The Caldwell tribune. [volume] (Caldwell, Idaho Territory [Idaho]) 1883-1928, 1914-11-13
DRAINING THE PIONEER IR
RIGATION DISTRICT.
By F. T. Grove, Engineer in Charge.

by r. L. NTOWe, GhSlhSSA Al Nll"A 81
The district.-The Pioneer Irriga-
ton District is organized under the
laws of the State of Idaho and is To-
Gated in the Boise River Valley IN
Ada and Canyon Counties. The tract
comprises 900 acres OF lrrigaole
lands, the greater portion of which
has been irrigated for the past ~
years. 1t is fairly compact area APP
proximately 10 miles long and miles
wide. 1t has slightly rolling surface
with a general slope to the northwest
of feet per mile. Within the same
natural drainage basin and above the
tract there are approximately /O,UOU
acres or irrigated land.
The soil of the tract consists of a
heavy loan on the surface underla1d
with either clay or hardpan which
covers for a depth of from to Il
feet strata of sand and gravel or very
coarse sand. The strata between the
sand and gravel and the surface loan
contain a large quantity of alkah,
which, when brought to the surface
by the ground waters, kills practically
all profitable agricultural crops.
Water supply.-The water supply is
secured by diversion from the natural
water flow of the Boise River through
the Caldwell and Phyllis Canals.
These systems give the tract an
abundant water supply during the first
three months of the irrigated sea-
son, but during the late summer the
natural flow the Boise River is very
low and the prior rights on the river
cut down the available supply for the
district to such an extent that there
is insufficient water for the proper
irrigation of its lands. Consequently
contract has been entered into with
the Reclamation Service for a late
season water supply from the Arrow
rock Reservoir when completed.
Ground waters.-In 1910 ground
waters appeared in few low areas in
the main creek beds which pass
through this district These areas
increased in numbers and size until
1912, when practically all the land in
the low valleys of the district had
become immense swamps covered
with rushes, and many acres on the
side slopes were also made uncultiv-
able by ground waters rising to the
surface by capillary attraction and
bringing arge quantities of injurious
alkali. 1t was eliminated that from
5000 to 1000 acres in the district were
seriously affected by the rising OF
ground waters.
The rise of ground water is due to
water losses by percolation in the
canals and laterals in the district and
in the immense irrigated tracts above
the district, the slopes and porosity
of the water-bearing strata being in.
sufficient to carry off the enormou:
supply of ground waters.
Drainage investigations.-In tht
spring of 1912 the Secretary of thu
Interior authorized the Reclamation
Service to investigate the drainag,
possibilities in the district as a par
of a general drainage system of tn,
Boise project. Lines and profle
were run up the main draws through
out the district, test pits were dug
and a complete study made of the ele
vations of water-bearing strata ant
ground waters. 1t soon became evi
dent that dep open-cut drains travers
ing all the main draws and reachin,
well down into the water-bearinl
strata were the only feasible method
by which the ground waters could b
lowered and carried off together wit
surface water coming down from tn
irrigated tracts above the distric
This involved the construction of an
proximately As miles of opene drain
verying in depth from 7 to IA feet an
in bottom width from to 10 fee
with ~ to l it, side slopes. Thi
would require the excavations of ar
; proximately 100000 cubic yards {
, earth, the construction of 10 concret
culverts, and II timber bridges. TIL
estimated cost to cover this work wa
placed at $437,0 This system.
t was thought, with numerous privat
= and community drains leading into i