DEPARTMENT OF THE INTERIOR
UNITED STATES RFCI "M'.TION SERVICE
MEASUREMENT of
IRRIGATION WATER
WASHINGTON
GOVERNMENT PRINTING OFFICE
1918
DEPARTMENT OF THE INTERIOR
UNITED STATES RECLAMATION SERVICE
MEASUREMENT of
IRRIGATION WATER
WASHINGTON
GOVERNMENT PRINTING OFFICE
1918
MEASUREMENT OF IRRIGATION WATER.
INTRODUCTORY STATEMENT.
1. Importance of -measurement. — Accurate measurement of irri-
gation water is of fundamental importance to good irrigation man-
agement. A perfect understanding of some of the primary^ principles
relating to the subject of water measurement is therefore necessary.
For the purpose of furthering an understanding of these principles
and for the purpose of having information and tables on the subject
convenient for field use, this booklet was compiled in 1913 by F. W.
Hanna.^
2. General units of measurement. — The units of measurement
at present employed in irrigation practice in the West are the miner's
inch, the second-foot, and the acre-foot. The miner's inch is
not a definite unit, varying as to quantity in the different States.
Fifty miner's inches are equivalent to i second-foot in Idaho,
Kansas, Nebraska, New Mexico, North Dakota, and South Dakota.
In Arizona, California, Montana, and Oregon, 40 miner's inches are
equivalent to i second-foot, while in Colorado, 38.4 miner's inches
are equivalent to i second-foot. A second-foot is that unit of flow
that will produce i cubic foot of volume in one second of time. An
acre-foot is that imit of quantity required to cover i acre of land
I foot in depth. It should be noted that the element of time enters
into the miner's inch and into the second-foot, but that the acre-
foot does not involve the element of time.
3. Units of measure adopted. — Owing to the fact that the miner's
inch, made definite by the use of the second-foot as a unit, has a
different value in different States, it is an undesirable unit of meas-
ure to use, and the ser\dce has adopted the second-foot as the unit
of measure where flow is considered. Owing to convenience of
size and its particular application to land areas, the acre-foot has
been adopted as the unit of measure where volume is considered
independently of time.
4. Kinds of measuring devices. — In the measiu-ement of irrigation
water the service has adopted weirs, submerged orifices, and current-
meter gaging stations. Where there is sufficient available fall, and
the quantity of water to be measured is not too large , the most service-
able and economical measuring device that can be used is the weir;
where there is little available fall, the quantity of water is small
' The text of the 1913 edition has been used unchanged.
4 MEASUREMENT OF IRRIGATION WATER.
and there is not too much floating debris, the submerged orifice is
applicable; where the quantit}^ of water is large and there is not
available sufficient fall for the use of a weir, current-meter gaging
stations are applicable. These three methods of measuring irrigation
water are, therefore, supplemental to one another in covering the
entire field of need.
PART I. WEFRS.
5. Definition and classification of weirs.- — A weir may be defined
as a notch in the top of a vertical wall through which water flows.
The determination of the quantity of water that v/ill flow through
such a notch under specific conditions depends upon experimental
data taken in connection with the cross-sectional area of the dis-
charge sheet through the notch. The weirs generally employed
for the measurement of irrigation water are the trapezoidal weir of
the Cippoletti type and the rectangular weir. Each of these types
inay again be divided into free weirs and submerged weirs. The
free weir is one in which the water elevation on the downstream side
of the weir does not reach up to the elevation of the weir crest. The
submerged weir is one in which the water elevation on the down-
stream side of the weir rises to an elevation above the crest of the
weir. Weirs are also classified as suppressed or contracted weirs.
The contracted weir is one with its sides so far removed from the
sides of the channel that the filaments of water are fully contracted
as the water passes through the weir. The suppressed weir is one
with its sides coincident with the sides of the channel, so that the
filaments of water pass through the weir without being deflected
from their normal course .
6. Types of weirs adopted.- — The type of weirs adopted by the
service for the meiisurement of irrigation water are the sharp-crested
and sharp-sided contracted rectangular weir, the sharp-crested
suppressed rectangular weir, and the sharp-crested and sharp-sided
Cippoletti weir. These three types of weir will be hereinafter
designated, respectively, as the standard contracted rectangular
weir, the standard suppressed rectangular weir, and the standard
Cippoletti weir. It is the aim of the service to use these weirs without
submergence, although there may be cases where it will be necessary
to permit submergence for short periods at least.
7. Definition and conditions for accuracy of standard contracted
rectangular weirs. — A standard contracted rectangular weir is a
rectangular weir wnth its crest and sides consisting of a thin-edged
plate and so far removed, respectively, from the bottom and sides
of the leading channel as to cause the filaments of water to be fully
deflected from their normal course. The deflection is approximately
the maximum deflection that would obtain with the crest and sides
of the weir at imlimited distajices from the channel boimdaries.
WEIRS. 5
The crest and sides may be made of planks if the upstream edges are
definite rectangular corners, but it is best to use a thin metal plate.
Several extended series of experiments have been conducted for
determining the proper coefficient to apply to the contracted weir
of the type here discussed and to establish conditions that insure
perfect contraction. As a result of these experiments, the following
conditions are considered necessary for accuracy of measurements:
(a) The upstream crest and side edges of the weir should be sharp
and smooth, and the distance of the crest and sides respectively from
the bottom and sides of the leading channel should preferably be not
less than twice the depth of water on the weir, and in no ease be less
than I foot.
(6) The overflowing sheet should touch only the upstream edges
of the crest and sides.
(c) Air should circulate freely both under and on the sides of the
overflowing sheet.
(d) The upstream face of the weir should be vertical.
(e) The crest should be level from end to end.
(/) The sides should be truly vertical.
(g) The measurement of head on the weir should be the actual
elevation of the water surface above the level of the weir crest, and
should be taken from 4 to lo feet upstream from the weir.
(k) The cross-sectional area of the leading channel for 20 to 30 feet
upstream from the weir should be at least six times that of the
overflowing sheet at the weir crest.
(i) Corrections should be made for velocity of approach where
appreciable errors are caused by neglecting the head due to it.
8. For->nulas for standard contracted rectangular weir'. — Two widely
used formulas for computing the discharges over standard contracted
rectangular weirs are those of Hamilton Smith and J. B. Francis.
The formulas proposed by Hamilton Smith require the use of coeffi-
cients of discharge varying with the head of water on the weir, and
also with the length of v/eir, which makes them somewhat incon-
venient, although they are accurate for the ranges of coefficients
usually given. The Francis formula for this type of weir without
velocity of approach is as follows:
(i) C?=3-33HML-o.2//);
and with velocity of approach is as follows:
(2) S^=3-33[(^+A)^-A'] (L-0.2 H);
in which is the discharge in second-feet without velocity of
approach; O' the discharge in second-feet with velocity of approach;
L the length of weir, in feet; H the head on the weir, in feet; and h
the head due to velocity of approach, in feet. It will be noted
that the Francis formulas contain constant discharge coefficients,
6 MEASUREMENT OF IRRIGATION WATER.
which make computations by them easy without the use of tables.
The Francis experiments were made on comparatively large weirs,
most of them lo feet long, with heads ranging from 0.4 to 1.6 feet,
so that the formulas apply particularly to such weirs rather than to
short Aveirs with low heads. Experiments on 6-inch, i-foot, 2-foot,
and 3-foot weirs on the Boise project, Idaho, show that these formu-
las apply fairly well to shorter weirs, provided the head of water on
the weir is not greater than about one-third the length of the weir.
For a ratio of depth to length greater than this the actual discharges
exceed those given by the formulas by an amoimt which increases
gradually from about o per cent for a ratio of 3-^ to about 30 per cent
for a ratio of 1 .
9. Definition and conditions for accuracy of standard suppressed
rectangular weir. — A standard suppressed rectangular weir is a rec-
tangular weir with its crest consisting of a thin plate so far removed
from the bottom of the leading channel as to cause the filaments of
water to be fully deflected from their normal course, and with its
sides coincident with the sides of the leading channel, so that there
is no change in direction laterally of the filaments of water passing
through the weir. All conditions for accuracy of measurements for
this type of weir are identical with those of the contracted rectangu-
lar weir, except those relating to side contraction. In the suppressed
weir the sides of the leading channel should be coincident with the
sides of the weir, and the over-falling sheet should not be allowed
to expand immediately downstream from the weir. Special care
must be taken in this type of weir to secure the proper aeration
beneath the overflowing sheet below the crest.
10. Formulas for standard suppressed rectangular weir. — The two
principal formulas used for computing the discharge of the standard
suppressed rectangular weirs are also those of Smith and Francis.
In the Smith formulas for suppressed weirs, as for contracted weirs,
the coefficients of discharge var>- with the head on the weir and with
the length of the weir, so these formulas are not convenient for com-
putations without the use of tables of coefficients. The law of these
variations for the two types of weirs is different, so it is necessary to
provide a separate table' for each. The Francis formula for the stand-
ard suppressed rectangular weir without velocity of approach is as
follows:
(3) Q=Z-ZZLHh
and with velocity of approach is as follows:
(4) G^=3-33^ [{H+h)i-hn.
In these formulas the letters have the same significance as in those
for contracted weirs, and the coefficient of discharge was obtained by
Francis from the same general set of experiments as those stated for
WEIRS. 7
the. contracted weir. No extensive tests have been made to
determine the applicability of these formulas to weirs less than 4 feet
in length.
n. Definition and conditions for accuracy of standard Cippoletti
weir. — A standard Cippoletti weir is a trapezoidal weir with its
crest and sides consisting of a thin plate, and so far removed from
the bottom and sides of the leading channel as to cause the filaments
of water to be deflected from their normal course and with its sides
sloping outward as they rise in a ratio of i to 4. While this weir is
necessarily a contracted weir, and should be so considered as far as
requirements of installation are concerned, yet, in discharge effect,
it is a suppressed weir. This is due to the fact that Cippoletti in
his formula has allowed for the reducing effect in the discharge due
to end contractions b)'^ making the sides of the weir sufficiently
sloping to overcome this effect. All conditions for accuracy stated
for the standard contracted rectangular weir apply to the Cippoletti
weir except that of the slope of the sides.
12. Formulas for standard Cippoletti weir. — Theoretically the
formula for the standard Cippoletti weir without velocity of approach
should be the same as the Francis formula for the standard sup-
pressed rectangular weir. Cippoletti, from his experiments, how-
ever, increased the Francis coelffcient by about i per cent, so that
his formula, without velocity of approach, is as follows:
(5) 2=3.367 LH^:
The discharge for this weir with velocity of approach may be ob-
tained from the following formula:
(6) 2^=3.367 L(//-f 1.5 A)f
In these formulas the letters have the same significance as in the
preceding formulas. The correction for velocity of approach may
be applied as in the Francis formula also with fair results.
13. Velocity of approach in weir measurements . — So far as practi-
cable weirs should be installed so as to make the velocity of approach
negligible; but where it is impracticable to do this appropriate
corrections should be made. vSuch corrections for the Francis
formulas are difficult to make without the use of tables providing
percentages of increase to apply to the computed discharges. In
the formula given for use with the Cippoletti weir the correction can
be applied to the measured head directly and the proper discharge
readily obtained, or the discharge can be obtained as indicated by
the Francis method and use of tables. Attention is called to the
fact that moderate velocities of approach with low heads on the
weir produce large errors, whereas comparatively high velocities of
3k MEASUREMENT OF IRRIGATION WATER.
approach with large heads on the weir produce relatively small
errors. The velocity of approach may be computed from the follow-
ing formula:
(7) v=Q^A;
in which t; is the velocity of approach in feet per second, Q the dis-
charge in second-feet, and A the cross-sectional area of the leading
channel in square feet. The discharge may be computed by the
appropriate weir formula without velocity of approach, with suffi-
cient accuracy for determining v for ordinary cases. Successive
approximations may be used to determine -v to any desired degree
of accuracy for special cases. Having obtained the value of v, the
velocity of approach head may be computed from the following
formula:
(8) /t=o.ois6 v^.
After h has been computed from formula (8), the effective head, D,
on the weir can be computed from the measured head, H, by means
of the following formula:
(9) D=[{H+hy'-h^i■,
in which H and h have the same significance as in preceding formulas,
and D is the effective head due to the measured head and velocity
of approach. The weir discharge is then given by the proper formula
for each type.of weir as hereinbefore given. For any type of weir, if
the Francis method of correcting for velocity of approach is used by
comparing formula (2) to formula (i), or formula (4) to formula (3),
it is seen that the increased discharge with velocity of approach
bears to the discharge for the same weir and head without velocity
of approach the ratio shown in the following formula:
(10) ^=— j=C;
Q H^
in which Q^, Q, H, and D have the same significance as in preceding
formulas and C is a ratio varying with H and the velocity of approach.
It is obvious that C applied as a coefficient to Q will give Q .
14. Suhnergence 0/ weirs. — Accurate measurement can not be made
of submerged weir discharges, on account of lack of extensive accu-
rate experiments for determining the discharge coefficient. Practi-
cally all of the older experiments on submerged weirs were on sup-
pressed rectangular ones. Clemens Herschel, from a discussion of
these experiments, derived a formula for computing discharges for
such weirs. The Herschel formula is as follows:
(11) e,=3-33^("^^)'';
WEIRS. 9
in which L and H have their usual significance, as applied to a free
suppressed rectangular weir, Q^ is the discharge in second-feet with
submergence, and n is a factor of correction taken from a table for
varying values of the ratio of submergence, (d-i-H), d being the
downstream head and H the upstream head on the weir, both in
feet. Recently,' limited experiments have been made on sub-
merged contracted weirs by J. C. Stevens, on the Sunnyside project
of the service. These experiments were considered and combined
by Stevens with the older ones and a diagram prepared for determin-
ing the discharges of submerged weirs, both contracted and sub-
pressed, from appropriate tables of free weirs. These results differ
only slightly from those of Herschel, so it may be roughly con-
sidered that Herschel 's coefficients apply approximately to con-
tracted as well as to suppressed weirs. In Herschel 's formula the
coefRcient n is applied to the observed head above the weir crest on
the upstream side. By comparing formula (ii) to formula (3), the
corresponding formula without submergence, it is seen that accord-
ing to Herschel 's formula the discharge of a submerged weir bears to
that of a free weir with the same length and head the ratio shown in
the following formula:
^ ' Q H^ '
in which Qi, Q, H and n have the same significance as in preceding
formulas and C^ is a ratio varjdng with ?i or with the ratio of sub-
mergence. It is obvious that C^ applied as a coeflicient to Q will
15. Construction of weirs. — Weir boxes should be substantially
constructed of lumber or concrete. The weir box should in all
cases extend downstream from the weir crest far enough to still
the water before it passes back into the earth channel below. The
floor of this downstream portion of the box may well be slightly
depressed to form a stilling pool; the sides should be coincident
with the overflow sheet for suppressed weirs, and should be set
back slightly from the sides of the weir crest for contracted weirs.
In suppressed weirs a pipe or other means should be provided for
admitting air to the underside of the overfalling sheet in order to
assure accurate contraction. The weir baseboard might well be
made removable, so that the silt accumulating in the weir pool
can be flushed out from time to time. In cases of suppressed weirs
the weir box should be extended upstream several feet in order to
insure perfect suppression of the end contractions. The crest of
the weir in any case should be placed sufficiently high above the
bed of the canal to insure perfect crest contraction. The sides of
1 The text of the 1913 edition has been used unchanged.
57737—18 2
lO MEASUREMENT OF IRRIGATION WATER.
contracted weirs should likewise be built sufficiently far from the
sides of the channel to permit of perfect end contractions. Wing-
walls or cut-off walls should be extended into the banks of the canal,
both at the upper and lower end of the weir box, for the purpose
of preventing leakage around the box, and for preventing back-
cutting at the canal banks.
i6. Installation of weirs. — The weir box should be installed suffi-
ciently far from the turnout to permit of constructing a pool of the
required length for stilling the water before passing through the
weir. The leading channel or weir pool should be made with uni-
form dimensions, and of the required length to give proper approach
and contraction of the water. The weir box should be carefully
leveled in both directions at the time of installation. The weir
crest should be accurately leveled and the sides of the weir set to
the required slopes for the type of weir being installed. The struc-
ture should be carefully puddled to prevent the passing of water
around or underneath it. There should be substantialh* installed
a metallic gage reading to hundredths of a foot, located sufficiently
far above the" weir crest to be out of the effect of the draw-down at
the weir crest. This gage should be accurately installed with its
zero-point at the same elevation as that of the weir crest, and at a
convenient location for checking these elevations from time to
time. Where the elevation of the water-surface in the canal is low
in comparison with adjacent land to be irrigated, and where there
is but little fall in the land, extra precaution should be taken to
prevent submergence of the weir.
17. Care of weirs. — The weir and weir pool should be freed from
weeds and trash at each round of the canal rider and the weir pool
should be cleaned of silt from time to time as it accumulates. The
level of the crest should be checked from time to tim.e, and should
also be checked with reference to the elevation of the zero of the
gage. Inspection should be made to determine whether there is
leakage around the weir, and in the event of such leakage the struc-
ture should be immediately repuddled and carefully rechecked to
see that the crest is level and at the elevation of the zero of the gage.
18. Table i. — This table contains discharges in second-feet for
standard contracted rectangular weirs without velocity of approach,
computed from the Francis formula for the lengths and heads ordi-
narily used in measuring small quantities of irrigation water; except
that for the 6-inch, i-foot, 2-foot, and 3-foot weirs, for heads greater
than one-third the crest length, the experimental values obtained
on the Boise project have been used instead of the values given by
the formula. This table may, therefore, be considered to give
fairly accurate discharges for weirs of the above-stated lengths and
for w-eirs of other lengths where the head does not exceed one-third
the length of the weir crest. The method of using the table is
apparent.
WEIRS. II
19. Tabk 2. — This table contains discharges in second-feet for
standard Cippoletti weirs withovit velocity of approach, computed
from the Cippoletti formula for the heads and lengths of weirs gener-
ally used in measuring small quantities of irrigation water; except
that for the 6-inch, i-foot, 2-foot, and 3-foot weirs, for heads greater
than one-third the crest length, the discharges have been taken from
experiments made on the Boise project. The data should, there-
fore, be considered fairly accurate for weirs of the above-stated
lengths for all heads given in the table and for weirs of other lengths
for heads not over one-third the crest length. This table is applicable
also to standard suppressed rectangular weirs, as indicated in para-
graph 12.
20. Table j. — Table 3 gives coefficients, which, applied to the
discharges taken from Table i or 2 , will give the discharges for the
same weirs when velocity of approach exists. When there is con-
siderable velocity of approach, corrections should be made by
means of this table. For this purpose the velocity of approach
should first be computed as hereinbefore described. The discharge
without velocity of approach should then be taken from Table i or
2 and Multiplied by the coefficient given in Table 3.
Illustration: Suppose it is desired to find the discharge of a
standard suppressed rectangular weir with a crest length of 6 feet
under a measured head of 2.5 feet and when there is a mean
velocity of approach determined to be 1.5 feet per second. By
Table 2 the discharge without velocity of approach is 79.85 second-
feet. From Table 3, for a velocity of approach of 1.5 feet per
second and with a head, H, of 2.5 feet, the coefficient is 1.019.
79.85 X 1. 019 = 81.367 second-feet discharge with velocity of
approach.
21. Table 4. — Table 4 gives coefficients, which, when applied to
the discharge of a weir as taken from either Table i or 2, will give
the discharge of the same w'eir when submerged. These coefficients
will give approximate results at best and can not be relied upon
for a high degree of accuracy in any case. To obtain the discharge
of a submerged weir by means of these coefficients, first the discharge
of the same weir, free, should be taken from Table i or 2 for the
head on the upstream side of the weir and this discharge then
multiplied by the proper coefficient obtained from Table 4.
Illustration: Suppose it is desired to find the discharge over a
submerged standard Cippoletti weir with a crest length of 3 feet
when the head on the upstream side is found to be 1.32 feet and the
head on the downstream side of the weir 0.33 foot. By Table 2
the discharge of the same weir, free, under the same head, is 15.71
second-feet. The ratio d -i- H = 0.33 -h 1.32 = 0.25, for which
Table 4 gives a coefficient of 0.958. The product, 15.71 X 0.958 =
15.5 second -feet, the discharge of the weir, submerged.
12 MEASUREMENT OF IRRIGATION WATER.
•
22. Tabic 5. — Table 5 contains the acre-foot equivalents of given
second-foot discharges for stated lengths of time. This table is
designed to assist in reducing weir discharges to acre-foot quantities
in working up the field records for oflice use. By means of this
table the acre-foot equivalent of any second-foot discharge far any
length of time may be obtained. For values not given directly in
the table it is nccessarj- only to multiply by the proper factors
and add.
