the boom, affording him a full view of his work. The main boom has a
360-degree horizontal swing with a vertical movement of 45 degrees
below the horizontal. The two spray arms attached at the end of the
boom are hydraulically operated from the control panel and each is
capable of a 180-degree horizontal swing and a 90-degree up-and-down
movement. This allows positioning of the spray pattern to conform to
any normal drain section or canal side slope and berm. Each spray arm
is equipped with six nozzles, operated in groups of three by valves
operated from the control panel.

Other noteworthy features include the jet-agitated 1,800-gallon tank
capable of being filled in 6 minutes, with the 3-inch centrifugal
pump using a power takeoff from the truck transmission. Photograph 3
below shows a front view of the spray truck with the liquid herbicide
tank clearly visible. One auxiliary gasoline engine powers the spray
pump and the hydraulic pump for the boom operation.

The three-axle, 6 by 4 truck is mounted on high-flotation super single
tires which will permit it to operate over most canal and drain bank
roads under normal conditions.

The total cost of the rig was approximately $19,000, including $10,500
for the truck and $3,500 for the bare boom and pedestal.

The subject machine, along with its immediate prototype developed in
1967, has convinced District personnel that they are on the right track

Photograph 3 - P214-D-64742D

17


along the canal. The tem-
porary trashracks or por-
table pipe grids for
catching the dislodged
weeds are 8 to 15 feet
long, with a maximum width
of 8 feet, so they may be
legally hauled along high-
ways. The trashrack is
composed of two header bars
constructed from 2-inch
galvanized pipe as shown in
Figure 5, with a hole
drilled through one wall of
the headers on 5-inch cen-
ters. One-inch galvanized
pipe is inserted into the
holes drilled in each
header, then fastened with
two each 1/2- by 1/4-inch
galvanized bolts. In this
way, the l-inch pipes can
be easily replaced, if
damaged.

Figure 5 - Photo P25-D-64727D

ll


Photograph 4 - P20-703-S840NA

of 3/8-inch steel, 4 inches wide. Each walker is notched at intervals
of about 8 inches and has several weld spots to further roughen the
top surface and aid in the upward movement of the trash, as shown in
Photograph 5S on the next page. The walkers are spaced 1-3/4 inches
apart.

A piece of 3/8-inch steel is used on each side of the walker to elimi-
nate lateral movement and also to give a closer fit as the walkers
slide in the groove on the eccentric. It was found that better results
were obtained if the bearing surface was bronzed at the bottom

of the walker where it makes contact with the eccentric. The shaft
makes 42 revolutions per minute and is powered electrically with a
1-1/2-horsepower motor. The walker-eccentric contact surface is
greased once a day and it was discovered that wheel bearing grease
gives the best results.

The Belt Conveyor

The view of the conveyor belt also is shown in Photograph 6 at the
bottom of the next page. This particular conveyor belt is 60 feet
long and 2 feet wide and also is powered electrically by a 3/4-
horsepower motor. The smooth type belt does not move the lighter
weight weeds as well as it should. A rough surfaced belt 3 feet wide
is recommended. It is believed that the added width is needed to
handle longer logs and large objects.

21


40,000 miles of canals, laterals and drains throughout the Pacific
Northwest each irrigation season for the suppression of submersed
aquatic weeds. This involves the use of approximately 800,000 gallons
in more than 10,000 applications each season. This program was carried
out during the irrigation season of 1968 without any report of injury
to man, crops, livestock or wildlife.

The xylene is applied to the water in these irrigation channels at 4

to 10 gallons per cfs over periods of 30 to 45 minutes. It is nonmis-
cible with water and consequently can be dispersed in the water only
with the help of an emulsifier. Over 20 years' experience together with
extensive research shows that the treated water can be used safely for
irrigation of crops. We estimate that 95 percent of the water containing
xylene is used for the irrigation of crops. This includes irrigation
by sprinklers, furrow, corrugation and flooding. If plants should be
covered with the water containing xylene when the concentration is
highest, there may be some burning of the plants. However, in most
cases they recover quickly. Only small seedling plants are perma-
nently injured or killed from such burning. Farmers avoid flooding

such fields.

Crop Tolerance Supported by Research

The experience described above is supported by research conducted by
the Agricultural Research Service2/ wherein typical crops were irri-
gated with water containing various concentrations of xylene” These
studies showed that reductions in yields did not occur until concen-
trations were three times the maximum used by irrigation districts.

