The Coconino sun., 1924-05-02


had passed through the strata IN
question and into softer material,
that the real bed rock is at a con-
siderable depth as mentioned in a for
mer u. S. geological survey report
on that vicinity.
Specimen samples of the samples
collected by the city and also sam
pies collected by the Santa lF'e's rep
resentatives, were submitted to Ray
mond G. Osborne, bureau of tests and
inspection, Los Angeles, with request
for such analyses and tests to be
made to determine it's suitableness
| for foundation for dam and also for
retaining water in storage reservoir.
The following report was received
from Raymond G. Osborne:
"Two samples of material taken
| from excavation of test pits of Flag
staff, Arizona, have arrifed from you
and / have made careful examina-
ton of same.
81 find that the samples show little
resistance to the passage of water
through them. AS a consequence they
would not hold water in a reservoir
under any appreciable head.
"For foundation purposes, | would
consider either material, if well COM
pacted, capable of sustaining loads up
| to four or five tons per square foot,
| provided, however, the material is
confined and not allowed to get wet.
This material would not be possible
as foundation for multiple arch
j dam.
| "Under a powerful glass the in
dividual particles are almost all shown
to be small crystals, probably very
| largely quartz. No colloidal material
was observed in the test specimens
and it can-be assumed that practically
none exist.
"This material is not satisfactory
for the purpose indicated"
All of the above information, am
alyses and tests confirm our report
and that of Mr.. Davenport, made YER
bally to the city council at an infor-
NAL meeting on February IL, 1924,
Immediately after our inspection OF
the site and material.
! The only conflicting report IS that
by John S. Eastwood, consulting en-
gineer, Oakland, California.
| Before any inspection of the ma
terial in the deeper test pits were
made at the suggestion of Mr.. Daven-
port, who later communicated with
Mr.. Eastwood, asking some prelimin-
ary estimates and advice on the feas-
ibility of a multiple arch dam as a
saving over gravity type or earth
filled dam. Later Mr.. Eastwood in
passing through Flagstaff stopped
over and inspected the site. Upon his
return to Los Angeles, at a confer
ence with Mr.. Eastwood in Mr.. Dav-
enport's office, our Chester A. Smith
and Mr. Davenport did not agree with
the conclusions of Mr.. Eastwood on
the bearing capacity of the material
or the character of the formation.
Mr.. Eastwood offered to furnish de-
signs and have a contractor build the
dam and furnish insurance under
Lloyds of London as to the stability
of the dam. We then asked Mr.. East
wood for a more detailed estimate of
cost and also data on stresses and
foundation pressures that might occur
under this design. Under date of
April Ia, 1924, a communication from
Mr.. Eastwood was received, in which
he states that a pressure of nine tons
per square foot can be secured uIKler
the plan that he had estimated upon.
This is still in excess of what we
would allow for foundation loading
for this material.
AS to the character of the material,
the assertions and assumptions made
by Mr.. Eastwood at the conference IN
. Mr.. Davenport's office, have not been
sustained by the geologists and chem
lists reports.
AS to- the insurance feature, this
would cover the cost of the replace
ment of the dam if it failed, but
would not cover damages to the town
railroad and other property, nor would
it guarantee that the material would
. hold water or prevent leakage under
the dam.
Mr.. Eastwood's estimate is $780,
600 for the cost of a 90-foot dam.
With the foregoing data, tests, an
alyses and consultation with eminent
authorities on the conditions, togeth-
! er with our personal Investigations
and conclusions, we recommend
e against the construction of multiple
arch or any thin arch dam in Schulz
canyon.
The location of dam in a canyo1
). from which the drainage flow
!, !, through a city, on foundation tha
is questionable, introduces an ele
> ment of danger to the lives and prop
erty in the city that is not commen
!. seurable to the saving in cost. Th'
7 recent failure of the Glenco dam il
Italy, in which over 500 lives wer
Z lost, is a warning to use careful con
sideration before locating dan
= where lives are in danger.
5 Assuming that the material woul,
I sustain approximately so foot hea'
g of water without appreciable loss du
:. to percolation, we have estimated tn
: cost Of a gravity type masonry dan
i that would impound approximate.
7 50,000,000 gallons, to be approximate
" $175,000. This allows for cut-of
S walls, additional foundation footing
h to prevent excess pressures when tn
S dam is either full or empty, and fo
g change in the present flow line il
~ Coh,,ly napvnu th at would hn nncnc ca y.