WSP00392

• File Number: 8276.150
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/1/1992
• Title: 1991 Annual Report: Grand Valley Salinity Control Project Monitoring and Evaluation Program
• Water Supply Pro - Doc Type: Annual Report

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II. HYDROSALINITY MONITORING AND EVALUATION

1. setting

a. Irrigation Delivery Systems: The Grand Valley area obtains
water for irrigation through the different canal systems located in
the Valley. The irrigation monitoring sites were established in
various locations and under different canal systems. Irrigation
water from the Colorado River is delivered to the farm through both
private and Federal canal systems. The private systems include the
Grand Valley Irrigation Company, Palisade Irrigation District, Mesa
County Irrigation District, Orchard Mesa Irrigation District and
Redlands Water and Power Company. The Federal system includes the
Grand Valley Water Users Association (Government Highline Canal).
Each private canal system delivers water to a large number of
laterals which are independently owned and operated. The laterals
under Government Highline Canal are mostly under Federal control.
Irrigation water from the various laterals is delivered to
individual fields through open ditches, lined or unlined and also
by underground pipeline. Water delivered to the field is
distributed to the field through different irrigation systems.

The irrigation systems commonly used by farmers include: earth
ditch to siphon tubes, concrete ditch to gated pipe, ported
concrete ditch, underground pipeline to gated pipe as well as
various kinds of sprinkler systems. These may be drip, microspray,
solid set sprinkler or sideroll sprinkler.

b. Monitoring site Description

Overview: The initial goal was to monitor 35 sites annually as
outlined in the 1983 Grand Valley Monitoring and Evaluation Plan.
Since then, it has been decided that at least 16 active monitoring
sites would be maintained each year. A total of 35 sites could be
monitored over the life of the M&E Program by maintaining 16 to 20
operating sites each year and rotating the equipment to new fields
after three to five years of irrigation monitoring. Only about 16
to 20 sites can be maintained each year because of limited funds
and equipment. Equipment cost for a monitoring site with one
outlet and an inlet runs from $5,000 to $6,000. This is a one-time
capital cost and not a repeating annual cost. Annual expenditures
include nominal operation and maintenance costs.

On-farm irrigation monitoring started in 1984 with the installation
of 12 monitoring sites. Since then a minimum of 16 sites have been
maintained each year. Table 1 provides information on status of
the various sites established since 1985. Of the 16 original sites
installed in 1985, at least six were still being monitored through
1991 (Table 1). The remaining ten sites have been dropped because
of various problems with maintenance and operations.

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