CONTROL OF LAND WEEDS
Pasturing of Canal Rights-of-way

Pasturing of ditchbanks is an accepted and practical method of
controlling weeds and utilizing forage along irrigation ditchbanks
and on adjacent rights-of-way. However, proper control of the
livestock requires fencing, and unless cattle guards are installed
the ditchriders are confronted with the delaying chore of opening
and closing gates. The cattle guards may be of the conventional
type as shown in Figure 35, or some special type discussed on the
following pages.

Cattle Guards

There is a considerable difference of opinion among O&M and other
project personnel regarding the design of cattle guards on canal-
operating roads. In the interest of economy, many feel that the
number of cattle guards installed on our canal-operating roads

can be reduced. Nevertheless, it is agreed by all that cattle guards
are a definite need under certain circumstances and especially
serve a vital purpose inexpediting travel through stock-raising
country.

Most field offices report that where cattle guards have been installed
in accordance with the Bureau's standard design, Figure 35, they
have given generally satisfactory service, except where exception-
ally heavy traffic must be accommodated. The principal objection
by most field people to the standard design is the cost of construc-
tion. On the other hand, it is pointed out that from an O&M stand-
point, the original cost may not be the important cost.



The actual screen is made
up of two layers--a support
screen on the bottom and a
fine screen on the top. The
support screen, 1/2-inch
mesh galvanized hardware
screen, is stapled to the
frame first. The fine screen,
Nos. 40 to 60 mesh, is then
stapled on top of the support
screen. The Nos. 40 to 60
mesh screen is fine enough to
screen out nearly all varieties
of weed seed. To prevent cor-
Fig. 26 rosion, the fine screen should
be of nonmetallic material--
either saran plastic or fiberglas. Both resist acid, alkali, and elec-
trical corrosion.

In stapling the screens to the frame, it is absolutely essential to get
them "drum tight" so that they will vibrate with the action of the fall-
ing water. This will bounce the sand and silt particles and the swirl-
ing water will move them across the screen.

Many variations are possible in the frame box. Basically, it holds
the screen frame below the farm turnout and includes provisions for
leading the water into the farm ditches or pipelines. Boxes vary
from simple posts at each corner of the screen frame to elaborate
poured-concrete structures, Figure 26. The downstream end of the
box is left open for easy cleaning. The sides should be at least

6 inches high to prevent splashing and overflow.

There should be some clearance between the screen and the water
below it. Bubbles touching the screen reduce the flow of water
through the screen. Screens work best when they are level. Tilting
creates problems. With pipe turnouts or flumes, the water must be
directed so that it will be discharged above the screen. This may
require construction of a pooling box and weir.

The more screen area the water hits as it falls, the less drop needed.
Increasing the width of the waterfall will lessen the amount of drop
that is necessary, and flat screens can be used with as little as

3 inches of drop, if a device is added to create agitation. This aids
the movement of the water through the screen.

Agitation may be created by an undershot water wheel, by wedges
placed on the screen to divide the water or by boards or small flum-
ing apparatus that divide the water and drop it onto the screen in
several positions.

29



Page 39 Fig. 38



which is extremely small but heavy, was seeded at the rate of approx-
imately 1 pound per mile of waterline. Approximately 2 miles of
waterline per hour were seeded by one man walking on the lateral
roadway. Seeding was done in summer on saturated soil. No seed
covering was necessary. No wire agitator was needed to cause the
seed to flow. A single nail hole punched in the bottom of the can was
adequate for metering the seed output.

The principal problem in the use of the gravity-flow seeder is design
and calibration for seed mixtures, particularly for seeds which do
not flow freely.

The low-cost grass-legume seeder for use on brush-cleared range-
lands, shown in Figures 14 and 15 was devised by Allen P. Johnston,
manager of the Kapapala Ranch, and chairman of the Kau Soil Con-
servation District, Hawaii.* The seeder was developed after years
of wrestling with range seeding problems. The seeder can be built
at a cost of about $25, including both labor and materials.