Illustration: Suppose it is desired to ascertiiin how many acre-
feet are represented by a discharge of 14.52 second-feet flowing for
2 hours and 15 minutes. From the table (remembering that the
tabular values are multiplied by 10 or by 100 by moving the
decimal point one or two places to the right, respectively):
Acre-feer
14 second-feet flowing 2 hours equals 2. 314
14 second-feet flowing 15 minutes equals '. . 289
o. 52 second-feet flowing 2 hours equals c86
o. 52 second-feet flowing 15 minutes equals on
14. 52 second-feet flowing 2 hours and 15 minutes eqfuals. ... 2. 700
PART II. SUBKEROED ORIFICES.
23. Use of submerged orifices v. weirs. — Where there is sufficient
fall to permit of the measurement of water by means of a weir of
reasonable length, the weir should by all means be chosen as the
most desirable measuring device, as it will be free from detrimental
effects from weeds and trash. Where, however, the amount of fall
available for measuring the water is not adequate for the use of a
weir of reasonable length, the submerged orifice should be used.
In the measurement of water in laterals and farm ditches a weir
can generally be used for all cases where there is as much as 0.5 of
a foot of fall available, and even under the most adverse conditions
the weir can be used for all falls exceeding one foot.
24. Definition and classification of orifices. — An orifice may be
defined as an opening so placed in a wall of a channel or vessel
carrying or holding water that the opening lies completely below
the surface of the water on the upstream side thereof. The wall
may have any angular position from horizontal to vertical, the
opening may have any geometrical shape, the water may discharge
into air or into water, and the issuing stream may or may not be
contracted. The orifices generally employed for the measurement
of irrigation water are either circular or rcctangtilar and are vertical,
that is, are placed in a vertical wall in a canying channel. In the
early days of irrigation such an orifice usually discharged into air,
in which case the orifice was said to be free. Since the more general
adoption of the weir for measuring irrigation water the free orifice
SUBMERGED ORIFICES. 1 3
has been practically abandoned because it requires considerable
fall for its use and, when this fall is available, the weir is more
applicable. Later practice has developed the use of an orifice that
discharges into water; such an orifice is said to be submerged. The
submerged orifice is used where there is insufficient fall for the use
of a weir. In addition to the subdivision of vertical orifices into
free and submerged orifices, either of these classes may be con-
tracted or suppressed. A contracted orifice is one with its perimeter
so far removed from the bounding surfaces of the water prism in the
channel of approach or other surfaces of a disturbing nature that
the filaments of water are fully contracted as they pass through
the orifice . A suppressed orifice is one with its perimeter coincident
with the sides of the channel of approach or with other sui faces
eliminating contraction. Evidently an orifice may be contracted
or suppressed on any part or all of its perimeter or it may be imper-
fectly contracted and suppressed on any part or all of its perimeter.
This latter condition is the result of the existence of a disturbing
surface intervening between that prodticing contraction and that
producing suppression. If the opening is not sharp-edged or if the
wall in which it is cut or formed has material thickness or if a dis-
charge tube is attached, then the opening becomes a submerged
tube. This condition may exist all arovmd the opening or only
partially so, or it may be caused b}^ placing too close to the opening
the bounding surfaces of the water prism in the channel of approach.
For these different conditions different coefficients of discharge
apply. ^ y ;, _
25. Type of orifice adopted. — The principal type of orifice adopted
by the service for the measurement of irrigation water is the vertical,
sharp-edged, contracted, rectangular, submerged, orifice. This
type will be hereafter designated as the standard submerged rec-
tangular orifice. The reasons for selecting this type for general use
are that it is well suited for securing accuracy and is the principal
type f.Dr which the discharge coefficient has been carefully deter-
mined.
26. Definition and coiidilions for accuracy of standard submerged
rectangular orifices. — The standard submerged rectangular orifice is
a submerged rectangular orifice with its four sides consisting of thin-
edged plates, each so far removed from the adjacent side, bottom, or
top of the water prism in the leading channel as to cause the fila-
ments of water to be fully deflected from their normal course as
they pass through the orifice. The deflection is approximately
the maximum deflection that would obtain with the sides of the
orifice at unlimited distances from the water prism boundaries.
The sides of the orifice may be made of planks if the upstream edges
are deiinite, rectangular comers, but it is best to use a thin metal
plate. The conditions that are considered necessary to secure per-
fect contraction and accuracy of measurement are as follows:
14 MEASUREMENT OF IRRIGATION WATER.
(a) The upstream edges of the orifice should be sharp and smooth
and the distance of each from the bounding surfaces of the channel,
both on the upstream and on the dowiistream side, should preferably
be not less than twice the least dimension of the orifice.
(6) The UDStream face of the orifice wall should be vertical.
(c) The top and bottom edges should be level from end to end.
(d) Tlie sides should be truly vertical.
(e) The head on the orifice that should be measured is the actual
difference in elevation between the water surface on the upstream
side of the orifice and the water surface on the downstream side
thereof. . . r i.
(/) The cross-sectional area of the water prism for 20 to 30 feet
from the orifice on the upstream and on the downstream side thereof
should be at least six times the cross-sectional area of the orifice.
(g) Correction should be made for velocity of approach where
appreciable errors are caused by neglecting the head due to it.
27. Suitable dimensions for standard submerged rectangular orifices.—
The most suitable dimensions for standard submerged rectangular
orifices are those in which the height is considerably less than the
length. This is due to the fact that the ratio of depth to width of
irrigation canals and laterals is small. Convenient dimensions for
submerged orifices are }4 foot by i foot, 2 feet, or 3 feet; }4 foot by i
foot, lii feet, 2 feet, 2^ feet, or 3 feet; % foot by j}4 feet, iK.ieet,
2 feet, 2}i feet, or 2% feet. These dimensions will give orifices
varying in" area from 0.25 to 2.0 square feet in intervals of 0.25 square
foot. Where possible an orifice of i square foot area should be chosen,
as the unit area simplifies the discharge determination somewhat and
will give discharges ranging from 0.0 to nearly 3.5 second-feet under
heads varying from 0.0 to 0.5 foot. However, the size of the orifice
selected will necessarily be determined by the quantity of water to
be measured and the available fall that can be utilized therefor.
28. Formulas for standard submerged rectangular orifice. — The for-
mula for computing the discharge of the standard submerged rec-
tangular orifice, without velocity of approach, is- as follows:
{13) e=o.6iV^ A;
and with velocity of approach is as follows:
(14) Q'=o.6i V29 (H+h) A;
in which O is the discharge in second-feet without velocity of ap-
proach; Cthe discharge in second-feet with velocity of approach;
g gravity' in feet; H the measured head on the orifice in feet, being
equal to the difference in elevation of the water surface on the up-
stream side of the orifice and the water surface on the downstream
side thereof; h the head due to velocity of approach in feet, and A
the area of the orifice in square feet.
SUBMERGED ORIFICES. 1 5
29. Velociiv of approach in submerged orifice meastirements . — So far
as practicable submerged orifices should be so installed as to make
the velocity of approach negligible, but where this is impracticable
appropriate corrections therefor should be made. Attention is
called to the fact that neglecting moderate velocities of approach
with low heads on the orifice produces relatively large errors, whereas
neglecting comparatively high velocities of approach with large
heads on the orifice produces relatively small errors. The velocity
of approach may be computed from formula (7), page S, and after the
velocity of approach is determined, the head due to the velocity of
approach may be computed from formula (8), page 8. This velocity
head, designated as h, should be added to the measured head, as
indicated by formula (14), before computing the discharge by the
formula or before taking it from the discharge table.
30. Correction for suppression of coniraciion in submerged orifica. —
While it is deemed desirable to use the standard submerged rec-
tangular orifice so far as conditions will permit, it may be necessary
in some cases, for the purpose of avoiding accumulations of silt on
the upstream side of the orifice, to suppress bottom contraction by
placing the lower side of the orifice at canal grade, and cases may
now^ and then arise i\"here it will be necessar\' to determine the dis-
charge of submerged orifices that have also their side contractions
suppressed. The discharge coefl'.cients where suppression exists are
not well determined, and it is therefore undesirable to permit sup-
pression except where unavoidable. In such cases the discharge for
the submerged rectangular orifice without velocity of approach may
be computed approximately by the following formula:
(15) 2i=o-6i (i-f 0.15 r) V29// A;
and w ith'velocity of approach by the following formula:
(16) Q\=o.6i (i-fo.i5 r) V29 {H-^K) A;
in which Qx is the discharge in second-feet of the suppressed orifice
without velocity of approach; 0\ the discharge in second-feet of the
suppressed orifice with velocity of approach; r the ratio of the sup-
pressed portion of the perimeter of the orifice to the whole perimeter,
and H, A, and h have the same significance as in formulas (13 ) and
(14). By comparison of formula (15^ to formula (13) and formula
(16) to formula (14) the following relations are derived:
(^7) §-=§J' = i+o.i5 r=C;
in whichTc',?C?^3 Qi, Q\, and r have the same significance as in for-
mulas (13) to (16) and Cis aconstant equal to i-f 0.15 r. Itis obvious
that C applied as a coefilcient to Q or O' will give 0^ or Q\, respec-
tively.
l6 MEASUREMENT OF IRRIGATION WATER.
31. Construction of submerged orifices. — Submerged orifice boxes
should be substantially constructed of lumber or concrete. The
orifice box should be of sufficient length to extend downstream
from the orifice wall far enough to still the w^ater before it passes
back into the earth channel below. The floor should be depressed
below the canal grade to form a stilling pool and the floor and sides
should be set at distances from the orifice opening of not less than
twice the least dimension of the orifice. A flashboard may be placed
at the lower end of the orifice box to secure submergence of the
orifice, but the box must have sufficient length in such a case to
prevent disturbance in the water issuing from the orifice. The
orifice wall should be set truly vertical and should reach only to the
maximum water level so as to form an overflow in case of trouble.
Wing- walls or cut-off walls should be provided, both at the upper
end and the lower end of the orifice box, for the purpose of preventing
erosion of the canal banks and leakage on water around the structure.
32. Installation of submerged orifices. — The orifice box should be
installed sufficiently far from the" turnout to permit the construc-
tion of a pool of the required length for stilling the water before
it passes through the orifice. The pool should be made with uni-
form dimensions and with its bottom about one foot below^ the
normal grade of the canal to insure bottom contraction. The struc-
ture should be carefully levelled when installed and thoroughly
puddled to prevent leakage. A gage should be placed on the
upstream side of the orifice and another on the downstream side
thereof having the same zero elevation. The upstream gage should
be located at a convenient place on the upstream side of the orifice
wall and the downstream gage should be placed on the side-wall of
the orifice box sufficiently far downstream from the orifice wall to
register the true back pressure on the orifice. This distance will be
at least two feet for small orifices. Great care should be taken to fix
the gages truly vertical and to set their zero marks at the same
elevation.
33. Care of submerged orifices. — The submerged orifice and pool
should be freed from weeds and trash at each round of the canal
rider and the pool should be cleared of silt often enough to maintain
proper stilling of the water and bottom contraction of the orifice.
The orifice should be carefully checked from time to time to insure
that the dimensions and elevation are unchanged, the sides truly
vertical, the upper and lower crests level and the zero marks of the
gages at the same elevation. Inspection should be made from time
to time to determine whether there is any leakage around the struc-
ture and, in event of such leakage, the structure should be immedi-
ately repuddlcd and the orifice should again be checked as above
indicated.
CURRENT METER MEASUREMENTS. IJ
34. Table 6. — Table 6 contains discharges in second-feet of standard
submerged rectangular orifices without velocity of approach for com-
monly used heads and orifice areas, computed from formula (13), page
14. The method of using the table is apparent. The head, H, is
the observed head plus the head due to any velocity of approach
that may exist.
35. Table 7.— Table 7 gives coefficients, which applied to a dis-
charge given by Table 6 will give the discharge of the same orifice
suppressed on the bottom alone or on the bottom and two sides. For
an orifice constructed as a suppressed orifice or one in which silt has
collected sufficiently to effect suppression, the discharge should be
corrected by means of this table. First the discharge without sup-
pression should be taken from Table 6 and then multiplied by the
proper coefficient taken from Table 7.
Illustration : Suppose it is desired to find the discharge of a standard
submerged rectangular orifice 0.5 by 2.5 feet with bottom and side
suppressions under a head of 0.18 foot. For an area of 1.25 square
feet (=0.5X2.5) and a head of 0.18 foot. Table 6 gives a discharge of
2.593 second-feet. For a height, d, of 0.5 foot and a length, /, of 2.5
feet, with bottom and sides suppressed. Table 7 gives a coefficient of
1.09. Then 2.593Xi-09==2.826 second-feet, the discharge desired.
PART III. CURRENT METER GAGING STATIONS.
36. Use of current meter stations v. weirs and submerged orifices. — •
Where the quantity of water to be measured is large and the available
fall small, or where the quantity of water is small and extremely
heavily laden with silt, the use of current meter stations is advis-
able. Their use should be reduced to the minimum, however, as
their operation is comparatively expensive and the results are
relatively unsatisfactory. Only a very brief discussion of current
meter stations will be given here and the reader is referred to the
Water-Supply Papers of the United States Geological Survey and
technical books on the subject for further information.
37. Selection of current meter stations. — A current meter station
should be located in a straight uniform stretch of canal with smooth
banks and bed of permanent nature, so far removed from turnouts,
drops, and checks that the relation of discharge to gage height will
not be disturbed by these. In many canals these conditions are
difficult to find in combination and unusual care has to be taken to
obtain a station that will give good results.
38. Current meter station equipment. — The essential features of a
current meter station are a gage, a bench mark, fixed measuring
points in the channel cross section, and a stayline to hold the meter
in the measuring plane or cross section when the velocity is high
57737—18 3
1 8 MEASUREMENT OF IRRIGATION WATER.
and the water deep. Tlie gage should be of a good design, sub-
stantially installed where it will indicate the water elevation at all
stages, and should be so graduated as to permit accurate readings to
hundredths of a foot. (See fig. 2.) The bench mark should be
conveniently and permanently located and the elevation of the
datum of the gage should be carefully referred to it. The measuring
points should be located in a cross section at right angles to the
stream flow on a tagged wire stretched across the channel or on a
bridge located at the station. Where the canal is shallow enough
to permit of wading measurements, the tagged wire will be appli-
cable; otherwise a highway bridge or a small bridge constructed
for the purpose should be used. The measuring points should be
permanently fixed and marked at equal intervals of from two to ten
feet depending upon the size of the canal. The stayline should be
stretched across the canal far enough above the measuring section
to hold the current meter in proper position. (See fig. i.)
39. Ctirrent meters. — The essential features of all current meters
are a wheel capable of rotation by impact of water and a device for
determining the number of revolutions of the wheel. The relation
of the velocity of the water to the angular velocity of the wheel or
the number of revolutions of the wheel in a given time is deter-
mined by experiment, and should be checked and redetermined
from time to time. A sample rating table for 4 small Price meter
is given in Table 8. The two types of meters most widely used are
the Haskell and the Price. The wheel of the former consists of a
screw-shaped head mounted on a horizontal axis, while that of the
latter consists of a group of conical cups set with the axes of the
cones tangent to a circle, the whole group being mounted on a ver-
tical axis. Both types are provided with vanes to keep the wheel
headed against the current, weights for sinking the meter, a cable
for handling the meter, and electric or acoustic sounder for indicating
the number of revolutions and connections from the meters to the
sounding devices. The Price meter has been developed by the
United States Geological Survey for use in its work and a cut of it
as now manufactured is shown in figure 4.
40. Methods of measurement. — Soundings, either with a meter or
with a special sounding line and weight, should be made at the per-
manent measuring points. The mean velocity at each of these
measuring points should then be determined by means of the cur-
rent meter, in accordance with one of the approved methods of
determining mean velocities.
41. Methods of determining mean velocities. — There are five general
methods of determining mean velocities in a vertical line with a
current meter: (a) By taking the velocity at 0.2 and that at 0.8 of
the water depth and obtaining one-half the sum; (i) by taking the
velocity at 0.6 of the water depth; (c) by taking the velocities at
CURRENT METER MEASUREMENTS. 1 9
equal vertical intervals of 0.5 of a foot or more and obtaining their
arithmetical mean, or finding the mean value from a curve derived
by plotting the measurements on cross section paper; {d) by taking
the velocity near the water surface and using from 0.85 to 0.95 of
the result, depending on the depth of water, its velocity, and the
nature of the canal Ised, and (e) by taking velocity in the vertical
line by slowly and imiformly lowering and raising the meter through-
out the range of water depth one or more times. Of the methods
given, the first two are most used in canal work.
42. Methods of compzituig discharge tneasurements . — There are two
important methods of computing discharges from measurements
made by current meters. Both of these methods are based on
determining tlie discharges of the elementary areas between the
measiu-ing points and taking their sum. In one of the methods the
discharge is computed separately for each elementary area on the
assumption that both the velocity and the water depth vary uni-
formly from one measuring point to another. This may well be
termed the "straight-line" method, and the formula for computing
the discharge of the elementary' area is as follows:
(,S),.(I^')("-f»),
in which a and b are the water depths in feet at two adjacent
measuring points, Va and Vb the respective mean velocities in
feet per second at these points, I the distance in feet between the
points, and q the discharge in second-feet for the elementary area.
Formula (18) is well suited to computing discharges in canals con-
forming in cross section to their original trapezoidal or rectangular
dimensions. In the other method the discharge is computed for
consecutive pairs of elementary areas on the assumption that the
velocities and the water depths for three consecutive measuring
points each lie on the arc of a parabola. This method might well be
termed the parabolic method and the formula for computing the
discharge for each pair of elementar}'' areas is as follows:
in which a, b, and c are the water depths in feet at three consecutive
measuring points, Va, Vb, and Vc the respective mean velocities
in feet per second at these points, / the distance in feet between the
consecutive points, and q^ the discharge in second-feet for the pair
of elementary areas. Formula (19) is more particularly applicable
to river channels and old canals that have cross sections conforming
in a general way to the arc of a parabola or to a series of arcs of dif-
ferent parabolas. (See Table 9.)
20 MEASUREMENT OF IRRIGATION WATER.
43. Range of discharge measurements. — ^The discharge measure-
ments of a canal at a current meter station should be taken at suffi-
cient intervals of gage heights to permit of making accurate velocity,
area, and discharge curves. Inasmuch as water is usually turned into
the canals gradually in the beginning of each irrigation season, it
is possible at this time to get well-distributed measurements for tlie
condition of the canal at this season . The canal bed at a well-
selected current meter station is generally permanent in character,
and a permanent rating curve for the canal could be made were it
not for the fact that increased vegetable growth in the canal and on
its banks during the irrigation season, together with accumulations
of silt, decrease the discharge capacity- for all gage heights during
the latter part of the irrigation season. This fact must be taken
into consideration in computing the quantity of water carried by a
canal during the irrigation season. If the canal is cleaned diiring
the season, the relation of discharge to gage height is again dis-
turbed. These changing relations of discharge to gage height are
the chief source of errors and difficulties in irrigation canal
hydrography.
44. Daily gage heights. — In order to determine the quantity of
water carried by a canal at a current meter station it is necessary
to read the gage twice daily and additionally at such times as
changes of stage are made in the canal. These readings should be
taken by the canal riders while on their daily rounds. The gages
should be read accurately, generally to the nearest hundredth of
a foot. The gage should be read carefully also b^- the hydrographer
both before and after taking a current meter measurement.
45. Computation of discharges. — The current meter measurements
at a station are interpreted and extended to cover all gage heights
at the station by means of curves drawn on cross-section paper.
To construct these curves the discharges of the canal in second-feet
as computed from individual current meter discharge measurements,
the corresponding mean velocities in feet per second and the cross
sectional areas in square feet for each measurement are plotted as
abscissas, each to a convenient scale, with the common gage heights
as ordinates. The most probable area curve is drawn through the
area plottings and from this the accuracy of the area computations
and of the soundings are checked and, in case of a shifting channel,
changes in the rating section are discovered. The most probable
velocity curve is drawn through the velocity plottings on the sheet
to provide a graphic means of finrling inaccuracies in the computa-
tions and noting disturbances in the velocity due to obstructions in
the channel or changes in the velocity due to increased roughness
of the channel from vegetable growths in the canal. The discharge
curve is then drawn through the discharge points on the cross-section
CURRENT METER MEASUREMENTS. 21
paper, giving due weight to the various measurements and to prod-
ucts of the mean velocity and area abscissas for various gage heights
throughout the range of canal depths. WTiere the conditions of
flow of the canal have not been changed during the irrigation season,
it will generally be comparatively easy to draw a satisfactory curve.
WTiere, however, the relation of discharge to gage height has been
afTected by vegetable growth, or the introduction of other obstruc-
tions, these conditions must be given careful consideration and
another curve dra-'.vn for that part of the irrigation season during
which such conditions have existed. The discharge curve for these
conditions will generally be parallel to the discharge curve for the
earlier part of the irrigation season when the canal is clean. For
the period during which the change is in progress the discharges
must be estimated on the theory- of proportion from the two ciu-ves
constructed for the extreme conditions. (See fig. 3.)
