The Idaho Republican. [volume] (Blackfoot, Idaho) 1904-1932, 1912-01-26
ately 1-50 of a cubic foot per second,
Or 8 gallons ner minute

alSiy LOU OI u CUBIC loot e SecOn(
!. or 8 gallons per minute.
!. 2. The flow of a cubic foot DC
second-approximately SO miner
inches, or $50 gallons per minute.
3. One cubic foot per. second fo
"a hours-approximately' acre fee
4. One acre foot-enough water t
cover an acre exactly a foot in dept
or 1850 cubic feet.
5. One miners incn per acre TO
100 days-3.9i feet deep on tn
land.
8. One miners inch per acre TO
$50 days-5.95 feet deep on the land
Z. F~ive-eights miners inch De
acre for 100 days-2.48 feet deep OF
the land.
8. Five-eighths miners inch pc
acre for $50 days-3.72 feet dee
on the land.
y. One-half miners inch per acr,
for 100 days-1.98 feet deep on tn,
land.
10. One-half miners inch per acre
for $50 days-2.98 feet deep on the
land.
Weirs and Weir Measurements
The most accurate, practical and
economical method of water measure.
ment that has been devised for the
measurement of comparatively small
heads of water is the weir measure
ment. The weir consists essentially
OF a thin notch of a specific shape,
which the water is caused to flow
over. The amount of flow depends
upon the depth of water flowing over
the crest, as the bottom of the notch
is called. The weir has been used for
the measurement of water for hun
dreds of years and the method of its
installation and the discharge of wa
ter over, it have both been worked
out SO carefully that water can be
measured over 1t with an error of
less than n per cent, if care is
used.
There are severa1 forms or weirs,
name OF each designating the
shape of the notch. C%ippoletti. an
Italian engineer, evolved and per-
fected the weir which bears his name
many years ago, this being the weir
nat is now most generally used in
he west. Other weirs, namely, the
rectangular and the triangular weirs. !
re constructed and operated in much
he same way, the same rules being
deserved in the measurement, practi-
ally the only difference existing
icing, as has been stated, in the
hape of the notch and the formula
sed in the computation of the dis
barge. The Cippoletti weir notch !
trapezoidal in shape, having a
traight bottom or crest with sides
nat slope outward from the vertical
t the rate of n horizontal to four
critical. A n foot Cippoletti weir
as a straight horizontal bottom or
'est one foot in length with a width
etWeen the sides of Is inches at a
eight of 6 inches above the crest. !
the notch is made of wood the
des and bottom should be beveled l
I on the down stream side, leaving =
sharp thin edge on the upstream : :
De. This is necessary in order to /
cure a sharp clear-cut issuing =
ream which it is necessary to Sc !,
re If accurate measurement is to i,
obtained. 1t is usually the best y
llcy to line or face the upper side y
the weir board with a piece OF >
iron from which the prop II
size and shape notch has been =,
t. In this case the notch in the :,
ard should be cut slightly larger : =,
an that In the galvanized iron -
ping or beveling the edges in the d
ne manner as before. The use of p
, galvanized iron or other metallic 81
'st is especially recommended as it =,
only insures a sharp clear-cut is ~
ng stream upon which accurate ~
asurement depends, but in addi- w
1T also furnishes a permanent W
,hangeable crest for the water to -
W through. Provided the neces- W.
y requirements are observed in nc
construction and installation of IA.
1eir, the amount of water flowing W.
r 1t depends upon but two factors !"
ne length of crest and the depth ,,,
the water on the crest. The WV
9Th of crest being known, the 81
tn OF the water should be meas
q, not on the crest, but from a oh
Mt level with the crest and up ~
am from it a distance equal to it's ~,
9Th. 'n'
Weir Box-In order to maintain vo
weir in a proper and constant ho,
ltion and to prevent leakage ~.
lnd and under it, and in order
all water that is to be meas uo
should be conducted over it, it Nv
necessary to construct ~
e sort of box or frame to hold 90 So.
weir in place. A common form "
,ype of this box which is rec +,o
nended for a n foot Cippoletti 10
Is 3 feet long, 2h feet deep an-
3 feet wide inside measurement, ~
with a one-foot weir will meas :
with accuracy amounts ranging .he
! 10 to SO Idaho miners inches. ~,
here a weir box is built, it is tho
ssary that 1t be made of suffic- ~
size and depth in comparison to feo,
size OF the weir notch to elimin- fon
ali excess velocity of approach. If not
box is built too narrow or too ;nd,
low 1t will add to the velocity of oaa
zach to such an extent that cor 49,,
measurement can not be secured. aho,
but a mere matter of convent sn,,,
however, to have a box of the ~
length prescribed, for that part ,ano