WSP10438

• File Number: 8443
• Description: Narrows Unit
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 4/4/1977
• Title: Narrows Operations Studies - Jackson Lake Fish and Wildlife Accounts - Status Reports
• Water Supply Pro - Doc Type: Data

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R. E. Swain
4/4/77

LINE EXPLANATION OF NARROWS OPERATION STUDY
, JACKSON LAKE FISH AND WILDLIFE ACCOUNT

Historic

1. Diversion - Historic measured diversions to Jackson Lake from Water
Commissioner's field books.
2. Release - Historic measured releases from Jackson Lake from Water
Commissioner's field books.
3. EOM Content -Jackson Lake end-of-month content from Water
Commissioner's field books. Used in determining the amount of
water required in Narrows Reservoir to' meet the historic releases
from Jackson Lake.

Project

Infiow ;. Inflow to Jackson Lake each year in May and October so it is to a
content of 25,400 acre-feet. In years when the supply W:1ll not available
filling occurred as soon as was possible.
Evaporation - Computed by using monthly polynomial equations and previous
end-of-month content.
Seepage - Computed by using polynomial equation' and previous end-of-month
content. ,
EOM Content - Jackson Lake end-of-month content with Narrows Project
computed and equal to previouS' month line 7 + line 4 - line 5 - line 6. '

INFLOW TO NARROWS RESERVOlR

8. Jackson Lake Change W/OP - Change in inflow to Narrows Reservoir due to
change in ope'ration of Jackson Lake with project. It was assumed that
the seepage return flow from Jackson Lake fish and,wilcD.ife pool will be
the same as the historic ,returns. Computed and equal to line 1 - line 2
- line 4.
9. Rist. Diversion Weldon - Historic diversion to Weldon Valley Canal from
Water Conunissionerls fieldmoks.
10., Rist. Diversion Ft. Morgan - Historic diversion to Fort Morgan Canal from
Water Commissioner's field books.
11. Rist. Flow into Narrows - Historic South Platte streamflows at Narrows Dam
site. These flows arc gaged l'lmoff of the South Platte River at Weldon::!,.
USGS gage number 7585, plus the estimated gain between the Weldona gage
and Narrows Dam site. The estimated gain was computed by a point flow
analysis which took into consideration all gaged flows; recorded diversions
and inflows, and a theoretical even distribution of gains. '
12. Total Narrows Inflow - Total Narrows Reservoir inflow computed and equal to
( line 8, + line 9 + line 10 + line ll.
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