Livestock Not Injured with Xylene

Water containing xylene is not palatable and under normal conditions
livestock will not drink water containing it. Since application is
usually made over a period of 30 minutes, animals at a given location
would be exposed to this dosage for considerably less than 1 hour.
Accordingly, it is unlikely that animals would be forced to drink the
treated water. Experiments were conducted at Utah State University
in 1952 in which 32 guinea pigs were confined on water treated with
xylene at concentrations of 400 to 800 ppm, the upper range being
greater than that applied by irrigation districts. While they drank
very little of the treated water during the first 2 days of the
trial, on the third day of confinement they drank considerable quan-
tities without visible ill effects.2/

To the extent to which guinea pigs are comparable to livestock, the
results of these tests indicate that there is no hazard to livestock
from drinking water treated with this material. In this experiment

2/USDA Circular 971, 1955.


and as each unit of the present fleet of manually operated, swing-boom
rigs is phased out it will be replaced by hydraulically operated equip-
ment similar to that described on these pages. Specific nomencalture
of the various components of this new rig is listed below:

Truck Specifications

1. Manufactured cab and chassis

2. 39,000 gross vehicle weight

3 Three-axle, 6 x 4

4. V-6 cylinders, 400.9 cubic inches

5. Wheelbase 157 inches with C.A. 84 inches
6. Transmission 5-speed

7. Auxiliary transmission 4-speed

8. Tires 15 - 22.5

9. Minimum speed of 1.5 mph at 1,600 rpm
10. Rear axle heavy duty

ll. Addition to rear frame - 16 feet from cab to end of frame
12. Section modulus increased

1. Shop-built 1,800-gallon tank with baffle

Suction Pump

1. Centrifugal 3 by 3 inches
2. Power takeoff from transmission
3. Tank fills in approximately 6 minutes

1, With hydraulic control pedestal

2. Two 10-foot 5-inch hydraulic-operated with vertical and
horizontal motion

3. Hydraulic controls mounted on boom

Auxiliary Engine

1. Engine rated at 25 hp at 2,400 rpm

Engine powers both the spray pump and the hydraulic pump

3. Hydraulic pump rated at 1,200 rpm giving 6-1/2 gpm with a
9-1/2 hp output from engine. Spray pump at 2,400 rpm with
maximum 360 gpm using 11 hp from engine

nN

Spray Booms

1. Two l-inch id by 10-foot 5-inch hydraulically operated booms
with six nozzles per boom, producing 3.4 gpm at 30 psi.

kk RR

18


SCRAPER FOR CLEANING CANALS1/

A unique scraper for cleaning sediment and algae from the concrete lin-
ing of a canal is used by the Metropolitan Water District of Los
Angeles, California. The scraper was developed by the District and
consists of an old track from a tractor on which scraper blades have
been mounted.

Photograph 1 - P214-D-64736D

Photograph 2 - P214-D-64737D

The scraper blades are about 6
to 8 inches long and are bolted
to the tractor tracks, which
makes an articulated section.
The length is about 6 feet and
it is supported on a bar to
which it is attached at three
points; at both ends and the
middle. A sling attached to
this bar is then pulled from
the crane. Special sheaves at
the end of the boom were devel-
oped to make this job possible.

Photograph 1 shows the articu-
lated scraper. The frame sup-
ports the track at both ends
and the center. The sling is
attached to the frame. Photo-
graph 2 is a closeup view of
the scraper and the hard metal
pieces bolted to the track.

Two 25-ton rubber-tire-mounted
truck cranes are used continu-
ously to clean the canal linings
in the District. The truck
cranes drive along the operating
roads, which are on both sides
of the canal, and drag this
particular piece of equipment
along the canal lining to remove
the sediment and algae.

It takes six passes to clean
one reach of canal; two passes
for the bottom and two for each
of the sides. The passes can be
made from either side of the
canal.

I/Taken in part from a field trip report by J. K. Shankland, H. E.
Pelham, and T. L. Steel of the Office of Chief Engineer, dated

June 11, 1969.


as:

St

Photograph 2 - P20-703-5912NA

Photograph 3 - P20-D-64743D

20


HYDRAULICALLY OPERATED SPRAY RIG FOR WEED CONTROL1/

A combination of fertile soils, water and a year-around growing season
have provided the essential ingredients for the thriving agricultural
economy of Southern California's Imperial Valley. These same elements,
however, also result in an undesirable by-product - weeds of unexcelled
luxuriance and stamina,

Through the years Imperial Irrigation District, which operates over
3,000 miles of main canals, laterals, and drains, serving in excess of
500,000 acres of irrigated farmland, has run the gamut in methods of
weed control. From the early-day use of labor gangs equipped with
shovels, brush axes, and machetes, through the period of extensive use
of weed burners, the District has progressed to the present-day method
of chemical weed control, employing relatively sophisticated machines
for the application of various liquid herbicide mixtures.

Nearly one-half million dollars is expended annually by the District
in its weed control program. Such a sizeable expenditure, coupled
with the rather extensive area to be covered, demands close attention
to efficiency and economy of operation as well as to its overall effec-
tiveness. The District's management team has concluded that the con-
tinued spiraling of labor and equipment costs makes it imperative that
time-saving innovations be employed.

