light
lraught towboats and barges, the former
drawing from % to feet, and the barges
rom to feet. Lumber RATS draw
rom is to 10 inches, but require wide
straight chanbel,
ECONOMY IN TRANSPORTATION
S largely dependent upon the capacity of
he carrier, which increases in more
apid ratio than the draught or cost of con-
truction and operation. Barges on the
upper river built with limit of draught
If five feet, carry about $4,000 bushels of
srain, while those used below Cairo, where
depth of eight or nine feet can be OBJ
aimed for large part of the year, carry
1000 bushels on five feet, $4,000 on
even feet. and 10000 on eight or nine
eet.
1T may be safely stated that the present
appliances for this commerce are designed
o fully utilize the navigation now afford
d. and are limited and impaired thereby,
nd that the requirements of an economi-
al and safe system of transportation will
lot be secured with less that six feet of
water from st. Paul to st. Louis through
ut the channel and throughot the year
sCFTla he Il