9593

• UCREFRP Catalog Number: 9593
• Author: Tetra Tech Inc.
• Title: Concept Development Report Hartland Diversion Dam Fish Passage Structure Delta, Colorado.
• USFW Year: 2000.
• USFW - Doc Type: Grand Junction, CO.
• Copyright Material: NO

III. FISH PASSAGE CRITERIA
The target species for fish ladder design at the Hartland diversion dam are the Colorado
pikeminnow and the razorback sucker (Burdick 1996). Three primary types of information
pertinent to the design of the fish passage structure include the timing of migration patterns,
swimming ability and behavior. In terms of swimming ability, standards for the fish ladder have
been based on the swimming abilities of the razorback sucker, as the sucker is believed to be a
weaker swimmer than the Colorado pikeminnow (Mefford 2000; Pfeifer 2000). The fish
passage is designed and constructed to allow for non-selective passage (i.e. no trapping
facilities).
3.1 Migration
Both the Colorado pikeminnow and the razorback sucker undertake riverine migrations
for feeding and spawning during different periods of the year. Various studies on the
reproductive ecology of these two species suggest that the Colorado pikeminnow tend to make
more extensive and longer migrations to spawning areas than the razorback sucker (Burdick
2000c). Based on studies in the Upper Colorado River Basin both species migrate upstream
and downstream to reach spawning sites (Tyus and McAda 1984; Tyus et al. 1987; Tyus 1990;
McAda and Kaeding 1991; Irving and Modde 2000). Mature razorback sucker spawn on the
ascending limb of the hydrograph, whereas Colorado pikeminnow begin migrating to spawning
areas as peak runoff subsides and water temperatures are increasing (Tyus 1990, 1991:
McAda and Kaeding 1991). Following spawning, both species may make return migrations to
former areas to rest and feed (Wick 2000).
In addition, data collected from fish capture in the fish trap at the Redlands facility on
the Gunnison River in Grand Junction, Colorado, indicate that a significant number of sub-adult
and adult Colorado pikeminnow move up through the fish ladder during July and August
(Burdick 2000c). This movement is associated with the post-spawning period for this species

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