Imperial Irrigation District, also being in the power generation,
transmission and distribution business, utilizes a fleet of line
trucks equipped with personnel booms. It was only natural that some-
one would eventually ask as to why couldn't an adaptation of these
hydraulically operated units be used effectively to support a spray
bar, as well as put an operator out over his work?

One such unit was developed in the headquarters shops of the District,
and field tested during the 1967 fall spraying season. Photograph 1
on the following page shows a full view of the new hydraulic-operated
spray truck. The advantages of the automated boom and chemical-flow
control were readily apparent. It appeared, however, that by reliev-
ing the boom of the weight of the operator and personnel basket, the
boom could be lengthened from 20 to 25 feet, plus the addition of a
pair of movable spray arms mounted at the end of the boom. These and
other refinements were incorporated in a hydraulically operated
articulated aerial boom spray rig fabricated at Imperial in the spring
of 1968 and placed in service during the summer spraying period.

It will be noted in Photograph 2 also on the following page that the
operator sits at a control panel mounted on the swinging pedestal of

I/This article was written and presented for inclusion in this bulletin
by Mr. R. F. Carter, General Manager, Imperial Irrigation District,
Imperial, California 92251. Inquiries for further information should
be directed to Mr. Carter.

15


and regrowth is rapid. This practice requires collection and removal
of large quantities of silt, broken pondweeds, and other debris loos-
ened by the chains. Naturally, this condition interrupts or prevents
water deliveries and irrigation. With the advent of sprinkler irri-
gation and the need for constant supplies of water free of debris,
the practice of chaining and dragging was gradually abandoned by many
irrigation districts and canal companies and replaced by the use of
xylene and other herbicides. This has eliminated use of 1 or more
chaining crews, each of which usually include 2 tractors, 2 pickup
trucks, and 10 to 12 men. Some of the larger districts employed 2
or 3 crews of this size. One man, 1 truck, and a tank of xylene

as shown in the cover photograph does a better job at only a fraction
of the cost of chaining, and with the use of xylene it is possible to
run the canals and laterals free of debris and with no interruption to
the water supply.

Cost of Pondweed Suppression with Xylene Versus Chaining

Submersed aquatic weeds in irrigation systems are suppressed with
xylene at only a fraction of the cost of attempted control through
mechanical methods such as chaining. The term "attempted control" is
used because none of the mechanical methods used were really effective.
At best, only a small portion of the weeds were broken loose by the
chain or disc. The remainder were only pushed into the mud on the
stream bottom where they continued to grow.

Mr. Russell Unrue, Marmager of the Bitter Root Irrigation District,
Hamilton, Montana, reports that mechanical methods of controlling pond-
weed would increase the cost of pondweed control 450 percent as com-
pared to present costs of controlling these weeds with xylene. The
following paragraph is quoted from Mr. Unrue:

"Our cost for pondweed control requiring one treatment for 1968
was $1,326 for xylene, emulsifier, labor and equipment for treat-
ing approximately 32 miles of canal, delivering 195 cfs for
8,000 acres of irrigable land. The cost for controlling the
pondweed in the same canal area by hand labor and chaining opera-
tion would be $5,500 to $6,000 and irrigation water turned off
for 15 to 20 days or more if sufficient labor is not available
at the proper time."

In a paper given at Preston, Idaho, in 1969, Mr. Carroll Wilcomb,
Civil Engineer, Bureau of Reclamation, Salt Lake City, reviewed his
and his successor's experience in the control of aquatic weeds in
canals and laterals operated by the North Side Canal Company, Jerome,
Idaho. The following is quoted from Mr. Wilcomb's paper:

"In 1966 the North Side Canal Company discontinued chain mossing
altogether in favor of chemicals. The company presently uses
around 20,000 gallons of xylene and 2,600 gallons of acrolein.


are packed in sytrofoam
containers and shipped
to Denver. Samples are
in route less than 24
hours by this mode of
transportation. On
arrival in Denver the
samples are unpacked,
Photograph 3 below, and
stored under refrigera-
tion until the analyti-
cal procedures are com-
menced. The number of
samples collected from
each canal and included
in each shipment may
vary from 100 to 150

Photograph 2 - P222-D-64733D depending on the number

of sampling stations

employed which varies with length of the canal

The analysis of samples from the first two collections are nearly
completed but the 2,4-D chromatograms have not been processed. Very
low concentrations of 2,4-D are found in most of the samples analyzed.

