WSP05450

• File Number: 8220.114.I
• Description: Dolores Participating Project
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 2/1/1995
• Author: USDOI-BOR
• Title: Draft Environmental Assessment - Proposal to Modify Operation of McPhee Reservoir and Acquire Additional Water for Fish and Wildlife Purposes
• Water Supply Pro - Doc Type: EIS

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Reservoir were reduced from 78 cfs to 20 cfs three days later. Trout
Unlimited (TU) , CDOW, and others immediately objected to the reduction
in flow claiming that the established trout fishery would be irreparably
damaged. As result of this reduction in flow, a significant decline in
the number of fish occurred over the 1990-1991 period.

A short-term resolution of the issue was achieved after several meetings
and negotiations between Reclamation, project water users, TU and the
CDOW. An agreement between Reclamation and DWCD was reached for an
additional 6,000 AF of Project water to be released downstream of the
reservoir through October 1990. Releases were increased to 35 cfs on
June 15, and to 50 cfs by June 20, 1990 to minimize adverse effects on
the trout fishery. On September 4, 1990 releases were reduced to 31 cfs
through October 31, the end of the Dolores Project users water year.

Subsequent trout monitoring studies conducted in the fall of 1990 and
twica .in 1991 confirmed that the trout population between McPhee Dam and
Bradfield Bridge had been significantly reduced as a result of low flow
conditions in 1990. It was clear to all of the agencies involved in
managing fish and wildlife resources downstream of McPhee Dam, the three
varying minimum flows of 20, 50 and 78 cfs were not acceptable, due in
part because of the inflexibility of varying flow to off-set other
habitat variables, such as water temperature. However, most
significantly, the negative effects the 20 cfs flow had on the
downstream aquatic ecosystem were considered unacceptable.

Reclamation in consultation with several other groups and agencies
proposed that flow downstream of Mcphee Dam be managed based on an
annual pool allotment that allowed for flexibility in downstream
releases. This concept was formally agreed with by the CDOW and the
Service. Consequently, an Interim oceratinq Aqreement for operation of
McPhee Dam from October 31, 1990 through October 31, 1993 (subsequently
extended to March 31, 1994) was executed between Reclamation and the
DWCD. The interim agreement provided for alternative dam operation
until a long-term solution to the water release and trout fishery issue
could be implemented. This agreement provided a total of 30',100 AF of
water annually to be released in any manner as recommended by a team of
interagency biologists. In addition, during designated spill periods
there would be no net reduction of water volume remaining in the fishery
pool.

Since late 1990, Reclamation has been engaged in discussions with the
project water users, TU. the CDOW, the U,S. Fish and Wildlife Service
(Service), and other incerested individuals and groups to identify a
long-term solution. Reclamation has also conducted additional project
operation studies and conducted biological studies of the downstream
trout fishery. Presently, Reclamation is negotiating a long-term
Ooerations Aqreement for the Dolores project with the DWCD.

Reclamation has also reviewed the Project's operation study used for the
1977 DPR/FES. The water release criteria were originally established
from a computer model that predicted the volume of water that could be
released in varying water years without adversely affecting other
project water users. This model used existing U.S.G.S. flow information
for the years 1928-1973. The results from the model indicated that
during 28% of this 45-year planning period, average minimum flows of 78
cfs would have occurred (so-called "wet" years). Fifty percent of the
time these flows would have amounted to 50 cfs (so-called "normal"
years) and 22% of the time, the flows would have been 20 cfs (so-called
"dry" years).

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