9526

• UCREFRP Catalog Number: 9526
• Author: LaGory, K. E., J. W. Hayse and D. Tomasko.
• Title: Recommended Priorities for Geomorphology Research in Endangered Fish Habitats of the Upper Colorado River Basin.
• USFW Year: 2003.
• USFW - Doc Type: Argonne, Illinois.
• Copyright Material: NO

Geomorphology Research Priorities September 2003
upstream of Westwater Canyon, and focused on the effects of a few high-water years in the
1990s. It is important to study flow-habitat relationships in more years and to determine the role
of peak-flow magnitude, duration, frequency, and variability on habitat maintenance. In addition,
geomorphic processes affecting backwaters in the Moab Bridge to Green River reach have not
been studied, and the processes identified for the gravel-bedded upper river would not apply to
this sand-bedded reach. As for the Green River, additional studies of backwater availability need
to be conducted because of the dynamic nature of this habitat.
No studies have been conducted of spawning habitat in any reach in the upper Colorado
River subbasin because spawning apparently is not concentrated in a few areas as it is in the
Green River subbasin. However, studies of spawning habitat and the underlying geomorphic
processes that affect availability and characteristics during the spawning season are critically
needed. Studies should focus on identifying suitable spawning habitats and determining the
effects of peak flow, base flow, and sediment characteristics on spawning habitat.
We suggest that reach-habitat priorities based on existing levels of reach use be used
wherever possible to avoid the uncertainties associated with potential use. However, the
population status of razorback suckers in the upper Colorado River subbasin and barriers to fish
passage in the upper river reduces the value of using existing use patterns in developing priorities
for geomorphic research. Consequently, we recommend basing prioritization on potential reach
use for the upper Colorado River subbasin. As the status of populations change in response to
management actions, including stocking, habitat improvements, and reconnection to historic
habitat, priorities for the upper Colorado River subbasin should be reconsidered.
We recommend a phased, integrated approach to implementation of the research
priorities identified in this report. Primary information needs for overall reach-habitat priorities
should be considered the highest priorities for research because research on these topics and
reaches has the potential to have the largest benefit to recovery of the endangered fishes.
Consideration should also be given to those primary species-specific information needs. Primary
information needs for overall reach-habitat priorities in the Green River and upper Colorado
River subbasins include:
Green River Subbasin (based on existing conditions in the subbasin)
1. Connected backwaters and side channels (Split Mountain Canyon to Desolation
Canyon and Labyrinth and Stillwater Canyons)
• Role of peak flow (magnitude, duration, and frequency) and sediment on
formation and maintenance of habitats.
• Effects of antecedent conditions (flow and sediment) and base-flow magnitude on
habitat availability.
• Effects of base-flow variability on inter-annual availability, intra-annual stability,
and within-day stability.
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