Photograph 3 - P222-D-64734D

It is planned that this study be continued through 1971. Different
herbicides will be monitored during this period. Herbicides selected
for future study will be based on the need for this type of informa-
tion to support their continued use.

kK RR

27 GPO 883-927


pointed out, it can be retained in water for a short period only with
the use of selected emulsifiers. Monitoring studies conducted by this
office, Bureau of Reclamation laboratories in Denver, Colorado, and
the Kennewick Irrigation District, show that 7-1/2 gallons of xylene
per cfs (approximately 555 ppm) applied to a canal at two locations
was almost completely lost to the air in 24 hours. ‘Twenty-four hours
after application, at the end of the channel 17 miles downstream, the
water contained .3 ppm xylene. Farm fields which have been irrigated
at least twice per season each year for 20 years with water contain-
ing xylene show no signs of an accumulation of xylene or any detrimen-
tal effects on crop production.

A letter dated January 17, 1969, from one of the leading oil companies
in the United States stated that xylene is not retained in the soil.
Following is a paragraph from that letter:

"Should a xylene compounded as a carrier for toxicants or soil
fumigants be injected into the soil, the manufacturer of such
products normally insists on leaving the treated area untouched
for a minimum of five to seven days. The xylene, however, will
completely evaporate in 55 minutes at 80° F. No xylene is
retained in the soil, if sufficient time for evaporation is
provided."

Xylene Is Not Toxic to Soil Bacteria

The following paragraph is quoted from page 28, USDA Circular 971,
dated 1955:

"In connection with the crop-tolerance tests, Jones3/ analyzed
soil samples taken from solvent-treated plots at Phoenix, Arizona,
and Meridian, Idaho, to determine the possible toxicity of
effluent to beneficial soil bacteria. The analyses showed that
the activity of ammonifying and nitrifying bacteria in the soil
was not affected by aromatic solvents, even at concentrations
as high as 2,400 ppm, which were introduced over 30-minute
periods. Apparently there is little danger of destroying
beneficial soil bacteria through the use of aromatic solvents
at rates which presently are recommended for aquatic weed
control."

Xylene Characteristics Similar to Gasoline

Like gasoline, cleaning solvent and aromatic solvents, xylene is
derived from petroleum oils. As much as 10 percent of "high test"
or premium gasoline is xylene. Irrigation districts, canal compa-
nies, and governmental agencies handle xylene much in the same
manner as they do gasoline.

3/Unpublished data from experiments conducted by L. W. Jones,
Bacterialogical Department, Utah Agricultural Experimental Station.


the guinea pigs were confined to the treated water, whereas under nor-
mal conditions, livestock would have access to treated water for a
matter of only minutes two or three times during an irrigation season.

The June 1957 issue of Ilygienic Guide Series states that: ''No fatal
cases from inhalation of vapor consisting wholly or chiefly of xylene

have been reported."

Xylene Suppresses but Will Not kill Pondweeds

Photograph 1 - P222-D-50462NA

Photograph 2 - P222-D-S0461NA

Because xylene affects
only those portions of
the pondweeds above
ground, control is tem-
porary. It is necessary
to repeat treatment when
new growth of the weeds
begins to fill the chan-
nels. Two or more appli-
cations are required
during each growing sea-
son. Canals and laterals
which have been treated
for more than 20 years
show no reduction in num-
ber or size of pondweeds.
Pondweeds have clogged
this lateral as shown in
Photograph 1. However,
through the use of xylene
the dense growth shown in
the photograph could have
been prevented. Sub-
mersed aquatic weeds are
rooted, or attached, to
the bottom of canals,
laterals, or drains. They
grow freely in water,
buoyed by air cells in the
leaves and stems. ‘The
Giant Sago pondweed, shown
in Photograph 2, is 12 to
15 feet in length.

Xylene Does Not Remain
in Water or Soil

Xylene, like gasoline and
other related products,
is volatile and evaporates
when exposed to air. As


Photograph 1 - P214-D-64740D

Photograph 2 - P214-D-64741D

16


Photograph 3 - P3-100-147

Photograph 4 - P3-100-148

Chaining (Dragging) Canals and Laterals

Since the beginning of irrigation in the West, men have tried and

under some conditions must continue to remove pondweeds from canals
and laterals by dragging these channels with chains, discs, binder
wheels and other instruments. Although this method may be repeated
every 10 to 15 days throughout the irrigation season, it generally
is very ineffective. Only a fraction of the weeds are broken loose


Photograph 6 - P20-703-5842NA

There are no plans of the trashrack available, as it was built and
altered as ideas and problems arose. However, if further information
is desired, it can be obtained by writing to the Northport Irrigation
District, Post Office Box 547, Bridgeport, Nebraska 69336.

kk RK

22


Department of the Interior, Bureau of Reclamation

IRRIGATION OPERATION AND MAINTENANCE

BULLETIN NO. 69
July, August, September 1969
LST viPY D io
0 NOT R ined —
>
tad

(ast coPY - DO NOT REMOVE

In This Issue:

The Use of Xylene for the Suppression of Submersed
Aquatic Weeds in Canals and Laterals

Weed Control and Removal Equipment

Hydraulically Operated Spray Rig for Weed Control
Mechanical Trashrack

Pumping Plant Trashrack
Seraper for Cleaning Canals

Herbicide Monitoring Study in Irrigation Systems


WEED CONTROL AND REMOVAL EQUIPMENT1/

Gang Discs and Chain

Gang discs, dragging a loop ot heavy-duty anchor chain, have been
found highly successful where mechanical methods are desirable in
dislodging aquatic weeds in the Salt River Project canal system. The
discs tear up the soil and loosen weeds. Then the chain drags out
weeds by the roots and smooths the disced canal bottom.