The first seeder constructed was mounted on 4- by 4-inch timbers on
the back of a large crawler-type tractor at about the same height
above the ground as the driver's seat. The seeder is well suspended
about 5 feet above the ground, well away from the rocks, brush, and
rough terrain that so
often damages the
conventional drill.
The seeder required
few repairs, but a
few slight improve-
ments were made as
the original model
was put to test.

The seeder box, or
hopper, Figure 16,
is constructed very
much after the pat-
tern of a seeder box
on most conventional
drills, The box is
about 12 feet long
and about 12 inches

Fig. 14 deep. The top of the

box is 12 inches wide

and tapers at the bottom to about 6 inches. The box was constructed
of unplaned lumber 1 inch thick,

A condensation from an article by Roy I. Shipley, Range Conserva-
tionist, Soil Conservation Service, Hawaii, as published in the October
1953 issue of Westland Pasture Journal.

20


The present high cost of lumber and labor and the short life of
wooden structures may prove that an even more costly design,
one calling for concrete and steel construction, as shown in the
Drawing, Figure 36, is less expensive over a period of years
because of lower maintenance and replacement cost. In this
regard, it is interesting to note that although many object to the
original cost, there is a tendency in replacement and repair of
cattle guards to use steel and concrete construction in an effort
to reduce replacement and maintenance costs in the future.

In accordance with the above, design of a cattle guard should
embody features that will result in lowest possible cost for mate-
rials, labor, and construction, as well as maintenance and replace-
ment. Some of the more specific suggestions and recommendations
for cattle guard designs are:

1. One design standard for cattle guards will not meet the
requirements for all projects or operating conditions.

2. '"Bed-spring" type cattle guards, wire gates, or 'bumpgates"
can be used in some locations in lieu of the more costly cattle
guards,

3. Commercially available, prefabricated cattle guards should
be installed wherever possible. They are manufactured in
quantity and, therefore, are less costly.

4. Narrower and less costly cattle guards could be installed on
canal-operating roads for passage of light traffic, providing
adjacent wire gates for the passage of heavy equipment and
traffic.

5. Where the more costly type of cattle guard must be used,
specify as many similar guards as possible in one contract
to take advantage of mass production and resulting lower
cost.

6. Eliminate the 24-inch pit under deck of the cattle guard by
using heavy railroad rails, or by setting the stringers of the
cattle guard deck level with the roadway and ramping the road-
way over the structure.

7. Provide guard posts adjacent to cattle guards to eliminate
damage by the passage of wide equipment over it or to prevent
equipment for approaching the cattle guard at an angle.

8. Avoid placing a cattle guard on a sharp curve. It is diffi-
cult to approach in a manner that permits traffic to move
through it without damage to wing guards.

36



9, Use lighter material in construction of wing guards, 1-inch
instead of 2-inch material.

10, Fabricate wing guards separately and provide for tying them
to the guard posts and surface-guard framing by metal strips
and bolts or lag screws.

11. Avoid use of mesh-type decking material for cattle guards.
Much difficulty has been encountered in breakage of the
unsupported mesh.

There are other low-cost cattle guards available such as the

"auto-gates' manufactured on a commercial basis, as shown
in the drawing, Figure 38. These are being used extensively
on some of our midwestern projects in Nebraska and Kansas.

In the March 1953 issue of the Reclamation Era, Mr. Theodore
Nelson, Chief, O&M Division, Region I, iWlustrated and discussed
a practical, cheap, portable cattle guard fabricated from light metal
strips and small coil springs, mounted upon a tubular frame,

Figure 37. Several field offices believe the device especially
practical and easily made standard with a few improvements. If,
under constant use, annual replacement might be necessary,
however, its original low cost may offset this. It appears the
"bed-spring" cattle guard would be satisfactory for an installation
which accommodates traffic at low speeds and of limited weight.

