The La Jara chronicle., 1910-06-17
BANK EROSION OF RES
ERVOIRS AND CANALS.

Small bitches or laterals made in
the field for the delivery of water
to the crop are only temporary and
the erosion in them is quite notice
able. They are sometimes made
with a steep gradient, and through
comparatively loose soil, soon cut
a deep trench and make it difficult
to apply the water. a remedy for
such condition will be to ziszas
the ditch or small lateral across the
slope. thus reducing the gradient
and hence the velocity of the water
At the point on the slope where the
ditch changes direction small head
gate may be found effective
The looser the soil the more easily
it is washed away and deposited at
some lower point. and if conditio..:
are such that a loose. sandy soil cao.
not be avoided in the building of tn,
ditch or canal, the grade must be re.
duced and the sectional area of TIA
ditch will necessarily need to be
enlarged. When loose soil is en-
countered and the grade seems to
excessive, erosion is taking p ace.
and the loose material carried by the
water is filled in the lower parts of
1 the cana'. Such cases have some
times been improved by the build
ing OF drops, which may be imagined
as small dams placed at these sec
tions of erosion to check the velo-
city and cause the water surface to
be lowered considerably at one point
| At points where canal makes a
turn the bank that receives the force
of the current is worn, and to pre-
vent this cutting. willows are en-
couraged to grow on the bank, their
matted roots holding the soil In
ace. Piles are sometimes driven
| in and facing of planks nailed t.
them on small canals; extra long
fence posts may be sharpened at one
end and driven into the bank and
board facing nailed to them.
| Sodding has been successful in
some localities. to prevent the ero.
sion of banks; but this can be made
effective only through some period
of time. This, of course, may apply
equally well to the growth of the will
low, but since its roots are consider
ably longer. Ii is capable of prot Ct
ing a larger amount of the bank. The
willow is of rapid growth and de
sirab'e thing to have along the canal
Fence posts with barbed wire
stretched from post to post is at
times used, the wire being depended
upon to catch trash and thus check
the force of the current.
The best remedy for erosion of
canals and bitches is to construct
them with such grade that the veloc-
| ity will not erode the banks The
character of the material wi | in all
probability determine the grade L
use. Generally the less dense the
soil the less the grade shou be,
and the wider and the deeper the
| canal. The hard clays and gravel
will. of course, stand higher velo-
city.
You may naturally ask, Why do
you want high velocity in the can
al? Years of experience have taught
us that conditions exist in Colorado
and elsewhere that make such ero-
sion practically unavoidable
The erosion of the entertainments
of reservoir has been prevented
in various ways; the most common
method in use is riprapping. This
has been found effective, in some
cases. and absolutely useless in
others. The growth of trees upon
the reservoir embankment is not
a desirable thing, but grass should
be encouraged to grow. A perman
ent protection should be provided
and if the material comprising the
dam is of such a nature as to erode
easily, measures must be taken TO
eliminate such erosion. If the ma
terlal will permit, riprapping with
cobble stone to depth of 6 to II
Inches. laid with some care as to fin
ish surface, will be found the most
economical. If the stone is near at
hand. A substitute, where stone is