the pump. Additional information may be obtained by writing to the
Regional Director, Bureau of Reclamation, Box 937, Boise, Idaho, or
to the Assistant Commissioner and Chief Engineer, Bureau of Recla-
mation, Denver Federal Center, Denver 25, Colorado, Attention:
D-410.

UNIVERSAL JOINTS INSTEAD OF EYEBOLTS ON SPRAY RIG
(Suggestion R1-61-21)

The North Side Irrigation Field Division, Minidoka Project Office, re-
ports less downtime when universal joints replaced the eyebolts on
spray rigs. Mr. Charles H.
Edwards made the suggestion
that the eyebolts installed on
the standards on the boom
where the hydraulic cylinder
is fastened be replaced by
universal joints. This in-
stallation and the formerly
used eyebolt are shown in
Figures 1 and 2.

Mr. Edwards states that the
eyebolts which were used
formerly, crystallized and
broke from strain and vi-
bration. An eyebolt would
last about 3 or 4 days before
. it broke, causing the spray
Photo No, 1 rig to lose from 4 to 6

hours field time while it was
being repaired at a cost in
downtime of about $10.00 per
hour. Mr. Edwards further
reports that they get
smoother and better opera-
tion with less strain on the
hydraulic cylinder.

Should anyone be interested
in receiving more informa-
tion about this suggestion, it
may be obtained by writing to
the Regional Director, Bu-
reau of Reclamation, Box
937, Boise, Idaho, or the
Assistant Commissioner and

Photo No. 2

17


piping and subsequent recurrence of the sinkhole. Care should be
exercised to repair an area large enough to avoid the development
of new holes around the periphery of the repaired area. Any settled
areas should also be brought back to grade before water is reintro-

duced into the channel.

The repair of sinkholes or piping holes around structures has been

Photo No. 12

Photo No. 13

11

accomplished on some
projects by puddling
methods using a vibra-
tor to work the mud
down into the hole.
One thing to bear in
mind in using the pud-
dling method is that
the puddled backfill
does not become sta-
ble until the excess
water has drained
away through the
foundation material.
For that reason it
may be undesirable to
puddle in locations
where the foundation
material is very slow
draining or impervi-
ous. By the same
token the backfill mate-
rial used in puddling
should be semi-
pervious. Thus silty
sands, and low plas-
ticity silts are good
for this purpose.

Correct procedures
for puddling are
described in the Earth
Manual, 1960, page
302. Figure 12 shows
a typical puddling
operation around a
turnout and weir box
structure on a lateral.
The occurrence of the
break shown in a large
canal, Photograph No.
13, at a culvert leads
one to suspect that


A 3-WHEELED WHEELBARROW

The removal of rock from a concrete-lined section of a main canal on
the Kittitas Division of the Yakima Project where reaches of the canal
are located in sidehill cut, Photo No. 1, cannot be classed as a major
maintenance item, but it is one that is awkward to accomplish, be-
comes time consuming if done by hand, and costly and inefficient, for
the amount of work to be done if large equipment is used. The depth of
the canal below existing operating roads precludes the use of smaller

motorized equipment.

Photo No.

Watermaster Adcock
has constructed a 3-
wheeled wheelbarrow,
Photograph No. 2,
which is pulled up to
the lower canal bank
to the operating road
by a small gasoline
powered winch mounted
on the rear of a truck
bed. The operation is
quite efficient and ef-
fective.

Photo No. 2

21


depending upon the conditions prevailing, and he will know what to do in
case the ditch breaks in spite of his precautions.

Consider also that this experienced operator can be used in a number
of other ways on the construction engineer's staff and that he will be
available to supervise the operation and maintenance of the completed
works when service to the lands is established. This man should be
on the job at least a year before it is time to start priming the system
so that he may be entirely familiar with local conditions.

Soils, Geology and Topography

The soils, the geology and the topography through which the system is
located will have a great deal to do with the difficulties experienced in
priming and puddling a system. Light sandy or silty soils can become
very unstable when water is first introduced into the channels and the
banks become saturated. Serious subsidence of the area adjacent toa
large lateral is shown in Photograph No. 1. This is more or less
typical of what may be expected in light uncompacted soils.

