9344

• UCREFRP Catalog Number: 9344
• Author: Camp Dresser & McKee Inc.
• Title: Replacement of the Plateau Creek Pipeline.
• USFW Year: 1996.
• USFW - Doc Type: Denver.
• Copyright Material: NO

1
of 28,589 ac-ft in the year 2045. The CDM computer model was used to simulate the operation of
the District's water supply system to meet this demand and to provide the information required to
calculate future depletions.
Based on modeling of the District's system, 27,586 ac-ft/yr are provided utilizing water rights
currently held by Ute Water and adjudicated for municipal use under the future scenario. The
remaining 1003 ac-ft/yr are provided by agricultural rights currently held by Ute Water. The
1003 ac-ft/yr water rights include Mason and Eddy Ditch water rights, which have been transferred
from agricultural to municipal use, and additional rights on Coon Creek and Big Creek. All of these
water rights are within the Plateau Creek Basin and will be transferred to municipal use.
3.2.4 Consumptive Use Transfers
As discussed previously, some of the District's water rights were originally decreed for both
agricultural irrigation and domestic use. Such rights have been, or will be, transferred to unicipal
use in such a manner that only a portion of the water historically consumed for agricultur use may
' be used by the District for municipal purposes, since historical return flows will have to be left in
the basin of origon. The District's Mason and Eddy ditch transfer was adjudicated on t e basis of
water that was actually consumed, so as to not injure junior water rights on the str axn. The
District's other agricultural rights on Coon Creek and Big Creek will undergo similar tr sfers.
Prior to transfer, these agricultural water rights were used in a pattern and at a rate predicat d by both
their decreed size and use, with some portion consumptively used and the remainder ret ed to the
stream system. This generally means that the rights were diverted at a rate no greate than the
decreed capacity, and only during the irrigation season, typically April to October, with eak usage
occurring in July and August, as supply permits. When these rights are transferred to m 'cipal use,
the District must undertake a detailed engineering study of the water rights' historical us to define
the rates, volumes, and pattern of use. In addition, both the volume and timing of hist ric return
flows to the stream system must be evaluated. Such an analysis typically includes alyses of
cropping patterns, modeling of historic consumptive use by the crops (which is a functi n of crop
type, location, soil properties, and climate), and modeling of groundwater return flows ough the
alluvial system to the receiving stream. This information is used by the Water Court to se terms and
conditions of the transfer such that the District's use of the water, after transfer, will attern the
historical use of the right, with the intent that the effect of the diversions on the stream w uld be the
same as if the right had never been transferred. However, the Courts tend to error in f vor of the
stream with terms and conditions which result in more water left in the stream than w uld occur
without the transfer, thus ensuring no injury to other water rights.
1

During discussions with the Colorado Division 5 Engineer, who administers the operati n of water
rights in the Colorado River Basin, it was indicated that transfers of agricultural water ri hts in the
Colorado River Basin generally allow diversions in the range of 30-60 percent o historical
diversions, with a value of 50 percent representative of transfers in the Plateau Creek tributaries
where the District's rights are located. As the District will not conduct detailed enginee ng studies
until they elect to initiate the transfer process, the representative 50 percent consumptiv use (CU)
CDM Camp Dresser & McKee q
0:8047-1IO~DOCIAPPEND•B.DOC B-`r