7046 ‎(2)‎

• UCREFRP Catalog Number: 7046
• Author: Valdez, R. A., W. J. Masslich and A. Wasowicz.
• Title: Final Report\
• USFW Year: 1992.
• Copyright Material: NO

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Reach I (RM 0.0 - 22.7) This reach included a wide variety of substrates, channel configuration
and habitat types. From the confluence (RM 0.0) to approximately RM 12.0, the river was relatively
shallow, with numerous runs interspersed with cobble rimes, small rapids and pools at the mouths of
ephemeral tributaries. Substrate at tnbutary mouths was large boulder and rubble fans, while cobble
and gravel dominated rime areas, and finer sands and silt were in slow: ~ and other low velocity
habitat. Above RM 12.0 to Stateline Rapid (RM 22.7) the river flowed through a narrow canyon.
The gradient was slightly higher with more rapid and pool habitat. Maximum depth was 13 feet in
a pool at RM 15.9. Approximate depths observed for various habitats at low flows ranged from 6 to
8 feet in pools, 2 to 4 feet in runs and 0.5 to 3 feet in rimes. Channel widths of 33 to 100 feet
reported by Valdez et a1. (1982) were consistent with our observations in 1990.

Reach II (RM 22.7 - RM 41.3) This reach was characterized by a relatively wide floodplain and
braided channel, with a diversity of habitats and substrates. Areas of long slow runs were prevalent,
interspersed with cobble rimes and small alluvial rapids associated with mouths. of side canyons.
Channel widths of 82 to 100 feet and a mean depth of 3.3 feet with a maximum depth of 11 feet were
reported by Valdez et a1. (1982). In 1991, at flows of approximately 200 cfs, mean channel width was
127.2 feet, mean depth was 2.7 feet and a maximum depth was 13.2 feet. One perennial tributary,
West Creek, flowed into the Dolores River from the east at RM 31.2.

Reach III (RM 41.3 - RM 64.4) The floodplain became more constricted in this reach as the
river flowed through narrow deep canyons. Several small rapids occurred at mouths of side canyons,
but the reach was characterized by a series of rimes, pools and long slow runs. Numerous pools with
depths greater than 10 feet were identified in this reach. Valdez et ale (1982) reported 6.5 and 33
feet as the mean and maximum depths, respectively, for this reach, and channel widths of 82 to 115
feet. In 1991, at flows of approximately 200 cfs, mean channel width was 98.5 feet, a mean depth was
2.7 feet and a max depth was 10.5 feet. Perennial tnbutaries in this reach included Blue Creek (RM
44.3), Roc Creek (RM 54.7) and the San Miguel River (RM 64.4).

Reach IV (RM 64.4 - RM 74.8) This reach was composed of two distinct areas including a short
narrow canyon above the San Miguel confluence and a reach where the Dolores River traversed
Paradox Valley. The canyon reach was composed of a continuous series of shallow rimes and runs.
With the exception of a large deep pool immediately above the confluence of the San Miguel River,
pool habitat was sparse in this reach. Rubble, cobble and boulders were the predominant substrates.
Where the Dolores River traversed Paradox Valley, the river was characterized by a wide floodplain,
low velocities and fine substrates. Average depth in this reach was approximately 1 to 2 feet. River
widths of 80 to 100 feet were reported by the Valdez et a1. (1982). In 1991, at flows of approximately
40 cfs, mean channel width was 63.6 feet, mean depth was 0.83 feet and a maximum depth was 3.3
feet.

Reach V (RM 74.8 - 128.7) This reach encompassed several narrow canyon reaches, including
one canyon 32 miles long. The river also traversed several small valleys. In the canyons the river was
generally characterized by series of riffles, pools and slow runs. Several small rapids were located at
tributary mouths. Silt was the predominant substrate in areas with low velocities, with cobble more
prevalent in rimes and rapids. Rubble and boulder substrates were associated with alluvial fans of
tnbutaries. Maximum depth measured in this reach was 11 feet in 1990. In 1991, at approximately
40 cfs, mean channel width was 52.9 feet, mean depth was 1.7 feet and a maximum depth was 5.3
feet. La Sal Creek, which flowed perennially, entered the Dolores River from the west at RM 79.5.