P222-117-37415

Photo No. 1



Chief Engineer, Bureau of Reclamation, Denver Federal Center,
Denver 25, Colorado, Attention D-410,

HK ok ok

THE USE OF LOW PRESSURE GAS
FOR REMOTE POWER UNITS

The problem of maintaining remotely located equipment driven by water-
cooled gasoline fueled engines usually becomes quite expensive as cor-
rosion, carburetor and gas tank gumming and other deteriorating proc-
esses occur.

The Salt River Project was faced with these same problems in main-
taining their motor-generator sets which operate the spillway gates at
four hydroelectric dams.

The project's solution to reduce the cost of maintenance is described in
this article prepared by T. W. Bent, Supervisory Mechanical Engineer,
and J. L. MacLaren, Mechanical Engineer, District Engineering, Salt
River Project.

In 1960 an engine replacement program was engineered and inaugurated
by the Engineering Department to materially reduce or eliminate main-
tenance difficulties. Each year for a period of 4 years one of two gas-
oline engines at each location was to be replaced with an air-cooled,

Photo No. 1

18


Remoteness of equipment can be thought of in two ways: First, ge-
ographical but with ease of access for operational and maintenance pur-
poses; second, geographical but with moderate to difficult access. The
motor generator sets of the project fall into both categories with three
of the four installations in the latter.

It will be noted in Photograph No. 4 the motor generator house is lo-
cated on one side of the dam and approximately 1, 000 feet from the
access road on the other. In this type of installation the use of LPG
has an additional advantage over gasoline in that the LPG tank can be
remotely located from the engine to allow ease of filling with the gas
being piped to the desired location.

Photo No. 4

In summation some of the advantages of utilizing air-cooled, LPG en-
gines where feasible are as follows:

1, Elimination of cooling system problems.
2. Elimination of carburation problems.

3. Elimination of internally corroded gasoline tanks and their re-
sulting difficulties.

4. Reduction of fuel handling problems.

By adopting this replacement program the project expects relatively
maintenance free operation of these sets for many years to come.

20


There may be several ways to accomplish the braking as stated pre-
viously; however, the method described was used because several of
the components were available from surplus material on hand. The
device has proven to be quite successful.

If further information is desired, write the Chief, Folsom Field Divi-
sion, Bureau of Reclamation, Post Office Box 37, Folsom-Auburn
Road, Folsom, California, or the Assistant Commissioner and Chief
Engineer, Bureau of Reclamation, Denver Federal Center, Denver 25,
Colorado, Attention: D-410.

kK KOR

COMPRESSED AIR ACCIDENT
(From Safety Record published monthly by the Office
of Assistant Commissioner and Chief Engineer,
Bureau of Reclamation, Denver, Colorado. )

A Michigan mechanic with a small cut on the side of a finger washed
some small parts in cleaning fluid and then, holding them in his hand,
he played the airhose on them to dry the parts off.

Shortly after, in great pain, he staggered over to the manager com-
plaining his body and head felt as if they were going to explode. At the
hospital, his ailment was diagnosed as ‘‘air bubbles'' in the blood-
stream caused by the air jet striking the small wound on his finger,
forcing entry into the bloodstream. This man recovered, but might
have died. Using an airhose to ‘blow off‘ parts held in the hand is an
unsafe practice, as this case bears out.

KOK OK OK

LOSS OF AIR IN TRUCK BRAKE SYSTEMS
(Suggestion R2-61-71)

Mr. Airon C. Burchett, of the Tracy Operations Field Branch, Delta-
Mendota Canal Maintenance Unit, Central Valley Project, reports that
while going over rough terrain the bleeder valve on a dump truck was
knocked open, resulting in loss of air in the truck's braking system.

To eliminate a possible serious accident from happening in the future
due to a sudden drop in the air reserve, Mr. Burchett suggested that
such an eventuality could probably be eliminated by putting a cap on the
bleeder valve, or by installing a suitable guard over the existing valve.

The valves on all trucks equipped with airbraking systems were ac-
cordingly examined in the project garage. Except for three dump

15



Photo No.

8

clean, the introduc-
tion of silt or clay
above the structure,
or the mixing of clay
with the backfill, will
usually give good
results.

