Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1900-03-07
BIG SANITARY CANAL.
Description of the Channel Re-
Gently Opened In Chicago.
ITS BUILD, COST AND DIMENSIONS.

Rock Description of Controlling
Works For Regulating Flow of
Water-TotaI Cost Amounts to $685.
6o5,Go1 Machinery For Excava-
zion.
Two ends have been sought in the
planning and execution of the sanitary
canal which was recently opened in
Chicago-the primary one of protecting
the city's water supply from pollution
and the equally important one, in the
opinion of many, of supplying the first
link in a chain of waterways that shall
finally make it possible for deep draft
vessels to pass from the eastern sea-
board of the country TO the gulf of
Mexico via Chicago.
In its sanitary aspect the canal is
designed to furnish n continuous flow
of water from the Chicago river, into
which all the sewers of the city will
soon empty, into the Desplaines riv-
er at Lockport. This flow will be 20
600 cubic feet per minute for each
10000 population in the sanitary dis
trict, which comprises practically all
Of the city north of Eighty seventh
street and several suburbs. According
TO the calculations of the special state
commissioners, the population is at
present 100000, and the canal will
carry without difficulty 100000 cubic
feet.
About half the canal is through solid
rock, and here the law has required it
to be made of sufficient capacity to ac-
commodate COO, 900 cubic feet per min
the channel will be enlarged in the flu
ture to accord with the growth of pop
ulation. The full capacity of 100000
cubic feet, therefore, will provide drain
age for a population of 100000 says
the Chicago Record. The cross sec
ton in earth has n width of 40 feet on
the bottom, the side slopes being two
horizontal to one vertical. AS the
depth of the canal throughout is to be
% feet, the width at the water line
throughout the earth sections will be
19S feet. In the rock the sides are
made vertical, and the width is 16O
feet. Velocity in the canal, according
TO the law, must he not more than
three miles per hour. For navigation
purposes these general dimensions will
provide ample room for the largest
vessels afioat on the lakes.
Chicago connection of the canal with
the river is by means of the south
branch, at ROby street, about seven
miles from the mouth. In addition 20
the canal proper, the sanitary trustees
have decpened the river TO 90 feet
throughout, except at the tunnels, and
have constructed an expensive ''by
pass" between Van Buren, and Adams
streets in order to provide sufficient
flow. At Lockport, the present termi-
nus of the canal, a 'windage basin"
for turning about ships has been con-
structed, on one side of which are the
elaborate controlling works for regu
lating the flow of the water.
These works consist of seven sluice
gates of metal, each 80 feet wide and
having a vertical play of 20 feet, and
a bear trap dam, 1G0 feet wide and
designed TO move II feet vertically.
This dam is essentially two great met
al leaves hinged together at the top,
making huge V with the apex upper
most One leg of the V is free TO move,
and the admittance or withdrawal of
the water under the dam raises or low
ers the structure. The cost of the con-
trolling works was S261, 80.
In addition to the main canal, which
has cost S1S,31S. COS, the sanitary trus-
tees have provided a new channel for
the Desplaines river 1913 miles long ana
built about 10 miles of leveeS to keep
out flood waters. This auxiliary work
has cost $1,0O0.156. From the control
ling works to Joliet channel has been
built for the water from the canal,
costing $500, 126. The improvement of
the Chicago river has used S53I ,9I5,
and bridges have added S2,611 ,34S
more. With miscellaneous items the
construction total foots up 500, 693 OH.
Administra ton, right of way, capital
iZatiOn for maintenance of railroad
bridges and general account items
bring the grand total cost of the work
TO $50. 52J, 691, all of which has been
expended since the beginning of the
excavation in 1892
In the excavation of this channel
there have been removed 2S, 800, 900 Gu
bic yards of glacial drift" (all meteriaI
everything BEDROCK and 100000 cubic
yards Of solid rock. besides the build
ing of 3SO.05O cubic yards of retaining
wall throughout the sections where the
channel is partly in earth and partly in
rock. For carrying on the excavation
OF these enormous quantities machin-
cry was designed OF a magnitude and
efficiency undreamed of before. The
great cantalever hoisting and convey
ing machines and cable ways used on
the rock section took out on the aver
age 21.365 cubic yards of rock in June.
1895. requiring the use of eight tons of
dynamite. Machinery of this efficiency
has never been known before in the
history of the world.