WSP01861

• File Number: 8271.300
• Description: Colorado River Basin Salinity Control Program - General Information and Publications-Reports
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 12/1/1989
• Title: Colorado River Salinity Control Program - McElmo Creek Unit
• Water Supply Pro - Doc Type: Publication

Background:

The United States has an agreement with Mexico
which sets the maximum level of salt that can be in the
Colorado River when it crosses the border. It is estimated
that one million tons of salt will need to be removed.
annually to achieve these levels. It was estimated in 1986
that salinity in the Colorado River system was adversely
affecting 18 million people and one million irrigated acres
in the downstream areas.
In June 1974 the Colorado River Basin Salinity Control
Act authorized salinity control studies in 12 areas of the
Colorado River system, to include the McElmo Creek Unit.
The United States Bureau of Reclamation (USBR) was
named as the administrative agency by this act. The main
role of the USBR is to investigate and construct reservoirs
and improvements to water delivery systems, which is
considered the off~farm portion of this project.
In 1984 an amendment to the original act authorized a
voluntary cooperative sal:i.nlty control program to be
administered by the United States Department of
Agriculture (USDA). Under this program, salinity control
practices are installed by landowners (or groups of
landowners) to benefit individual farms. which is
considered the on-farm portion of the project. The McElmo
Creek Unit is scheduled to -begin implementation of the on. '
fann program beginning in fiscal year 1990.

Source Of Salt:

Shale of the Mancos Formation underlies much of
Montezuma Valley. This shale is of marine origin with high
salt content which provides the main salt source for the
McElmo Creek Unit. Excessive irrigation and seepage from
on-farm delivery systems cause percolation through the
shale. The water dissolves salt. moving downward until it
reaches a moderately impermeable layer, then moves
laterally.
In some cases the water may become trapped in a low
place, raising the water table and creating wet areas on the
surface. In other cases the water continues lateral
movement until it is discharged into an open drainageway.
The resultant salt load from on.farm irrigation is
responsible for about 54,000 tons of salt each year. This is a
major portion of the total of 119,000 tons of salt contributed
ann~~toM~~oili~. 4439

Objective:

The USDA on-farm portion of the project will reducethe
salt load by an estimated 38,000 tons annually. The USBR
off-farm portion of the project should reduce salt loading by
an additional 24,500 tons annually. The reduction in
. seepage losses and improvement in irrigation efficiencies
will save, almost 44,000 acre-feet of water per year.

Cost Share Program:

Cost sharing will be strictly on a multi-year contract
basis with a minimum contract life of 3 years and a
maximum of 10 years. Cost share levels are set at 65% with
water user paying the balance. There will be a maximum
individual cost share limit of $100,000.
Groups and some non-agricultural producers may also
be eligible fQr cost share with maximum contract levels
possibly increased. Eligible practices would primarily be
those that would improve irrigation water management or
would benefit wildlife. Examples of eligible practices are
irrigation _ pipelines, concret9 ditches, improved irrigation
systems (sprinklers, drip irrigation, gated pipe, etc.)
pumping plants, wildlife ponds, and food plots for wildlife.

Eligible Areas and Priority System:

Any area irrigated prior to 1987 whose return flow
would eventually drain into McElmo Creek at or above
Hartman Draw. or would drain into Navajo Wash is eligible
for salinity cost share. This - is essentially all of the area
irrigated by the Montezuma Valley Irrigation (MVI) system
as well as part of the Summit Irrigation system.

Participation in the salinity program is strictly voluntary
and limited to the irrigated. ground Within these boundaries.
Priority for planning will be based on a point system
using several different criteria. The item given the most
weight will be the ability to install and utilize at least one
cost-shared practice within one year of the request for a
contract. When this item is met. the next priority will be the
farm location.
The project area is subdivided into several sub-areas
based on salt loading. Irrigated land in the Navajo Wash
and Mud Creek drainages will receive the most points for
location. Next will be the irrigated areas east of Highway
666 which drain into McElmo Creek. Third will be irrigated
land draining into Hartman Draw, Crow Creek, or Alkali
Creek. The remaining irrigated land within the project
boundary will have the lowest location priority.

PriOr1.tyll.~
Pdortry 12 ~
Priority IJ ~

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FIGURE VII-l PUOlITY AREAS
Kc:EUlO CllEEK. S.u..l1IITY CONTROL snmy.
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Other criteria causing higher priority include practices
need~d due to changes caused by USBR features,
installation of wetland or wildlife practices, and number of
acres benefitted.
Finally, if two farms have the same rating under the
point system the one with the earliest request date will be
serviced :first.