In compacting backfill,
care must be exer-
cised to obtain good
density throughout the
backfill and through
the plane of contact
with the adjacent or
underlying undisturbed
natural material.
Lack of density can
result in the develop-
ment of weak areas
which invite piping

around the structure or between the backfill and the adjacent natural
soil. Where the compacted backfill may have shrunk away from the
structure, a lot of good can be accomplished by spading and working the
backfill against the structure as the priming water is checked up. The
addition of silt and clay soils at these points is often necessary.

Because of uncertainties in evaluating the geological conditions and the

Photo No.

9

performance of sur-
rounding soils, inad-
equate resistance to
percolation may exist
at structures and
areas of weakness may
sometimes develop.
This is particularly
true in fine sandy and
silty soils and soils
which subside appre-
ciably upon wetting.
The damage to an auto-
matic wasteway struc-
ture founded on loessal
soil, Photograph No,
9, occurred about 10
weeks after water
first reached the


The same type of problem
occurred at the smaller baf-
fled apron drop shown in
Photograph No. 4. Settle-
ment of the foundation mate-
rial upon becoming wet per-
mitted water to pass under
the upstream cutoff, wash a
pathway under the structure,
and emerge on the left side
as shown. A somewhat sim-
ilar problem in silty loessal
soils is shown in Photograph
No. 5, where failure of a
grade control structure in
this type of soil was attributed
to post construction consoli-
dation and subsidence.

In some areas also pervious
or open gravel strata under-
lying canals have provided
percolation paths for seeping
water to follow, resulting
ultimately in piping and seri-
ous washouts. In many
cases the existence of these
pervious strata remain
undiscovered until the break
has occurred, or, in some
more fortunate cases,
springs along the lower bank
are discovered in time to
prevent serious damage.

Sinkholes in gravels in the
bottom of a lateral are
Photo No. 5 shown in Photograph No. 6.
Water passing into the under-
lying gravel strata through
the sinkholes reappeared outside the channel bank, but continued for
only a relatively short time.

Problems have also been encountered where siltstone underlies the
canal bottom. Photograph No. 7 shows a large crevice in siltstone
that had been filled with permeable material. Seepage from the canal
into the crevices caused piping that resulted in washouts and canal bank
failures.


Settlement cracks that develop upstream from a structure such as the
baffled apron drop, Photograph No, 2, can create a serious problem.
In this instance the subgrade material was sand and silt with an under-
lying gravel strata. Storm water in the channel caused bank settlement
and subgrade subsidence with serious damage resulting before the chan-
nel had been primed. The photograph on the cover page, and Photo-
graph No, 3 are other views of this same structure. Water washing
under the upstream cutoff of the structure, as shown on the front cover,
passed along the left side of the inclined section of the drop and emerged
at the lower right corner, Photograph No. 3. Only quick action by
project forces saved the structure from destruction.

Photo No, 2

Photo No. 3


trucks, it was found that bleeder-valves on all other trucks in service
on the project unit were positioned in the reserve air tanks in such a
way as to be sufficiently protected during operation through high veg-
etation or rough terrain. On the three trucks not so equipped the
valves with longer handles have been replaced with small drain cocks
having short T-handles which will effectively eliminate the hazard.

Although Mr. Burchett's recommendation was not used as suggested,
it emphasized a potential safety hazard and one that could cause a se-
rious accident. It is suggested that others may wish to examine the
airbraking systems on their equipment and provide a different type
bleeder valve or protection of the valve as the case may be.

MOVING DEEP WELL PUMPS
(Suggestion R1-61-23)

During a rectification program on the North Side Irrigation Field Divi-
sion of the Minidoka Project, an ingenious method was developed for
moving turbine deep well pumps and their accessories.

This method was suggested by Mr. Virgil D. Temple, turbine pump
repairman. He suggested that one end of the sand line of the pump rig
be anchored by staking it near the place where the pump and the acces-
sories are to be placed, as shown in the photograph below. Then by
using a single sheave pulley over the line, the task of moving pump and
its accessories can be accomplished very satisfactorily, as shown.

Previously on the Minidoka
Project, a wrecker or winch
truck was used to move the
pump and its accessories
and $5.00 an hour was
charged for the use of this
piece of equipment.

Mr. Temple's suggestion
does not eliminate any per-
sonnel from the four man
pump crew that is normally
used to pull or install pumps,
but it does relieve the truck
and driver for other work.