The Kittitas Reclamation District is using a spring-suspended
grill made of surplus steel landing mats fora guard, Figure 39. The

38



18 to 24 square feet of
screen should be allowed
for each second-foot of
water flow.

Most vertical screens are
in the form of an A-frame
10 to 12 feet long on each
side. Construction is very
similar to that of flat screen
frames with double layers of
screen stapled to a wooden
frame. A box of rocks or

another weight placed on the
PN ee POS «= | “topihelds:the:sereen in-place.

The edges are buried in the

ditch side to make a tight

Fig. 33 seal,

Drawbacks to vertical screens presently used are undermining and
washing around the wings and difficulty in cleaning. These problems
can be avoided by using a diagonal screen, instead of an A-frame
screen, and incorporating it with a concrete check. Also, a stilling
basin along the side of the ditch can be used to divert the trash.

There are other solutions for systems with no drop.

Where no fall is available, a low-lift pump may be used to lift water
from the weir pool to a height of a foot or more and drop it onto a
flat screen. This increases the cost of screening weed seeds, but
still may be a low-cost weed control measure.

Weed screens available from
commercial builders will
screen water in the absence
of fall. These vary from
rotating wire barrels to end-
less belt-type screens. Here
again the cost of the screening
installation goes up, but the
cost of the installation may be
much below the cost of weed
control,

A bag-type weed seed screen
designed and constructed by
a Columbia Basin Project

ARPPeape-ses34

33


fence in the center of the photograph. Fence sections are approxi-
mately 3 feet high and 10 feet long, containing two attached braces
which fold flat for transport. Wind velocity was reduced for a dis-
tance of approximately 30 feet beyond the fence and facilitated seed-
ing operations,

Chemical Preventive Methods

Chemicals which prevent weed growth include the use of pre-emergence
applications of herbicides, the use of copper sulfate to reduce popu-
lation of algae to a low level, and soil sterilization. Many of the mate-
rials and procedures used in the prevention of weeds also are employed
in their control. Equipment used in application of the materials is
discussed in that portion of this bulletin devoted to control.

Soil Sterilants

Sterilization of soils is one method of chemical treatment that could
be applied during construction of the canal or lateral system if condi-
tions should warrant. In an annual report of a regional weed control
program, the Irrigation Division of Region 7, Bureau of Reclamation,
points to the success
achieved in using soil
sterilants to control
weeds in laterals on
the Bostwick Division
of the Missouri River
Basin Project.

Figures 21 and 22 are
of adjacent laterals.
Figure 21 shows a
section of a lateral

not treated with the
sterilant, while Fig-
ure 22 shows the condi-
tion of the adjacent
lateral on June 14,
1956, that had been
treated with soil steril-
ant during the period
April 30 to May 15.

Fig. 21 About 30 miles of lat-
erals were treated with
soil sterilant in 1956. An area about 8 feet wide in the wetted perim-
eter of the lateral was treated. It was mixed with water and applied
at the rate of 12 pounds per acre with a specially designed hand boom.

25


bottom of the hopper by small screws exactly over the 3/4-inch hole
drilled through the bottom of the hopper.

The seeder broadcasts the seed behind the tractor. A chain is
dragged behind for covering the seed. Observations of germination
and stand on some of the earliest seedings show a surprisingly uni-
form stand of seedling. Johnson sums up the results of the seeder
in this way:

"The stand is much more uniform than when seed was broad-
cast by hand and there is a considerable saving in labor. Now
one man is doing a better seeding job than three men were
previously doing. This is accomplished by seeding and cov-
ering the seed in one operation, "

Calibrating the seeder to drop enough, but not too much seed, was a
stickler until Johnson hit on an idea. The gimmick was a 2-pound
coffee can with a hole in the bottom large enough to slide upward over
one of the wire ends hanging below the seeder. The can was then tied
against the bottom of the hopper so as to catch all the seed coming
through one opening.

