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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.~ Irrigation monitoring sites were established to represent the
general conditions in the Grand Valley with regard to crops, soils,
irrigation system and management practices. Criteria established
for site selection include: sites be isolated from other fields,
i.e. water source for inflow must be independent and tailwater from
outflow must be isolated so that water from other sources do not
get mixed. A monitoring site is defined as a single field or a
fixed portion of a field, that is irrigated as a single irrigation
set or a series of sets. A site has a fixed size throughout the
irrigation season.

Daily evapotranspiration (ET) data obtained from the two Soil
Conservation Service (SCS) weather stations was made available to
two local television and radio stations daily, Monday through
Friday. Weekly ET data was provided to two local newspapers and
Colorado State University Cooperative Extension at Grand Junction
and Delta for their cOde-a-phone service for local producers.

1991 Irrigation Monitoring: In 1991, twenty-three irrigation
monitoring sites were established in 18 different fields with
improved irrigation systems (Table 1, Figure 1). Of the 18 fields
monitored, 13 of them had one monitoring site each, five of them
had two monitoring sites each for side-by-side comparison of
conventional with surge irrigation.

For each site monitored in 1991, information on soil type, texture
and intake rate, slope, field size, length of run, and irrigation
systems is provided in the individual site summary data sheet
located in Appendix D. Figure 1 shows the location of the 1991
irrigation monitoring and evaluation sites.

All 1990 monitoring fields were monitored in 1991 with the
exception of fields 12 and 27. site 45 was also dropped because
the owner decided to irrigate the whole field with a surge system.
These three sites were dropped because of problems with ownership
changes and field irrigation operations. Field 13 was reactivated
again after a few years of not being monitored; the original
cablegation system was replaced with a new surge system. However,
one new field (49/50) was added in 1991 (Table 1).

In 1990 four surge sites (39, 41, 44, 46) were added to four
different fields where conventional sites were located for
comparison with conventional irrigation (Table 1). These sites were
established in conjunction with Colorado state Cooperative
Extension's and us Bureau of Reclamation's (USBOR) "Surge Project"
in order to provide them with accurate inflow and outflow data.
Each cooperator was provided with a surge valve and a controller
and trained in the use of surge valves. The surge system was set
up prior to the first irrigation and used throughout the season.
In 1991, two more fields were added for comparison of surge and
conventional irrigation (26/51 and 49/50). However, site 45 from
1990 was not used for comparison. Therefore, five comparison sites
were established in 1991.

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