It also puts less strain on
the pump rig while moving

16


Canals located on steep hill-
sides have always been
sources of troubles for oper-
ators, especially in the early
stages of operating or prim-
ing the system. A washout
occurring in such a location
is likely to destroy the entire
ditch section before the water
can be shut off. Repair of
such washouts usually is
expensive, involving the
movement of rather large
quantities of earth.

In case a leak or spring
develops through the lower

Photo No, 7 canal bank and for one rea-

son or another it is not

stopped by repairing immediately, daily measurement of the flow of the
leak should be made and reported by the patrolman. This assures that
he makes a special inspection of the leak so that any change in quantity
of flow is immediately noted and any cloudiness of the water, indicating
active erosion is taking place, is obvious.

Structure Backfill

The materials selected for backfilling around structures and the care
exercised in compacting these materials can have a lot of influence on
whether or not trouble is experienced in priming. The material should
be stable, impervious and nonshrinking so that it will be fully effective
when the time comes, possibly several months after the backfill is
placed, to run the first water through the system. If the backfill has
dried out and shrunk during the interim, piping channels are likely to
develop around the structure unless corrective measures are taken,

The use of fairly well-graded sand-gravel material is favored by many
of our project operators for the backfilling of structures which have been
washed out, because the coarse particles lend stability. Photograph

No. 8 illustrates such a washout on the right side of a drop structure.

It is being repaired by backfilling with a silty and sandy gravel. This
particular structure had been in operation many years prior to the fail-
ure due to piping under a cutoff wall and is typical of such failures.

If the canal water contains reasonable amounts of colloids and silts,
any perviousness of the coarse backfill material is soon corrected by
the trapping of the suspended materials. Where the canal water is


AIRHAMMER PILEDRIVER
(Suggestion R3N-62-1)

The pneumatic, commercially available, paving breaker modified for
use as an airhammer piledriver shown in the photograph below was the
Suggestion of George A. Schwindt and Ralph H. McVey, foreman and
welder, respectively, of the Bureau's Needles, California Office, which
is responsible for the Colorado River Front Work and Levee System.
The suggestion fulfilled a need for lighter weight equipment capable of
driving railroad rail piling, posts, pipe, etc., in hard-to-reach places
and for equipment that could be transported without use of a large trans-
porting truck or tracked crane over the roads, sometimes for consid-
erable distances.

The project utilizes the device primarily in driving 65-pound railroad
rail as piling, and supports for water recording gage structures and

for boat docks. It can be used for other similar driving work. Driv-

ing time to obtain 15 to 18 feet of pile penetration has ranged from 20 to
45 minutes in silt, sand and light gravel. This includes the time nec-
essary for rigging the pile. Greater depth of penetration can be achieved,
but the driver is not recommended for use where the pile must be driven
in rock, cobblestones, or tightly packed gravel.

The paving breaker was re-
vised for mounting on a shop
fabricated piledriving hammer
to fit 65-pound railroad rail
as shown in the drawing, page
14. Provision for vibration
is provided by the use of
spring-loaded side rods held
in place with four belts. The
device can be powered by a
210-cubic-feet-per-minute-
compressor and handled by a
truck crane or truck-mounted
A-frame.

In addition to being more
easily transported with lighter
duty equipment and thus sav-
ing in transportation costs
over heavier equipment, the
same job can be accomplished
with less manpower.

22


Department of the Interior
Bureau of Reclamation

OPERATION AND MAINTENANCE

EQUIPMENT AND PROCEDURES
RELEASE NO. 41

July, August and September 1962

CONTENTS

Priming and Puddling Canals and Laterals
Electrodynamic Brake on Powersaw

Compressed Air Accident

Loss of Air in Truck Brake Systems

Moving Deep Well Pumps

Universal Joints Instead of Eyebolts on Spray Rig
The Use of Low Pressure Gas for Remote Power Units
A 3-Wheeled Wheelbarrow

Airhammer Piledriver



it may be desirable to place canal lining adjacent to structures at
siphons where steep slopes exist. The percolation of water along a
structure wall or floor may proceed very slowly or in the case of
shrunken backfill, it can travel very rapidly. This is a factor which
requires very close watching if serious troubles are to be avoided.