Two medium duty tractors, one on each side of the canal, pull the
equipment upstream and down along the canal bottom to tear out the
equatic plants. Figure 1 below shows the gang of heavy discs on the
canal bank prior to beginning a weed removal job. Figure 2 on the
following page shows how the water is churned up by the discs and
anchor chain during the weed removal operation. Up to five or six
passes are made in a single treatment.

Figure 1 - Photo P25-D-64723

1/This article was written by Mr. W. L. Simser, Superintendent,
Construction and Maintenance and Agriculture, Salt River Project,
Phoenix, Arizona.


Total annual cost in 1968, including material, equipment, labor
and overhead was about $25,000 or less than half our mechanical
operation in 1955. The cost saving is even greater because of
the substantial increase in operating costs since that time."
Through pool purchasing by a number of projects in an area, the cost
of xylene and emulsifier per gallon used in the suppression of pond-
weeds has been reduced 15 percent in the past 10 years. Accordingly,

the cost of pondweed suppression with xylene as compared with the cost
of chaining if practiced at this time would be much less.

ee RR

Driving attitudes can contribute to accidents. The following list
is excerpted from the National Safety Newsletter as a reminder to
drivers. Keep your calm and don't let these attitudes develop:
The ''me-first'' attitude. Shows lack of concern for others.
The self-important. Rules apply to the other fellow.
The over-confident. I know it all. I never had an accident.
The "live dangerously" type. It can't happen to me.
The fatalist. You go when your number is up.
The hostile type. Constantly angry towards others.
The inferiority type. Please don't push me around!
The competitor. Must always be ahead of the other fellow.
The "tired of living.'' A need of self-destruction.
The exhibitionist. A show-off.
The sadist. Derives pleasure from hurting or threatening.
The self-righteous. It is always the other fellow's fault.

It is easy to see that the attitude of one person could very well
determine his classification as a good driver.

tee RE


Circular No. 58, "Herbicides (How Poisonous are They?) ,'' published by
the University of Idaho in 1967, compares the toxicity of various
herbicides when injested by small animals. In this comparison the
herbicides are given numerical ratings: 1 - extremely toxic, 2 -
very toxic, 3 - moderately toxic, and 4 - almost non-toxic. Aromatic
solvents (xylene) and gasoline are both rated No. 3. Kerosene is
rated No. 2 to 3.

Canals and Laterals Do Not Support Fisheries

The small number of fish found in these channels are there by acci-
dent. These channels carry water only 6 to 7 months each year
during the growing season, being dry for the other 5 to 6 months.
Consequently these waters cannot be used as fisheries. Fish that do
enter the irrigation systems are doomed to perish at the end of the
irrigation season.

Xylene Is Toxic to Fish. Water Containing Xylene Is Not Permitted
to Enter Natural Streams

Xylene is toxic to fish; consequently, irrigation water containing
xylene is not permitted to enter natural streams and rivers. As
pointed out previously, water which has been treated with xylene is
used for irrigation of crops and under most conditions any of the
treated water remaining at the bottom of the fields after irrigation
has lost the xylene to the air. In the few cases where xylene may
remain in the water after irrigation, the water is wasted into hold-
ing ponds, or onto noncultivated areas. At the end boundary of some
districts, waste water containing xylene can be spilled over drops
causing extreme agitation and loss of xylene into the air.

Controlling Pondweed by Drying

During the period of early settlement in the West and until about
1930, water for irrigation was plentiful and the methods of irriga-
tion and the type of crops grown tolerated interruptions in water
deliveries. Drying of ditches 4 to 5 days for the control of pond-
weed was a common practice. The need for maintaining uniform moisture
conditions associated with row crop farming and a greater demand for
water have made the practice of drying unacceptable to most farmers.

Hand Mowing Pondweeds

During the period preceding 1950, it was not uncommon to find crews
of three to six men engaged in cutting pondweeds in the shallower
laterals and canals with scythes, as shown in Photograph 3 on the
next page. The cut weeds, also shown on the following page in
Photograph 4, were collected on trashracks and lifted from the
streams. This very costly practice was repeated every 8 to 12 days
depending on the severity of the weed infestation, water tempera-
tures, and the demand for water.


