9450

• UCREFRP Catalog Number: 9450
• Author: Land and Water Fund of the Rockies.
• Title: Gunnison Basin Water
• USFW Year: 2003.
• USFW - Doc Type: No Panacea for the Front Range.
• Copyright Material: NO

The Gunnison: A Basin In Balance
River drainage. Both Spann and Trampe hold absolute water rights totaling in excess
of 300 cfs, with priority dates going back as far as the late 19th Century; they typical-
ly divert more than 250 cfs out of the East River. The Upper Gunnison District
reports a total of 6,458 cfs of decreed absolute rights for irrigation purposes within
the District ;21 many of these rights date to back to the 19th Century as well.
just counting the decreed rights, irrigators divert more water than required by
the consumptive needs of hay and pasture.25 Ranchers maintain, however, that most
of the water diverted in excess of actual irrigation needs is not lost to the river sys-
tem, but replenishes groundwater tables and/or rejoins the river system above Blue
Mesa, likely within two to three weeks and certainly in the same year it was
diverted."
Construction of the Aspinall Unit had a great impact on the basin.
Throughout its consideration of CRSPA, Congress recognized that construction and
operation of the Aspinall Unit would inundate over forty miles of prime trout habitat
and valley bottom. Many in the Upper Basin also were concerned that the magnitude
of Aspinall's water rights would preclude future development premised on water
rights obtained subsequent to those of the Aspinall Unit, including certain additional
"participating projects" contemplated in CRSPA.
As a result of these concerns, Upper Basin interests received a commitment
from the United States allowing development of reservoirs and other facilities even if
Aspinall water rights left little water available for appropriation subsequent to
November 13, 1957. This commitment was finally formalized in a "Subordination
Agreement," also known as the "depletion allowance," in which the United States
agreed to subordinate its Aspinall rights up to 60,000 AFA of depletions in the Upper
Basin: 10,000 AFA between Crystal and Morrow Point dams, 10,000 AFA between
Morrow Point and Blue Mesa dams and another 40,000 above Blue Mesa Dam.27 To
date, about 8,373 AF of this depletion allowance is in use, 7,126 AF of it upstream
from Blue Mesa.28
b. Lower Basin Agriculture
An average of 365,000 AFA of water arising in the Upper Basin is delivered to
the Uncompahgre Valley through the Gunnison Tunnel (absolute decree of 1175 cfs
with priority date 1905). In an extremely dry year, the UVWUA could divert as much
as 475,000 AFA. The portion of water diverted that is not consumptively used by
crops returns to the Uncompahgre River and then rejoins the Gunnison River at
Delta.
In the Lower Gunnison Basin, just upstream from Grand junction, the
Redlands Canal holds three absolute water rights for off-stream diversion: 670 cfs
(priority date 1911) for irrigation and power generation, 80 cfs (priority date 1944) for
irrigation, power and domestic uses, and 100 cfs (priority date 1994) for power gener-
ation. Redlands' two more senior rights can divert 750 cfs and an average of over
530,000 AFA.29 Due to their senior priority dates, these rights can affect water use in
the Upper Basin.
Gunnison Basin Water • 7