WSP10304

• File Number: 8273.100
• Description: Colorado River Basin Salinity Control - Federal Agencies - Bureau of Reclamation
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/3000
• Author: BOR
• Title: Irrigating the Lower Colorado Region -- Waters of the Colorado Series
• Water Supply Pro - Doc Type: Publication

" and to regulate and control rivers.

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Before the Bureau of
Reclamation

The Colorado River was unpredictable before
dams tamed it. Like other western streams, the
Colorado River ran high in the late spring and
early summer, fed by rapidly melting snows
from the Rocky Mountains. The flow was often
little more than a trickle between high water
periods. Because the river carried a large load
of sediment, people said it was too thick to
drink and too thin to plow.

Reclamation Act

[n 1902 Congress passed the Reclamation Act
which created the U.S. Reclamation Service,
which is known today as the Bureau 01
Reclamation. A year later in 1903, Reclamation
moved into the Yuma area and created the
Yuma hTigation Project, Reclamation's first
development along the Colorado River. As part
01 the original Yuma Project, Laguna Dam was
built to divert water to farmlands in the Yuma
area. Laguna Dam, the first dam Reclamation
constructed on the Colorado River, is located
about 15 miles northeast of Yuma. Construc-
tion of Laguna Dam started in 1905 and
finished in ] 909, with the first water deliveries
to the Yuma area beginning in 1910.

Irrigating

Ever since the time of the Hohokam Indians,
larmers in the Southwest have irrigated their
fields by flooding them. Farmers simply open a
gate in an irrigation ditch to allow water to
spill out, cover the level fertile ground, and
seep into the soil to nourish the root systems
of plants.

Traditional irrigation methods are changing
and improving. New high-tech, state-ol-the-art
techniques of irrigating are not only increasing
crop yields but also reducing the amount of ir-
rigation water used. These techniques allow
farmers to use the minimum amount of water
to obtain the maximum crop yield.

Yuma Projects Office uses three tools to im-
prove irrigation application efficiency;
" the neutron probe (technicafly known as
the neutron moisture gage) used lor irriga-
tion scheduling;
!> the Infrared thennometer used lor measur-
ing plant watering;

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Slow' Neutrons

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THE RADIOA CTIVE ELEMENT shoots out a fast series of neutrons,
which speed through the soil, bouncing off the hydrogen atoms in
water molecules, losing momentum. Eventually they pass back
through the probe's detector tube at a much slower speed.

" and laser leveling equip-
ment used lor irrigation ap-
plication efficiency.

Reclamation's Yuma Projects
Ollice introduced the Irrigation
management tools in the Yuma
area by providing training and
technical assistance to irriga-
tion districts. [rrigation efficien-
cy programs improve the
scheduling 01 irrigations to
help conserve water and en-
hance crop yields.

Reclamation's Yuma Projects
Ollice, in coordination with the
Soil Conservation Service, con-
ducts an on-Iarm irrigation ef-
ficiency education program.
Working with water districts
like the Wellton-Mohawk Irriga-

tion and Drainage District, Im-
periallrrigation District, and
Yuma Mesa Irrigation and
Drainage District, water
management specialists inform
and educate locaf larmers
about proper irrigation
methods using readings Irom
the neutron probe, as well as
giving demonstrations.

Many districts own their own
laser levelling equipment, and
all of the large farmlands
around Yuma are laser leveled.
Independent farmers are still
discovering the uses of laser
leveling, the neutron probe,
and the infrared thermometer,
whlle lor others the service
provided by Yuma Projects Of-
fice and local irrigation dis-