MECHANICAL TRASHRACK

This mechanical trashrack used on the Northport Canal, North Platte
Project, Northport, Nebraska, is a product of 4 years of experimenta-
tion and improvement. Most of the construction and alterations that
were necessary for the efficient operation of this device were done
by Mr. N. E, Troudt of the Northport Irrigation District, Northport,
Nebraska.

It is basically a very simple mechanical device that is reported to
operate most efficiently. Photograph 1 below is a view of the trash-
rack looking up at it from the lower section. The trash moves up

the rack and falls on to the conveyor belt which moves it to a depres-
sion on the right side of the 60 cfs canal where it has been installed
at a drop structure. Photograph 2 at the top of next page shows the
eccentrics or camshaft detail. A full view of the mechanical trash-
rack installation is shown in Photograph 3. Photograph 4 on page 21
looking upstream shows the trashrack as it fits into the drop struc-
ture.

f is Feed
LEE ELS ET Bi
p . $b
LA bi (iil ai

ry

Photograph 1 - P20-703-5845NA
Trashrack Construction
The device is made of a 2-inch steel shaft that has eccentrics or cams

keyed to the shaft. These raise and lower alternate steel bars or
walkers approximately 2 inches with each stroke. The walkers are made

19


HERBICIDE MONITORING STUDY IN IRRIGATION SYSTEMS

Herbicide Residues

A 3-year herbicide monitoring program in cooperation with the Federal
Water Pollution Control Administration is in progress by the Bureau
of Reclamation to determine the fate of herbicides used on irrigation
systems. The program is part of a nationwide study in which the
Bureau is participating. Data obtained from the study will be used to
support national registration of commonly used herbicides.

Under the Department of Agriculture's compulsory registration program
for herbicides used in or near irrigation systems, evidence must be
submitted demonstrating that a herbicide can be used to prescribed con-
centrations without injury to man, wildlife, livestock, or crops
before that particular herbicide can be approved. Some herbicides
have now been in common use for as long as 20 years with very little
documentation having been obtained as to the residues of the herbi-
cides, The purpose of the study is to obtain such documentation.

The Columbia Basin Project in the State of Washington was selected for
the field phase of the study because of its broad system of canals,
laterals, and drains of various sizes, lengths, and conditions, and the
availability of personnel experienced in water monitoring procedures
and needs. The program is closely coordinated with the Quincy, East,
and South Columbia Basin Irrigation Districts, which actually carry
out the weed control operations on the Project.

Technical guidance is provided by the Chief Engineer's Office of the
Bureau of Reclamation in Denver, Colorado. The field segment of the
work consists of a number of operations required in the program, Some
of these include the planning of canal sampling and coordination of
it with district personnel making the herbicide application, tracing
the movement of water subjected to herbicide application through the
use of dyes, collecting water samples periodically at a number of
stations along the canal, recording data on all parameters involved,
performing the initial steps in the extraction of the herbicide from
the irrigation water, and the preparation of samples for shipment to
Denver.

The laboratory and data analysis phase of the work are performed in

the Research Division, Office of Chief Engineer, as a part of the
Bureau's cooperative weed control research program with the Agricultural
Research Service of the U.S. Department of Agriculture, Denver, Colorado.

The Study

Since the amine salt of 2,4-dichlorophenoxyacetic acid (2,4-D) is used
extensively on irrigation systems of the western states for controlling
broad leaved weeds on ditchbanks and it is not registered specifically

25


THE USE OF XYLENE FOR THE SUPPRESSION OF
SUBMERSED AQUATIC WEEDS IN CANALS AND LATERALS1/

Over a period of more than 20 years the use of xylene has made it pos-
sible for some irrigation districts and canal companies in the Pacific
Northwest to deliver adequate quantities of clean water to all farms on
their projects. This was not the case when the districts relied on
chaining and other methods to control these weeds. This program has been
carried out without injury to man, livestock or crops. Only in rare
cases of accidental spilling of treated water into natural streams has
there been damage to fish.

While the greatest benefit from the use of this product has been in
the districts being able to give uninterrupted service of adequate
quantities of clean water to all farms, the saving in cost to the
water users has been substantial.

Xylene Is Registered and Approved for Use in the Suppression of Pond-
weeds in Irrigation Systems

All herbicides used for the control of aquatic and terrestrial weeds
must be registered by the Pesticide Regulation Division, Agricultural
Research Service, U.S. Department of Agriculture. This registration

of a product requires the approval of the Pure Food and Drug Adminis-
tration, Sports Fisheries and Wildlife, National Pesticide Review Board,
and others. The Pesticide Registration Committee is staffed with per-
sons having broad experience and training in determining hazards con-
nected with the use of chemicals.

