CBT/WG Water Sharing Report

• Project Type: Ag/Muni Grant
• Applicant: Northern Colorado Water Conservancy District
• Project Name: Ag Options
• Title: Interruptible Supply Contracts for Water-Sharing Between the Colorado Big Thompson and Windy Gap Projects
• Date: 1/1/1996
• County: Larimer
• Water Conservation - Doc Type: Final Report

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The Windy Gap Project, completed in 1985, was built to provide additional water
supply for municipal and industrial use along the northern Front Range. The Project is
owned and operated by NCWCD's Municipal Subdistrict. It has its own water rights,
separate from the C-BT Project, but relies primarily on C-BT Project facilities to deliver
the water. Estimated yield for the Windy Gap Project is 48,000 af/yr. The 480 shares in
the Project are currently owned by ten municipalities and industrial users.

Integrated operations of the two Projects

NCWCD's board of directors has adopted an integrated operations approach for
the C-BT and Windy Gap Projects in order to maximize benefits to the water users
served by both Projects. This approach is embodied in the amended carriage contract
("the amendatory contract") for Windy Gap water, entered into by NCWCD, the
Municipal Subdistrict, and the Bureau of Reclamation effective March 1, 1990.

One feature of the integrated operations concept is borrowing of C-BT water by
the Windy Gap Project (also called "in-lieu delivery") in which C-BT water may be used
to meet Windy Gap demand. The borrowed water is to be accounted for and repaid to
the C-BT Project. The amendatory contract, ~lO(b), provides that this borrowing will be
permitted only if C-BT allottees are not injured by the borrowing. This requirement is
referred to as the "non-injury criterion".

NCWCD's board of directors on December 13, 1991 adopted operating criteria
for integrated operations of the two Projects, setting out guidelines to ensure that in-lieu
delivery of C-BT water to Windy Gap would meet the non-injury requirement. The
Operating Criteria provide that any water borrowed by Windy Gap will be considered as
part of the available water pool when the annual C-BT quota is fixed. (Operating
Criteria, ~1) In order to borrow C-BT water, the Windy Gap participant must maintain
a back-up supply of water that will be available to the District on call. (Operating
Criteria, ~10) This back-up supply may be in the form of C-BT units owned by the
participant, contracts to use C-BT units owned by another allottee, or other water rights.

This study focuses on the second of these alternatives -- contracts to use another
allottee's C-BT units to repay the water debt owed to the C-BT Project by the Windy
Gap participant. The use of interruptible supply, or dry-year options, contracts has been
the subject of considerable interest in the western United States in recent years. Under
these contracts, the buyer receives a right to use the seller's water upon the occurrence
of stated conditions. In other years, the water continues to be used by the seller.2

In the context of C-BT/Windy Gap integrated operations, the contracts would
provide that when water had been borrowed from the C-BT Project by Windy Gap and
could not be repaid from available Windy Gap supplies, the District would call in C-BT
units held under the contract. Thus, there would be no risk that C-BT alIottees would be

2 For further information on these options arrangements, see the consultant's
August 1994 report to the District, "Dry Year Options for Water Supply".

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