Another procedure employed by operation and maintenance people in
stopping incipient washouts, or washouts in their earlier stages, is the
introduction of bulky materials, such as hay or straw, along with earth
and gravel fill into a piping hole. This would be a temporary measure
to minimize damage as the canal was being drained to make permanent
repairs.

General Guides

While we can venture to give some general suggestions to be followed in
priming and puddling a new systerr, this operation needs to be governed
very closely by local conditions which, also, emphasizes the need for
an experienced man of the job. For average conditions, however, we
offer the following guides:

1. Small head of water. --Use relatively small heads of water for
initial priming, usually less than 10 percent of the designed capacity,
depending upon the canal size. Consideration must also be given to
the permeability of the canal materials since larger heads of water
may be required to make any progress in large channels through very
pervious soils. It has been found desirable on some systems to run
the initial head of water through to the end of the channel, flushing

it out.

2. Increase head by checking. --When this small flow has gotten
through the reach being primed, increase the depth slowly by check-
ing, beginning at the lower end and working back upstream. This
plan has certain advantages. In the control of the water, if washouts
or leaks develop, the initial bottom coverage will help locate any
weak points or incipient break areas. Also, with checking starting
at the lower end, it is possible to use the upstream areas for storage
of transit water in the event troubles develop in the area where check-
ing is occurring. Similarly as checking proceeds upstream, the
downstream areas have been tested to some extent and release of
water in the event of upstream trouble is less hazardous.

3. Constant patrol. --The closest watch must be kept on earth
embankments and sections and especially on all structures to prevent
piping or washouts. Constant patrolling of the canal or lateral is a
must. Watch for whirlpools, they will likely be very small ones, or
other indications that the canal water is escaping into the subgrade
or around a structure. The importance of reliable and rapid



Photo No. 10

structure and followed what would normally be considered to be an ade-
quate priming procedure. The washed-out structure illustrates the haz-
ards that must be expected when priming a new system.

Failure of a grade control structure in similar loessal soils attributed
to post construction consolidation and subsidence has been previously
shown in Photograph No. 5. The failure of another grade control struc-
ture is shown in Photograph No. 10. This failure was also attributed to
settling and subsidence. The cutoffs alongside the structure are clearly
evident and the path of the water can clearly be seen to have washed out
all material along the sides of the main structure.

It is often desirable to prewet natural soils of this type during construc-
tion. It also is possible in this type of soil for settlement of the founda-
tion to occur several months after the initial priming operation is com-
pleted. Operators are warned, therefore, against becoming complacent
about their stabilization problems where loessal-type soils are con-
cerned,

Structure Design

A favorite procedure among operation and maintenance men in the repair
of washed-out structures is to extend the cutoff walls deeper into the
banks and into the canal bottom. This is reasonable inasmuch as many
such failures are caused by water going around cutoff walls. A failure
of this type has been shown in Photographs No. 8 and 10. In some cases


Photo No.

6


Photo No. 2

low-pressure gas (LPG) engine. This has been successfully accom-
plished at two locations, with a third and fourth scheduled in 1962-1963.
The same process will be repeated for the remaining four stand-by en-
gines after the first part of the program has been completed.

In order to reduce the stock of spare parts a standard unit was specified
that would handle the load at all locations. Photographs No. 1 and 2
show a new standard LPG engine installation, while Photograph No. 3
depicts an original gasoline engine installation.

Photo No. 3

19


PRIMING AND PUDDLING CANALS AND LATERALS

The problems related to the priming and puddling of new canals and
laterals must receive careful attention if serious damage to new sys-
tems is to be avoided. To engender a keener appreciation by those in
charge of the need for particular care in carrying out the priming and
puddling operation, some of the inherent dangers are pointed out and a
few guidelines are given in this article.

The article has been prepared by the Division of Irrigation Operations
with the assistance of and in collaboration with the Earth Laboratory
Branch of the Division of Engineering Laboratories and the Canals
Branch of the Division of Design, Office of Assistant Commissioner
and Chief Engineer; irrigation operations personnel of Regions 1 and 7
of the Bureau of Reclamation; and operation and maintenance personnel
of the Columbia Basin Project.

