WSP04272

• File Number: 8277.600.10
• Description: Big Sandy River Unit - Colorado River Salinity Control Program
• State: WY
• Basin: Colorado Mainstem
• Date: 3/1/1989
• Title: Planning Report Concluding the Study on Big Sandy River Unit - Wyoming
• Water Supply Pro - Doc Type: Report/Study

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SUMMARY (Continued)

and other trona plants expressed no formal interest in Big Sandy
saline water. Because of this lack of need and interest,
alternatives 1, 2, and 6 were determined to be non-viable and
other alternatives were formulated.

Canal and Lateral Lining

Studies of lining the Eden Valley irrigation system canals and
laterals began in April 1985. The majority of the saline seep
inflow to the Big Sandy River was believed to result from
irrigation, and studies focused on controlling a portion of this
source by reducing seepage from canals and laterals. A review of
the Eden Project showed that approximately 49 miles of the total
114 mi~e canal and lateral system had been earth-lined either
during original construction in 1950-59, or during a lining and
rehabilitation program conducted from 1966-72.

Water budget studies indicated that the major source of
irrigation-related seep inflows entering the Big Sandy River
between the confluence of the Big Sandy River and Little Sandy
Creek and Gasson Bridge is irrigated land served by the Eden
Canal and Lateral system.

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Estimated seepage and salt-loading rates were used to develop
24 selective lining alternatives which included 6 alternatives
for each of four major systems: the Means Canal and M-1 lateral,
the Eden Canal and Lateral, and the West Side and Farson Lateral
systems. This initial alternative development showed all
alternatives to be well above the cost effectiveness ceiling of
$100 per ton. The cost effectiveness analysis for initial
alternative development is shown in summary table 2.

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Following initial alternative development, field investigations
were conducted in 1985 and 1986 to determine seepage rates.
Tests on the Farson Lateral system showed seepage rates were
lower than those used in initial alternative development for
which cost effectiveness values were significantly higher than
the viability ceiling of $100 per ton. Lining alternatives on
the Farson Lateral system were not viable and further
investigation was not warranted. Seepage investigations on the
Eden Canal and Lateral system in 1985-86 did not lead to a
conclusive seepage rate. The data obtained, however, indicated
that further investigations should focus on the Eden Canal and
Lateral system since lining alternatives appeared to be more
promising.

Using variable seepage rates dependent on soil types, variable
net salt loading rates dependent on seasonal changes, and

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