WSP03457

• File Number: 8276.100
• Description: Grand Valley Unit - Colorado River Basin Salinity Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/1/1992
• Title: Grand Valley Salinity Project Monitoring and Evaluation Program -- 1990 Annual Report
• Water Supply Pro - Doc Type: Annual Report

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13. Irrigation monitoring data show excessive deep percolation
losses and runoff from onion fields. Salinity control wi II be
difficult with existing surface irrigation techniques because
of the need for frequent short irrigations. Surge irrigation
might alleviate some of these problems on ollion fields as well
as other fields with annual crops.

14. The SCS wi II need to follow-up on IWM design information
provided to farmers. Determine if recommended furrow stream
si2e, time of set etc. for the new irrigation systems are
appropriate and are being appl ied and follo,"ed.

15. Actual field soil moisture needs to be compared with computer
generated values using crop ET data and appropriate
adjustments made. There is a need to obtain fast, rei iable
estimates of field soi I moisture conditions.

SCOPE

The initial goal was to monitor 35 sites annually as outl ined
1983 Grand Valley Monitoring and Evaluation Plan. Since then,
been decided that at least 16 active monitoring sites would be
maintained each year. A total of 35 sites could be monitored over the
I ife of the M&E program by maintaining 16 to 20 ope,'ating sites each
year and rotating the equipment to new fields after three to five
years of irrigation monitoring. Only a certain number of sites can be
maintained each year because of I imited 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 ,-epeating annual
cost. Annual expenditures include nominal operation and maintenance
costs.

in the
it has

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 shows the number of sites monitored
since 1985. Of the 16 original sites installed in 1985, at least
seven were sti II being monitored through 1990 <Tabl'l 1). The
remaining nine sites have been dropped because of various problems
with maintenance and operations.

Daily evapotranspiration (En data obtained from th.l two SCS weather
stations was made avai lable to two local T.V. and radio stations
dai Iy, Monday through Friday. Weekly ET data was p,'ovided to two
local newspapers and Colorado State University Extension at Grand
Junction and Delta for their code-a-phone service for local producers.

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