As a prerequisite for registration of a particular herbicide, informa-
tion and research data must be provided to convince the regulatory
government agencies that the use made of the herbicide will not be
injurious to man, crops, livestock, wildlife and our environment, and
yet be effective on the target organism. Xylene is registered for use
in the control of pondweeds in irrigation systems. This registration
carries the approval of the departments and agencies mentioned above.
Because of the broad use of xylene throughout the world as a pesticide
solvent and carrier and because of its safe use on crops, we anticipate
that any further consideration by regulatory agencies of its use in
irrigation water will place it in an exempt status as far as tolerances
are concerned.

Crops Not Injured with Xylene

Irrigation districts, canal companies, county and state governments,
Indian Service and the Bureau of Reclamation apply xylene to more than

1/This article was reprinted from a report prepared by Mr. W. Dean Boyle,
Regional Agronomist, Region 1, U.S. Bureau of Reclamation, Boise,
Idaho, in response to an inquiry concerning the use of this product.


A mobile crane, as shown in Figure 6 below, is used to set the grids in
place against various canal structures or bridges. They are positioned
in the water at an approximate 45-degree angle, as shown in Figure 7
Note that the grid is being set into the notches or scallops on the

lip of the structure. This holds the grid snugly and resists shifting
during the raking operation.

Figure 6
Photo
P25-D-64728D

Figure 7
Photo
P25-D-64729

12


growth. This latter procedure requires operating skill to avoid damage
to the grids.

Transportation of Equipment

A flatbed truck is used to haul the discs, chains, and grids from
station to station on the canals. The discs, chains, and bucket are
carried on the bed, while the grids are cradled in a rack built over
the bed. Figure 10 below shows a typical flatbed truck used for this
purpose. The equipment is offloaded by the same mobile crane which
is used to position and clean the grids.

Figure 10 - Photo P25-D-64732D

Costs

The described process, which costs about $170 per mile, is repeated
from station to station on the canals during the growing season to
maintain full canal capacity.

Anyone seeking additional information should contact the writer at
the Salt River Project, Post Office Box 1980, Phoenix, Arizona 85001.

a ed

14


IRRIGATION OPERATION AND MAINTENANCE
BULLETIN No. 69

July, August, September 1969

INTRODUCTION

This issue of the Bulletin is devoted exclusively to weed control meth-
ods and equipment being used on some irrigation projects in the west-
ern part of the United States. The use of xylene for the suppression
of submersed aquatic weeds in canals and laterals is the subject of an
article starting on page 1. Included is a comparison of the cost of
pondweed suppression with xylene and the chaining methods.

As a follow-up article to that appearing in Bulletin No. 64 on "Eval-
uation of Cost and Effecitveness of Canal and Lateral Aquatic Weed
Control," the second article in this issue of the Bulletin beginning
on page 9, describes the various types of equipment used for weed
removal from Salt River Project canals in Arizona. Removal of pond-
weeds by this method is a necessary part of their operation.

Beginning on page 15, an article by Mr. R. F. Carter, of the Imperial
Irrigation District, Imperial, California, describes the hydraulic
spraying equipment used by the District that is so necessary in this
particular environment on the project. The article describes a unit
developed and field tested during the 1967 fall spraying season.

A mechanical trashrack developed and used on the Northport Canal, North
Platte Project, Northport, Nebraska, is described and illustrated in an
article that begins on page 19.

To prevent frequent shutdowns at the Burbank No. 3 Pumping Plant on
the Columbia Basin Project, Ephrata, Washington, a supplemental trash-
rack was installed. The supplemental rack was built because of a heavy
concentration of debris. This problem and the new trashrack are
described in a short article on page 23.

On page 24, there is described a scraper for cleaning sediment and
algae from canals that was developed and fabricated by the Metropolitan
Water District of Los Angeles, California.

The purpose of a cooperative study to determine the fate of various
herbicides in irrigation water is the subject of an article starting
on page 25. This study is the result of routine herbicide applications
made on irrigation systems.


PUMPING PLANT TRASHRACK

A heavy concentration of debris on the trashrack at the Burbank No. 3
Pumping Plant, Columbia Basin Project, Ephrata, Washington, was contin-
ually interferring with the flow of water to the pump, causing frequent
shutdown at the plant.

In order to eliminate this problem another trashrack as shown in
Photograph 1 was constructed approximately 6 feet in front of the
original rack.

Photograph 2 at lower
left shows the original
trashrack that was
built with a 1-7/8-inch
spacing on a 1 to 3
slope. The supplemen-
tal trashrack with a
trash bar spacing of 3
inches, made from 1/2-
by 2-1/2-inch steel
bars, restricts the
larger material to the
forebay where it can
be removed easily.

The new rack has a much
flatter slope which
makes it possible to
clean both racks at
less frequent intervals.
This has been made pos-
sible because of the
heavier driftwood and
other large debris
being caught by the
auxiliary trashrack.