46. Rating table. — From the rating curve the rating table may
be prepared for each tenth or hundredth of a foot of gage height a^s
the condition of accuracy may require, ranging from zero to the ma:^:i-
mum height of water in the canal. In case of canals affected by
vegetable growth two such rating tables will have to made, one
applying to the early part of the irrigation season when the canal is
clean and the other to the latter part of the irrigation season when
the canal is in bad condition. Daily discharges will also have to be
estimated for the period in which the change in the canal is being
effected. In case the canal is cleaned at any time during the irriga-
tion season, this fact must be given consideration in preparing the
necessary additional rating curves. (See Table 10.)
47. Compilation of daily and montlily discharges. — By means of
daily gage heights and the rating tables the daily discharges may
readily be compiled, and adding these gives the monthly discharges
and the total amount of water carried by the canal during the
irrigation season.
I
i%
MEASUREMENT OF IRRIGATION WATER.
z
o
o
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z
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O <
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3 UJ
UJ Zj
S Q
a
H
I
MEASUREMENT OF IRRIGATION WATER.
23
0.
0.
0.
0.
Any Convenient Wfdth
Fig. 2. — Steward water gages.
24
MEASUREMENT OF IRRIGATION WATER.
113J Nl 1HDI3H ^OVO
MEASUREMENT OF IRRIGATION WATER.
25
•iR?
ri
d
A
fi^sw.jftr/
im-U) sRIrVJii-^ ■*!
-i I'VA^
rfl».*l»«W"?*N
h^^
,^i^f^^m.
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Fig. 4.— Small price meters.
57737—18 1
26
MEASUREMENT OF IRRIGATION WATER.
Table 1. — Discharge of standard contracted rectangular weirs in
cubic feet per second. Values below and to left of heavy line
determined experimentally; others computed from the formula
Q = 3.33 (L — .2H) Hi. (Sec paragraphs 8 and 18.)
Length of weir L, feet.
Head H,
, feet
j
0.5
1.0
1.5 2.0
3.0
4.0
5.0 6.0
7.0
8.0
9.0
0.01
0.002
0.003
0.005
0.007
0.010
0.013 0.016
0.020
0.023
0.026
0.030
.02
.005
.009
.014
.019
.028
.037
.047
.056
.066
.075
.085
.03
.009
.017
.026
.034
.052
.069
.086
.104
.121
.138
.1.55
.04
.013
.026
.040
.053
.079
.106
.133
.159
.186
.213
.239
.05
.018
.037
.055 .074
.111
.148
.186
.223
.260
.297
.334
.06
.024
.048
.073
.097
.146
.195
.244
.293
.342
.391
.439
.07
.030
.061
.092
.123
.184
.246
.308
.369
.431
.493
.554
.08
.036
.074
.112
.149
.225
.300
.375
.451
.526
.601
.676
.09
.043
.088
.133
.178
.268
.358
.448
.538
.628
.718
.807
.10
.051
.103
.156
.208
.314
.419
.524
.630
.735
.840
.945
.11
.058
.119
.179
.240
.362
.483
.605
.726
.848
.969
1.091
.12
.066
.135
.204
.273
.412
.550
.689
.827
.965
1.104
1.242
.13
.074
.152
.230
.308
.464
.620
.776
.933
1.089
1.245
1.401
.14
.082
.169
.257
.344
.518
.693
.867
1.041
1.216
1.390
1.565
.15
.091
.188
.284
.381
.575
.768
.962
1.155
1.349
1..542
1.736
.16
.100
.206
.313
.419
.632
.845
1.059
1.272
1.485
1.698
1.911
.17
.109
.225
.342
.459
.692
.926
1.159
1.392
1.626
1.859
2.093
.18
.122
.245
.372
.499
.754
1.008
1.262
1.517
1.771
2.025
2.279
.19
.132
.265
.403
.541
.817
1.093
1.369
1.644
1.920
2.196
2.472
.30
.142
.286 .435
.,584
.881
1.179
1.477
1.775
2.073
2..370
2.668
.21
.152
.307
.467
.627
.948
1.269
1.589
1.910
2.230
2.551
2.871
.22
.162
.328
.500
.672
1.016
1.359
1.703
2.046
2.390
2.734
3.077
.23
.173
.350
.534
.718
1.085
1.452
1.820
2.187
2.554
2.921
3.289
.24
.184
.373
.568
.764
1.156
1.547
1.939
2.331
2.722
3.113
3.505
.25
0.195
.395
.603
.811
1.228
1.644
2.060
2.476
2.893
3.309
3.725
.26
.419
.639
.860
1.301
1.743
2.185
2.626
3.067
3.509
3.951
.27
.442
.675
.909
1.376
1.843
2.311
2.778
3.245
3.712
4.179
.28
.466
.712
.9.59
1.4.53
1.946
2.439
2.933
3.426
3.919
4.413
.39
.490
.750
1.010
1.530
2.050
2.570
3.090
3.610
4.130
4.650
.30
.514
.788
1.061
1.609
2.156
2.703
3.251
3.797
4.344
4.892
.31
.539
.827
1.114
1.689
2.263
2.838
3.413
3.988
4.563
5.137
.33
.564
.866
1.167
1.770
2.373
2.975
3.578
4.181
4.784
5.387
.33
.590
.905
1.221
1.852
2.4S3
3.115
3.746
4.377
5.009
5.640
.34
.35
.615
.945
.986
1.275
1.331
1.936
2.020
2.596
2.710
3.256
3.399
3.916
4.089
4.577
4.778
5.237
5.468
5.897
.658
6.157
.36
.686
1.027
1.387
2.106
2.825
3.545
4.264
4.983
5.703
6.422
.37
.714
1.069
1.443
2.193
2.943
3.692
4.441
5.191
5.941
6.690
.38
.743
1.111
1.501
2.281
3.061
3.841
4.621
5.401
6.181
6.961
.39
.772
1.153
1.559
2.370
3.181
3.992
4.803
5.614
6.425
7.236
.40
.801
1.196
1.617
2.460
3.302
4.145
4.987
5.829
6.672
7.514
.41
.830
1.240
1.677
2. .551
3.425
4.299
5.173
6.048
6.922
7.796
.42
.860
1.283
1.737
2.643
3.549
4.456
5.362
6.269
7.175
8.081
.43
.890
1.328
1.797
2.736
3.675
4.614
5.553
6.492
7.431
8.370
..44
.920
1.372
1.858
2.830
3.802
4.774
5.746
6.718
7.690
8.661
.45
.9.50
1.417
1.920
2.925
3.930
4.935
5.941
6.946
7.951
8.956
^4C
.981
1.463
1.982
3.021
4.060
5.099
6.138
7.177
8.216
9.255
.47
1.012
l.,509
2.045
3.118
4.191
5.264
6.337
7.410
S.483
9.556
.48
1.044
1.555
2.108
3.216
4. .323 5.431
6.538
7.645
8.753
9.860
.49
1.077
1.601
2.172
3.315
4.457 5..599
6.741
7.8g3
9.026
10.168
0.5O
1.111
1.648
2.237
3.414
4.591 5.769
6.946
8.123
9.301
10.478
MEASUREMENT OF IRRIGATION WATER.
27
Table 1. — Discharge of standard contracted rectangular weirs in
cubic feet per second. Values below and to left of heavy line
determined experimetitally; others computed from the formula
Q = 3.33 (L — .2H) Hi . (See paragraphs 8 and 18.)
Head B,
feet
Length of weir L, feet.
1.5
2.0
3.0 { 4.0
5.0 6.0
7.0
8.0
9.0
0.51
.52
.53
.54
.55
.56
.67
.58
.59
.60
.61
.63
.63
.64
.65
.66
.67
.68
.69
.70
.71
.72
.73
.74
.76
.76
.77
.78
.79
.80
.81
.82
.83
.84
.85
.86
.87
.88
.89
.90
.91
.92
.93
.94
.95
.96
.97
.98
.99
1.00
1.695
2.302
1.743
2.367
1.791
2.434
1.839
2.500
1.888
2.567
1.937
2.635
1.986
2.703
2.036
2.771
2.085
2.840
2.136
2.909
2.186
2.979
2.237
3.050
2.28S
3.121
2.339
3.192
2.391
3.263
2.443
3.335
2.495
3.408
2.547
3.58
2.599
3.66
2.652
3.74
2.705
3.82
2.759
3.90
2.813
3.98
2.866
4.06
2.920
4.14
4.22
4.30
4.38
4.46
4.54
4.62
4.70
4.78
4.87
4.96
5.05
5.14
5.23
5.32
5.41
5.50
5.59
5.68
.....
5.77
5.86
5.95
6.04
6.13
6.22
'
6.31
3.515
3.616
3.719
3.821
3.925
4.030
4.136
4.242
4.349
4.457
4.566
4.675
4.786
4.897
5.00s
6.121
5.234
5.348
5.462
5.578
5.694
5.810
5.928
6.046
6.164
6.283
6.403
6.524
6.645
6.767
6.8S9
7.013
7.136
7.260
7.385
7.511
7.635
7.763
7.S90
8.018
8.146
8.275
8.404
8.534
8.664
8.795
8.927
9.059
9.191
9.324
4.727
5.940
7.153
4.S65
6.114
7.362
5.003
6,288
7.573
5.143
6.464
7.786
6.284
6.642
8.000
5.426
6.821
8.217
5..J69
7.002
8.435
6.713
7.184
8.655
5.858
7.307
8.877
6.005
7.552
9.100
6.152
7.739
9.325
6.301
7.927
9.553
6.451
8.116
9.781
6.602
8.307
10.012
6.753
8.499
10.244
6.906
8.692
10.477
7.060
8.886
10.712
7.215
9.083
10.9,50
7.371
9.280
11.188
7.528
9.478
11.429
7.686
9.678
11.670
7.845
9.879
11.913
8.005
10.082
12.1.59
8.165
10.285
12.405
S.327
10.490
12.653
8.490
10.696
12.902
8.653
10.903
13.153
8.818
11.112
13.406
8.983
11.321
13.660
9.150
11.533
13.915
9.317
11.745
14.172
9.485
11.958
14.431
9.C54
12.172
14.690
9.824
12.388
14.951
9.995
12.604
15.214
10.106
12.822
15.478
10.339
13.041
15.743
10.512
13.261
16.010
10.6S6
13.482
16.278
10.861
13.704
16.547
11.0.37
13.927
16.818
11.213
14.152
17.090
11.391
14.377
17.363
11.509
14.603
17.638
11.748
14.S31
17.915
11.927
15.060
18.192
12.10s
1.5.289
18.471
12.289
15.520
18.7.50
12.471
15.751
19.032
12.654
15.984
19.314
8.. 366
8.611
8.858
9.107
9.359
9.612
9.S6S
10.126
10.386
10.647
10.912
11.178
11.447
11.717
11.989
12.263
12.539
12.817
13.097
13.379
13.663
13.948
14.236
14.525
14.816
15.109
15.403
15.700
15.998
16.298
16.000
16.903
17.208
17.515
17.823
18.134
18.445
18.759
19.074
19. .391
19.709
20.029
20.350
20.673
20.998
21.324
21.652
21.981
22.312
22.644
9.579
9.800
10.143
10.428
10.717
11.008
11.301
11.597
11.895
12.195
12.498
12.804
13.112
13.422
13.734
14.04S
14.365
14.684
15.005
1.5.329
15.655
15.982
16.313
16.645
16.979
17.315
17.0.53
17.094
IS. 336
IS.GSl
19.027
19.376
19.726
20.079
20.433
20.790
21.147
21.508
21.809
22.234
22.599
22.967
23.337
23.708
24.081
24.4.56
24.833
25.212
25.592
25.974
10.791
11.108
11.428
11.750
12.075
12.403
12.734
13.067
13.404
13.743
14.085
14.430
14.777
15.127
15.479
15.8,34
16.191
16.552
16.914
17.280
17.647
18.017
18.390
18.704
19.142
19.521
19.903
20.288
20.074
21.064
21.455
21.849
22.244
22.643
23.043
23.445
23.8.50
24.257
24.665
25.077
25.490
25.906
26.323
26.743
27.165
27.588
28,015
28.442
28.872
29.304
28
MEASUREMENT OF IRRIGATION WATER.
Table 1 — Discharge of standard contracted rectangular weirs in
cubic feet per second. I'alues to left of heavy line determined
experimentally; others computed from the formula Q = 3.33
(L — .2H) Hi. (Sec paragraphs 8 and 18.)
Length of weir
L, feet.
Head //.
feet
3.0
4.0
5.0
6.0
7.0
8.0
9.0
1.01
9.87
12.838
16.218
19.598
22.978
26.358
29.738
1.03
10.01
13.022
16.452
19.883
23.313
26.743
30.174
1.03
10.15
13.207
16.688
20.169
23.050
27.131
30.612
1.04
10.30
13.394
16.924
20.4.56
23.988
27.. 520
31.051
1.05
10.45
13.579
17.162
20.714
24.327
27.910
31.493
l.OS
10.60
13.763
17.401
21.035
24.669
28.303
31.937
1.07
10.75
13.954
17.640
21.325
25.011
28,697
32.383
1.08
10.90
14.143
17.880
21.618
25.3,55
29.093
32.830
1.0!)
11.05
14.332
18.121
21.911
25.700
29.490
33.279
1.10
11.20
14.522
18.364
22.206
26.047
29.889
33.731
1.11
11.35
14.713
18.607
22..501
26.. 395
30.290
34.184
1.13
11. ,50
14.904
18.851
22.798
26.745
30.692
34.639
1.13
11.65
15.096
19.096
23.096
27.096
31.096
35.096
1.14
11.80
15.289
19.342
23.390
27.448
31.501
35.555
1.15
11.95
15.482
19.589
23.696
27.. 802
31,909
36.016
1.16
12.10
15.676
19.8.37
23.997
28.157
32.318
36.478
1.17
12.25
12.40
15.871
16.006
20.085
20.335
24.. 300
24.603
28.513
32.728
36.943
1.18
28.871
33.140
37.408
1.19
12.55
16.202
20.585
24.908
29.231
33.553
37.876
1.30
12.70
16.4.59
20.836
25.214
29..591
33.969
38..346
1.31
12.85
16.656
21.088
25.521
29.953
34.385
38.817
1.33
13.00
16.854
21.341
25.829
30.316
34.803
39.291
1.33
13.15
17.053
21.595
26.138
30.681
35.223
39.700
1.34
13.31
17.252
21.850
26.448
31.046
35.644
40.243
1.35
13.47
17.452
22.105
26.759
31.413
36.067
40.721
1.36
13.63
17.652
22.362
27.072
31.782
36.491
41.201
1.37
13.79
17.853
22.619
27.385
32.151
36.917
41.683
1.38
13.95
18.055
22.877
27.700
32.522
37.345
42.167
1.39
14.11
18.257
23.136
28.015
32.894
37.773
42.652
1.30
14.27
18.460
23.396
28.331
33.267
38.203
43.139
1.31
14.43
18.663
23.656
28.649
33.642
38.635
43.628
1.33
14.. ^9
18.867
23.918
28.968
34.018
39.068
44.119
1.33
14.75
19.072
24.180
29.287
34.395
39.503
44.611
1.34
14.91
19.277
24.443
29.608
34.773
39.939
45.104
1.35
15.07
10.483
24.706
29 929
35.153
40.376
45.599
1.36
15.23
19.689
24.970
so! 2.52
35.533
40.815
46.096
1.37
15.39
19.896
25,236
30.576
35.915
41.255
46.595
1.38
15..55
20.104
25.502
30.900
36.299
41.697
47.096
1.39
15.71
20.312
25.769
31.226
36.083
42,140
47.598
1.40
15.87
20.520
26.036
31.553
37.069
42,585
48.101
1.41
16.03
20.729
26.305
31.880
37.455
43.031
48.606
1.43
16.19
20.939
26.574
32.209
37.843
43.478
49.113
1.43
16..35
21.149
26.843
32.538
38.2.32
43.927
49.621
1.44
16.51
21.359
27.114
32.808
38.622
44.376
50.131
1.45
16.68
21.571
27.385
33.200
39.014
44.828
50.643
1.46
16.85
21.783
27.657
33.5.32
39.406
45.281
51.155
1.47
17.02
21.995
27.930
33.805
39.800
45.735
51.670
1.48
17.19
22.208
28.204
34.199
40.195
46.191
52.187
1.49
17.36
22.421
28.478
34.534
40.. 59 1
46.647
52.704
1.50
17.53
22.635
28.753
34.870
40.988
47.105
53.223
MEASUREMENT OP IRRIGATION WATER.
29
Table 1 — Discharge of standard contracted rectangular weirs in
) cubic feet per second, computed from the formula Q = 3.33
{L — .2H) Hi. (See paragraphs 8 and 18.)
Length of
weir L, feet
Head H,
feet
4.0
6.0
6.0
7.0
8.0
9.0
1.51
22.849
29.028
35.207
41.386
47.565
53.744
1.63
23.065
29.305
35.545
41.786
48.026
54.267
1.53
23.279
29.581
35.883
42.185
48.487
54.780
1.54
23.495
29.859
36.223
42.587
48.951
55.315
1.55
23.712
30.138
36.564
42.990
49.416
55.842
1.56
23.929
30.417
36.905
43.394
49.882
56.370
1.57
24.146
30.697
37.248
43.799
50.349
56.900
1.58
24.364
30.978
37.591
44.205
50.818
57.432
1.59
24.583
31.259
37.935
44.612
51.288
57.965
1.60
24.801
31.540
38.280
45.019
51.7.59
58.498
1.61
25.020
31.823
38.626
45.428
52.231
59.034
1.63
25.240
32.106
38.973
45.839
52.705
59.571
1.63
25.460
32.390
39.320
46.250
53.180
60.110
1.64
25.681
32.G75
39.60a
46.662
53.650
60.649
1.65
25.902
32.960
40.018
47.075
54.133
61.191
1.66
26.124
33.246
40.308
47.490
54.612
6 1.7.34
1.67
26.346
33.5.32
40.719
47.905
55.092
62.278
1.68
26.568
33.819
41.071
48.322
55.573
62.824
1.69
26.791
34.107
41.423
48.739
56.055
63.371
1.70
27.014
34.395
41.776
49.1.57
56.538
63.919
1.71
27.239
» 34.685
42.131
49.577
57.024
64.470
1.73
27.463
34.974
42.486
49.998
57.509
65.021
1.73
27.687
35.265
42.842
50.419
57.997
65.574
1.74
27.913
35.556
43.199
50.842
58.485
66.128
1.75
28.138
35.847
43.556
51.265
58.975
66.684
1.76
28.364
36.139
43.914
51.689
59.465
67.240
1.77
28.590
36.4.32
44.274
52.115
59.957
67.798
1.78
28.817
36.725
44.633
52.541
60.449
6S.358
1.79
29.045
37.019
44.994
52.969
60.944
6S.919
1.80
29.272
37.314
45.356
53..397
61.439
60.481
1.81
29.500
37.609
45.718
53.827
61.936
70.043
1.83
29.729
37.905
46.081
54.257
62.433
70.610
1.83
29.958
38.201
46.445
54.689
62.932
71.176
1.84
30.187
38.498
46.809
55.121
63.432
71.743
1.85
30.416
38.798
47.175
55.554
63.933
72.312
1.86
30.646
39.094
47.541
55.988
64.435
72.882
1.87
30.877
39.392
47.908
56.423
64.938
73.454
1.88
31.108
39.691
48.275
56.859
65.443
74.027
1.89
31.339
39.991
48.644
57.296
65.949
74.601
1.90
31.571
40.292
49.013
57.734
63.455
75.177
l.Sl
31.803
40.593
49.383
58.173
60.963
75.753
1.93
32.035
40.894
49.753
58.612
67.472
70.331
1.93
32.267
41.196
50.125
59.053
67.981
70.910
1.94
32.501
41.499
50.497
59.495
68.493
77.491
1.95
32.734
41.802
50.870
69.937
69.005
78.073
1.96
32.968
42.106
51.243
60.381
69.518
78.656
1.97
33.202
42.410
51.617
60.825
70.032
79.240
1.98
33.437
42.715
51.992
61.270
70.518
79.824
1.99
33.672
43.020
52.368
61.716
71.064
80.412
3.00
33.907
43.326
52.745
62.163
71.582
81.001
30
MEASURExMENT OP IRRIGATION WATER.
Table 1 — Discharge of standard contracted rectangular weirs in
cubic feet per second, computed from the formula Q = 3.33
(L — .2H) H%. . {See paragraphs 8 and 18.)
Length of weir L, feet
Length of weir L, feet.
