White Bluffs spokesman. [volume] (White Bluffs, Wash.) 1907-1938, 1925-09-11
WHAT BECOMES OF
IRRIGATION WATER?

small part of the water diverted for
irrigation. From the time the water is
diverted from the river or source oil
supply until it reaches the farm il
suffers continuous losses. These los
ses between the point of diversion
and point of delivery to the farm have
been more or less accurately meas
ured on all government irrigation pro-
jects and on numerous private sys-
TENS for many years. On the Sunny
side Division of the Yakima Project,
for instance, the average of the total
conveyance losses for the last three
years are; 1874 per cent for 1922;
IT'S per cent for 1923; and 27.o per
cent for 1924
The losses which occur, however,
after the stream reaches the farm
have not often been measured. In fact
they have scarcely been Investigated
or realized, and in most cases they are
difficult to measure accurately.
The sequence of these losses from
the farm may be listed as follows;(l)
Seepage and evaporation from farm
bitches and fumes cD Evaportion
from irrigated fields. (3) Deep perco-
lation losses from the irrigated fields
below the feeding zone of plants.
90 Surface run-of.
On the Irrigation Branch Expert
ment Fam at Prosser an attempt has
been made this year to measure some
of these losses. The seepage and evap-
Grafton loss from one of the farm ir-
rigation lines which consists of 285
feet of earth ditch and 725 feet of 10
inch tlume was measured by dis
charging the water over one cippoletti
weir at the head of the line and over
anothe. at the foot of the line. The
difference between the two measure
ments represents the loss by seepage,
leaks and evaporation. Both ditch
and f'ume are kept in fair condition.
The amount of water carried varied
from O5 to Is second feet. From all
the measurements made during the
season the average loss was 60 per
cent.
Evaporation from non-cropped ir-
rigation fields was measured by
means OF six small check or basins to
which measured quantities Of water
were applied. The basins were 80
feet square each surrounded by dixie
about IL inches high. Soil moisture
determinations were made to depth
OF six feet Immediately after irrigation
and again II days later. The diff
ference in moisture found in this six
foot blanket of soil between the two
sampling dates was considered to rep
resent the loss by evaporation. When
there was no percolation below the
sixth foot. The average of these re-
suits show a IS per cent loss.
1t can not be said that the per-
co'ation was measured. 1t was. es-
timated. The estimate was based on
previous experiments which give fair
knowledge of the water holding capa-
city of the soil, the evaporation rate
Of water ftom the soil, and the time it
takes for irrigation moisture to come
into equilibrium with gravity. This
estimated precolation loss amounted
to 16.5 per cent.
The surface run-off was measured
by catching it from one plot at a time
in one channel and passing it through
submerged orifice equipped with
Lyman meter which records the dis
charge in acre-feet and fractions
thereof. This loss averaged IFS per
cent.
To summarize these results then
the total loss through the four
sources mentioned above was 10 per
cent. This leaves oply 30 per cent OF
the water received on the farm for
actual use by the crop plants. And
only ZIG per cent of that diverted
from the source.
These figures represent only one
seasons data and are far from being
complete or exhaustive. The need
for more accurate investigation con-
corning the source, cause, magnitude,
and prevention of these losses ke-
comes mo:b apparent as land and
water costs increase.
At the Salt Lake meeting of the
American Society of Civil Engineers
in July, DIR. Elwood Mead, Commits
sioner Of Reclamation, said that on
five reclamation projects authorized
by the last congress OIL which work
has not vet been begun, and on two
completed, the construction costs
average Sl25 per acre; by the time
the water light and farm development
cost is added to the land cost, and
before the first crop is produced, the
settler will face cost of 5000 to $3.50
per acre or from $4,000 to $4,000 per
farm. Therefore if irrigation farming
in the future is to be this expensive
1t is obvious that the farmer must
have an adequate water supply and
that study Of the losses on the
farm especially those which are nre