Lincoln County times. (Jerome, Idaho) 1911-1919, 1912-03-07

onstration Train Lecture
The greater part of the land in III,
west would be practically worthless
without water with which to irrigat'
1t, yet there is far less attention
given TO the measurement OF thi:
water than there is to the measure
ment of the land. Under the Carey
Act the land is sold to the settler
for so cents per acre and would
hardly be worth that without the
water. while water costs the settler
all the way from s25 TO 500 per
acre.
Miners Inch
Water was first used in Idaho and
other western states for mining pur-
poses. the common method OF meas
urement being called the miners
inch method The miners inch was
the unit upon which such measure
ment was based being the amount
of water that would flow through a
sharp edged orihce one inch square
tity called for by miners inch,
however. varied in different states.
due to the fact that the pressure over
the oriice was not the same.
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 Idaho
legislature in 1899. II is commonly
known as the second foot" and rep
resents the flow of water which will
exactly fill q vessel containing one
cubic foot each second of time for
as long a period as it is allowed TO
flow. Hence. q flow of one cubic
foot per second delivers 50 cubic feet
per minute. or $500 cubic feet per
hour, or S6.4O0 cubic feet in a day of
twenty-four hours.
1t is found that one cubic foot per
second equals a flow of almost exactly |
90 Idaho miners inches. or $50 gallons
per minute. A fume one foot wide /
and one foot deep. if filed with water
that Is flowing at the rate OF exactly |
one foot per second. will carry one /
cubic foot per second. and otner
fumes or bitches in the same proper /
ton. The quantity discharged de.
ponds upon the velocity of the flow /
and the area Of cross section of the /
advancing stream of water. These /
two factors are taken into consider /
alton when determining the flow of
large streams and canals. it being |
only necessary to determine the area
OF the cross section and the average
velocity. which two amounts multi
piled together gives the DISCHARGE.
The cross section is found by multi
plying the average depth of the
stream by the width The average
velocity is found by measuring the
rate OF the same either with floats
DR. with current meter especially
constructed for the purpose. A close
approximation of the velocity can be
secured by noting the time that is
required for surface float to ad-
rance through 100 or more lineal
eet OF the ditch. This gives the sur
ace velocity, and to find the average
one must multiply the sur
ace velocity by 8. since the aver :
lge velocity is that much slower !
nan the surface velocity. owing to I
he friction on the sides and bottom {
4 the channel.
Acre Foot.
Where large volumes of water are
be considered the expression of i
he amount in cubic feet would in d
olive the use Of such large numbers t
hat the same would be cumbersome. a
a order to simplify these expires.
Ions the term "acre-foot" is used. $
hitch represents enough water to v
over an acre one foot in depth or 9
5000 cubic feet. The use of this !
srm has the additional advantage of :.
eing easily compared with the acre =
ge; as for example. a reservoir con- n
lining 10000 acre feet of water V
ould furnish a depth of two feet il
IT $4,000 acres of land. A cubic Il
'ot OF water per second flowing con- c
nuously for twenty-four hours fur
shes almost exactly two acre feet n
water ID
ydraulie Equivalents Which Will be y,
Found Useful to lrrieators. :.
l. Idaho miners inch EQUALS an n
'oximately l.50 of a cubic foot per T
'cond. or nine gallons per minute el
?. The flow of cubic foot Der al
cond equals approximately 80 min W
S inches. or $50 gallons per min. W
e. n;
3. One cubic foot per second for ~ ~
hours equals approximately . acre =.
ct
4. One acre foot equals enough st
ater to cover an acre exactly W
OF in depth. or 43 $50 cubic feet Sc
.. One miners inch per acre for 81
0 days equals 3.s7 feet deep on the is
nd.
No D0uhf