Mountain Home maverick. [volume] (Mountain Home, Idaho) 1906-1911, 1911-01-05

inch as commonly used is variable (
quantity. Small quantities of water
may be measured by the miners inch
if the conditions be complied with, |
but since the head must be no more
than six inches the opening would
have to be of an impractical ZENITH
to measure large vol
umes of water accurately.
The miners inch measurement is
therefore impractical. Further the
miners inch is not the same in all
states, which fact adds to the con-
fusion.
The simplest method of measuring
water in a ditch is by means of
chip of wood floating on the surface
to determine the velocity. The time
it takes the chip to float a certain
distance. say 100 feet, is noted and
the velocity per second can be fig
ured. The chip will flow somewhat
faster than the body of water in the
bitches as a whole. Multiply the vel
ocity as determined by g viii give the
average velocity. Multiply the squire
feet of area of the cross section
of the ditch by the corrected veloc-
ity per second and the product will
be the discharge Of the ditch in sec
ond feet.
What is known as the Cippolelli
weir is used everywhere to measure
water for irrigated farms. This is
definite and practical way of mea-
surfing water and is the same in all
states. The weir is but one part of
the weir box. Many call the weir box
weir. The opening through which
the water flows is the weir and the
width of the bottom of it and the
depth of water flowing over are the
points that determine the discharge
The opening is trapezoidal, the sides
fiaring one inch from the vertical foi
every four inches of depth. Engin-
GERS have prepared tables giving tho
discharge of different depths of weir:
of different sizes. The depth of water
flowing over is measured. Then by
referring to the weir table one finds
the discharge. The measurement is
not taken right on the crest as th'
water lowers somewhat as it flows ov
er. but back in the box on STAKE
set on a level with the crest and bacl
at a distance twice the width of thu
weir. The width of the crest is tn
width of the weir as given in the tab
les. The ditch above the weir shouli
be straight for a number of rods an
in line with it, The velocity must b
reduced to such an extent that tn
surface of the water is smooth. Thi
p is done by widening the ditch jus
2 above the weir so as to make poe
( and the weir box serves this purpos'
The crest and sides of the wei
+ are leveled and the sharp edge is nj
= stream so that the water will flo
e over clear, there being an air spae
r between the walling water and tn
p weir. The water must not back Il
T against the weir and obliterate I'll
f air space as the measurement wi
Y not then be accurate.
s. The discharges of weirs are n
" proportioned to the depth of wat'
? flowing over For instance the di
It charge when the depth is four inch'
h is more than twice that when Il
IS depth is two inches. The discharg
S however, is directly proportional
s. the width. With the same depth
IS weir two feet wide Will discharl
r twice as much as one that is OF
IS foot wide
IS Professor f. d. Farrell gave an a
r dress on the common abuses Of
rigaticn. Many farmers irrigate a &c
p tam crop. wheat for instance, a &c
lie tain number of timec and at certa
IT dates year after year They do tn
If irrespective of the needs Of the err
A. in each instance Should the err
sr need water sooner than the set da
e. that makes no difference. 1t is fri
1t gated at the regular time Should
lie not need water, perhaps an exami
7s alton would clearly show, it is
ID rigated at the usual time just 4
rs same. The folly of such practic
IF is obvious for seasons will vary al
s. the farmer must of necessity pa
he judgment in each instance on t
n needs of the crop.
a Another mistake is that of app
Of ing too much water. This affects Z
ID quality. growth, the soil and the D
a. bility to disease.