Head H,
Head H,
feet
feet
1
5.0
6.0
7.0
8.0
9.0
6.0
7.0
8.0
9.0
2.01
43.632
1
53.122 62.601 72.091
' 81.580
2.51
72.805
86.047
99.289
112.531
2.03
43.939
53.499 63.060i72.620
82.180
2.52
73.212
86.533
99.864
113.175
2.03
44.247
53.878 63.509173.141
82.772
2.53
73.625
87.026: 100.427
113.828
2.04
44.554
54.257 63.959i73.662
83.365
2.54
74.032
87.512 100.992 114.472
2.05
44.863
54.637, 64.411i74.185
83.959
2.55
74.444
88.004 i 101.564 116.124
a.06
45.172
55.018 64.863 74.709
84.555
2.56
74.856
88.496' 102.136 115.776
2.07
45.481
55.399 65.316 75.233
85.151
2.57
75.26S
8S.988i 102.708 116.428
2.08
45.791
55.781 65.770 75.760
85.749
2.58
75.679
89.479 103.279 117.079
2.09
46.104
56.166 66.228 76.290
86.352
2.59
76.090
89.970! 103.850 117.730
2.10
46.414
56.548 66.6S2i76.S16
86.950
2.60
76.506
90.467! 104.428 118.389
2.11
46.723
56.929 67. 135i77.341
87.547
2.61
76.917
90.957 104.999 119.039
2.12
47.037
57.316 67. 595177.874
88.153
2.62
77.332
91.454 105.576 119.698
2.13
47.350
57.702 68.054 78.406
88.758
2.63
77.747
91.9501106. 153 120.356
2.14
47.663
58.088 68.513 78.938
89.363
2.64
78.162
92.4461106.730 121.014
2.15
47.976158.474168. 972179.470
89.968
2.65
78.527
92.8831107.239 121.595
2.16
48.2S815S.859 69.43080.001
90.572
2.66
78.996
93.443ll07.890|l22.337
2.17
48.605
59.250 69.895 80.540
91.185
2.67
79.410
93.9381108.466
122.994
2.18
48.917
59.635 70.353 81.071
91.789
2.68
79.829
94.439! 109.049
123.659
2.19
49.233
60.025 70.817 81.609
92.401
2.69
80.248
94.9401109.632
124.324
2.20
49.549
60.415 71.281 82.147
93.013
2.70
80.666
95.440
110.214
124.988
2.21
49.865
60.805 71. 745'82.685
93.625
2.71
81.084
95.940
110.796
125.652
2.22
50.184
61.199 72.214183.229
94.244
^2.73
81.502
96.440
111. .378
126.316
2.23
50.499
61. 5SS 72. 677183.766
94.855
2.73
81.925
96.945
111.967
126.987
2.24
50.819
61.983 73. 147i84.311
95.475
2.74
82.341
97.445
112.547
127.651
2.25
51.137
62.376i73.615
84.854
96.093
2.75
82.764
97.950
113.136
128.322
2.26
51.456
62.770,74.084
85.398
96.712
2.76
83.185
98.455;ii3.723'12S.993
2.27
51.774
63.16374.552
85.941
97.330
2.77
83.607
98.959|114.311
129.663
2.28
52.092
63.556|75.020i86.484
97.948
2.78
84.028
99.463 114.898
130.333
2.29
52.415
63.955'75. 495187.035
98.575
2.79
84.454
99.973 115.4912
131.011
2.30
52.732
64.347175.962187.577
99.192
2.80
84.875
100.477 116.079
131.681
2.31
53.054
64.74576. 436I8S.127
99.818
2.81
85.300
100.986ill6.672
132.359
2.32
53.375
65.142 76. 909 1 88.676
100.443
2.82
85.720
101.4891117.258
133.027
2.33
.53.696
65.539'77. 382 89.225
101.068
2.83
86.145
101.998ill7.851
133.704
2.34
.54.021
65.941 77.861 89.781
101.701
2.84
86.575
102.513 1118.451
134.389
2.35
54.342 66.338 78.334190.330
102.326
2.85
86.999
103.021 119.043
135.065
2.36
54.667
66.739178. 81390.885
102.959
2.86
87.423
103.529 119.635
135.741
2.37
54.991
67.141i79.291
91.441
103.591
2.87
87.852
104.043! 120.2.34
136.425
2.38
55.315
67.542 79.769
91.996
104.223
2.88
88.276
104.551 i 120.826
137.101
2.39
,55.639
67.943 80.247
92.551
104.8.55
2.89
88.704
105.0641121.424
137.784
2.40
55.962
68.343 80.724
93.105
105.486
2.90
89.132
105..577'122 022
138.467
2.41
56.290
68.749 81. 208'93.667
106.126
2.91
89.559
106.089 122.619
139.149
2.42
56.613
69.149 81. 685i94.221
106.7.57
2.92
89.992
106.608,123.224
139.840
2.43
56.939
69.553 82.167194.781
107.395
2.93
90.419
107.120 123.821
140.522
2.44
57.266
69.958 82.650i95.342
108.034
2.94
90.851
107.638 1 124.425
141.212
2.45
57.593
70.363 83.133195.903
108.673
2.95
91.277
108.149 125.021
141.893
2.46
57.919
70.767;83.615{96.463
109.311
2.96
91.709
lOf.667! 125.625
142.683
2.47
58.249
71.176 84.10397.030
109.957
2.97
92.140
109.184 126.228
143.272
2.4S
.58.575
7 1.579, 84.. 585! 97.589
110.595
2.98
92.571
109.701 1126.831
143.961
2.49
58.904
71.988 85.072 98.156
111.240
2.99
93.006
110.223
127.440
144.657
2.60
59.233
72.397i85.5.59i98.723
1 1
111.885
3.00
93.438
110.741
128.044
146.348
MEJASUREMENT OF IRRIGATION WATER.
31
Table 1 — Discharge of standard contracted rectangular weirs in
cubic feet per second, computed from the formula Q =^ 3.33
(L — .3H) H%. (See paragraphs 8 and 18.)
Length of weir L, feet.
Length of weir
L, feet.
Length
of weir
Head H,
Head H.
Head H,
L, feet.
feet
1
feet
feet
[ 7.0
8.0
9.0
1 ■**
8.0
9.0
9.0
3.01
11L261 128.650
146.040
3.51
159.812
181.710
4.01
219.214
3.03
lll.737il29.207
146.676
3.52
160.451
182.443
4.02
219.981
3.63
112.300 129.864
147.427
3.53
161.092
183.178
4.03
220.750
3.04
112.821(130.471
148.121
3.54
161.733 183.912
4.04
221.517
3.05
113.343 131.081
148.818
3.55
162.373
184.646
4.05
222.286
3.06
113.865 131.690
149.514
3.56
163.016
185.383
4.06
223.055
3.07
114.389 1.32.301
150.213
3.57
163.657
186.118
4.07
223.824
3.08
114.912 132.912
150.912
3.58
164.301
186.857
4.C8
224.595
3.09
11.5.435 133.523
151.610
3.59
164.945
187.595
4.09
225.341
3.10
115.959! 131. 134 152.310
1 3.60
165.588
188.333
4.10
226.139
3.11
116.484:134. 747:153.011
3.61
166.233
189.074
4.11
226.912
3.12
117.010 135. 36lll53.713
3.62
166.878
189.813
4.12
227.684
3.13
117.536 135.976,154.416
3.G3
167.525
190.555 1
4.13
228.458
3.14
118.064 136.592115.5.121
3.64
168.171
191.297
4.14
229.232
3.15
118.590 137. 207! 155.824
3.65
168.817
192.038
4.15
230.006
3.16
119.117
137.823
156.528
3.66
169.466
192.782
4.16
230.782
3.17
119.846
138.440
157.235
3.67
170.113
193.525
4.17
231.557
3.1s
120.1771139.0601157.944
3.G8
170.763 1194.271 1
4.18
232.333
3.19
120.704 139. 6771158.650
3.69
171.412 1195.016
4.19
233.110
3.20
121.234 140.295
159.357
3.70
172.061 1 195.761
4.20
233.887
3.21
121.765 140.917
160.068
3.71
172.713 196.509
4.21
234.667
3.22
122.296 141.537
160.778 '
3.72
173.363
197.256
4.22
235.446
3.23
122.827! 142. 158
161.489
3.73
174.014
198.003
4.23
236.224
3.24
123.360ll42.780
162.201
3.74
174.666
198.751
4.24
237.005
3.25
123.892 143.402: 162.913!
3.75
175.318
199.500
4.35
237.785
3.26
124.425; 144.026 163.G27
3.76
175.972
200.251
4.36
238.565
3.37
124.9.59*144.650 164.341
3.77
176.625 '201.001
4.27
239.-348
3.2s
125.492 145.273 165.054
3.78
177.281 201.754
4.28
240.130
3.29
126.027; 145.8991 165.771
3.79
177.9.34 202.503
4.29
240.914
3.30
126.562 146.5241 166.486
3.80
178.591 203.259
4.30
241.698
^.31
127.098 147.1511167.204
3.81
179.245 ,204.010
4.31
242.481
3.32
127.634! 147.778
167.922
3.82
179.902 204.764
4.33
243.267
3.33
128.171 148.406
168.642
3.83
180.561
205..521
4.33
214.053
3.34
128.709 149.035
169.362
3.84
181.217
206.274
4.34
244.837
3.33
129.245!l49.663 170.081
3.S5
181.874 ,207.030
4.35
245.67D
3.36
129.7841 150.294' 170.803
3.86
182.534 1207.787
4.36
246.411
3,37
130.323 150.924 171.525
3.87
183.193 208.545
4.37
247.197
3.38
130.863: 151.555 172.249
3.88
183.8.52
209.302
4.38
247.986
3.39
131.402 152.187
172.972
3.89
184.513
210.062
4.39
248.774
3.40
131.947 1.52.825
173.702
3.90
185.173
210.821
4.40
249.562
3.41
132.482 153.451
174.420
3.91
185.834
211..5S0
4.41
250.352
3.43
133.023 154.084
175.146
3.93
186.713
212.587
4.42
251.141
3.43
133.565: 154.719
175.873
3.93
187.158
213.101
4.43
251.934
3.44
134.107 1.55.3541176.600 |
3.94
187.821
213.864
4.44
252.725
3.45
134.649
155.988
177.327
3.95
188.485
214.627
4.45
253.516
3.46
135.192
156.624
178.056
3.96
189.148
215.389
4.46
254.307
3.47
13.5.735
157.260
178.785
3.97
189.813
216.154
4.47
255.100
3.48
136.280
157.898
179.516
3.98
190.477
216.918
4.48
255.859
3.49
136.825
158.536
180.247
3.99
191.142
217.682
4.49
256.637
3.30
137.368
159.173
180.977
4.00
191.808
218.448
4.50
257.481
32
MEASUREMENT OF IRRIGATION WATER.
Table 2. — Discharge of standard Cippoletli and standard suppressed
rectangular weirs in cubic feet per second. Values below and
to left of heavy line deiermined experimentally; others com-
puted from the formula Q = 3.367 L H \ . (See paragraphs
10,
12 (
2nd 19.)
Length of weir L, feet.
Head //,
feet
#>
0.5
1.0
1.5
2.0
3.0
4.0
5.0 6.0
7.0
8.0
9.0
«.01
0.002
0.003
0.005
0.007
0.010
0.013
0.017
0.020
0.024
0.027
0.030
.02
.005
.010
.014
.019
.029
.038
.048
.057
.067
.076
.086
.US
.009
.018
.026
.035
.053
.070
.087
.105
.123
.140
.157
.04
.013
.027
.040
.054
.081
.108
.135
.162
.189
.215
.242
.05
.019
.038
.057
.075
.113
.151
.188
.220
.263
.301
.339
.06
.025
.050
.074
.099
.148
.198
.247
.297
.346
.396
.•499
.445
.07
.031
.062
.093
.125
.187
.249
.312
.374
.437
.561
.08
.038
.076
.114
.152
.229
.305
.381
.457
.633
.609
.686
.0»
.045
.091
.136
.182
.273
.364
.455
.545
.636
.727
.818
.10
.053
.107
.160
.213
.319
.426
.532
.639
.745
.852
.958
.11
.061
.123
.184
.246
.369
.491
.614
.737
.8601 .983
1.105
.12
.070
.140
.210
.280
.420
.560
.700
.840
.980
1.120
1.259
.13
.079
.158
.237
.316
.473
.631
.789
.947
1.106
1.202
1.420
a*
.088
.176
.265
.353
.529
.705
.882
1.058
1.245
1.411
1.587
AS
.098
.196
.293
.391
.587
.782
.978] 1 173
1.369 1.565
1.760
A6
.108
.216
.323
.431
.646
.862
1.077
1.293
1.508] 1.724
1.939
A7
.118
.236
.257
.354
.386
.472
.514
.708
.771
.944
1.028
1.180
1.285
1.416
1.543
1.652 1.SS8
1.800' 2.057
2.124
.18
.129
2.314
.19
.139
.279
.418
.558
.837
1.115
1.394
1.673
1.9521 2.231
2.509
.29
.151
.301
.452
.602
.903
1.205
1.506
1.807
2.108J 2.409
2.710
.21
.162
.324
.486
.648
.972
1.296
1.620
1.944
2.268 2.592
2.916
.22
.174
.347
.521
.695
1.042
1.390
1.737
2.084
2.432i 2.779
3.127
.23
.186
.371
.557
.743
1.114
1.485
1.857
2.228
2.599i 2.971
3.342
.24
.200
.396
.594
.792
1.187
1.583
1.979
2.375i 2.771; 3.167
3..563
.25
0.214
.421
.631
.842
1.263
1.683
2.104
2.525
2.946' 3.367
3.787
.2S
.446
.669
.893
1.339
1.785
2.232
2.678
3.124! 3.571
4.017
.27
.472
.709
.945
1.417
1.889
2.362
2.834
3.306
3.779
4.251
.28
.499
.748
.998
1.496
1.995i 2.494
2.993
3.492
3.991
4.4S9
.29
.526
.789
1.051
1.577
2.103
2.629
3.155
3.680
4.200
4.732
.30
.553
.830
1.106
1.660
2.213
2.766
3.319
3.872! 4.426
4.979
.31
.581
.872
1.162
1.743
2.324
2.905
3.487
4.06Si 4.649
5.230
.32
.609
.914
1.219
1.828
2.438
3.047
3.057
4.2G6i 4.875
5.486
.33
.638
.957
1.276
1.915
2.553
3.191
3.829! 4.467
5.100
6.744
.34
.067
1.001
1.046
1.335
1.394
2.002
2.091
2.670
2.788
3.337
3.486
4.005
4.183
4.672
4.880
5.340
6.577
6.007
.35
.697
6.274
.88
.727
1.091
1.4.'54
2.182
2.909
3.636
4.363
5.090
6.818
6.545
.37
.758
1.137
1.515
2.273
3.031
3.789
4.546
5.304
6.062
6.819
.38
.789
1.183
1.577
2.366
3.155
3.943
4.732
5.520, 6.309
7.098
.39
.82Q
1.230
1.640
2.460
3.280
4.100
4.920
5.740 6.560
7.380
.49
.852
1.27S
1.703
2.555
3.407
4.259
5.110
5.962
6.814
7.665
.41
.884
1.326
1.768
2.651
3.535
4.419
5.303
6.187
7.071
7.965
.42
.916
1.375
1.833
2.749 3.665
4.582
5.498
6.415
7.331
8.247
.43
.949
1.424
1.899
2.848
3.797
4.747
6.690
6.645
7.594
8. .544
.44
.983
1.474
1.965
2.948
3.930
4.913
6.896
6.878
7.861
8.843
.45
1.016
1.524
2.033
3.049
4.065
6.0s 1
6.098
7.114
8.130
9.147
.46
1.050
1.575
2.101
3.151
4.201
5.252
6.302
7.363
8.403
9.453
.47
1.0S5
1.627
2.170
3.254
4.339
6.424
6.509
7.594
8.678
9.763
.48
1.122
1.679
2.239
3.359
4.478
5. .598
6.718
7.837
8.957
10.076
.49
1.161
1.732
2.309
3.464
4.619
6.774
6.929
8.083
9.238
10.393
0.50
1.200
1.785
2.381
3.571
4.761
5.951
7.142
8.332
9.522
10.713
MEASUREMENT OF IRRIGATION WATER.
oo
Table 8 — Discharge of standard Cippoletti and standard suppressed
rectangular weirs in cubic feet per second. Values below and
to left of heavy line determined experimentally; others com-
puted from the formula Q = 3.367 L H\ . {See paragraphs
10, 12 and 19.)
Head //,
feet
Length of weir L, feet.
1.5 2.0 3.0 4.0
5.0
6.0
8.0 9.0
0.51
.&%
.63
.54
.55
.66
.57
.58
.59
.60
.61
.63
.63
.64
.G.5
.66
.67
.68
.69
.70
.71
.73
.73
.74
.75
.76
.77
.78
.79
.SO
.81
.83
.83
.84
.85
.86
.87
.88
.89
.90
.91
.93
.93
.94
.95
.96
.97
.93
.99
l.CO
1.S30
2.451|
1.891
2.5251
1.949
2.698
2.004
2.672
2.060
2.747
2.116
2.822
2.173
2.89S
2.231
2.974
2.289
3.051
2.347
3.129
2.406
3. 208
2.465
3.287
2.525
3.367
2.. 586
3.447
2.646
3.529
2.708
3.610
2.769
3.693
2.832
2.894
2.9.58
3.021
3.085
3.150
3.215
3.2Sn
3.810
3.895
3.980
4.06
4.15
4.24
4.33
4.415
4.51
4.60
4.69
4.78
4.87
4.96
5.05
5.14
5.24
5.34
5.44
5.64
5.64
5.74
5.84
5.94
6.04
6.14
6.25
6.36
6.47
6.58
6.69
6.80
6.91
3.679
4.905
6.131
7.357
3.787
5.050
6.312
7.575
3.897
5.196
6.495
7.794
4.008
5.344
6.680
8.016
4.120
5.493
6.866
8.239
4.233
6.643
7.054
8.465
4.346
5.795
7.244
8.693
4.461
6.948
7.435
8.923
4.. 577
6.103
7.629
9.154
4.694
6.259
7.823
9.388
4.812
6.416
8.020
9.624
4.931
6.574
8.218
9.861
5.051
6.734
8.417
10.101
5.171
6.895
8.619
10.342
5.293
7.057
8.821
10.586
5.415
7.221
9.026
10.831
5.539
7.386
9.232
11.078
5.663
7.551
9.439
11.327
5.789
7.719
9.64S
11.578
5.915
7.887
9.859
11.830
6.042
8.057
10.071
12.085
6.171
S.227
10.284
12.341
6.299
8.399
10.499
12.599
6.429
8.573
10.716
12.859
6.560
8.747
10.934
13.120
6.692
8.922
11.153
13.384
6.824
9.099
11.373
13.649
6.958
9.277
11.596
13.915
7.092
9.456
11.820
14.184
7.227
S.636
12.045
14.454
7.363
9.817
12.271
14.726
7.500
10.000
12.499
14.999
7.637
10.183
12.729
15.275
7.776
10.368
12.959
15.551
7.915
10.553
13.192
15.830
8.055
10.740
13.425
16.110
8.196
10.928
13.660
16.392
8.338
11.117
13.896
16.675
8.480
11.307
14.134
16.960
8.623
11.498
14.373
17.247
8.768
11.690
14.613
17.535
8.913
11.883
14.854
17.825
9.058
12.078
15.097
18.117
9.205
12.273
15.341
18.410
9.352
12.469
15.587
18.704
9.500
12.667
15.833
19.000
9.649
12.865
16.081
19.298
9.799
13.065
16.331
19.597
9.949
13.265
16.581
19.898
0.100
13.467
16.833
20.200
8.583
8.837
9.093
9.352
9.613
9.876
10.142
10.410
10.680
10.953
11.228
11.505
11.784
12.066
12.350
12.636
12.924
13.215
13.507
13.802
14.099
14.398
14.699
15.002
15.307
15.614
15.923
16.235
16.548
16.863
17.180
17.499
17.820
18.143
18.468
18.795
19.124
19.465
19.787
20.122
20.468
20.796
21.136
21.478
21.821
22.167
22.514
22.863
23.214
23.5671
9.809
10.099
10.392
10.688
10.986
11.287
11.591
11.897
12.206
12.517
12.832
13.149
13.468
13.790
14.114
14.441
14.771
15.103
15.437
15.774
16.113
16.455
16.799
17.145
17.494
17.845
18.198
18.554
18.912
19.272
19.634
19.999
20.366
20.735
21.107
21.480
21.858
22.234
22.614
22.996
23.380
23.767
24.155
24.546
24.939
25.334
25.731
26.129
26.530
26.933
11.036
11.362
11.691
12.024
12.359
12.698
13.039
13.384
13.761
14.082
14.436
14.792
15.151
15.514
15.879
16.247
16.617
16.991
17.367
17.746
18.127
18.611
18.899
19.2S8
19.680
20.075
20.473
20.873
21.276
21.681
22.089
22.499
22.912
23.327
23.745
24.165
24.588
26.013
26.441
25.871
26.303
26.738
27.175
27.614
28.056
28.500
28.947
29.395
29.847
30.300
34
MEASUREMENT OF IRRIGATION WATER.
Table 2 — Discharge of standard Cippoletti and standard suppressed
rectangular weirs in cubic feet per second. Values below and
to left of heavy line determined experimentally ; others com-
puted from the formula Q = 3.367 L Hi. (See paragraphs
10, 12 and 19.)
Length of wcir L, feet.