The seeder was then operated over a distance of about 1, 000 feet.
Seed collected in the coffee can over this distance traveled is weighed
and multiplied by the total openings in the drill. Thus it was possible
to calculate the pounds of seed being applied per acre to the land.
When too much seed was going through an opening, the metal plate
was moved so that a smaller opening was used,

Mr. Johnson explains that the second seeder mounted on the back of a
smaller crawler tractor did not seed at the same rate as the one behind
the larger tractor. The speed at which the seed drops through the
seeder openings is dependent upon vibration of the particular tractor
and movement of the wires hanging pendulum-like below the seeder
box. The seed automatically quits flowing once the machinery is
stopped. The second model was speedily calibrated to seed the right
amount by changing to the proper opening in the metal plate.

Seed Covering Equipment

The 14-foot length of finger weeder, a flexible spring-toothed harrow,
shown in Figure 17 being lowered onto a large canal bank, was ade-
quate for covering grass seed on the Columbia Basin Project, Washing-
ton. Seed was broadcast in front of the harrow by means of an electri-
cally operated broadcast seeder mounted on the right front of the small
crawler tractor. The center 6-foot section of the finger weeder was
clamped to the tubular sidearm drawbar. End sections, each 4 feet
long were hinged to the center section and were free to move over
obstructions not common to the whole length of the weeder.

The finger weeder is a common type used on farm equipment, resem-
bling a long-finger type spring-tooth harrow. A similar weeder is

22



The feeder openings
bored through the bot-
tom of the hopper are
about 3/4 inch in diam-
eter and spaced 16
inches apart. The box
is divided into small
compartments by fitted
wedge-shaped wooden
dividers. The dividers
prevent the grass and
legume seeds from
"running" to one end
on rough terrain or
when traveling on a
slope. The wooden
dividers are fastened
midway between the
openings.

Fig. 15 A 1/2-inch pipe runs
the entire length of the
seeder box and is mounted in the top center so that the lid can be closed
without binding on the pipe.

The problem of getting grass seed to flow evenly through feeder open-
ings was overcome by the use of No. 6-gage galvanized wire, about

4 or 5 feet long. It runs through the feeder openings and is fastened
at the top to the 1/2-inch pipe mounted inside and near the top of the
box, The pendulum
motion of the wires
aids in a steady flow of
seed through the open-
ings.

In calibrating the seeder
to seed the proper pounds
per acre, three holes,
3/8-, 7/16-, and 1/2-
inch diameter respec-
tively and about 2 inches
apart, were bored
through pieces of heavy
tin about 2 inches wide
and 6 inches long. The
2- by 6-inch tinplates
were then slipped over
the wire through the
size of opening desired
and were fastened to the

21


farmer for attachment to a weir structure is shown in Figure 34.
The metal frame at the mouth of the bag was constructed to inter-
cept the water without interfering with the weir as a measuring
device. The bag was made of saran, a plastic filter screen con-
taining approximately No. 40 mesh per square inch.

Seams were
sewn with nylon thread.

34



bottom of the slope as well as from the top. Tines lost or broken on
rocky soil are replaced rapidly and at little expense.

Including a cable drum, hydraulic or electric boom lift would be an
advantage in the operation of the device. The weeder produced a
noticeable side draft on the small tractor used. A larger tractor
would be more satisfactory.

Accessory Equipment

As shown in Figure 19, a household-type vacuum cleaner is being
used to remove one
seed mixture from a
grain drill prior to
the planting of another
mixture type. A
1,500-watt, 120-volt,
alternating-current
portable generator has
many uses in the field
for driving portable
electrical tools, and
it was used to power
the vacuum cleaner.

The cleaner was used
on the Columbia Basin
Project, Washington,
where studies were
made to determine
which grasses and
legumes were best
Fig. 19 adapted to wasteway

impoundment areas

which were to receive
water. Establishment of desirable
vegetation was expected to retard
the invasion of noxious weeds and
phreatophytes onto wetted lands to
which access would eventually be
difficult.

