WSP07117

• File Number: 8276.130
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 11/1/1990
• Title: Final Environmental Assessment: Price and Stubb Ditch Improvements - Grand Valley Unit
• Water Supply Pro - Doc Type: EIS

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CHAPTER IV

CONSULTATION AND COORDINATION
COMMENT LETTERS

RONALD JOHNSTON, PROJECTS MANAGER
JULY 16. 1990

PAGE 2

of each canal. The annual salt reduction of the Stubb Ditch will be 4,300 tons and the
annual salt reduction for the Price is to be 7,200 tons, totalling 11,500 tons/year.

The assumption is made that the entire lengths of the Stubb and Price Ditches are dirt and
that both canals are seeping and loading salt at the rate of 7.10 which is the factor for tons
per acre foot for the Price and Stubb Canals (VM 1986, page VIl-14, Table VII-?). The net
reduced seepage for the Price Ditch would be 1,150 acre feet and for the Stubb 610 acre
feet for a total of 1,760 acre feet

and

Chapter II, page 4, 3rd paragraph states:

"The canal improvements consist of lining or piping portions of the Price
Ditch. The Stubb Ditch improvements would consist of replacing the open
channel with pipe... the ditch would be lined."

At a minimum, the last 2.5 miles of the Price Ditch is concrete lined which is 27% of the
total ditch length. The Stubb Ditch has 3.5 miles concrete lined or 33% of its total length.
(CRBSCP. Stage Two Development. Grand Valley Unit, Supplement to Definite Plan
Report. June 1983, BOA, Chapter II, page 15, paragraphs 1 and 2).

Consequently, the dirt Stubb Ditch is loading 2.820 tonstyear instead of 4,300 tons (66%
of 4.300 tons). The Price Ditch is loading 5,256 tons instead of 7.200 tons (73% of 7,200
tons as per Table 1).

This creates a total of 8.094 tons, instead of 11,500 tons. to be removed annually as a
result of canal improvements.

As a reference of comparison, the 1986 FEIS, page 48, Table 13 lists cost effective figures
for salt removal from the same mileage of ditches to be $135/ton for the Stubb Ditch and
$140/ton for the Price Ditch. Cost of construction not cited. To quote from 1986 FEIS:

-Based on procedures used in conjunction with Stage One monitoring
results. a recent update of the hydrosaJinity analysis indicates that some
of these nine increments are actually more cost effective than some of the
last increments of alternatives A and B (B is the preferred alternative]...
The increments shown in Table 13 were not included in either alternative
A or B because their cost effectiveness exceeds increments currently
being considered for implementation."

Table 13 shows the Stubb Ditch contributing 2.800 tonstyear and the Price Ditch 5,800
tons/year for a combined total of 8,600 tons/year.

The DEA salt reduction figures and the cost effective figures. as presented in Chapter II,
page 4. Table 1, do not reflect the improvements to the Stubb and Price Canals which
inhibit saft loading.

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