WSP08285

• File Number: 8221.108
• Description: Holbrook Project
• State: AZ
• Basin: Colorado Mainstem
• Date: 3/1/1950
• Title: Report on Joseph City Unit - Holbrook Project Arizona
• Water Supply Pro - Doc Type: Report/Study

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limit, but the percentage of sodium was always high,! exceeding the
permissible limit in all except two of the samples...!:.! The samples
were classified in respect to the effect of sodium on quality of water
for irrigation by a procedure developed by the Rigional Salinity and
Rubidoux Laboratories, Riverside, California.~ The results of the
classification of the 28 samples indicates the following quality of water
for irrigation:

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Quality of Water

Percentage of Samples

Excellent to good
Good to permissible
Permissible to doubtful
Doubtful to unsuitable
Unsuitable

o
7
53
36
4

As the quality of water in over 90 percent of the samples was below
permissible, the quality of the surface water supply for irrigation of
the Joseph City area must be considered poor.

28. As previously indicated, the virgin soils of the project area
vary from heavy clays to sandy loams and loamy sands and are low in
organic matter, nitrogen, and available phosphorus but contain con-
siderable quantities of salts except where conditions are favorable to
leaching. The heavy sediment load of the irrigation water, which has
been used in the area for over 70 years, has left a deposit of fine clay-
like material that was observed to be one foot or more deep in many
places.

29. Little Colorado River water is generally low in total salt
content and high in percentage of sodium. Continued use of this type
of water will eventually cau,se a large proportion of replaceable sodium
to accumulate in the soil.~1 The tillage difficulties associated with the
very fine clay-like materials are intensified by the concentration of
sodium in the soil because sodium has a deflocculating effect on fine
textured soils. It is not surprising, therefore, that the practice is
prevalent in the Joseph City area of abandoning temporarily fields
with these heavy accumulations and using the water on other lands.
The continued use of undiluted Little Colorado River water on these
heavy soils may be expected to cause increasingly detrimental effects

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1/

The sodium content of the water sampled ranged from 52 to 92
percent of the positive ions, and was over 75 percent in the
majority of samples.

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2/ U. S. D. A. Technical Bulletin No. 962, The Quality of Water
for Irrigation Use, L. V. Wilcox, September 1948.

3/

U. S. D. A. Circular No. 707 Saline Soils, Their Nature and
Management, by O. C. Magistad and J. E. Christiansen, September
1944, page 8.

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