Bonk

ge. meee
peteuie-42220/

Sand fences as shown in Figure 20

on the Columbia Basin Project,
Washington, may be employed to
protect a water channel and road in
preparation for seeding grass. Wind-
borne soil which could cover the seed
to depth and prevent germination, is
deposited on the leeward side of the

24


inexpensive war sur-
plus landing mats are
suspended 3 to 4 inches
above the ground by use
of a single spring on
each side of the 90- by
120-inch mat. The
springs, which are only
10 by 1 inch in size,
connect a triangularly
braced strap iron,
welded to the mat,
with the top of a side
post. A guide is
attached at the base
of each post. Thus

Fig. 39 the mat is permitted

to move only in an up

and down position. Use to date is limited and the Project believes
some improvements may be needed. However, the cost of con-
struction and installation is substantially less than the conventional
pit-type guards.

A range cattleguard constructed of rubber strips and wires on the
Columbia Basin Project, Washington, is shown in Figure 40. The
wires carry an intermittent charge from a battery-type electric
fence charger. This cattleguard appears to be effective against
livestock. In more populated areas, it would be a hazard to
children. The wires, being under tension may be pulled loose by
automobiles which cross too rapidly.



Broadcast Seeders

Broadcast-type seeders are used to advantage on some projects, Seed-
ing equipment in use by a contractor on the Columbia Basin Project,
Washington, employs two electrically operated broadcast seeders fol-
lowed by a 15-foot width of chain harrow, Figure 9. The chain harrow
follows small irregularities in the soil and is not as subject to clogging

with weed, brush, and
debris as the spike
tooth harrow. On the
other hand, the chain
harrow cannot be
weighted for scarify-
ing the heavier soils,

The jeep-mounted elec-
tric seeder shown in
Figure 10 also was used
on the Columbia Basin
Project, Washington for
seeding of wet areas not
accessible to two-wheel
drive equipment. This
is an electrically powered
broadcast seeder with
controls in the cab of
the pickup.



3. Should sodium chlorate be spilled on the clothing, such cloth-
ing, since it constitutes a dangerous fire hazard when dry, should
immediately be removed and thoroughly washed. Rubber boots
and gloves should be worn by workmen when spraying with the
chemical,

4, A person should not be permitted to walk or ride, or to move
equipment of any kind through treated areas, and livestock should
be kept out of such areas until after a heavy rain, as even slight
friction is likely to ignite the vegetation and cause serious fire
damage. Areas near buildings where fires might result in loss

of life or property should not be sprayed. Smoking should be pro-
hibited while applying sodium chlorate or while working around
sodium chlorate containers, equipment, or treated areas.

Weed Exclusion Devices

Equipment for mechanical exclusion of seed and plant parts capable

of reproducing the plant may be screens, weed traps, diverters within

the water channel and livestock fences, They exclude the weeds them-
selves or the agencies which carry the weed propagating parts of plants
onto the rights-of-way and into the water channel. The use of many of

these devices is closely associated with weed disposal and is discussed
in more detail in that portion of the bulletin devoted to this subject.

Weed Seed Screens

Weed seeds do enter farms through irrigation water, and screens have
been developed which will remove seeds of the most important weeds.
For simplicity, low cost, and ease of maintenance, a flat, horizontally
mounted screen, Figure 23, appears to fill the requirements. *

If the irrigation system has a drop, the flat screen shown placed at the
farm turnout can be used. The flat screens have a frame, Figure 24,

with screen stretched across it and a box, Figure 25, which holds the

screen frame. The box usually has high sides to control splashing and
provides for overflow, The action of the water falling onto the screen
causes vibration. The swirling water then pushes the trash and seeds

to the sides of the screen.

NOTE: *Condensation from a publication "Weed Seed Screens for Irriga-
tion Systems," prepared by Walter Bergstrom, County Extension Agent,
Grant County, Washington. This extension circular may be obtained

at county offices or at State offices in Pullman, Washington, Corvallis,
Oregon, or Moscow, Idaho.

