WSP01772

• File Number: 8220.128.A
• Description: Silt Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 12/1/1940
• Author: USDOI - BOR
• Title: Report on Silt Project-Colorado ‎(Draft of Project Investigations Report No.48)‎ - Part 2 of 2
• Water Supply Pro - Doc Type: Report/Study

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Operation of Rifle Gap and Harvey Gap Reservoir~*

Unit - 1000, acre-feet ~less otherwise noted
: Available: Net: Inflow: Rifle :Release: Rifle : Harvey: Harvey
: Run-off :Diversion: to Gap :to Rifle: Gap Gap Gap:
Year: in to Silt :Rifle Gap:Reservoir: Valley :Reservoir: Reservoir: Reservoir:
:Rifle Cr.: Project :Reservoir: Loss Canals Spill Inflow Loss !
(1) (2) (3) (L.) (5) (6) (7) (8):

:
1929-30: 47.9
31: 38.5
32: 56.8
33: 43.5
34: 27.8
35: 34.1
36: 33.3
'" 37: 34.0
l\) 38: 52.1
39: 35.4
Mean : 40.3

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19.4
17.8
19.4
19.1
13.8
16.3
16.5
15.3
19.4
15.9

17.3

Silt Project
Net Supply
: Percent of
:Full Supply
(9) (10)

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28.5 v': .7 14.0 13.8 18.4 .4 18.0 100
20.7 .6 14.3 5.8 16~9 .4 16.5 92
37.4 .7 15.1 21.6 . 18.4 .4 18.0 100
.
24.4 .7 14.7 9.0 Hl.l : .4 17.7 98
14.0 .6 11".8 1.6 13.1 . .3 12.8 71
.
17.8 .8 11.6 5.4 15.5 .3 15.2 :84
16.8 .8 12.0 4.0 15.7 .3 15.4 86
18.7 .6 14.6 3.5 14.5 .3 14.2 79
32.7 .7 14.1 17.9 le.4 .4 IB.o 100
19.5 . .6 : 14.9 4.0 .15,1 .4 14.7 82
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23.1 .7 13.7 8.7 : 1M .4 . 16.0 gg

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-)< -Rifle Gap Reservoir, 6000 acre-feet, and Hervey Gap Reservoir, 4850 acre-feet, would fill each ye[tl'.
(1) Natural flow at Rifle Gap.
(2) Diversion to Sil,t Project by 45 second-foot canal up to amounts needed for a supply of 18,000 crere-
feet ror Silt Project.lands, plus losses in Grass Valley Canal and Harvey Gap Reservoir, after
passing 5 second-feet for irrigation between Falls and Rifle Gap and supplying direct flow require-
ment for Rifle Creek canals equal to past diversions, less Grass Valley canal losses returned to
Rifle Creek and estimated at 5% of diversions. '
(3) From Table9A
(4) and (8) Reservoir evaporation 2.75 feet depth per year.
(5) Release sufficient to furnish all Rifle Valley Ditches below Rifle Gap the same supply as in the
past in amount and distribution.
(6) Spills from a full reservoir plus storage remai ning a fter October 31 which is assumed rele[,sed before
storage begins in succeeding year. '
(7) 95% of (2), allowing for 10% loss in Grass Valley Canal (part of this water actually to be used
above Harvey Gap Reservoir).
(9) Supply available to project lands, assumed at Harvey Gap outlet.
{10) B~sed on 3.0 acre-feet per acre on 6000 acres, or 18,000 acre-feet per year.