The Coconino sun., 1925-12-11

supply Of all the developments there
particularly for the well-known E.
I Tovar hotel. Two large lumber mills
are also supplied with water, so that
4 domestic use is a relatively small per-
U centage of the total. The percentage
\ Of use Of water il as follows:
Railroads, AS per cent; lumber
4nnills, 80 per cent; domestic consump-
/ tion, 20 per cent; business consump-
ton, 5 percent.
| About ten miles directly north OF
| the town are the San Francisco noun
/ tain peaks, which were originally
parts of one volcanic cone which rose
to a height 5000 feet higher than the
/ present elevation, with the core at the
west end Of what is now known as the
interior valley. The eastern wall OF
this cone was broken out and, CEN
I turies later, the interior valley was
| erodedl over lengthsof three miles by
glacial action, leaving heavy moraine
deposits, which cover the floor of the
valley to great depths. These de-
posits are largely coarse material,
with much disintegrated lava. The in
lterior valley narrows at the eastern
end; it has a drainage area of APP
proximately five square miles above
| this narrow neck The elevation of
the valley at the narrow point is
about 5000 and the surrounding peaks
are approximately 10000 feet above
sea level.
The average rainfall at Flagstaff is
about % inches per annum, which is,
roughly, twice that at any other
point in the state. This is due to the
San. Francisco mountains, on the
southern slopes Of. which the town is
located The warm air currents
strike the mountains and, being de-
Elected upward, are cooled and the
moisture precipitated. There are two
wet seasons, one in summer, the other
/ in winter
There is no means of estimating
the precipitation on the mountain, but
there is no doubt that it is greater
than that recorded at Flagstaff. Both
winter and summer storms are more
severe in the peaks. "A large part of
the precipitation is snow which ac-
cunfulates to great depth in the in
terror valley, lasting well through the
summer months.
The glacial deposits in the interior
valley serve as an ideal collecting
area, retaining a large part of the
precipitation, which breaks. out in the
form of springs. The maximum flow
from these springs occurs in the
month of June, when the snow is
melting. It drops off to its minimum
in the fall after the snow is melted
and after prolonged dry spells,
The location of the springs gives
them d natural protection against poll
luton. The quality of the water is ex-
cellent, very low ir- hardness and
mineral content, so that these springs
are ideal for municipal supply.
In 1898, pipe line was installed
from them to small reservoir above
the town. This became Inadequate as
demands increased and, in 1914, the
common interests Of the town and the
Santa Fe railroad resulted in an
agreement between the two whereby
the railroad company financed the
necessary improvements and the town
agreed to operate and maintain the
structures.
The water is collected from the
springs by small criblike structures
set over screen, boxes, and in some
cases by tunnels with. timber lining.
Gathering lines from these spring de-
velopments converge at a point near
the mouth of the valley, where a weir
box Of concrete is installed.
Collecting lines are of slip joint,
riveted, asphalt-coated steel pipe; this
material was selected for its lightness
and durability. Some of this pipe has
been in service for close to twenty
years and is still in good condition.
From the weir box at the springs to
the reservoir there are now two vitri-
fled sewer pipe gravity flow lines, one
consisting of s, and 6-inch pipe, and
the other of 8 and 7-inch pipe. Com
crete sunps with overflows are
spaced along these lines about 1000
feet apart. The length of line is about
Is miles.
Lines are laid partly with mortar
joint and partly with asphaltic COM
pound joints; this was done in an at
tempt to prevent roots from growing
into the pipe and filling it with a
fibrous matlike growth. The trouble,
however, is serious with both types
Of joints and each year the line must
be opened and cleared of these inn
pediments at certain places.
The first reservoirs. was of 2,500,000
grade carrying from per cent to A per
cent and the second line, constructed
in 1914, closely parallels the first.
The first reservoir was of 2,5z0,000
gallons capacity and, in 1914, large
reservoir of 50,000,O0O gallons capac-
ity was put into service. This reser-
voir has sloping sides, double floor
and slopes, with -proofing mem
brane between the layers.
It is Iiow1found that the storage is
not sufficient to provide all the water
desired through the long dry spell.
Storage basins alone will not remedy
the situation, as there must be enough
pipe line capacity to fill the basins
quickly. when the spring flow is ample
for this purpose.
The quantity Of water required at
present is an average of approximate
" 1000, 900 gallons per day when use
is not curtailed. The future require
ments, it is expected, will increase at
the rate of about 2 per cent per year.