Some Factors to be Considered

The job of priming and puddling a new system may proceed as a fairly
routine operation or it may develop into a very costly troublesome pro-
cedure, depending upon a number of factors, such as:

1, Availability of experienced personnel who are familiar with
priming and puddling methods.

2. Types of soils and geologic and topographic details of the loca-
tion.

3. The condition of the structure backfill at the time of priming.

4. Design characteristics of the structure in the system.

Experienced Personnel

There is no good substitute for experienced personnel when it comes to
accomplishing a job as full of uncertainties as is priming and puddling
an irrigation system. The best assurance available to a construction
engineer, or other official in charge, that his priming and puddling
operation will be carried out with a minimum of difficulty, is the-plac-
ing of an experienced irrigation system operator in charge of this work.
This man, of course, must have had actual experience under varying
conditions so that he will be prepared to meet the problems as they
develop. He will know what materials, equipment, and help he needs
before he turns the water into the system and he will know what proce-
dures to follow to anticipate and avoid piping and breaks in the banks.
He will know how to recognize the first indications of weak areas or
incipient breaks and he will know how to strengthen such places. He
will also know how large a priming head of water he should use,



piping along the structure may have had something to do with the
failure. Careful puddling and care in placing the backfill is impor-
tant in such locations.

7. Lateral priming. --The priming of laterals is basically not much
different from methods used to prime canals. There are, however,
generally more structures on the laterals and the banks are lighter.
On the other hand, water depths in the canals are greater and so
exert more pressure on any existing weak spots.

8. Utilize daylight hours to advantage. --While canals and laterals
being primed must be patrolled day and night, by proper planning
the most hazardous operations such as checking up and puddling of
structures may be performed during daylight hours.

9, Announcing availability of water. --It is quite important that all
systems be thoroughly primed before any attempt is made to use
them to maintain dependable service to irrigated lands. This will
require careful planning in the announcement of the date of availa-
bility of irrigation water in relation to the time required to "Prime
and Puddle" after construction is completed. Sometimes the pres-
sure from water users for irrigation water prevents proper priming
prior to heavy demands for use. If a break occurs during the prim-
ing stage the expense of making repairs is regretted, but if there are
valuable crops depending upon irrigation water from the system, a
break and the resulting crop loss could be disastrous.

Seasonal Filling of a Canal System

While the above discourse is concerned primarily with new canals and
laterals, on many operating projects the procedure of filling the irriga-
tion system with water each spring incorporates many of the above prin-
ciples. This is particularly true in those areas where severe cold may
cause movement of structures and the establishment of percolation
paths around the structures, where expansive clay banks may dry out
and crack deeply during the winter, where burrowing animals may per-
forate the banks during the nonirrigation season, or where other haz-
ards may develop while water is out of the ditches. Under such condi-
tions the filling of the systems at the beginning of the irrigation season
must be attended by reasonable precautions and watchfulness to avoid
costly ditch breaks.

12



|x-------------------------------- 220 V.AG -------------------------------->

CN. Stort | Stop
x ole
Ye
tf
x
x (3H x
te 1+ worer} al
_---Silicon rectifiers
Y c Y

Braking System

X-TOR

\ x

“Set to open in ten seconds
after de-energizing

The photograph presents a view of the 16-inch powersaw with the dy-
namic brake system components mounted in a panel at the right of the
saw. On starting, with reference to the schematic diagram, the start
button is pushed, energizing the ‘X"' contactor through the normally
closed stop button. The contactor will ''seal-in'' through the "X"' con-
tact which is in parallel with the start button. Closing of the 'X" con-
tactor starts the motor, opens the normally closed 'X"' contact in the
"y" contactor circuit, and closes the X-TDR contact.

On stopping, the stop button is pushed, allowing the ''X" contactor to
open, deenergizing the motor. The normally closed "X" contact
closes, energizing the ‘'y" contactor through the time delay '"X" con-
tact. The "Y"' contactor closes, energizing the coasting motor with

12 volts direct current. This voltage is sufficient to excite the motor
windings now being used as a direct current field. This induces a very
high current into the rotating motor rotor. This very high current in
the rotor is effectively short circuited requiring considerable torque to
maintain rotation. Under these conditions the retarding effect stops
the motor is approximately 6 seconds compared to 17 minutes if al-
lowed to coast.