27



The boom was oper-
ated by a man walking
in the bottom of the
lateral.

The chemical was
applied, as stated
previously, between
April 30 and May 15,
after all dry weeds
had been burned out of
the laterals and they
had been cleaned with
a ditcher, where nec-
essary.

Excellent results were
obtained. No broad-
@#1>70-2771 ‘ é leaf weeds or weedy
: grasses were observed
before July 15. After
Fig. 22 July 15, a few weedy
grasses were observed;
however, they were sparse and obtained only limited growth which
caused no operational difficulties.

The Region feels confident that the sterilization of the wetted perim-
eter of laterals has cut down operation costs, reduced the amount of
water lost by transpiration and reduced silt deposits in the bottom of
laterals. Heavy silt deposits in untreated laterals greatly reduced
their capacity.

Sodium Chlorate and Safety

The use of sodium chlorate as a weed sterilant or weed control mate-
rial is not generally recommended because of its dermatitis and fire
hazard problems. If used, sodium chlorate and other chlorate weed-
killing compounds should be handled with extreme caution. The follow-
ing precautions should be rigidly observed:

1. Sodium chlorate should not be permitted to come into contact
with the skin or the eyes. If it gets on the skin or in the eyes, the
chemical must be removed immediately by thoroughly flushing the
surfaces with water.

2. Sodium chlorate should be stored in tightly covered metal con-

tainers. The containers should never be opened in buildings, or
placed in fields where there is any livestock.

26


shown in more detail in Figure 18, where a section of the device was
modified to follow a gravity-type seeder for seeding waterlines.

One of the major advantages of the combination finger weeder and
seeder shown in Figure 17 is its adaptability to seeding from the

P222-117-38397

Fig. 18

23


9¢ “Sta Lg oFeq
BODE erp eee el Tei
3 pug nS 49%) 40 21025 pub dia1 2 puoy woe
aie petite T 1 wae. aurno. 301s

Savoy ONILWYIdO YOd CAYND 27LL¥I
awew> vas0rH

pagnnsy so poompos anyye ag 04 s130d pao’ ap!
fou pein 79S" 81 O9- OE WOH) 109 28%) FH0H

wg 001 Pon
Teroce snonunpstln
Boag Beactguiny
35/009 (508s pain) init jwonganas
we asst
pverbayse? ove 204)
saicianmnd. dauriis3

5 toserem oy | aE

ents | 2

3
2]
[ 4
“]

cone puet pions |"

indir 109 woysuy | 36

1004 109 sowed |
‘pus 209 aa2005 |p
Sner'aeg 103805 ”| “G2
2
2
z
paoné oes | 2
pont ws | PT
fo wee |e
swoiswamia |” Norarwosza_| Sev

uaa 40 709

0 WwL30 a¥eLS LM awynD

pas sou pedojesip son
5-3 NorLvAda Go NolLvAz7a

fl pated

wep fed aoe:

mses eB POOR ag gee
sayues os ae

lon ba ‘aied onar

“atom Wot

1 worzsae
09 f 40) 2009 ~!

yom equ yoou"ss09 66

4 om ois yooy ' 820g bP

£

yom a prog
$0008

8-9 NOILD3S

em 40) 9204s

puen6 a 100

Spur) ane

= 4109 s0v2UP af

1g w0ysu0 jo



(b) The seed reflector behind one fan was extended approximately
8 inches to the outside so that all the seed cleared the truck bed,

(c) Bushings were placed behind the gears operating the fans so
that the gears had a closer fit and ran smoother at high speeds,

(d) The engine pulley was replaced with a smaller one. A
1-1/2-inch pulley was found best.

