The Richfield recorder. (Richfield, Idaho) 1909-1931, 1911-12-14

less IN the past water meas
urement.
diners Inch-Water was frs
} used in Idaho and other westerl
states for mining purposes, the com
mon method of measurement beinl
called the miners incl method. Tn
miners inch was the unit upon which
such measurement was based, beinl
the amount of water hat would FLOW
through a sharp edged orifice on
inch square under a given pressure
The quantity called for by a miner
inch, however, varied in differen'
states, due to the fact hat the pres.
sure over the orifice was not the
same. The Idaho statute called fol
a pressure of 4 inches over the cen
ter of the orifice while III Montana
law called for a 6-inch pressure. This
variation resulted in 40 end of confu-
sion and as the miners inch was not
adapted to the measurement of large
streams its use has been %discontin-
ued for the cubic foot per second.
The cubic foot per second which
represents a definite tangible amount
that is easily understood, was ADOPT
ed as the legal standard for the
measurement Of water by the Ida
no legislature in 1899. It is com
monty known as the second foot
and represents the flow of water
which viii exactly fill a vessel con-
tanning one cubic fOu eacn secOad
of time for as long a period as it is
allowed to flow. Hence, a flow Of
one cubic foot per second delivers so
cubic feet per minute, or $500 Gu 3ic
feet per hour, or $1,000 cubic feet in
a day of "a hours.
1t is found that one cubic foot per
second equals a flow of almost ex-
actly so Idaho miners inches, or 400
gallons per minute. A flume one foot
wide and one foot deep, if filled with
water that is flowing at the rate OF
exactly one foot per second, will car
one cubic foot per second, and
other fumes or bitches in the same
proportion. The quantity discharged
depends upon both the velocity of
the flow and the area of sec
ton of the advancing stream OF wa
ter. These two factors are taken in
to consideration when determining !
flow of large streams and canals,
it being only necessary to determine
average velocity, which WI amounts
LlulllDlltU LOSCllCI SlNCS lIC Q4o-
charge. The cross section is found
Dy multiplying the average depth OF
he stream by the width. The aver
velocity is found by measuring
he rate of the same either with
'loats or with a current meter espec-
ally constructed for the purpose a
lose approximation of the velocity
,an be secured by noting the time
hat is required for a surface float to
through loo or more lineal
eet of the ditch. This gives the
velocity, and to find the aver
lge velocity n must multiply the
velocity by eight-tenths, since
he average velocity is that much
lower than the surface velocity, ow-
ng to the friction on the sides and !
'ottom of the channel.
While the above mentioned meth
are those used by engineers and
theirs for the measurement of large {
annals and rivers, this method is not {
to the continuous measure |
of small streams and bitches {
ecause of the time involved and the {
ability for error where the measure S
rents are not carefully made. 5
Acre Foot=Where large volumes '
L WdIeT dIe 10 U6 COuSlQeltQ tut a
of the amount in cubic feet {
'ould involve the use of such large !
umbers that the same would be 1
lmbersome. In order to simplify Il
expressions the term 'acre-foot o
used, which represents enough wa
sr to cover an acre one foot in depth L
1880 cubic feet. The use of this '
srm has the additional advantage o
7 being easily compared with the )
creage; as for example, a reservoir u
,ntaining $4,000 acre feet of water a
Guild furnish a depth of 2 feet for o
5 900 acres of land. A cubic foot c
water per second flowing contin- a
ously for "a hours furnishes almost II
Sactly two acre feet of water. a
Hydraulic equivalents which will Il
: found useful to irrigators:= "
1. Idaho miners inch-approxim- a
ely $50 of a cubic foot per second, {
9 gallons per minute. '
2. The flow of a cubic foot per
icond=approximately so miners L
ches, or $50 gallons per minute. a
3. One cubic foot per second for
hours-approximately 2 acre feet. p
4. One acre foot-enough water to a
yer an acre exactly a foot in depth s.
1880 cubic feet. q
5. One miners incn per acre for Il
20 days-3.9I feet deep on the q
nd. u
6. One miners inch per acre for u
20 days-5.95 feet deep on the land. D
Z. Five-eights miners inch per CT
re for 100 days-2.4S feet deep on rs
e land. "
8. Five-eighths miners inch per
re for $50 days-3.72 feet deep u
the land. &C
>. One-half miners inch per acre W
r 100 days-1.9S feet deep OF the y
nd. III
10. One-half miners inch per acre :.
r $50 days-2.98 feet deep OF the u
nd. ~
Weirs and Weir Measurements-C,
The most accurate, practical and -,
onomical method of water measure -,
hat has been devised for the
S1ramant of cOmDarafivpIv small -