WSP08813

• File Number: 8046
• Description: Section D General Studies - DSS
• State: CO
• Water Division: 1
• Date: 2/6/1996
• Author: George M Fosha
• Title: Colorado Decision Support System - 1997-2001 - 1332.2 CRDSS - Colorado Documentation - Denver Water ‎(Moffat Tunnel System and Dillon/Roberts Tunnel System)‎
• Water Supply Pro - Doc Type: Report/Study

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RECEIVEO-FEB 0 13 1895

DENVER WATER - MOFFAT TUNNEL SYSTEM

The Denver Board of Water Commissioners (Denver) operates extensive water collection systems
in the Williams Fork and Fraser River basins. The water is diverted through a system of open
canals, closed conduits and tunnels to the West Portal of the Moffat Tunnel. The tunnel conveys
the water to the headwaters of South Boulder Creek on Colorado's eastern slope. Delivery of the
transmountain water is regulated using the storage in Gross Reservoir and Ralston Reservoir. The
following discussion summarizes the key components of the Moffat Tunnel System.

The Williams Fork Diversion Proiect

The WilliamS'F6l1< Diversion Project (Numerous WOlD's) collects water from a'number of
small tributary streams at the headwaters of the Williams Fork River and diverts it into the Gumlick
Tunnel (aka the Jones Pass Tunnel (WDID 514603). The major streams from which water has
historically been diverted include: (1) McQuery Creek; (2) Jones Creek; (3) Bobtail Creek; and (4)
Steelman Creek. The decreed amounts that have been made absolute are summarized in the
following table. These water rights were all adjudicated on November 5, 1937 and granted an
appropriation date of July 4, 1921 (Administration No. 30870.26117).

Source Total Decree Amount lefsl

Amount Absolute lefs)

McQuery Creek 70
Jones Creek 25
McQuery - Jones Creek 11 5
Bobtail Creek 195
Steelman Creek 150
Middle Fork - Williams Fork 350
Allen Creek 250
South Fork - Williams Fork 200
Middle Fork Feeder 50

48.6
21.5
70.0
115.0
90.0
o
o
o
o

Denver has also adjudicated a number of conditional water rights for a future extension and
enlargement of the Williams Fork collection system, including rights on Darling Creek. These rights
carry a 1 953 priority date

The Gumlick Tunnel has a decreed capacity of 620 cfs under the 1921 priority date, of
which 214 cfs has been made absolute. The maximum physical capacity is limited to
approximately 500 cfs. The Tunnel conveys the water into the headwaters of the West Fork of
Clear Creek. Here, the water can be delivered directly into the Clear Creek drainage; however, the
flow is normally re-diverted back to the West Slope through another tunnel, the Vasquez Tunnel,
for ultimate delivery to Gross Reservoir via the Moffat Tunnel.

According to Denver personnel, the primary operational objective for the Williams Fork
Collection System is to achieve a fill of Gross Reservoir. As such, the collection system has a
higher operational priority than storage in Williams Fork Reservoir. One it is determined that Gross
Reservoir will fill, the general practice has been to cease diversions at the collection system in
favor of storage at Williams Fork Reservoir.

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