Head //.
feet
3.0
4.0
5.0
CO
7.0
8.0
9.0
1.01
10.46
13,671
17.089
20.504
23.921
27.338
30.756
i.oa
10.62
13.874
17.343
20.809
24.277
27.745
31.213
1.03
10.78
14.079
17.599
21.116
24.635
28.1,54
31.674
1.04
10.94
14.284
17.855
21.424
24.995
28.565
32.136
1.05
11.10
14.490
18.113
21.734
25.356
28.978
32.601
1.06
11.20
14.698
18.373
22.045
25.719
29.393
33.067
1.07
11.42
14.907
18.033
22.358
26.084
29.810
33.537
1.08
11. .58
15.116
18.895
22.672
26.451
30.229
34.008
1.09
11.74
15.326
19.158
22.987
26.819
30.650
34.481
1.10
11.90
15.538
19.423
23.305
27.189
31.073
34.957
1.11
12.06
15.750
19.688
23.623
27.560
31.497
35.435
1.12
12.22
15.964
19.955
23.943
27.933
31.924
35.915
1.13
12.38
16.178
20.222
24.264
28.308
32.353
36.397
1.14
12.54
16.393
20.491
24.587
28.685
32.783
36.881
1.15
12.71
16.609
20.761
24.911
29.063
33.215
37.367
1.16
12.88
16.826
21.033
25.237
29.443
33.649
37.856
1.17
13.05
17.044
21.305
25.564
29.825
34.085
38.346
1.18
13.22
17.263
21.579
25.893
30.20S
34.523
38.839
1.19
13.39
17.483
21.854
26.222
30.593
34.963
39.333
1.20
13.56
17.704
22.1.30
26.554
30.970
35.405
39.830
1.21
13.73
17.926
22.407
26.888
31.367
35.848
40.329
1.22
13.91
18.149
22.686
27.223
31.757
36.294
40.830
1.23
14.09
18.372
22.965
27.559
32.148
36.741
41.333
1.24
14.27
18.597
23.246
27.895
32.544
37.194
41.843
1.25
14.45
18.822
23.527
28.233
32.939
37.644
42.349
1.26
14.63
19.048
23.811
2S.573
33.335
38.097
42.859
1.27
14.81
19.276
24.095
28.913
33.732
38.551
43.370
1.28
14.99
19.504
24.380
29.456
34.132
39.008
43.874
1.29
15.17
19.733
24.666
29.599
34.532
39.466
44.399
1.30
15.35
19.962
24.953
29.944
34.934
39.925
44.915
1.31
15.53
20.154
25.242
30.290
35.339
40.307
45.436
1.32
15.71
20.425
25.531
30.638
35.744
40.850
45.957
1.33
15.89
20.658
25.822
30.986
36.151
41.315
46.480
1.34
16.07
20.891
26.114
31.337
36.560
41.782
47.005
1.35
16.25
21.125
26.407
31.688
36.969
42.250
47.532
1.36
16.44
21.360
26.701
32.041
37.381
42.721
48.061
1.37
16.63
21.596
26.995
32.394
37.793
43.192
48.591
1.38
16.82
21.834
27.292
32.750
38.209
43.667
49.126
1.39
17.01
22.071
27.589
33.121
38.625
44.142
49.660
1.40
17.20
22.310
27.887
33.465
39.043
44.620
50.197
1.41
17.39
22.549
28.187
33.824
39.401
45.098
50.736
1.42
17.58
22.790
28.487
34.184
39.882
45.579
51.277
1.43
17.77
23.031
28.789
34.546
40.304
46.062
51.819
1.44
17.96
23.272
29.091
34.909
40.727
46.545
52.363
1.45
18.15
23.516
29.395
35.273
41.152
4-7.031
52.910
1.46
18.34
23.759
29.699
35.639
41.579
47.518
53.458
1.47
18.53
24.004
30.005
36.005
42.006
48.007
54.008
1.48
18.72
24.249
30.311
30.374
42.436
48.498
54.501
1.49
18.91
24.495
30.619
36.743
42.867
48.990
55.114
1.50
19.10
24.742
30.928
37.114
43.299
49.485
55.669
MEASUREMENT OF IRRIGATION WATER.
35
Table 2 — Discharge of standard Cippoletti and standard suppressed
rectangular weirs in cubic feet per second, computed from
the formula Q = 3.367 L //I. {See paragraphs 10, 12
and 19.)
1
1
Length of weir L, feet.
Head H, \
feet
1
4.0
5.0
6.0
7.0
8.0
9.0
1.51
24.990
31.238
37.486
43.733
49.981
56.228
1.52
25.239
31.. 549
37,858
44,168
50.478
56.787
1.53
25.479
31.849
38.219
44.589
50.958
57.328
1.64
25.738
32.173
38.608
45.042
51.477
57.911
1.55
25.990
32.487
3S,9S4
45.482
51.979
58.477
1.56
26.242
32.802
39.362
45.923
52.483
58.944
1.57
26.494
33.118
39.742
46,365
52.989
59.612
1.58
26.748
33.435
40.122
46,809
53,496
60.183
1.59
27.002
33.753
40.504
47,2.54
54,005
60.755
1.60
27.253
34.066
40.879
47.692
54.506
61.319
1.61
27.513
34.391
41.270
48.148
55.025
61.906
1.62
27.770
34.713
41.655
48.597
55.. 540
62.483
1.63
28.028
35.035
42,041
49.048
56.055
63.062
1.64
28.286
35.357
42,428
49.500
56.571
63.623
1.65
28.545
35.681
42,817
49.953
57.090
64.226
1.66
28.805
36.006
43,207
50,408
57.610
64.811
1.67
29.066
36.332
43,598
50,865
58.131
65.398
1.68
29.327
36.659
43.991
51.323
58.654
65.986
1.69
29.589
36.987
44.384
51.781
59.178
66.576
1.70
29.852
37.315
44.778
52.241
59.704
67.167
1.71
30.116
37.645
45,174
52.703
60.232
67.761
1.73
30.381
37.976
45.571
53.196
60.762
6S.357
1.73
30.646
38.307
45.969
53.631
61.292
68.9.53
1.74
30.912
38.640
46.368
54.096
61.824
69.552
1.75
31.075
38.969
46.583
54.557
62.150
70.144
1.76
31.446
39.308
47.170
55.031
62.893
70.754
1.77
31.715
39.643
47.572
55..501
63,430
71.358
1.78
31.984
39.980
47.976
55,972
63,938
71.964
1.79
32.254
40.317
48.383
56,445
64,508
72.571
1.80
32.524
40.655
48.787
56,918
65.049
73. ISO
1.81
32.796
40.995
49.194
57..393
65,592
73.791
1.82
33.0G8
41.335
49.602
57,869
66.136
74-403
1.83
33.341
41.677
50,012
58,347
66.682
75.018
1.84
33.614
42.018
50,422
58,825
67.229
75.632
1.85
33.889
42.361
50.834
59,306
67.778
76.251
1.86
34.164
42.705
51.247
59.788
68.-329
76.870
1.87
34.440
43.050
51.660
60.270
68,580
77.490
1.88
34.717
43.396
52.075
60.754
69,434
78.113
1.89
34.994
43.743
52.491
61.239
69,988
78.737
1.90
35.272
44.091
52.909
61.727
70.545
79.003
1.91
35.551
44.439
53.327
62.215
71.102
79.990
1.92
35.830
44.788
53.746
62.703
71.661
80.618
1.93
36.111
45.139
54.166
63.194
72.222
81.249
1.94
36.392
45,490
54.588
63,686
72.784
81.882
1.95
36.674
45.842
55.010
64.179
72.347
82.516
1.96
36,956
46.195
55.434
64.673
73.912
83.142
1.97
37.239
46.549
55.869
65.169
74.478
83.788
1.98
37.523
46.904
56.285
65,666
75.046
84.427
1.99
37.808
47.260
56.712
66,164
75.616
85.068
2.00
38.094
47.617
57.140
66.664
76.187
85.711
36
MEASUREMENT OF IRRIGATION WATER-
Table 2 — Discharge of standard Ctppoleiti and standard suppressed
rectangular weirs in cubic feet per second, computed from
the formula Q = 3.367 L H^. (See paragraphs 10, 12
and 19.)
Length of weir L, feet.
5.a 6.0 7.0
47.974157.
48.333157
48.692;5S
49.052 58
49.413'59
49.775 59
50.138 60
50.502
50.809
51.225
51.597
51.966
52.335 1 62
.52.704163
53.073; 63
53.443164
53.817164
54.185165
•54.559165
54.930 '65
.55.307i66
•55.687 1 66
.56.061 67,
•56.440:67,
56.819I6S,
57.199i68.
57.57769
57.9.57,69
.58.34170
.58.715:70
59.105 70
.59.489171
.39.873 71
60.26272.
60.647172,
61.035173
6I.425I73,
61.S15i74,
62.203174
6.2.58575,
62.98775
63.377 76
56967,
999:67,
63.771
64.165
64.559
64.953 77,
65.3.53 78
65.747 78
66.147 79
66.540 79
,430
,862
,296
731
166
602
043
,470
916
3.59
803
245
638
131
580
023
471
916
369
764
273
728
183
638
093
518
009
458
925
336
848
314
776
243
710
177
644
102
581
052
525
998
471
,944
63,
63
69,
69,
70
70
71,
71,
72,
72,
73,
73,
74,
74,
75,
75,
76,
76.
77.
77.
78.
79.
79.
80
SO.
;^1
81.
S2
si
S3.
83
84
84
85
85.
86.
87.
87.
88.
38.
89.
89,
90,
90,
424 91
897 92
37692
848:93
164
665
169
673
,179
086
193
703
,217
715
236
752
,270
,786
302
819
.343
860
383
902
431
982
485
016
47
078
()09
40
077
201
46
284
822
67
885
450
995
540
085
019
182
727
279
831
383
935
494
047
8.0
9.0
Head
H,
feet
Length of weir L, feet.
6.0
76.
77.
77.
78.
79.
79.
80.
80.
81.
81.
82,
83,
83.
84.
84.
85.
86.
86.
87.
87.
88.
89.
89.
90.
90.
91.
92.
92.
93.
93.
94,
95
95,
96,
97,
97,
98,
98,
99,
100,
100.
101.
102.
102.
103.
103.
104.
10.5.
758
332
907
483
062
,041
221
803
390
960
555
146
737
326
917
508
106
097
295
888
492
099
86.;
86.!
87.i
88.;
88.'
89.
90.;
90.'
91.
92.:
92.;
93.
94.:
94.:
95.,
96.
98.:
97..
98.:
98.;
99..
100.:
(>9S!100.S
006 105
156 106
304
911
518
124
731
340
044
507
182
797
419
034
657
280
903
526
136
779
402
033
604
295
926
505
196
835
4G4
101.
102.:
102.'
103.'
104.:
105.1
105.'
100.:
107.1
107.'
108.'
109.
109.:
llO.i
111.
111.
112.1
113.:
114.
114.
115.
116.:
116.;
117.1
118.:
119.1
119.'
353
3.51
999
3.53
646
3.5;t
294
a.54
944
2.55
596
3.56
248
3.-57
904
3.58
564
3.59
205
3.00
875
3.01
539
3.63
204
3.63
867
3.64
531
3.65
197
3.66
870
3.67
534
8.68
207
3.69
874
3.70
553
3.71
237
3.73
910
3.73
592
3.74
275
3.75
957
3.76
639
3.77
323
3.78
014
3.79
087
2.80
38.S
3.81
079
3.83
771
3.83
472
3.84
164
3.86
864
3.86
565
3.87
260
3.88
966
3.89
653
3.90
377
3.91
078
3.93
787
3.93
497
3.94
207
3.95
910
3.96
635
3.97
345
3.98
045
3.99
772
3.00
80.
80,
81.
81.
82.
82.
83.
83.
SI.
84.
85.
85.
SO.
80.
87.
87.
88.
S3.
89,
S9,
90,
90,
91,
91,
92,
92.
93,
93,
94,
94.
95,
95,
90,
96,
97,
97,
93.
93,
99,
99,
100,
100.
101.
101.
102,
102,
103,
103,
104,
104.
335
814
299
7.0
8.0
9.0
93.
94,
94,
724 107,
779 95
264 95
74 9 j
2.34;
720 1
205
684
IS2I
6731
90.
97.
97.
98.
98.
99.
99.
165 100,
650 101.
093 101.
645; 102.
136 102.
027 103.
131 103.
616 104.
127 105.
02i 105.
127 106.
025 100.
123 107.
632 108.
136 108,
6;i9:l09,
148 109,
644 110.
162 111.
665; HI.
175,112.
691 112.
200 113.
107,
103
109,
109,
110
110
111
112
112
113
114,
283
849
409
975
541
107
673
239
798
379
952
5201114
099|115
609 110
116
117
118
na
552:119
1481120
72S 120
315 121
890 122
483 122
071 1 123
658' 124
2451 124
840 125
418 126
022: 120
6091 127
204! 123
800 1 123
253
820
393
930
120.502
121.221
121.949
122.008
123.396
124.123
124.852
125..580
120.308
127.026
127.773
128.610
129,247
129.984
130,039
860:131.407
516,132.205
.170 i;!2.941
.842' 133.097
4S8i 134.424
.169113,5.190
832' 13.5.930
503! 130.700
.166 137.437
838 138.192
510:138.948
18l|l39.703
852 140.459
118
752
399
038
686
332
979
626
274
912
.676
.231
886
554
.124
709
226
735
251
756
282
804
320
841
357
878
400
922
450
964
113
114
115
115
110
110
117
118
US
119,
120,
120
121
121
122
400
994
590
129
130
130
1911131
793' 1:^2
33211.33
990' 133
004 1 134
200 135
815 135
4171 130
025 137
03411,37
242 13,-J
S,-)8 139
458 139
531
.192
882
554
.233
921
000
279
967
.640
334
.008
.710
405
093
788
476
171
8(57
5(i2
260
952
141.223
141.060
1-12.743
143.498
144.262
145.036
145.800
146.564
147.338
143.102
143.876
149.034
1 .50.423
151.205
151.979
152.761
153.535
154.318
155.101
1.5,5.883
150.666
157.446
MEASUREMENT OF IRRIGATION WATER.
m
Table 2 — Discharge of standard Cippoletti and standard suppressed
rectangular weirs in cubic feet per second, computed from
the formula Q
and 19.)
3.367 L H% . {See paragraphs 10, 13
Head H,
feet
Length of weir L, feet.
7.0
8.0
9.0
Head H,
feet
Length of
weir L, feet.
8.0
9.0
I Length
of
Head//, feet,
feet
9.0
I
3.01
.3.02
3.03
3.0A
3.G.5
S.OC
3.07
3.«8
3.ft9
3.10
3.11
3.13
3.13
3.14
3.15
3.16
g.l7
3.18
3.19
3.30
3.;J1
3.23
3.23
3.24
3.35
3.36
3.37
3.28
3.29
3.30
3.31
3.32
3.33
3.34
3.35
3.36
3.37
3.38
3.39
8.40
3.41
3.43
3.43
3.44
8.45
3.46
3.47
3.48
3.49
3.50
123.082
12.'H.649
124.309,
124.925
125.643
126.130
126.7S0;
127.400
128.020i
128.632'
129.264
129.889
130.514
131.141
131.767
132.394
13:^.023
1.33.655
134.2851
134.9041
135.5501
13G.184;
136.8191
137.455
1.38.091'
138.729]
139.369
140.007
140.648
141.2741
141.&33!
142.576:
143.221
143.868
144.514
145.162
145.810
146.460
147.111
147.749
148.414,
149.067
149.722
150.377;
151.033
151.690
152.348
153.007
153.667
154.315
M0.G65
141.311,
142.06Si
142.771
143.478
144.183
144.891!
145.600]
146.309
147.008
147.730
148.444
149.158
149.875
150.591
151.307
152.020
152.749
153.408
1.54.176
154.914
155.G3S
156.304
157.091
157. 8]8
158.548
159.278
160.008
160.741
161.4.56
102.209
162.944
163.682
164.421
165.168
165.899
160.640
167.383
168.126
168.856
169.616
170.362
171.110
171.860
172.609
173.360
174.112
174.866
175.620
176.360
158.248
158.975
159.827
160.618
161.412
162.206
163.003
163.800
164.597
165.384
160.197
166.999
167.803
168.610
169.415'
170.221
171.030
171.842
172. G51
173.448
174.279
175.093
175.909
176.728!
177..546
178.367
179.1SS
180.009
180.833
181.638
182.485
183.312
184.142
134.973
185.803
186.637
187.470
188.306
189.142
189.963
190.818
191.658
192.499
193.343
194.185
195.0.30
195.876
196.724
197.573
198.405
3.51
3.53
3.53
3.54
3.55
3.56
3.57
3.58
3.59
s.eo
3.61
3.63
3.6a
3.6*
S.6S
3.6«;
3.GV
3.R8
3.C9
3.70
3.71
3.73
3>7^
3.74
3.75
3.76
S.77
3.78
3.79
3.80
3.81
3.83
S.8S
3.84
3.85
3.86
3.87
3.88
3.89
3.90
3.91
3.93
3.93
3.9*
3.93
3.96
3.97
3.98
3.99
4.0«
177.1.30
177.888
178.648:
179.407i
180.1671
180.930]
181.691
182.4561
183.222,
183.968'
184.7.54 >
185.522:
186.292]
187.0G2
187.833
18S.606
189.378,
190.154
190.930
191.688'
192.485,
193.263'
194.042
194.822
195.604
190.388,
167.171
197.958
198.742
199.512
200.31S
201.106
201.8981
202.6881
203.480:
204.272
205.070,
205.864
206.662
207.440
208.256
209.298
209.856
210.658
211.462
212.264
213.070
213.874
214.C80
215.464
199.270
200.1241
200.979
201.833
202.688
203.546
204.403
205.263
206.] 24
206.964'
207.8491
208.712i
209.579 i
210.445]
211.312!
212.182]
2I3.05il
213.9241
214.797;
215.649!
216.5451
217.4211
218.297;
219.175'
220.055'
220.937
221.818
222.702
223.584
22^^.451
225.357
220.245
227.357
228.024
228.915
229.806
230.703
231.597
232.494
!233.370i
234.2881
235.461
236.088;
236.991
237.894
238.797
239.703
240.609
241.515
,242.397
4.01
4.93
4.03
4.G4
4.95
4.06
4.07
4.«8
4.09
4.1«
4.11
4.13
4.13
4.1i
4.15
4.16
4.17
4.18
4.19
4.3«
4.31
4.33
4.'2I.1!
4.3i
4.3S
4.38
4.37
4.28
4.39
4.36
4.31
4.33
4.33
4.34
4.35
4.1(6
4.37
4.38
4.39
4.4«
4.41
4.43
4.43
4.44
4.45
4,4R
4.47
4.48
4.49
4.50
243.333
244.245
24 3.147
246.C70
246. OSS
247.900
248.815
249.733
250.624
251.. 550
252.444
253.415
254.340
255.263
256.183
2.57.115
2.58.043
'258.970
1259.899
I26O.8O2
261.763
202.697
263.6.30
264.500
265.503
266.439
267.370
268.313
209.2C0
270.171
271.140
272.0!;l
273.037
273.982
274.91:7
275.878
276.827
277.779
278.730
279.657
280.630
2^i..5t.O
282.. 54 9
2S3.5()u
2S4.4G3
285.421
286.382
287..345
288.306
289.242
38
MEASUREMENT OF IRRIGATION WATER.
Table 3 — Coefficients C to be applied to a discharge taken from
Table l or 2 for a head, H, to obtain the discharge of the
same weir zvhen a velocity of approach, v, exists; computed
Q' Dl
from the formula, C = ■ — = — -
Q H\
and 20.)