It was discovered that by closing one aperture and disconnecting the
broadcaster from the same side, the opposite broadcaster would then
throw sufficient seed a greater distance (when needed) than when both
broadcasters were operating. One fan was sufficient to distribute seed
with the seeder mounted on the side of the truck; however, for larger
areas with the seeder mounted

fh on the tail gate, the two fans were

used, The second fan can be
removed by loosening one set
screw from the gear on the fan
shaft, shown in Figure 13,

Except for the above and keeping
the gears well coated with a
heavy gear grease to reduce
wear, the project forces found
no need to improve upon the
seeder as furnished.

The seeder cost approximately
$150, complete with engine and
grass-seeding attachment.

Gravity-flow-type Seeders.

Several adaptations have been
made of the gravity-flow-type
seeder. Seeding of narrow
strips of waterline with grasses
may require a box only 2 or 3 feet
Fig. 13 long with two or three seed open-
ings. A light-weight box may be
attached to a retractable boom and a light-weight spike, chain, or spring-
tooth harrow could be attached to follow if covering of the seed is desir-
able,

An even simpler seeder was used on the Columbia Basin Proj-
ect, Washington, This seeder consisted of a 1- or 2-quart can
with a closeable lid (such as a coffee can or shortening can), It
was attached to a bamboo fishing pole and red top, a grass seed

19



The coarser screens, Nos. 40 to 50 mesh, may accumulate angular
sand particles, if any are present. The fine mesh apparently per-
mits the grains to bounce away.

Plastic screens may become clogged with diatoms, single-celled
algae, slime molds or bacteria. An occasional wash with a 5 per-
cent (1 pound in 2 and 1/2 gailons) solution of copper sulfate will
usually remove the slime.

The cost of a flat weed screen may range from $10 to $100, depend-
ing upon the size, construction necessary to accommodate the screen
and construction materials used. Flows of 1 to 7 cubic feet per sec-
ond have been efficiently handled with one screen. Larger flows may
be handled by multiple screens installed side by side.

Typical of a one-screen installation is the metal-framed seed screen
placed below a turnout structure on the Kennewick Division of the
Yakima Project, Washington, Figure 27. Weed debris covers about
40 percent of the screen,
Unless removed, the debris
would be pushed off the struc-
ture onto the ground. The
barrel in the background is
used to store debris from the
screen before it is dried and
burned.

A multiple screen installation
on the Columbia Basin Project,
Washington, is shown in Fig-
ures 28 and 29, Each of the
screens shown in Figures 27
through 29 are commercial
units, and the debris collected
may be an accumulation of
several days.

Flows of water greater than
10 cubic feet per second can
be screened effectively pro-
vided disposal of the seed is
possible and provided a rather
high initial cost and operation
cost can be justified.

At a still higher cost, pre-
sumably, the screens could
be designed for fully automatic

30


Fig. 31

Sock screens can be made
from No, 40-mesh saran
plastic filter cloth or simi-
lar flexible material, with
two 3-foot pieces stitched
into atube. The length
varies with the amount of
water to be screened. A
sock 10 feet long will have
an effective screen area of
about 60 square feet, and
should handle a flow of

3 second feet of water since
the requirement is 18 to 24
square feet of screen for
each second-foot.

A drawstring is sewn to
each end and permits the
sock to be opened and closed
for attachment to a pipe or
other submerged outlet and
cleaning.

Because of its length, the
lower end can usually be
removed from the stream
and cleaned without dis-
rupting the water flow.

The vertical screen is nothing more than a flat screen set on edge,

Figure 33. Its use is limited because it

has no self-cleaning action.

Therefore the screening area must be very large--usually three
times the area of the standard flat screen. This means about

32


For seeding slopes the seeder is used on the left side of the pick-up
truck as shown. For seeding larger areas, the seeder is mounted
over the tail gate. It is mounted on a platform designed to fit in the
bed of a pick-up truck, so that the broadcaster hangs over the side or
end of the truck bed. The operator on the pick-up controls the speed
of the seeder engine so that the seed is broadcast 10 to 50 feet onto
the spoil banks. On level ground the truck travels 8 to 10 miles per
hour,

The illustrations, Figures 11 and 12, do not show the attachment

for handling small seeds, but such an attachment is furnished with
the seeder. By using the grass seeding attachment, both large and
small seeds or two different kinds of seeds can be planted at the same
time without mixing prior to seeding.

