WSP03199

• File Number: 8276.100
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1975
• Title: 1975 Demonstration Farms for Salinity Reduction on the Colorado River
• Water Supply Pro - Doc Type: Report/Study

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Percent of Pack Out

Based on 2.2 Lugs/box

Standards

July Albertas

Giants*

1971
1972
1973
1974
1975

93
o
86
93
83

63.3
o
81. 7
102.0
98

70.4
o
90.6
86.0
89

*

Not under drip system

Because the Colorado River carries a large quantity of fine suspended
solids during runoff conditions it is difficult to clarify the water to a
degree that will prevent clogging of the emitters. This year we were able
to obtain a much more uniform filter sand (Ottawa Crystal Ko. 16) and owing
to the increased filter capacity and retention time it was only necessary to
clean the final filters twice each day during high runoff.

Last year we ran emitter checks and of the 12 emitters checked an overall
reduction of 25% less water was recorded. Visual observation will tell you
when an emitter is 100% plugged but emitter efficiency will decrease in time
without detection. For this reason we are recommending a thorough flushing
of all the emitters (4000 of them) each spring.

The addition of electric water level controls on the settlement pond
was a big step toward better water clarification, The float valve used in
previous years worked well except that the volume of the pond was greatly
reduced before the valve was opened enough to permit the inflow to equal out-
flow. A gear arrangement could be worked out so one could use the float
valve in locations where electrical power is a problem but the electric valve
and float switch are hard to beat. The float switch was set to keep the water
level from six to twelve inches below the top of the tank thereby obtaining
maximum settling capacity of the tank.

An automatic pump shut off is absoultely essential for this kind of
installation because the water supply can be interrupted at any time and a
pump left to run without water can be damaged beyond repair. Many pumps
have a built in thermal switch but some damage can be sustained before the
pump gets hot enough to shut off this switch. Another important aspect of
pump operation is testing the suction line for leaks. A small vacuum pump
and gauge can be used to test the suction line and thereby assure maximum
pump performance.

Despite the 1975 increase in production of (34% in the Standards) we
have noticed a decrease in the amount of growth in some trees in the upper
orchard and at the ends of the rows. Also by comparison with other orchards
in the area the shoot growth is generally slower in starting. Speculation as
to the causes of these things is as follows:

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