7729

• UCREFRP Catalog Number: 7729
• Author: Valdez, R. A., W. J. Masslich and A. Wasowicz.
• Title: Annual Summary Report - 1990\
• USFW Year: 1991.
• Copyright Material: NO

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hydrograph. Table 28 presents flows encountered in the Dolores River during the three 1990 field
trips. By comparing releases from McPhee Dam with the two gaging sites above the confluence of
the San Miguel River, it is apparent that flows in the upper Dolores River are generally dictated by
releases from the dam. The reading of 250 cfs recorded on July 11 at the Bedrock gage represented
the high flow for that gage in 1990.

Prior to 1990, flow regulation from McPhee Dam was based on informal agreements between the
Bureau of Reclamation (Reclamation), the Dolores Water Conservancy District and other water
interests. The creation and management of a blue ribbon trout fishery in the tailwaters below
McPhee Dam by the CDOW has also played a role in dam operations. Releases were generally
based on yearly predictions of water availability from high elevation runoff, with priority placed on
providing water to users serviced by the Dolores River Project. Releases of water in excess of
381,000 acre-foot storage capacity of McPhee Reservoir is influenced by recommendations of CDOW
for management of the tailwater trout fisheries. Depending on water level, the reservoir fills and
spills anytime between April and June. Peak runoff in the Dolores River below McPhee during spills
can range from 600 to 1000 cfs. Prior to 1990, base flows from the dam were generally maintained
at about 78 cfs.

Due to the persistent drought that has recently plagued the Dolores River drainage, operations of
McPhee reservoir were modified in 1990. As of March 5, 1990 (which coincidentally corresponded
to the first day of Trip 1), flows from McPhee Dam were reduced to 20 cfs. Reduction of flows were
based on predictions of low runoff from high elevation snow pack. Low flows from McPhee Dam
continued during the course of 1990, ranging from 20 to 50 cfs. Flow increases to 50 cfs during July
were based on recommendations by CDOW for temperature maintenance of the tailwater fishery.
As of November 1, 1990, a 3-year interim operations plan for McPhee Dam was agreed to by
Reclamation and the Dolores Water Conservancy District which allocates 30,100 acre-feet of water
specifically for the benefit of the tailwater trout fishery. This amount represents the minimum
amount of water that would be available for management of the tailwater fishery, with additional
water available on years when the reservoir spills. Based on recommendations of the Dolores River
Biological Team (Reclamation, Forest Service, Trout Unlimited and CDOW, Meeting of Nov.
1,1990), the following flows (not counting spills) are expected from McPhee Dam for the next 3 years:

Fall (Sept., Oct. and Nov.) - 30 cfs
Winter (Dec., Jan. and Feb.) - 45 cfs
Spring (Mar., Apr. and May) - 40 cfs
Summer (June, July and Aug.) - 50 cfs

Flows in the Dolores River below the confluence of San Miguel River increase substantially as the
San Miguel River becomes a prominent factor in the hydro graph of the system. The San Miguel
River is a free flowing river and exhibits a relatively normal hydrograph, with an average annual flow
of 410 cubic feet per second. Peak flows from the San Miguel River generally occur in late April and
early May and have ranged from below 1000 to above 8000 cfs for the period of record. Base flows
in the San Miguel River generally occur in late fall and winter and average 80 to 200 cfs. Irrigation
withdrawals above Uravan influence flows during the summer months. Table 28 presents the flows
encountered in the Dolores River below the confluence of the San Miguel River during the three
1990 field trips. Peak flow of 1200 cfs occurred at the gage near Cisco on the Dolores River on June
12. The gage readings near Cisco reflect the influence of flows contributed by the San Miguel River.

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