The seeder has a built-in metering device so that the adjusted density
of the broadcast seed is uniform, whether the fans are throwing seed
10 feet or 40 feet.

In mounting, the
seeder used on the
canal banks of the
Central Valley Proj-
ect, Figure 12, a
platform, large
enough to fill the
entire pick-up truck
bed, was secured to
the bed. The plat-
form should be suf-
ficiently high to per-
mit the seeder to
rest on the platform
and on the side or
tail gate of the truck
bed. The seeder was
attached to the plat-
form by two bolts on
the back side and two
clamps, which are
furnished with the
Fig. 12 machine.

DM-1154-CV

Some modifications were made to the seeder on the project, which
improved its operation and the results obtained. These modifications
were:

(a) The addition of a hand throttle to control the speed of the fans,
rather than use of the engine governor for this purpose,

18


The seeding equipment deseribed below and shown in Figure 11 was
particularly useful in the placement of heavy seed such as barley and
wild oats, wild oats being the adapted vegetation on nearby rangeland,
A high quantity of seed, by weight and by volume, was required on
each acre, By the use of this type of equipment, long slopes could
be seeded rapidly. The total cost of seed and seeding was less than
the normal cost of seeding perennial grasses.

Grass types and seeding time were adjusted so that no covering was
necessary, Banks which were not roughened by the normal contractors
finishing practices, were scarified with a spike tooth harrow prior to the
broadcasting of the seed,

The seeder performs very efficiently and with the exception of seeding
by helicopter, it is the fastest method used on the Central Valley Proj-
ect, California, for seeding large spoil banks and ditch-bank areas,
The seeder has been borrowed on several occasions by other public
agencies who also have found it to be fast and efficient.

DM4391-CV

17


Fig. 23 Fig. 24

Screens of this type are available commercially in several sizes.
They are usually constructed of metal. However, a serviceable
screen can be constructed; and if constructed, a rigid frame of

2 by 4 lumber is recommended so that there will be little chance
of sagging or warping. Since most screen material is 3 feet wide,
this is a good width for the frame. The length will vary with the
size needed to fit the particular site. The frame should be con-
structed to fit snugly in the frame box. It is not fastened to the
box since its removal may be necessary. From 6 to 8 square feet
of screen area is used for each second-foot of water flow.

SCREEN FRAME

FRAME BOX

OUTLET

Fig. 25

28



operation. The estimated
cost of installing a screen-
ing plant of the simplest type
to handle the flow of water to
6 farms was more than 10
times the cost of permanent
installations on each farm
delivery system. In addition,
operation would have required
at least 2 man hours per day
to clean the screens and dispose
Fig. 29 of the debris.

p222-0-29087 |

Screening of the larger flows may be more practical where municipal
and industrial water users cannot tolerate the small amount of living
and dead debris present in the raw water. Such an installation was
made at the water screening plant of the City of Ephrata, Washington,
Figures 30 and 31. Two of the flat farm-type screens were installed
to remove the small debris from the canal water the city uses to sup-
plement their well water supply during the summer. Mr. Peder
Hemstead, City Engineer, designed the plant.

Many other types of weed screens have been developed and used. They
include V-shapes, tubes, bags, and electrically operated drums.

The use of ''water-sock"
screens and vertical screens

is described by Walter
Bergstrom, County Extension
Agent, Grant County, Washing-
ton, in his previously cited pub-
lication. They can be used in
irrigation systems that do not
have a drop.

This type of screen, Figure 32,
is simple and economical to
build since it requires no fram-
ing or boxes for installation.
However, sock screens are
limited to sites where algae
Fig. 30 and moss are not a problem.

31