Project field personnel
fabricated this new
rack and a platform was
made from surplus land-
ing mats in which the
debris can be piled for
removal.

ak RR

Photograph 2 - P222-D-64739D

23


The Irrigation Operation and Maintenance bulletin is published quar-
terly, for the benefit of Irrigation project people. Its principal
purpose is to serve as a medium of exchanging operation and mainte-
nance information. It is hoped that the reports herein concerning
labor-saving devices and less costly equipment and procedures, devel-
oped by resourceful project people, will result in improved efficiency
and reduced costs of the systems for those operators adapting these
ideas to their needs.

To assure proper recognition of those individuals whose suggestions
are published in the bulletins, the suggestion number as well as the
person's name is given. All Bureau offices are reminded to notify
their Suggestions Award Committee when a suggestion is adopted.

wk KR

Division of Irrigation Operations
Office of Chief Engineer
Denver, Colorado 80225

COVER PHOTOGRAPH:

Watermaster for the Frenchtown
Irrigation District, Montana,
applying xylene to the Frenchtown
canal for the control of pondweed
and algae. Photo P222-D-50460NA



for use on this type area, top priority is given to this herbicide in
the first year of the study. Other herbicides will be monitored as
the program develops.

This entire monitoring program follows procedures reviewed and tenta-
tively approved by the Interagency Ad Hoc Committee on Use of Herbicides
in Aquatic Sites. The first steps of the analysis are performed in

a laboratory on the Columbia Basin Project. Extractions reduce the
volume of liquid for shipping from 1 quart to a few ounces and leaves
the 2,4-D in a liquid medium resistant to biological activity. On
arrival in Denver the samples of extracts are processed and analyzed
for 2,4-D content with the gas chromatograph. The data are transferred
to punch cards, and an automatic data processing program is used to
process these data for future reports and other purposes.

A total of five channels have been sampled. These are selected at
random throughout the project to obtain a cross sectional representa-
tion of the variability in water conveyance channels and herbicide
applicators.

Throughout the sampling program, agronomists will identify and
appraise both aquatic and terrestrial vegetation in the sampling areas
so that the effect of herbicides at the different sites can be evalu-
ated. Some of the things that are expected to be learned from the
study are the extent of dilution of particular herbicides as they move
through the irrigation system, the degree of absorption in soils or
plant life which takes place, and the amount of loss through evapo-
ration.

A typical example of collecting a set of three replicated water sam-
ples from a canal on the project is illustrated in Photograph 1 at left,
and, on the next page,
Photograph 2 depicts
the manner in which
three l-quart glass bot-
tles are positioned on
the sampler so that the
three replicates are
collected at the same
time. Water samples
collected are kept
under refrigeration
until the following day
when they are extracted.
The extracts are stored
under refrigeration in
4-ounce glass bottles
fitted with teflon-lined
caps until ready for
Photograph 1 - P222-D-64735D shipping. The bottles

26


Figure 2 - Photo P25-D-64724D

From S to 11 discs are used, depending upon the width of the canal. A
single disc unit is shown in Figure 3 below. The discs cost about $350
per unit and last about 3 seasons, with normal replacement and repair
of various parts.

The heavy-duty anchor chain
which the project obtained
from a salvage yard some
years ago, is about 90 feet
long, with links weighing
90 pounds each. As the
chain wears, the project
machine shop rebuilds the
metal on each link to retain
the necessary weight. The
chain also is equipped with
three large swivels to per-
mit it to roll without
twisting the cable leads.

Portable Trashracks

The dislodged growth floats
downstream and is trapped
by barriers of pipe grids,
Figure 4, temporarily set
up at various structures

Figure 3 - Photo P25-D-64725D

10


Figure 9 - Photo P25-D-64731D

13

Figure 8, at left is a view
of the grid set into the
scallops on the lip of the
structure, and also it
shows workmen securing the
grid to the structure chain.
Individual 1l-inch-diameter
pipes are laid in a similar
manner near the sides of
the canal as shown previ-
ously in Figure 4, to fill
in the gaps created by the
slope of the canal banks.
Average cost of the grids
is $150 each. They last
about two seasons, with
normal maintenance.

Weed Bucket

As the dislodged growth
floats downstream and
begins to lodge against the
grids, it is removed by the
bucket shown in Figure 9,
that was designed and built
for this purpose by the
project. The bucket is
lowered in such a position
to permit the bucket teeth
to pass between the grid
pipes. It is then raised,
removing the accumulated
growth to the canal bank
for partial drying before
the weeds are hauled away.

If the crane can be set up
directly behind the grids,
they can be cleaned by drop-
ping the bucket upstream
and pulling it up against
them. If it is necessary
to work from the side, the
bucket has to be lowered
carefully on the grids and
then pulled upstream and to
the side for removal of the