Evening capital news. (Boise, Idaho) 1901-1927, 1916-09-20

vague. "A
We believe the thickness of the floor
that is provided for the spillway. l. 9,
6 inches, to be inadequate. The speci-
fications provide that the spillway is
to extend a suitable distance toward
the river and terminate at point fat
enough away from the structure to 4
prevent any damage to 1t from back
wash" This also Is indefinite as this
important dimension Is not definitely 1
stated.
A cut off wall is to be constructed
at the western end Of the dam which
| Is to be feet thick, extend into the
dam a distance of feet and to be
carefully Joined to the solid rock OF
the limestone cliff. This wall Is in
adequate.
| We assume that In addition to in
sisting on the adequate protection OF
your city that you are anxious to as
sist and cooperate in the proper de-
velopment of this project which would
be of general benefit to the state OF
Idaho and to yours community. In
order to accomplish this 1t would be
necessary in our judgment to make
further field investigations to deter
mine whether 1t Is preferable to COM |
plete the Mackay dam. utilizing the
material already in place, or to erect
a structure at some other site. In
either case plans and specifications in
greater detail should be prepared.
This problem is an economic one and
| it would be necessary to make COM
parative estimates. There has been
great advance in engineering science
relative to arched dams in the last 10
years. and it is possible, II adequate
foundations can be found, that more
satisfactory and stable structure could
be built with economy at some other
| site.
The board of consulting engineers
appointed by the governor and land
board of the state Of Idaho to review
this structure, state in their report
dated Sept 2, 1910, relative to this
subject:
PROBLEM DIFFICULT.
I'VE believe it may be possible to
utilize in rome way the work and ma
terial which has been expended on the
present dam. Nothing could be done,
however towards the completion of
the dam to it's full height until a
Thorough investigation of the entire
foundation of the dam Is made by
means of dug pits, driven wells and If
necessary diamond drill borings. This
lis absolutely necessary and should
have been done in the first place. 1t
is possible that this investigation may
show that it would be cheaper to throw
away the work already done and seek
a new dam site than to make the pre-
sent dam safe"
They also state in their conclusions
I'VE believe that it may be possible
to construct a lower dam and utilize
some Of the material and work done
on the present dam in such way as
to impound water in the reservoir to
depth Of so feet = = . The plans and
specifications for the dam, however,
would have to be carefully considered
and passed upon by competent engin-
GERS experienced in this line of work."
AS engineers we naturally are in
clined to assist in the satisfactory
completion of this project rather than
its arbitrary criticism, and We believe
that you have the same attitude. The
( problem is difficult. You have to deal
with a dam partly constructed upon
E bad foundation where bed rock has not
] been found. 1t has not been built in
: accordance with sound engineering
practice. In order that this project
should be- successful and be a benefit
To tne community, the Jam SHOULD not
2 only be stable in that it is not a men
s ace to the town of Mackay, but 1t
t should be efficient in the impounding
e of water so that the fertile lands of
: your region may develop. To accom-
= plish this 1t Is our suggestion that an
"a engineering board be appointed, con-
= sisting of a representative from the
e state of Idaho, one from the Utah
g Construction company and one from
a your city; that this board conduct an
investigation and agree on an adequate
method of procedure. With such an
a arrangement 1t is assumed that the
= state and the Utah Construction COM
h pany should pay for the entire cost OF
n the Investigations. The state owes
II this to the people who have invested
in these lands with it's sanction. The
=. Utah Construction company as owners
I Of this project have large sums OF
1 money involved. 1t would be unfortun-
4 ate to be forced 10 condemn the entire
| project on the basis of the plans ano
y specifications submitted and we de-
I sire to have this letter considered as a
1 preliminary report for that reason
L Possibly some solution of the problem
1 may be worked out along the lines
4 suggested.
Very truly yours,
]. B. LIPPINCOTT,