(See paragraphs 13
h
h'
H
V
0.2
0.4
0.6
0.8
1.0
1.5 2.0 2.5 3.0
3.5
4.0
5.0
0.4
0.0025
0.0002
1.014
1.007 1.004 1.004
1.004 1.002 1.002
1
1.0021.001
1.001
1.001
1.001
0.5
.0039
.0003
1.027
1.013 1.009^1.006
1.006 1.004 1.003
1.002 1.002
1.002
1.001
1.001
0.6
.0056
.0005
1.037
1.019 1.013 1.009
1.008 1.005 1.004
1.003 1.003
1.002
1.002
1.C02
0.7
.0076
.0007
1.050
1.026 1.017
1.013
1.011
1.007 1.006
1.004
1.004
1.003
1.003
1.002
0.8
.0099
.0010
1.064
1.033 1.022
1.016
1.014
1.009 1.007
1.006 1.005
1.004
1.003
1.003
0.9
.0126
.0014
1.082
1.042 1.029
1.021
1.018
1.012 1.009
1.007 1.006
1.005
1.005
1.004
1.0
.0155
.0019
1.098
1.051 1.034
1.027 1.022
l.OloJl.Oll
1.009 1.007
1.006
1.005
1.005
1.1
.0188
.0025
1.122
1.062 1.041
1.031
1.02611.017 1.013
l.Olli 1.009
1.008
1.007
1.006
1.2
.0224
.0033
1.141
1.072 1.049 1.037
1
1.031 1.021 1.016
1.013 1.011
1.009
1.008
1.007
1.3
.0263
.0041
1.163
1.084 1.057| 1.043
1.036 1.024 1.018
1.015 1.012
1.011
1.009
1.008
1.4
.0305
.0051
1.1S6
1.096 1.066 l.OoO; 1.041
1.028 1.021
1.017 1.014
1.012
1.011
1.010
1.5
.0350
.0064
1.208
1.109 1.075
1.057
1.047
1.032 1.024
1.019 1.016
1.014
1.012
1.011
1.6
.0398
.0079
1.225
1.122 1.084
1.065
1.052
1.035 1.027
1.022' 1.018
1.016
1.014
1.012
1.7
.0449
.0095
1.254
1.135 1.09311.071
1.059! 1.040 1.031
1.025 1.021
1.018
1.016
1.014
1.8
.0504
.0111
1.277
1.149 1.104
l.OSO
I.O65I 1.045 1.034
1.027 1.023
1
1.020
1.017
1.016
1.9
.0561
.0132
1.308
1.165 1.115
1.089
1.072 1.049 1.038
1.030 1.026
1.022
1.019
1.017
2.0
.0622
.01.54
1.335
1.181 1.126
1.097
1.079 1.055' 1.042
1.0.34 1.028
1.025
1.021
1.019
2.1
.0686
.0179
1.363
1.197 1.137
1.106
1.087 1 1.060^ 1.046
1.037 1.031
1.027
1.024
1.021
2.2
.0752
.0206
1.391
1.213 1.149
1.118
1.094
1.065
1.050
1.039 1.034
1.029
1.026
1.023
2.3
.0822
.0235
1.420
1.231 1.161
1.124
1.102
1.071
1.054
1.044 1.037 1.032
1.02s
1.025
2.4
.0895
.0268
1.449
1.248 1.176
1.134
l.llOj 1.077 1.059
1.047 1.040 1.034
1.030
1.027
2.5
.0972
.0303
1.480
1.266 1.187
1.145
1.119 1.083 1.063
1.051 1.043 1.037
1.033
1.02!)
2.6
.1051
.0340
1.511
1.285 1.200
1.155
1.128 1.088 1.068
1.055 1.046
1.040
1.035
1.032
2.7
.1133
.0381
1.542
1.303 1.213 1.166
1.1371.095 1.073
1.059 1.050
1.043
1.038
1.034
2.8
.1219
.0426
1.573
1.322 1.228 1.178
1.1461 1.100| 1.078
I.O63' 1.053
1.046
1.041
1.036
2.9
.1307
.0472
1.606
1.341 1.242:1.189
1.153^1.108
1.083 1.067 1.057
1.049
1.043
1.039
3.0
0.1399
0.0524
1.637
1.361 1.256 1.199
1.165 1.115
1.088 1.07211.061
1.053
1.046
1.041
MEASUREMENT OF IRRIGATION WATER.
39
Table 4 — Coefficients C'' to he applied to a discharge given byTable 1
or 2 for a head H to give discharge of same weir submerged.
computed front the formula C = =
Q
graphs 14 and 21.)
Qi {nH)\
H\
{Sec para-
d-h H
0.00
0.01
0.03
0.03
0.04
0.05
0.06
0.07
0.08
0.09
Tenths
te
0.0
1.000
1.006
1.009
1.009
1.011
1.011
1.011
1.009
1.009
1.007
.1
1.007
l.OOo
1.003
1.000
.997
.994
.991
.988
.983
.981
.2
.078
.973
.970
.966
.963
.958
.955
.951
.946
.942
.3
.939
.9"5
.931
.926
.921
.917
.913
.909
.903
.900
.4
.895
.891
.885
.881
.875
.871
.865
.859
.854
.848
.5
.842
.837
.831
.825
.819
.812
.806
.799
.792
.785
.6
.778
.771
.764
.756
.748
.740
.733
.724
.715
.707
.7
.698
.689
.680
.670
.660
.649
.639
.626
.615
.603
.8
.589
.576
.562
.547
.531
.517
.501
.486
.469
.453
6.9
.435
.416
.396
.375
.351
.323
.293
.255
.209
.144
,•
40
MEASUREMENT OF IRRIGATION WATER.
Tatle 5 — Acre-fcct equivalent to a given number of second-feet
flowing for a given length of time. (See paragraph 22.)
'
Hours
Minutfs
Second-
feet
f
15
30
45
1
2
3
i
5
6
0.01
0.00021
0.00041
0.00062
0.00083
0.00165
0.00248
0.00,331
0.00413
0.00496
.oqi
.000! 1
.00083
.00124
.00105
.00331
.00S96
.00661
.00826
.00992
.03
.000(52
.00124
.00186
.00248
.00496
.00744
.00992
.01240
.01488
.04
.00083
.00165
.00248
.00331
.00651
.00992
.01322
.01653
.019.83
.05
.00103
.00207
.00310
.00413
.00826
.01240
.010.53
.02066
.02479
.06
.00124
.00145
.00248
.00289
.00372
.00434
.00496
.00992
.01488
.01735
.01983
.02314
.02179
.02893
.02975
.07
.00579
.01157
.03471
.08
.OOlfio
.00331
.00496
.00061
.01322
.019,83
.02045
.03306
.03967
.09
.00186
.00372
.00558
.00744
.01488
.02231
.02975
.03719
.04463
.10
.00207
.00113
.00020
.00826
.01653
.02479
.03306
.04132
.04959
.11
.00227
.00455
.00682
.00909
.01818
.02727
.03636
.04545
.05455
.li
.00248
.00496
.00744
.00992
.01983
.02975
.03967
.04959
.05950
.13
.00269
.00537
.00806
.01074
.02149
.03223
.04297
.05372
.06446
.14
.002S9
.00579
.00808
.01157
.02314
.0.3471
.04628
.05785
.06942
.15
.00310
.00'.20
.00930
.01240
.02479
.0.3719
.04959
.06198
.07438
.16
.00331
.00061
.00992
.0132?
.02545
.03967
.05289
.06611
.07934
.17
.00351
.00702
.01054
.01405
.02810
.04215
.05620
.07025
.08430
.18
.00372
.00744
.01116
.01488
.02975
.04463
.05950
.07438
.08926
.19
.00393
.00785
.01178
.01,570
.03140
.04711
.06281
.07851
.09121
.20
.001 ! 3
.0032')
.01240
.01653
.03306
.04959
.06611
.08264
.09917
.21
.00434
.00S6S
.01302
.01735
.03471
.05207
.06942
.08678
.10413
.23
.00155
.00909
.01364
.01818
.03336
.05455
.07273
.09091
.10909
.23
.00475
.009,50
.01426
.01901
.03802
.05702
.07603
.09504
.11405
.24
.00^06
.00992
.01488
.01983
.03907
.05950
.07934
.09917
.11901
.25
.00517
.01033
.015.50
.02066
.04132
.06198
.08264
.10331
.12397
.26
.00537
.01074
.01611
.02149
.04297
.06446
.08595
.10744
.12893
.27
.00558
.01116
.01673
.02231
.04403
.06694
.08926
.11157
.13388
.28
.00579
.01157
.01735
.02314
.0i628
.06942
.09256
.11570
.13884
.29
.00599
.01198
.01797
.02397
.04793
.07190
.09587
.11983
.14380
.30
.00620
.01240
.018.59
.02479
.049.59
.07438
.09917
.12397
.14876
.31
.00640
.01281
.01921
.02562
.05124
.07686
.10248
.12810
.15372
.32
.00661
.01322
.01983
.02645
.05289
.079.34
.10579
.13223
.15868
.33
.00682
.01364
.02045
.02727
.05455
.08182
.10909
.13636
.16364
.34
.00702
.01405
.02107
.02810
.05620
.08430
.11240
.14049
.16859
.35
.00723
.01446
.02169
.02893
.05785
.08678
.11670
.14403
.17355
.36
.00744
.01488
.02231
.02975
.05950
.08926
.11901
.14876
.17851
.37
.00764
.01529
.02293
.03058
.06116
.09173
.12231
.15289
.18347
.38
.00785
.01570
.02355
.03140
.06281
.09421
.12562
.15702
.18843
.39
.00806
.01611
.02417
.03223
.06446
.09669
.12893
.16116
t 19339
.40
.00S26
.01653
.02479
.03306
.06611
.09917
.13223
.16529
.19835
.41
.00847
.01694
.02541
.03388
.06777
.10165
.13554
.16942
.20331
.42
.00868
.01735
.02603
.03471
.06942
.10413
.13884
.17355
.20826
.43
.00888
.01777
.02665
.03554
.07107
.10661
.14215
.17769
.21.322
.44
.00909
.01818
.02727
.03636
.07273
.10909
.14545
.18182
.21818
.45
.00930
.01859
.02789
.03719
.07438
.11157
.14876
.18595
.22314
.46
.00950
.01901
.02851
.03802
.07003
.11405
.15207
.19008
.22810
.47
.00971
.01942
.02913
.03884
.07769
.116.53
.15537
.19421
.23306
AH
.00992
.01983
.02975
.03967
.079.34
.11901
.15868
.19835
.23802
.49
.01012
.02025
.03037
.04049
.0,8099
.12149
.16198
.20248
.24297
0.50
0.01033
0.02066
0.03099
0.04132
0.08264
0.12397
0.16529
0.20661
0.24793
MEASUREMENT OF IRRIGATION WATER.
41:
Table 5 — Acrc-fcet equivalent to a given number of second-feet
flowing for a given length of time. {See paragraph 22.)
Second-
Minutes
Hours
feet
15
30
45
1
2
3
4
5
6
0.51
0.01054
0.02107
0.03161
0.04215
0.08430
0.12645
0.16859
0.21074
0.25289
.52
.01074
.02149
.03223
.04297
.08595
.12893
.17190
.21488
.25785
.53
.01095
.02190
.03285
.04380
.08760
.13140
.17521
.21901
.26281
.54
.01116
.02231
.03347
.04463
.08926
.13388
.17851
.22314
.26777
.65
.01136
.02273
.03409
.04545
.09091
.13636
.18182
.22727
.27273
.56
.01157
.02314
.03471
.04628
.09256
.13884
.18512
.23140
.27769
.67
.01178
.02355
.03533
.04711
.09421
.14132
.18843
.23554
.28264
.58
.01108
.02397
.03595
.04793
.09587
.14380
.19173
.23967
.28760
.59
.01219
.02438
.03657
.04876
.09752
.14628
.19504
.24380
.29256
.60
.01240
.02479
.03719
.04959
.09917
.14876
.19835
.24793
.29752
.61
.01260
.02521
.03781
.05041
.10083
.15124
.20165
.25207
.30248
.68
.01281
.02562
.03843
.05124
.10248
.15372
.20496
.25620
.30744
.63
.01302
.02603
.03905
.05207
.10413
.15620
.20826
.26033
.31240
.M
.01322
.02645
.03967
.05289
.10579
.15868
.21157
.26446
,31735
.65
.01343
.02686
.04029
.05372
.10744
.16116
.21488
.26859
.32231
.66
.01364
.02727
.04091
.05455
.10909
.10364
.21818
.27273
.32727
.67
.01384
.02769
.04153
.05537
.11074
.16611
.22149
.27686
.33223
.68
.01405
.02810
.04215
.05020
.11240
.16859
.22479
.28099
.33719
.69
.01426
.02851
.04277
.05702
.11405
.17107
.22810
.28512
.34215
.70
.01446
.02893
.04339
.05785
.11570
.17355
.23140
.28926
.34711
.71
.01467
.02934
.04401
.05S68
.11735
.17603
.23478
.29339
.35207
.72
.01488
.02975
.04463
.05950
.11901
.17851
.23802
.29752
.35702
.73
.01508
.03017
.04525
.06033
.12066
.18099
.24132
.30165
.36198
.74
.01529
.03058
.04587
.06116
.12231
.18347
.24463
.30579
.36694
.75
.01550
.03099
.04049
.06198
.12397
.18595
.24793
.30992
.37190
.76
.01570
.03140
.04711
.06281
.12562
.18843
.25124
.31405
.37685
.77
.01591
.03182
.04773
.06364
.12727
.19091
• .25455
.31818
.38182
.78
.01611
.03223
.04835
.06446
.12893
.193.39
.25785
.32231
.38678
.79
.01632
.03264
.04897
.06529
.13058
.19587
.26116
.32645
.39173
.89
.016.53
.03306
.04959
.06611
.13223
.19835
.26446
.33058
.39669
.81
.01673
.03347
.05021
.03694
.13388
.20083
.26777
.33471
.40165
.82
.01694
.03388
.05083
.06777
.13554
.20331
.27107
.33884
.40661
.83
.01715
.03430
.05145
.06359
.13719
.20579
.27438
.34297
.41157
.84
.01735
.03471
.05207
.06942
.13884
.20826
.27769
.34711
.41653
.85
.01756
.03512
.05269
.07025
.14049
.21074
.28099
.35124
.42149
.86
.01777
.03554
.05331
.07107
.14215
.21322
.28430
.35537
.42645
.87
.01797
.03595
.05393
.07190
.14380
.21570
.28760
.35950
.43140
.88
.v;l81S
.03636
.05455
.07273
.14.545
.21818
.29091
.36364
.43636
.89
.01839
.03678
.05517
.07355
.14711
.22066
.29421
.36777
.44132
.90
.01859
.03719
.05579
.07438
.14876
.22314
.29752
.37190
.44628
.91
.01880
.03760
.05640
.07521
.15041
.22562
.30083
.37603
.45124
.92
.01901
.03802
.03702
.07603
..15207
.22810
..30413
.38017
.45620
.93
.01921
.03843
.05764
.07686
.15.372
.23058
.30744
.38430
.46116
.94
.01942
.03884
.05826
.07769
.15537
.23306
.31074
.38843
.46611
.95
.01903
.03926
.05888
.07851
.15702
.23554
.31405
.39256
.47107
.96
.01983
.03967
.05950
.07934
.15868
.23802
.31735
.39669
.47603
.97
.02004
.04008
.06012
.08017
.16033
.24049
.32066
.40083
.48099
.98
.02025
.04049
.06074
.08099
.16198
.24297
.32397
.40496
.48515
.99
.02045
.04091
.06138
.08182
.16364
.24545
.32727
.40909
.49091
1.00
0.0206G
0.04132
0.06198
0.08264
0.16529
0.24793
0.33058
0.41322
0.49587
42
MEASUREMENT OF IRRIGATION WATER.
Table 5 — Acre-feet equivalent to a given number of cecond-feet
flowing for a given length of time. (See paragraph 22.)
Hours
10
11
12
13
14
15
0.00579
.01157
.01735
.02314
.02893
.03471
.04049
.04028
.nr,2()7
.0.3785
.00304
.00942
.07521
.080991
.08078
.09256'
.09835;
.104131
.10992!
.11570
.12149]
.12727
.133061
.138841
.14463
.15041
.15020
.16198
.16777!
.17355!
.17934'
.18512!
.19091!
.19069!
.202481
.20826 1
.21405
.219831
.22562!
.23140!
.23719!
.24297;
.24876!
.25455,
.26033;
.266111
.27190]
.27709
.283471
0.28926,0,
.00661
.01322
.01983
.02045
.03306
.03967
.04028
.05289
.05950
.00011
.07273
.07934
.Oj;595
.09256
.09917
.10579
.11240
.11901
.12562
.13223
.13884
,14545
,15207
,15808
,10529
,17190
,17851
.18512
,19173
,19835
.20496
.21157
,21818
.22479
,23140
,23802
.24463
.25124
,25785
.26446
.27107
,27769
.28430
.29091
.29752
.30413
.31074
.31735
.32397
33058
0.00744
.01488
.02231
.02975
.03719
.04463
.05207
.05950
.06694
.07438
.08182
.08926
.09669
.10413
.11157
.11901
.12645
.13388
.14132
.14876
.15620
.16304
.17107
.17851
.18595
.19339
.20083
.20826
.21570
.22314
.2.50.58
.23802
.24545
.25289
.26033
.20777
.27521
.28264
.29008
.29752
.30496
.31240
.31983
.32727
.33471
.34215
.34959
.35702
.36446
.37190
0.00826
.01653
.02479
.03306
.04 132
.04959
.05785
.OoOll
.07438
.0S264
.09091
.09917
.10744
.11570
.12397
.13223
.14049
.14870
.15702
.16529
.17355
.18182
.19008
.19835
.206611
.21488
.223141
.23140
.23907
.24793
.25620
.26446
.27273
.28099
.28926
.29752
.30579
.31405
.32231
.33058
.33884
.34711
.35537
.36364
.37190
.38017
.38843
.39669
.40496
0.41322
0.00909
■
0.00992
0.01074
0.01157
.01818
.01983
.02149
.02314
.02727
.02975
.03223
.03471
.03636
.03967
.04297
.04628
.04545
.04959
.05372
.05785
.0.5455
.05950
.06446
.06942
.0ti304
.06942
.07521
.08099
.07273
.07934
.08595
.09250
.08182
.08926
.09669
.10413
.09091
.09917
.10744
.11570
.10000
.10909
.11818
.12727
.10909
.11901
.12893
.13884
.11818
.12893
.13967
.15041
.12727
.13884
.15041
.16198
.13636
.14876
.10116
.17355
.14545
.15868
.17190
.18512
.15455
.16859
.18264
.19369
.16364
.17851
.19339
.20826
.17273
.18843
.20413
.21983
.18182
.19835
.21488
.23140
.19091
.20826
.22562
.24297
.20000
.21818
.23636
.25455
.20909
.22810
.24711
.26611
.21818
.23802
.25785
.27769
.22727
.24793
.268.59
.28926
.23636
.2,5785
.27934
.30083
.24.545
.26777
.29008
.31240
.25455
.27769
.30083
.32397
.26364
.28760
.31157
.33554
.27273
.29752
.32231
.34711
.28182
. .30744
.33300
.35868
.29091
.31735
.34380
.37025
.30000
.32727
.35155
.38182
.30909
..33719
.30529
.39339
.31818
.34711
.37003
.40496
.32727
.35702
.38678
.41653
.33636
.36694
.39752
.42810
.34545
.37686
.40826
.43967
.35455
.38678
.41901
.45124
.36304
.39669
.42975
.46281
.37273
.40661
.44049
.47438
.38182
.41653
.45124
.48595
.39091
.42645
.46198
.49752
.40000
.43636
.47273
.50909
.40909
.44628
.48347
.52006
.41818
.45020
.49421
.53223
.42727
.46011
.50496
.54380
.43636
.47603
.51570
.5.5537
.44545
.48595
.52045
.56694
0.45455
0.49587
0.53719
0.57851
0.0124C
.02479
.03719
.04959
.06198
.07438
.08678
.09917
.11157
.12397
.1363P
.14£76
.16116
.17355
.18595
.19835
.21074
.22314
.23554
.24793
.26033
.27273
.28512
.29752
.30992
.32231
.33471
.34711
.35950
.37190
.38430
.39669
.40909
.42149
.43388
.44628
.45868
.47107
.48347
.49587
.50826
.52066
.53306
.54545
.55785
.57025
.58264
.59504
.60744
0.61983
MEASUREMENT OF IRRIGATION WATER.
43
Table 5 Acre-fcct equivalent to a given number of second-feet
flowing for a given length of time. (See paragraph 22.)
