WSP04510

• File Number: 8220.128.J
• Description: Silt Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1951
• Author: USDOI - BOR
• Title: Silt Project-Colorado - A Supplement to the Colorado River Storage Project Report - Part 2 of 2
• Water Supply Pro - Doc Type: Report/Study

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FISH AND v~ILDLIFE SERVICE REPORT

9. The Silt Project would provide supplemental irrigation water to
about 5,400 acres of land between Rifle Creek and Elk Creek and a
full irrigation supply to about 1,900 additional acres.

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10. Pertinent engineering data. - Elevations, areas, and capacities
of units of the Silt Project are tabulated below.

Rifle Gap Reservoir

Elevation

Acre-feet Capacity

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(1) Normal pool
(2) Dead Storage pool
(3) Stream bed

5,940'
5,222'
5,828 I

10,000
1,000

300
51

Grass Valley Canal:
Davie Ditch:
Lateral canals: (1)
(2)

Capacity - 50 second-feet; length - 6 miles.
Capacity - 18 second-feet; length - 6 miles.
Capacity - 20 second-feet; length 4 miles.
Capacity - 12 second-feet; length - 4 miles.

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Fishery Section

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11. In the upper reaches of West, Middle, and East Rifle Creeks,
fishery values are moderately high. These values, however, would not
be affected. In the four miles of streams within the proposed Rifle
Gap Reservoir Basin and in the seven miles of stream below the pro-
posed dam, present values are very slight, due to turbidity, diversions
for irrigation, and poor stream cover. No monetary value can be as-
signed to these portions of the streams.

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12. Harvey Gap Reservoir is Slbject to wide fluctuation each year.
Apparently en~ugh water remains, however, to keep alive a large
population of pike-perch which are a source of dissatisfaction to local
sportsmen. No change in operation is anticipated in connection with this
reservoir. Existing fisheries value, if such exists, will not be
affected.

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13. Rifle Gap Reservoir would be drawn down each season to meet irriga-
tion needs and data on hand indicates that the average minimum pool
would be JrclCtically synonymous with the dead storage pool of 51 surface
acres. It is expected, due to soil and climatic conditions, that pro-
duction in t he reservoir would be not over 50 percent of the average
for a reservoir of this size. Consequently, a post-project value of
$735 is estinated for the Rifle Gap impoundment.

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14. Summary of pre-project and post-project fishery values. - No
measurable value for fisheries exists within the pro ject area at this
time. It is estimated that construction of Rifle Gap Reservoir would
result in an annual value of ~735. The net result would be a gain of
$735 annually in fishery values.

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