PUB00053

• Year: 1999
• Title: Metropolitian Water Supply Investigation Final Report
• Author: Hydrosphere Resource Consultants
• Description: Metropolitian Water Supply Investigation Final Report
• Publications - Doc Type: Water Resource Studies

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Metropolitan Water Supply Investigation

MWSI Results

and the District, policies established by the District, and operating practices of the
Bureau.

The Windy Gap Project was constructed by the Municipal Subdistrict of the Northern
Colorado Water Conservancy District, with the agreement and cooperation ofthe District
and the United States, to provide an additional independent water supply of at least
48,000 acre feet (AF) per year from the Colorado River to municipal and industrial water
users located within the Subdistrict by more fully using the capacity of CBT Project
facilities. The Windy Gap Project was completed in 1985, Its operation is subject to
water rights decrees; a Carriage Contract between the United States, the District and the
Subdistrict; an integrated operations plan; individual par\icipant allotment contracts and
various policies established by the Subdistrict.

The potential availability of CBT and Windy Gap project water for conjunctive use was
initially examined using information from previous modeling studies.

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CBT Project Water

CBT project water is allocated to District water users based upon their ownership of CBT
units and an annual quota set by the District Board, All CBT units are owned and
actively used by water users in the District; in that sense there is no "excess" quota water
available for conjunctive use. In addition, District policies and Federal repayment
contracts prohibit the use ofCBT project water outside the boundaries of the District.

Occasionally the District Board also makes "non-charge" CBT water available to water
users within the District. Non-charge water is issued when anticipated runoff makes a
spill from Granby Reservoir imminent. Non-charge water is provided on a first come-
first serve basis to all water users in the District who can that water to immediate
beneficial use; ownership of CBT units is not required. Non-charge water has only been
. issued in ten years since the CBT project began operations, although large amounts of
non-charge water (over 120,000 acre-feet) have been delivered in individual years. Given
that non-charge water is not owned by individual water users, it could be considered as a
potential surface supply for conjunctive use.

However, the same prohibition of use ofCBT project water outside District boundaries
applies. Also, delivery of meaningful amounts of non-charge water into the metro
Denver area would require major new storage and conveyance facilities. For these
reasons it was concluded that CBT project water would not be available as a potential
surface supply for conjunctive use in the metro Denver area. However, non-charge water
could be used in a conjunctive use arrangement within the Northern Colorado Water
Conservancy District boundaries.

Windy Gap Project Water

The Windy Gap project was designed to provide an average supply of 48,000 acre-feet
per year to project participants. The project began operating in 1985, and is currently
operating at less than 50% of capacity. However, full use of Windy Gap project water by

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Prepared for the Colorado Water Conservation Board, Colorado Department of Natural Resources by
Hydrosohere Resource Consultants. 1002 Walnut Street. Suite 200. ROUIct~L rn RmO?