The evening times. [volume] (Grand Forks, N.D.) 1906-1914, 1906-02-20

The Cano and the Gigantic, the latter
including it's principal tributary, the
Gigantic. are to be cut off by dams.
The Trinidad will occupy the old
channel of the Charges river and the
Charges diversion. The Gatun will be
cut off from the canal by the partly
finished Gatun diversion, into which
also will be conducted the Mindi
river, which has not been gagged, but
which is a stream of considerable i'm
portance. The others are to be taken
into the canal. They must, however,
be temporarily diverted during the ex-
cavation of the canal; and in the case
of the Rio Grande this invoices a tun-
mel seven-eighths of a mile long. In
all the diversion channels together, the
amount of excavation and levee build
ing, with the necessary muck bitches
and riprap levee and bank revetments,
tunnels, ETC., cannot be less than TO-
900 cubic yards. In view of the facts
that in many cases the work is isolated
and the field of operations narrow and
contracted, that much special work,
such as revertment, is required, and
that the operations of excavation for
channels and entertainments for levees
are separate an ddistinct, and that the
material is not uniform, involving both
earth and rock, the unit prices will be
high.
The Cano and the Gigantic are to be
cut off by dams, lakes being thus Gre
ated which will overflow through spill
ways provided in the divide near the
heads OF those streams. In this scheme
four dams and three spillways are pro-
jected. The dam to close the Gigantic
will be about $500 feet long, that to
close it's main tributary, the Gigantic.
will be about 400 feet long, and that
to close the Cano about $40 feet long,
the height in each case being about rs
feet avobe tn eground, the depth to
which the foundations must be sunk
being unknown. A dam about 535 feet
long and rs feet high will be required
to close depression in the rim of one
of the lakes. These and the spill
ways are expensive works. Their To-
SAeAohso INV z hCtCi UCSu SAdullutu DN
behring's or exact topography, with the
exception of the Gigantic spillway.
Their cost cannot be accurately esti-
mated without further examinations,
but under favorable circumstances can
hardly be less than 100000.
The streams taken into the canal,
whose beds at point of junction with,
the canal are considerably above the
canal prism, are to be discharged over
masonry stepped aprons or throug'.
metallic discharge pipes, or these beds
will be sloped and lowered SO as to
prevent Objectionable currents at juno
ton points, The elevation above sea
level at which these streams reach the
canal is given in the foregoing table;
and varies from 10 to 10 feet. \ pro-
visional treatment of such important
features OF sea level-canal should rot
be considered. From the point of
view of thoroughness and permanency,
the sloping and lowering of the beds
SO as to prevent Objectionable currents
at junction points would not be good
practice. 1t may be surely anticipated
that the accelerated velocity down the
increased slope, unless it's bottom and
sides are lined with masonry, will
operate with destructive effect both on
the lowered channel and the bed and
banks of the canal. Metallic dis
charge pipes are not adapted to this
purpose on streams which are tor
rental in character and may bring
with their flood drift trash and bowld-
ers. The use of masonry-stepped
aprons must therefore be considered,
under the conditions presented by
most of these streams, as the only adj
visable way of bringing them from
high to low level. The construction
of these would necessarily be very
heavy and therefore very expensive.
AS in the case of the dams, the sites
Of these aprons have not been care
fully examined. and the estimate of
cost can only be a rough approxima-
ton. It is the opinion Of the commits
sion that the sum Of $3,50O,OO0, as
signed by the majority of the board
to the completion Of the diversion
channels, the construction Of the dams
and spillways, and the construction
Of these aprons, b inadequate, and
should be increased by at least So,
10000, which, with the usual 20 per
cent added for contingencies, makes
an increase Of $500, 900 ito this item
Of the estimate.