Hours
Second-
feet
7
8
9
10
11
12
13
14
15
0.51
0.29504
0.33719 0.37934!0.42149
0.46304
0.50579
0.54793
0.59008
0.63223
.S2
.30083
.34380
.38678
.42975
.47273
.51570
.55868
.60165
.64463
.53
.30661
.35041
.39421
.43802
.48182
.52562
.50942
.61322
.65702
.54
.31240
.35702
.40165
.44628
.49091
.53554
.58017
.62479
.66942
.55
.31818
.30364
.40909
.45455
.50000
.54545
.59091
.63636
.68182
.56
.32397
.37025
.41653
.46281
.50909
.55537
.60165
.64793
.69421
.67
.32975
.37686
.42397
.47107
.51818
.56529
.61240
.65950
.70661
.58
.33554
.38347
.43140
.47934
.52727
.57521
.62314
.67107
.71901
.59
.34152
.39008
.43884
.48760
.53636
.58512
.63388
.68264
.73140
.GO
.34711
.39669
.44628
.49587
.54.545
.59504
.64463
.69421
.74380
.61
.35289
.40331
.45372
.50413
.55455
.60496
.65537
.70579
.75620
.62
.35868
.40992! .46116
.51240
.56364
.61488
.66611
.71735
.76859
.63
.36446
.41653
.46859
.52066
.57273
.62479
.67686
.72893
.78099
.64
.37025
.42314
.47603
.52893
.58182
.63471
.68760
.74049
.79339
.65
.37603
.42975
.48347
.53719
.59091
.64463
.69835
.75207
.80579
.66
.38182
.43636
.49091
.54545
.60000
.65455
.70909
.76364
.81818
.67
.38760
.44297
.49835
.55372
.60909
.66446
.71983
.77521
.83058
.6S
.39339
.44959
.50579
.58198
.61818
.67438
.73058
.78678
.84297
.69
.39917
.45620
.51322
.57025
.62727
.68430
.74132
.79835
.85537
.70
.40496
.46281
.52066
.57851
.63636
.69421
.75207
.80992
.86777
.71
.41074
.46942
.52810
.58678
.64.545
.70413
.76281
.82149
.88017
.72
.41653
.47603
.53554
.59504
.65455
.71405
.77355
.83306
.89256
.73
.42231
.48264
.54297
.60331
.66364
.72397
.78430
.84463
.90496
.74
.42810
.48926
.55041
.61157
.67273
.73388
.79504
.85620
.91735
.75
.43388
.49587
.55785
.61983
.68182
.74380
.80579
.86777
.92975
.76
.43967
.50248
.56529
.62810
.69091
.75372
.81653
.87934
.94215
.77
.44545
.50909
.57273
.63636
.70000
.76364
.82727
.89091
.95455
.78
.45124
.51570
.58017
.64463
.70909
.77355
.83802
.90248
.96694
.79
.45702
.52231
.58760
.65289
.71818
.78347
.84876
.91405
.97934
.80
.46281
.52893
.59504
.66116
.72727
.79339
.85950
.92562
.99173
.81
.46859
.53534
.60248
.66942
.73636
.80331
.87025
.93719
1.00413
.82
.47438
.54215
.60992
.67769
.74545
.81322
.88099
.94876
1.01653
.83
.48017
..54876
.61735
.68595
.75455
.82314
.89173
.96033
1.02893
.84
.48595
.55537
.62479
.69421
.76364
.83306
.90248
.97190
1.04132
.85
.49173
.56198
.63223
.70248
.77273
.84297
.91322
.98347
1.05372
.86
.49752
.56859
.63967
.71074
.78182
.85289
.92397
.99504
1.060U
.87
.50331
..57521
.64711
.71901
.79091
.86281
.93471
1.00661
1.07851
.88
.50909
.58182
.05455
.72727
.80000
.87273
.94545
1.01818
1.09091
.89
.51488
.58843
.66198
.73554
.80909
.88264
.95620
1.02975
1.10331
.90
.52066
.59504
.66942
.74380
.81818
.89256
.96694
1.04132
1.11570
.91
.52645
.60165
.67686
.75207
.82727
.90248
.97769
1.05289
1.12810
.92
.53223
.60826
.08430
.76033
.83636
.91240
.98843
1.06446
1.14049
.93
.53802
.61488
.69173
.76859
.84545
.92231
.99917
1.07603
1.15289
.94
.54380
.62149
.69917
.77686
.85455
.93223
1.00992
1.08760
1.16529
.95
.54959
.62810
.70661
.78512
.86364
.94215
1.02066
1.09917
1.17769
.96
.55537
.63471
.71405
.79339
.87273
.95207
1.03140
1.11074
1.19008
.97
.56116
.64132
.72149
.80165
.88182
.96198
1.04215
1.12231
1.20248
.98
.56694
.64793
.72893
.80992
.89091
.97190
1.0.5289
1.13388
1.21488
.99
.57273
.65455
.73636
.81818
.90000
.98182
1.06364
1.14545
1.22727
1.00
0.57851
0.66116 0.74380
0.82645
0.90900
0.99173
1.07438
1.15702
1.23967
44
MEASUREMENT OP IRRIGATION WATER.
Table 5 — Acre-feet equivalent to a given number of second-feel
flowing for a given length of time. {See paragraph 22.)
Hours
Second-
feet
13
17
18
19
30
31
Ti
33
24
0.01
0.01322
0.01405
0.01488
0.01570
0.01053
0.01735
0.01818
0.01901
0.01983
.02
.02645
.02810
.02975
.03140
.03306
.03471
.03636
.03802
.03967
.03
.03907
.04215
.01463
.04711
.04959
.05207
.05455
.05702
.05950
.04
.05289
.05620
.05950
.00281
.00611
.06942
.07273
.07603
.07934
.03
.06611
.07025
.07438
.07851
.08264
.08678
.09091
.09504
.09917
.06
.079.34
.08430
.08926
.00421
.09917
.10413
.10909
.11405
.11901
.07
.09256
.09835
.10413
.10992
.11570
.12149
.12727
.13.306
.13884
.08
.10579
.11240
.11901
.12562
.13223
.13884
.14.545
.1.5207
.15868
.09
.11901
.12645
.13388
.14132
.14S76
.15620
.16364
.17107
.17851
.10
.13223
.14049
.14876
.1.5702
.16529
.17355
.18182
.19008
.19835
.11
.14545
.154.55
.16304
.17273
.18182
.19091
.20000
.20909
.21818
.1«
.15808
.16859
.17851
.18843
.19835
.20826
.21818
.22810
.23802
.13
.17190
.18264
.193.39
.20413
.21488
.22562
.23636
.24711
.25785
.14
.18512
.19069
.20S26
.21983
.23140
.24297
.2,5455
.26611
.27769
.16
.19835
.21074
.22314
.23554
.24793
.26033
.27273
.28512
.29752
.16
.21157
.22479
.23802
.25124
.26446
.27769
.29091
.30413
.31735
.17
.22479
.23884
.25289
.20694
.28099
.29504
.,30909
.32314
.33719
.18
.2.3802
.25289
.26777
.28264
.29752
.31240
.32727
.34215
.35702
.10
.25124
.26694
.28264
.29835
.31405
.32975
..34545
.36116
.37686
.20
.26446
.28099
.29752
.31405
.33058
.34711
.36364
.38017
.39669
.31
.27769
.29.504
.31240
.32975
.34711
.36440
.38182
.39917
.41653
.23
.29091
.30909
.32727
.34.545
.36364
.38182
,40000
.41818
.4.3636
.23
.30413
.32314
.34215
..30116
.38017
.39917
.41818
.43719
.45620
.24
.31735
.33719
.35702
.37686
.39069
.41653
.43636
.45620
.47603
.25
.33058
.35124
.37190
.39256
.41322
.43388
.45455
.47521
.49587
.26
.34380
.30529
.38078
.40826
.42975
.45124
.47273
.49421
.51570
.37
.35702
.37934
.40165
.42397
.44628
.46859
.49091
.51322
.53554
.28
.37025
.39339
.41653
.43967
.40281
.48595
.50909
.53223
.55537
.2!)
.38347
.40744
.43140
.45537
.47934
.50331
.52727
.55124
.57521
.30
.39669
.42149
.44628
.47107
.49587
.52006
.54545
.57025
.59504
.31
.40992
.43554
.40116
.48078
.51240
.53802
.56364
.58926
.61488
.33
.42314
.44959
.47603
.50248
.52893
.55537
.68182
.60826
.63471
.33
.43636
.46364
.49091
.51818
.54545
.57273
.60000
.62727
.65455
.34
.44959
.47769
.50579
.53388
.56198
.59008
.61818
.04628
.67438
.35
.46281
.49173
.52006
.54959
.57851
.60744
.63636
.66529
.69421
.36
.47603
.50579
.53554
.56529
.59504
.62479
.05455
.681.30
.71405
.37
.48926
.51983
.55041
.58099
.61157
.64215
.07273
.70331
.73388
.38
.50248
.53388
.50529
.59069
.62810
.65950
.69091
.72231
.75372
.39
.51.570
.54793
.58017
.61240
.64463
.67686
.70909
.74132
.77355
.40
.52893
.56198
.59,504
.62810
.60116
.69421
.72727
.76033
.79339
.41
.54215
.57603
.00992
.64380
.67769
.71157
.74545
.77934
.81322
.43
.55537
.59008
.62479
.659.50
.69421
.72893
.76364
.79835
.83306
.43
.56859
.60413
.63967
.67.521
.71074
.74628
.78182
.81735
.85289
.44
.58182
.61818
.654.55
.60091
.72727
.76364
.80000
.83636
.87273
.45
.59504
.63223
.60942
.70061
.74380
.78099
.81818
.85537
.89256
.4«
.60826
.64628
.(58430
.72231
.70033
.79835
.83036
.874.38
.91240
.47
.02149
.60033
.09917
.73802
.77086
.81570
.S5455
.89339
.93223
.48
.>i.3471
.67438
.71405
.75372
.79339
.83306
.87273
.91240
.95207
.49
.r.4793
.68843
.72893
.70942
.80992
.8.5041
..S9091
.93140
.97190
0.50
0.06116
0.70248
0.74380
0.78512
0.82645
0.86777
0.90909
0.95041
0.99173
MEASUREMENT OF IRRIGATION WATER.
45
Table 5 — Acre-feet equivalent to a given number of secoiid-feet
flowing for a given length of time. (See paragraph 32.)
Hours
Second-
feet
16
17
18
19
29
21
23
23
24
0.51
0.67438
1 1
0.71853 0.75868 0.800S3
0.84297
0.8S512
0.92727
0.96942
1.011.57
.53
.6S7bO
.73058 .77355
.81653
.85950
.90248
.94545
.98843
1.03140
.53
.700S3
.74463 .78843
.83223
.87603
.91983
.96364
1.00744
1.05124
.54
.71405
.75868 .80331
.84793
.89256
.93719
.98182
1.02045i 1.07107
.55
.72727
.77273 .81318
.80364
.90909
.95455
1.00000
1.04545! 1.09091
.56
.740-i9
.78078 .83306
.87934
.92562
.97190
1.01818
1.00446 1.11074
.57
.75372
.80083
.84793
.89504
.94215
.98926
1.03636
1.08347 1.13058
.58
.76694
.81487
.80281
.91074
.95868
1.00661
1.05455
1.10248 1.15041
.59
.78017
.82893
.87769
.92645
.9752!
1.02.397
1.07273
1.121491 1.17025
.60
.79339
.84297
.89256
.91215
.99173
1.04132
1.09091
1.14049 1.19908
.61
.8006 1
.85702
.93744; .95785
1.00S26
1.0586S
1.10909
1.15950 1.20992
.63
.S19S3
.87107
.922311 .97355
1.02479
1.07603
1.12727
1.178511 1.22975
.63
.83306
.83512
.937191 .9S926
1.04132
1.09339
1.14545
1.197.521 1.24959
.64
.84628
.89917
.9520711.00496
1.05785
1.11074
1.16364
1.21653! 1.26942
.65
.859o0
.91.322 .9669411.02066
1.07438
1.12810
1.18182
1.23554! 1.2S926
.66
.87273
.92727 .93 lS2i 1.03036
1.09991
1.14545
1.20000
1.25455| 1.30909
.67
.88595
.94132 .90669] 1.05207
1.10744
1.16281
1.21818
1.27355; 1.32893
.68
.89917
.9.553711.01157,1.06777
1.12397
1.18017
1.23636
1.29256
1.. 34876
.69
.91240
.96012] 1.02645J1.08347
1.14049
1.19752
1.2.5455
1.31157
1.36859
.70
.92562
.98347 1.04132 1.09917
1.15702
1.21487
1.27273
1.33058
1.38843
.71
.93834
.99752 1.05620 1.11483
1.17355
1.23223
1.29091
1.34959
1.40S26
.73
.95207
1.01157, 1.07107|1.13058
1.19008
1.24959
1.30909
1.36859
1.42810
.73
.96529
1.025671 1.08595 1.14628
1.20661
1.26694
1.32727
1.38760
1.44793
.74
.97851
1.03967il.l0083'l. 16198
1.22314
1.28430
1.34545
1.4000!
1.46777
.75
.99173
1.0537211. 11570il. 17769
1.23967
1.30165
1.3C364
1.42562! 1.48700
.76
1.00496
1.0677711. 1305811. 19339
1.25620
1.31001
1.3S1S2
1.44463
1.50744
.77
1.01818
1.08182il.l4545il.20909
1.27273
1.33636
1.40000
1.40364
1.52727
.7S
1.03140
1.095S7|l.lG033jl.22479
1.28926
1.35372
1.41818
1.48204
1.54711
.78
1.04463
1. 10902a. i7521jl.24049
1.30579
1.37107
1.43036
1.501651 1.56094
.80
1.05785
1.12397il.l9008i 1.2.5620
1.32231
1.38S43
1.45455
1.52066
1.58678
.81
1.07107
1.13892, 1.20490]!. 27190
1.33SS4
1.40579
1.47273
1.63967
1.00001
.83
1.084.30
1.15207]1.21983 1.28760
1.35537
1.42314
1.49091
1.55S6S
1.C2645
.83
1.09752
1.166U,1.23471]1.3033i
1.37190
1.44049
1.50909
1.57769
1.64028
.84
1.11074
1. 18017]!. 2495911.31901
1.38843
1.45785
1.52727
1.59670
1.666!!
.85
1.12.397
1.10421 1.20440]1.3347!
1.40496
1.47521
1.54545
1.61570
1.68595
.86
1.13719
1.20826 1.27934|1.3.W4!
1.42149
1.49256
1.56364
1.6347!
1.70579
.87
1.15041
1.22231,1.29421:1.36611
1.43302
1.50992
1.58182
1.653721 1.72502
.88
1.16364
!. 23636]!. 30909;1.3S182
1.45455
1.52727
1.60000
1.67273 1.74515
.89
1.17686
1.25041 1.32397 1.39752
1.47107
1.54463
1.61818
1.69173 1.76529
.90
1.1900S
1.264-16 1.33884,1.41322
1.48760
1.56198
1.63036
1.71074 1.78512
.91
1.20331
1.27851 1.. 3.5372 11.42893
1.50413
1.57934
1.65155
1.72975 1.80496
.93
1.21653
1.29256 1.30859,1.44463
1.52066
1.59669
1.67273
1.74870
1.82479
.93
1.22975
1..3061U 1.. 38347 1.46033
1.53719
1.61405
1.69091
1.76777
1.84463
.94
1.24297
1.32066 1.39835 1.47603
1.55372
1.63140
1.70909
1.78678
1.86446
.95
1.25620
1.3347! 1.41322 1.49173
1.57025
1.64876
1.72727
1.8057S
1.83430
.96
1.26942
1.34 376 1.42810,1.50744
1.58678
1.66011
1.74545
1.82479
1.90413
.97
1.28264
1.36281 1.44297:1.52314
1.60331
1.68347
1.76364
1.84380
1.92397
.98
1.29587
1.37686,1.45785,1.53884
1.61983
1.70083
1.78182
1.86281
1.94380
.99
1.30909
1.39091 1 1.47273 i 1.55455
1.63636
1.71818
1.80000
1.88182
1.96364
1.00
1.32231
1.40496 1.48760
1.57025
1.65289
1.73554
1.81818
1.90083
1.98347
46
MEASUREMENT OF IRRIGATION WATER.
Tatle 5 — Acre-feet equivalent to a given number of second-feet
flowing for a given length of time. {See paragraph 22.)
i
Days of 24 Hours
Second-
feet
3
3
4
5
1
7
8
9
10
0.01
0.03967
1
0.05950 0.07934
0.09917
0.11901
0.13884' 0.1586S
0.17851 0.19835
.02
.07934
.119U1| .15868
.19835
.23S02
.27769
.31735
.35702
.39669
.63
.11901
.178511 .23802
.29752
.35702
.41653
.47603
.53554
.59504
.04
.15868
.2.3802 .31735
.39669
.47603
.55537
.63471
.71405
.793.39
.05
.19835
.29752
.39669
.49.587
.59504
.69421
.79339
.89256
.99173
.06
.23802
.35702
.47603
.59504
.71405
.833061 .95207
1.07107
1.19008
.07
.27769
.41653
.55537
.69421
.83306
.97190 >. 11074
1.24959
1.38842
.08
.31735
.47603
.63471
.79339
.95207
1.11074 1.26942
1.42810
1.58678
.09
.35702
.53554
.71405
.89256
1.07107
1.24959 1.42810
1.60661
1.78512
.10
.39669
.59504
.79339
.99173
1.19008
1.38843 1.58678
1.78512
1.98347
.11
.43636
.65455
.87273
1.09091
1.30909
1.527271 1.74.545
1.96364
2.18182
.13
.47603
.71405
.95207 1.19008
1.42810
1.68611 1.90413
2 14215 2.38016
.13
.515701 .77355
1.03140 1.28925
1.54711
1.80496 2.022811 2.32066, 2..57851
.14
.55537 .83306
1.1107411.38842
1.66611
1.94380 2.221491 2.49917, 2.77630
.15
.59504
.89256
1.19009
1.48760
1.78512
2.0S264| 2.38017 2.67769
2.97520
.16
.63471
.95207
1.26942
1.58678
1.90413
2.22149 2..53884 2.85620
3.173.55
.17
.67438
1.01157
1.34876
1.68595
2.02314
2.36033t 2.697.521 3.03471
3.37190
.18
.71405
1.07107
1.42810
1.78512
2.14215
2.49917 2.856201 3.21322
3.57025
.19
.75372
1.13058 1.50744
1.88430
2.26116
2.63802 3.01487
3..39173
3.76859
.30
.79339
1.19008' 1.58678
1.98347
2.38017
2.77686 3.17355
3.57025
3.96694
.31
.83306
1.24959 1.66611
2.08264
2.49917
2.91570
3..33223
3.74876
4.16529
.33
.87273
1.30909 1.74545
2.18182
2.61818
3.054.55
3.49091
3.92727
4.36363
.33
.91240
1.36859; 1.82479
2.28099
2.73719
3.193.39
3.64959i 4.10578
4.50193
.34
.95207
1.42810 1.90413
2..38016
2.85620
3.33223
3.80826 4.28430
4.76033
.35
.99173
1.48760 1.98347
2.47934
2.97521
3.47107
3.96694 4.462811 4.95867
.36
1.03140 1.5471li2.08281
2.57851
3.09421
3.60992
4.125621 4.64132
5.15702
.37
1.07107 1.6066112.14215
2.67768
3.21322
3.74876
4.28430
4.81983
5.35537
.38
1.11074 1.6661112.22149
2.77686
3.33223
3.88760
4.44297
4.99835
5.55372
.39
1.1.5041 1.72562' 2.30083
2.87603
3.45124
4.02645
4.60105
5.17686
5.75206
.30
1.19008 1.78512 2.38017
2.97520
3.57025
4.16529
4.76033
5.35537
5.9.5041
.31
1.22975' 1.84463 2.45950
3.07438
3.68925
4.30413
4.91901
5.53388
6.14876
.33
1.26942 1.90413 2.53884
3.17355
3.80826
4.442971 5.07769
5.712401 6.34710
.33
1.30909
1.96364 2.61818
3.27273
3.92727
4.58182
5.23636
5.89091 1 6.54545
.34
1.34876
2.0231412.69752
3.37190
4.04628
4.72066
5.39504
6.06942, 6.74380
.35
1.38843
2.0826412.77686
3.47107
4.16529
4.85950
5.55372
6.247931 6.94215
.36
1.42810
2.1421512.85620
3,57025
4.28430
4.99835
5.71240
6.42645! 7.14049
.37
1.46777
2.20165'2.93554
3.66942
4.40331
5.1.3719
5.87107
6.604961 7.33884
.38
1.50744
2.26116'3.014S7
3.76859
4.52231
5.27603
6.02975
6.78347
7.53719
.39
1.54711
2..32066'3.09421
3.86777
4.64132
5.41487
6.18843
6.96198
7.73553
.40
1.58678
2.38017
3.173.55
3.96694
4.76033
5.5.5372
6.34711
7.14049
7.93388
.41
1.62645
2.43967
3.25289
4.06611
4.87934
5.69256
6.50578
7.31901
8.13223
.42
1.66611
2.49917
3.33223
4.16529
4.99835
5.83140
6.66446
7.49752
8.33057
.43
1.70579
2.55868
3.41157
4.26446
5.11735
5.97025
6.82314
7.67603
S.52892
.44
1.74545
2.61818 3.49091
4.36363
5.23636
6.10909
6.98182
7.85455
8.72727
.45
1.78512
2.6776913.57025
4.46281
5.35537
6.24793
7.14049
8.03305
8.92561
.46
1.82479
2.73719 3.649.5914.56198
5.47438
6.38678
7.29917
8.21157
9.12396
.47
1.86446
2.7966913.72893
4.66115
5.59339
6.52562
7.45785
8.39008
9.32231
.48
1.90413
2.85620
3.80826
4.7()033
5.71240
6.66446
7.616.53
8.56859
9.52066
.49
1.94380
2.91570
3.88760
4.85950
5.83140
6.80331
7.77521
8.74711
9.71900
0.50
1.98347
2.97621
3.96694
4.95867
5.95041
6.94215
7.93388
8.92561
9.91735
MEASUREMENT OF IRRIGATION WATER.
47
Table 5 — Acre-feet equivalent to a given number of second-feet
flowing for a given length of time. (See paragraph 22.)
Days of $4 Hours
10
02.314 3.03471 4.
0u2Si 3.
10248'3.
1421.5;3,
18182 3.
09421
15372
21322
27273 4
221491 3.33223 1 4
391734
45124 4
261163,
.30083 3.
34049' 3.
3S017i3.
419S3[3.
459.50 3,
4991713.
