The Billings gazette. [volume] (Billings, Mont.) 1896-1919, 1902-04-25
Large Part Lost Per Mile After Leav.
ing Headsates by seepage
and Evaporation.

p4oAilAolo huGWlcuse Ol LNe QuLy OF
water in order to make intelligent con
tracts for their supply. This knowl-
edge is needed by the engineers and
investors in order to properly plan
canals and reservoirs. Without this
knowledge every important transac-
tton in the construction Of irrigation
works or in the distribution OF water
therefrom is very largely dependent
on individual judgment or conjecture.
Rights to the use Of water cannot be
impartially settled unless at least an
approximate knowledge Of the duty
Of water is available.
Average Depth Of Water.
Many works have been planned on
the assumption that water enough to
cover land to a depth of M foot dur
ing the Isl would bling the crops
to maturity, while the average depth
of water used, measured at the points
OF diversion, was over forty feet. A
large part of this water is lost from
the canals between the headgates and
the land irrigated by 'seepage and
evaporation. This loss has been
found to be much larger than had
been supposed; the average of all
the measurements reported showing
a loss of 2.47 per cent per mile of
the water taken in at the heads of
canals. The lowest measurement re-
ported is about a quarter of n per
cent per mile, while the largest is
more than 6 per cent per mile. Slight
improvements often greatly reduce
the loss due to seepage, If the places
where this is most serious IAN be
pointed out. The Investigations in
the field have this object in view. In
many places such work would result
in a doubling ct the water supply.
While the loss from canals is in it.
slef a serious matter, the greatest
harm is often done in the low lying
lands which become too wet to grow
crops, or, If the subsoils contain in
furious salts, these are brought to
the surface and vegetable growth is
made impossible. There will, there
fore, be q double saving from Improve.
ments which prevent large losses of
water from canals. The reports give
the methods employed in different
parts Of the west for reducing these
losses.
Must Have Storage.
All reports emphasize the need of
storage not only for increasing the
area cultivated, but to properly farm
the areas already under cultivation.
An important question in the con
struction Of storage reservoirs is the
amount and character of the salt car
ried by streams whose waters are
stored. Investigations of this ques-
ton have been begun in the south
west, but its study will have to be
carried on for a number Of seasons
before much definite information will
be available.
information in regard to pumping
water for irrigation. In many places
it is believed that this would be a
cheaper methcd Of obtaining a water
supply than the construction of long
canals. The report contains the rel
ord of cost and capacity of pumping
stations in Arizona and California. It
is estimated that water sufficient to
irrigate an acre Of ground can be sup
piled by pumping at an average cost
Of SO per acre in Arizona and in Cal
ifornia where electricity can be cheap
ly generated by water power the cost
does not exceed from % to 35 cents
per acre. The difference lies almost
altogether in the cost Of developing
power, for which no general estimates
can be made.
Experiments in Nebraska. :
In addition to the general investi-
| cations in the arid region, expert
ments were made in the semi-arid
region Of eastern Nebraska. A large
canal was built in a region where for
80 years crops had been raised by
rainfall alone. The results show that
even in regions where the rainfall
is ordinarily sufficient for the raising
Of profitable crops, the S Of an addi-
tonal supply Of water much more
than pays for the construction. of ir-
rigation works.
Aside from the principal questions