14



OPERATION AND MAINTENANCE
EQUIPMENT AND PROCEDURES
Release No, 41

July, August, and September 1962

INTRODUCTION

The Operation and Maintenance Equipment and Procedures release,
published quarterly, is circulated for the benefit of irrigation project
operation and maintenance people. Its principal purpose is to serve as
a medium for exchanging operation and maintenance information. It is
hoped that the labor-saving devices or less costly equipment developed
by the resourceful water users will be a step toward commercial
development of equipment for use on irrigation projects in a continued
effort to reduce costs and increase operating efficiency.

This issue, Release No. 41, includes an article on the priming and
puddling of new canals and laterals, presenting some factors to be con-
sidered and some general guides, page 1; an article on the use of low
pressure gas in lieu of gasoline as fuel for operation of remote power
units on remotely located equipment on the Salt River Valley Project

in Arizona is described beginning on page 18; and several suggestions
of project operation and maintenance personnel for improved devices
and practices.

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 Awards Committee when a suggestion is adopted.

Division of Irrigation Operations
Office of Assistant Commissioner and Chief Engineer
Denver, Colorado



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Cover Sheet. Storm water reached this structure one night prior to
priming and puddling. Settlement of the banks had occurred 12 hours
later, followed by water washing under the upstream cutoff. The left
bank was washed out and water washed down under the incline emerging
at the opposite side of the bottom as discussed and shown in the article
beginning on page 1. Photo No. PX-D-33699.


communications between the patrolman and his supervisor is empha-
sized, The permanent communication system installed for operation
of the project could be utilized.

4, Priming by stage checking. --Under some conditions it may be
desirable to prime the canal by stages checking the water up only to
one-third or one-half of normal depth in the first stage. After hold-
ing long enough to wet the banks thoroughly the water should be
dropped slowly and the banks permitted to stabilize for several days
before the next stage of priming when the depth of water might be
slowly increased to two-thirds of normal or to full depth. It is quite
important that large sudden changes in water level, either up or down,
be avoided.

5. Fal priming. --On some projects it has been found helpful, when
construction is completed too late in the fall to permit a normal
priming and puddling program, to run a small stream of water into
the new canal late in the fall and, without draining, permit the water
to seep away during the winter. The normal priming and puddling
of the canal in the spring should not be initiated until all frost has
left the banks.

6. Post-priming examination. --After emptying the canal or lateral
following priming, the wetted perimeter of the channel, and areas
adjacent to upstream ends of structures, should be closely examined
for evidence of sinkholes or serious settlement. Sinkholes in the
side of the canal such as those shown in Photograph No. 11, if left
unrepaired, would in all probability eventually result in failure of
the canal bank,

Sinkholes should be
dug out and enlarged
to a depth that will
permit backfilling

with sufficient mate-
rial to create an
impermeable and last-
ing bridge over the
underlying voids. This
often necessitates the
placing of coarse
gravel in the bottom

of the excavation, fol-
lowed by finer gravel
and sand covered by

a heavy layer of com-
pacted stable imper-
vious material of suf-
ficient depth to prevent

Photo No. 11

10



ELECTRODYNAMIC BRAKE ON POWERSAW
(Suggestion R2-61-56)

Two potential safety hazards existed in the operation of the electrically
powered saw shown below in the carpenter shop of the Folsom Opera-
tions Field Branch of the Central Valley Project, California. These
were:

1. The saw, being a 16-inch ball-bearing type, would decelerate to
approximately 1,200 rpm., at which speed it would become very
quiet; also the stroboscopic effect from the shop lighting would
make it appear that the saw blade was no longer rotating.

2. Due to the above condition, the men often stopped the saw by
holding a small board against the side of the saw blade.

The main objective of this suggestion, submitted by Raymond G. Stroh
of the electrical maintenance unit of the operations field branch, was
to reduce the coasting time of the powersaw from approximately 17
minutes to 6 seconds. Mr. Stroh explains that there are many ways to
incorporate braking devices on power equipment, but that by use of a
silicon rectifier, the use of electrodynamic braking is quite practical.
The installation and operation of the braking unit are explained by ref-
erence to the photograph below and the electrical schematic diagram on
page 14.

P214-0-34612

13