53884:3,
57S5ll3,
618183,
657853,
69752 4,
737194,
7768614,
SI653I4,
85620 4,
S95S7
93554
97521
0148714
05455 4
09421
13388
17355
21322
25289
29256
33223
37190
41157
45124
4909115
53058|5
57025 1 5
60992 1 5
64959'5
68925,5
72893 is
3
3
3,
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3,
3.927:
768.59 5
80826
84793
88760
92727
95694
51074
57025
62975
68925|4
74876 4
.80826
86777
92727
98678
04628
10578
16.529
22479
28430
34380
40331
46281
52231
58182J6
64132 6
70083
76033
81983
87934
93.SS4
99S35
05785
11735
17686
23636
29587
35.537
41487
47438
5338S
59339
65289
71240
77190
83140
89091
95041
04628 5.
12562,5.
204965,
28430!5,
36364'5,
44297J5,
52231 5,
601655,
6S099 5,
76033 5
83967! 6
9190116
99835
07769
15702
23636
31570
39504
47438
55372
63306
71240
79173
87107
95041
02975
10909
18843
26777
34711
42645
50578
58512
66446
74380
82314
90248
98182
06116
14049
21983
29917
37851
45785
53719
616.53
69587
77521
8.5455
93388
05785
15702
25619
35537
45454
553721 6
.65289 6
.75206
85124
95041
04958
.14876
24793
34710
.44628
54545
64462
74380
.84297
94215
04132
.14049
23907
,33884
43801
53719
63636
73553
83471
93388
03305
13223
23140
33057
42975
52S92I10
62809' 10
72727110
82644! 10
92561110
02479 10
12396' 10
22313|11
32231111,
,06942
,18843
,30744
,42645
,54545
,66446
,78347
,90248
.02149
.14049
.25950
.37851
.49752
.61653
.73554
.8.5455
.97355
.09356
.21157
.33058
.44959
,56859
,68760110,
,80661110,
,92562110,
,04463110.
.16364110.
,28264 10,
,401651 10.
,52066111,
,63967 11.
,75868 11.
,87769!ll.
,99669!ll.
,11570 11,
,2.3471 11.
,35372 12.
,47273 12.
,59173! 12,
,71074! 12.
,82975 12.
08099
219,83
35868
49752
63636
77521
91405
0.5289
19173
33058
46942
60826
74711
88595ilO,
02479 1 10
16364 10,
30248 10
.44132 10.
58016
71901
85785
99669111
13554 11
274381 11
41322,11
94876
08777
18678
42148
52066
619S3
71900
81818
91735
11.30578113.
11
11
11
11
11
.424 (y
.54380
.66281
.78182
.90083
55207
69091
82975
96859
10744
24628
38512
52397
66281
80165113
940491 13
079.34113
218181 13
35702114
495871 14,
63471 14,
77355! 14
91240 14,
05124' 14.
1900SI15
328934.5.
46777
60661
74545
88430
09256
25124
40992
56859
72727
88595
04463
20331
36198
52066
67934
838021 11
99669 11
15537 11
31405:11
47273 11
63140 11
79008112
94876:12
10744112
26611112
,42479 12
58347 13
74215113
90083,13
0595013
21818,13
37686 13
53554
69421
85289
01157
17025
32893
48760
6462S
80496
96363
12231
28099
43967
59835
75702
91570
07438
23306
39173
55041
70909
86777
.10413 10
.28264 10,
.46116 la
.63967110
8181810
99669
17521
35372
53223
71074
88925
06777
24628
42479
60331
.78182
.96033
.138,84
.31735
.49587
67438
85289
03140
20992 14
38843 14
56694 15
74.545 15,
92397 15
1024815,
2809915
4595016
6380116
81653!l6
9950416
17355! 16,
35207il7
53058' 17,
7090917,
8876017,
0661117,
.24463! 18,
42314 18
60165
78016
95868
13719
31570
49421
67273
85124
11,570
.31404
51939
.71074
.90909
10743
.30578
50413
.70247
.90082
.09917
.29751
.49586
.69421
.892.55
.09090
28925
.48760
.68594
88429
.082t)4
.28098
47933
.67768
87603
07437
27272
47107
.66941
.86770
.06611
.26445
,46280
,66115
,85919
,057,?4
,25619
,454.54
,65288
85123
04958
24792
44627
64462
84297
04131
23906
43801
63635
83470
48
MEASUREiMKNT OF IRRIGATION WATER.
Table 6. — Discharge of standard submerged rectangular orifices in
cubic feet per second, computed from the formula Q =■
0.61 yZgH A. (See paragraphs 28 and 34.)
Head H,
Cross-sectional area A of orifice, square feet.
feet.
0.35
0.5
0.J5
1.0 j 1.35
1.5
1.75
2.0
0.01
.03
.03
.04
.05
.06
.07
.08
.09
.10
.11
.12
.13
.14
.15
.16
.17
.18
.19
.■M
.21
.28
.23
.U
.25
.26
.27
.28
.29
.30
..31
.32
.33
.34
.35
.30
.37
.38
.30
0.40
0.122
0.245
0.367
0.489
0.611
0.173
0.346
0.518
0.G91
0.S04
0.212
0.424
0.635
0.S47
1.059
0.245
0.489
0.734
0.97S
1.223
0.273
0.547
0.820
1.093
1.367
0.300
0.599
0.899
1.198
1.497
0.324
0.647
0.971
1.294
1.617
0.346
0.691
1.037
1.383
1.729
0.367
0.734
1.101
1.468
1.835
0.387
0.773
1.160
1.557
1.933
0.406
0.811
1.217
1.622
2.027
0.424
0.847
1.271
1.694
2.118
0.441
0.882
1.323
1.764
2.205
0.458
0.915
1.373
1.830
2.287
0.474
0.947
1.421
1.895
2.369
0.489
0:978
1.467
1.95G
2.445
0.504
1.008
1.512
2.01C
2.520
0.519
1.037
1.556
2.075
2.593
0.533
1.066
1.599
2.132
2.605
0.547
1.094
1.641
2.188
2.735
0.561
1.120
1.681
2.241
2.801
0.574
1.148
1.722
2.296
2.870
0.5S7
1.172
1.759
2.345
2.931
0.600
1.198
1.797
2.396
2.995
0.612
1.223
1.834
2.446
3.057
0.624
1.247
1.871
2.494
3.117
0.636
1.270
1.906
2.541
3.176
0.646
1.294
1.942
2.589
3.236
0.6.59
1.319
1.978
2.638
3.297
0.670
1.339
2.009
2.078
3.347
0.681
1.363
2.045
2.726
3.407
0.C92
i.3S2
2.073
2.704
3.455
0.703
1.405
2.107
2.810
3.513
0.713
1.426
2.139
2.852
3.565
0.724
1.446
2.169
2.892
3.615
0.734
1.467
2.201
2.934
3.667
0.745
1.488
2.232
2.976
3.720
0.754
1.508
2.262
3.016
3.770
0.764
1.527
2.291
3.054
3.818
0.774
1.547
2.321
3.094
3.867
0.734
1.037
1.271
1.468
1.640
1.797
1.941
2.074
2.201
2.320
2.433
2.542
2.645
2.745
2.842
2.934
3.024
3.112
3.198
3.282
3.361
3.464
3.517
3.599
3.668
3.741
3.811
3.883
3.956
4.017
4.089
4.146
4.215
4.278
4.338
4.401
4.464
4.524
4.582
4.641
0.856
1.210
1.483
1.712
1.913
2.097
2.265
2.420
2.638
2.707
2.839
2.965
3.086
3.203
3.316
3.423
3.528
3.631
3.731
3.829
3.921
4.018
4.103
4.193
4.280
4.365
4.446
4.530
4.616
4.687
4.771
4.837
4.917
4.991
5.061
5.135
5.208
5.278
5.345
5.415
0.978
1.382
1.G94
1.957
2.186
2.396
2.588
2.766
2.935
3.094
3.244
3.389
3.527
3.660
3.790
3.912
4.032
4.150
4.264
4.376
4.482
4.592
4.690
4.792
4.891
4.988
5.082
5.178
5.276
5.356
5.452
5.528
5.620
5.704
5.784
5.868
5.952
6.032
6.109
0.188
MEASUREMENT OF IRRIGATION WATER.
49
Table 6. — Discharge of standard submerged rectangular orfices in
cubic feet per second, computed from the formula Q = 0.61
V2gH A. {See paragraphs 28 and 34.)
Cross-sectional area A of orifice,
square feet.
Head H,
feet.
0.35
0.5
•
0.75
1.0
l.%5
1.5
1.75
3.0
0.41
0.783
1..567
2.350
3.133
3.917
4.700
5.483
6.2GC
.43
0.792
1.585
2.377
3.170
3.962
4.754
5.547
6.339
.43
0.802
1.604
2.406
3.208
4.010
4.812
5.614
6.416
.44
0.811
1.622
2.433
3.244
4.055
4.S66
5.677
6.488
.45
0.820
1.640
2.461
3.281
4.101
4.921
5.741
6.. 362
.46
0.829
1.659
2.4*89
3.318
4.147
4.977
5. 807
6.636
.47
0.839
1.678
2.517
3.356
4.195
5.035
5.874
6.713
.48
0.847
1.695
2.542
3.389
4.237
5.084
5.931
0.77S
.49
0.856
1.712
2.568
3.424
4.280
5.136
5.992
6.848
.69
0.865
1.729
2.594
3.458
4.323
5.188
6.052
6.917
.51
0.873
1.746
2.620
3.493
4.366
5.239
6.112
6.986
.53
0.882
1.763
2.645
3.527
4.409
5.290
6.172
7.054
.53
0.890
1.780
2.670
3.560
4.451
5.341
6.231
7.121
.54
0.898
1.797
2.995
3.593
4.491
5.390
6.288
7.1S6
.55
0.907
1.813
2.719
3.626
4.533
5.439
6.345
7.252
.56
0.915
1.830
2.745
3.660
4.575
5.490
6.405
7.320
.57
0.923
1.846
2.769
3.692
4.615
5.538
6.461
7.3S4
.58
0.931
1.862
2.794
3.723
4.6.56
5.587
6.518
7.450
.59
0.939
1.879
2.818
3.757
4.997
5.636
6.575
7.514
.60
0.947
1.895
2.843
3.790
4.737
5.6S4
6.632
7.579
.61
0.955
1.910
2.865
3.820
4.775
5.730
6.685
7.640
.69
0.963
1.925
2.887
3.850
4.812
5.775
6.737
7.700
.63
0.971
1.941
2.911
3.882
4.853
5.823
6.793
7.764
.64
0.978
1.956
2.934
3.912
4.,S90
5.S68
6.846
7.824
•D9
0.986
1.972
2.9.5S
3.944
4.930
5.916
6.902
7.888
0.993
1.987
2.980
3.974
4.967
5.960
6.954
7.947
.67
1.001
2.C02
3.003
4.004
5.005
6.006
7.007
8.008
.68
1.008
2.016
3.034
4.038
5.040
6.048
7.056
8.064
.69
1.016
2.032
3.048
4.064
5.080
6.096
7.112
8.128
.70
1.023
2.046
3.069
4.092
5.115
6.138
7.161
8.184
.71
1.031
2. 062
3.093
4.124
5.155
6.186
7.217
8.248
.72
1.038
2.076
3.114
4.152
5.190
6.228
7.266
8.304
.73
1.045
2.090
3.135
4.180
5.225
6.270
7.315
8.360
.74
1.052
2.104
3.158
4.210
5.260
6.311
7.369
8.421
.75
1.059
2.118
3.178
4.237
5.296
6.355
7.413
8.475
.76
1.066
2.132
3.198
4.264
5.330
6.396
7.462
8.528
.77
1.072 .
2.145
3.217
4.290
5.362
6.434
7.507
8.579
.78
1.080
2.160
3.240
4.320
5.400
6.480
7.560
8.640
.79
1.087
2.174
3.261
4.348
5.435
6.522
7.609
8.696
0.80
1.094
2.188
3.282
4.376
5.470
6.564
7.658
8.752
50
MEASUREMENT OF IRRIGATION WATER.
Table 7 — Coefficients C to be applied to a discharge given by Table
6 to give the discharge of the same orifice suppressed, com-
puted from the formula C" = 1 + 0.15 r.
Size of orifice.
Bottom suppressed.
Bottom and ndea
suppressed.
d, feet.
I, feet.
A,
square feet.
r
c'
('
1.0
0.25
0.40
1.06
0.60
1.09
0.35
2.0
.50
.44
1.07
.56
1.08 '
3.0
.75
.46
1.07
.54
1.08
1.0
.50
.33
1.05
.67
1.10
1.5
.75
.37
1.06
.63
1.09
0.5
2.0
1.00
.40
1.06
.60
1.09
2.5
1.25
.42
1.06
.58
1.09
3.0
1.50
.43
1.06
.57
1.09
1.33
1.00
.32
1.05
.68
1.10
1.67
1.25
.34
1.05
.66
1.10
0.75
2.00
1.50
.36
1.05
.64
1.10
2.33
1.75
.38
1.06
.62
1.09
2.67
2.00
0.39
1.06
0.61
1.09
MEASUREMENT QP IRRIGATION WATER. 51
Table 8. — Sample rating tabic for small Price current meter.
03
5 Revolu-
tions.
10 Revolu-
tions.
20 Revolu-
tions.
30 Revolu-
tions.
40 Revolu-
tions.
DO
o
Velocity,
ft. per
second.
Diff.
Velocity,
ft. per
second.
Diff,
Velocity,
ft. per
second.
Diff.
Velocity,
ft. per Diff.
second.
Velocity,
ft. per
second.
Diff.
O o
40
41
43
43
44
45
46
0.316
.310
.304
.298
.293
.288
.283
.278
.273
.268
.263
.259
.255
.251
.247
.243
.239
.235
.232
.229
0.226
.006
.006
.006
.005
.005
.005
005
0.592
.578
..565
.553
.542
.531
.521
.014
.013
.012
.011
.011
.010
.010
.010
010
.009
.008
.008
.008
.008
.007
.007
.007
.007
.006
.006
1.14
1.11
1.08
1.06
1.04
1.02
1.00
0.981
.961
.942
.923
.905
.888
.872
.857
.842
.828
.814
.801
.788
.775
.03
.03
.02
.02
.02
.02
.02
.02
.019
.019
.018
.017
.016
.015
.015
.014
.014
.013
.013
,013
1.69
1.65
1.61
1.57
1.54
1.51
1.48
1.45
1.42
1.39
1.36
1..33
1.30
1.28
1.26
1.24
1.22
1.20
1.18
1.16
1.14
.04
.04
.04
.03
.03
.03
.03
.03
.03
.03
.03
.03
.02
.02
.02
.02
.02
.02
.02
.02
2.25
2.20
2.15
2.10
2.05
2.00
1.96
1.92
1.88
1.84
l.SO
1.77
1.74
1.71
1.68
1.65
1.62
1.59
1.56
1.53
1.51
.05
.05
.05
.05
.05
.04
.04
.04
.04
.04
.03
.03
.03
.03
.03
.03
.03
.03
.03
.02
4e
41
43
43;
44
45
46
47
4S
49
50
61
53
53
64
65
56
67
68
59
60
.005
.005
.005
.004
.004
.004
.004
.004
.004
.004
.003
.003
■-003
.511
.501
.491
.482
.474
.466
.458
.450
.443
.436
.429
.422
.416
.410
47
48
49
50
51
52
53
54
55
56
57
58
59
69
CD
50 Revolu-
tions.
60 Revolu-
tions.
SO Revolu-
tions.
100 Revolu-
tions.
150 Revolu-
tions.
o
.S m
Velocity,
ft. per
second.
Diff.
Velocity,
ft. per
second.
Diff.
Velocity,
ft. per
second.
Diff.
Velocity,
ft. per
second.
Diff.
Velocity,
ft. per
second.
Diff.
o
40
41
43
43
44
45
46
47
48
49
60
51
Bit
53
54
65
56
67
68
69
60
2.80
2.73
2.67
2.61
2.55
2.50
2.45
2.40
2.35
2.30
2.25
2.21
2.17
2.13
2.09
2.05
2.01
1.97
1.94
1.91
1.88
.07
.06
.06
.06
.05
.05
.05
.05
.05
.05
.04
.04
.04
.04
.04
.04
.04
.03
.03
.03
3.36
3.28
3.20
3.13
3.06
2.99
2.92
2.86
2.80
2.74
2.69
2.64
2.59
2.54
2.49
2.45
2.41
2 37
2.33
2.29
2.25
.08
.08
.07
.07
.07
.07
.06
.06
.06
.05
.05
.05
.05
.05
.04
.04
.04
.04
.04
.04
4.47
4.36
4.26
4.16
4.06
3.97
3.89
3.81
3.73
3.65
3.58
3.51
3.45
3.39
3.33
3.27
3.21
3.15
3.09
3.04
2.99
.11
.10
.10
.10
.09
.08
.08
.08
.08
.07
.07
.06
.06
.06
.06
.06
.06
.06
.05
.05
5.57
5.43
5.30
5.18
5.07
4.96
4.85
4.75
4.65
4.56
4.47
4.38
4.30
4.22
4.14
4.07
4.00
3.93
3.86
3.80
3.74
.14
.13
.12
.11
.11
.11
.10
•1.0
.09
.09
.09
.08
.08
.08
.07
.07
.07
.07
.06
.00
8.35
S.15
7.96
7.78
7.61
7.44
7.28
7.12
6.97
6.82
6.68
6.55
6.43
6.31
6.19
6.08
5.97
5.87
5.77
5.67
5..57
.20
.19
.18
.18
.17
.16
.16
.15
.14
.14
.13
.12
.12
.12
.11
.11
.10
.10
.10
.10
40
41
43
43
44
45
46
47 •
48
49
50
61
63
53
54
55
56
57
63
59
BO
52
MEASUREMENT OP IRRIGATION WATER.
Table 9 — Sample table of current tneter notes and computations,
by formula (18), for U. S. Reclamation Service Power Canal
at Spanish Fork, Utah.
UNITED STATES RECLAMATIOlSr SERVICE
Current Meter Notes
Date, Sept. 17, 1909, 10.30 A. M.; Stream, U. S. R. S. Power Canal;
Party, E. S. Fuller; Locality, Spanish Fork, Utah, Meter No. 400
Gage height, beg. 2.80, end 3.80, mean 2.80. Total area 19.0; Mean
velocity, 5.66; Discharge, 107.
Observations.
Com
putatioas.
Dist.
Depth
Depth
of ob-
servat.
Time
in sec-
onds
Rev-
olu-
tions
Velocity.
Mean
depth
Width
Area
from
initial
point
At
point
Mean
in ver-
tical
Mean
in sec-
tion
Dis-
cliaTKc
4.2
1.4
2.8
Est.
.8
.56
2.24
.56
2.24
.56
2.24
.56
2.24
.56
2.24
.8
Est.
3.49
4.98
6.64
5.20
6.49
6.05
6.32
5.72
6.12
5.61
6.02
5.27
4.87
3.41
3.49
4.98
5.92
6.27
6.02
6.86
5.64
4.87
3.41
5.6
7.0
46.0
34.4
44.0
35.2
37.8
36.2
40.0
37.4
40.8
38.0
43.4
47.0
100
100
100
100
100
100
100
100
100
100
100
100
4.24
5.45
.7
2.1
1.4
1.4
0.98
2.94
4.2
16.0
8.0
2.8
6.10
2.8
1.0
2.80
17.1
9.0
2.8
6.14
2.8
1.0
2.80
17.2
10.0
2.8
6.94
2.8
1.0
2.80
16.6
ii.o
2.8
5.75
2.S
1.0
2.80
16.1
12.4
13.8
1.4
5.26
4.14
6.62
2.1
.7
1.4
1.4
2.94
0.98
lfl.04
16.4
4.1
100.7
MEASUREMENT OF IRRIGATION WATER.
53
Table 10 — Sample rating table for U. S. Reclamation Service
Power Canal at Spanish Fork, Utah.
Gage height.
Discharge.
Difference.
Gage height.
Discharge.
DiSereuce.
Feet.
Scc.-ft.
Sec.-ft.
Feet.
Sec.-ft.
Sec. -It.
0.0
0.0
0.2
2.1
60.1
5.9
.1
0.2
0.5
.2
66.0
6.2
.2
0.7
0.8
.3
72.2
6.5
.3
1.5
1.1
.4
78.7
6.8
.4
2.6
1.4
.5
85.5
7.0
.5
4.0
1.7
.6
92.5
7.2
.6
5.7
1.9
.7
99.7
7.3
.7
7.6
2.1
.8
107
8
.8
9.7
2.3
.9
115
S
.9
12.0
2.5
3.0
123
8
1.0
14.5
2.7
.1
131
8
.1
17.2
3.0
.2
139
9
.8
20.2
3.3
.3
148
9
.3
23.5
3.5
.4
157
9
.-1
27.0
3.8
.5
166
9
.5
30.8
4.1
.6
175
9
.6
34.9
4.4
.7
184
9
.7
39.3
4.7
.8
193
9
S
44.0
5.1
.9
202
9
.9
49.1
5.4
4.0
211
2.0
54.5
5.6
o
UC SOUTHERN REGIONAL LIBRARY FACILITY
AA 000 471 411 9