9417

• UCREFRP Catalog Number: 9417
• Author: U.S. Department of the Interior.
• Title: Final Environmental Assessment
• USFW Year: 1998.
• USFW - Doc Type: Acquisition and Enhancement of Floodplain Habitats along the Upper Colorado, Green, and Gunnison Rivers as part of the Recovery Program for Endangered Colorado River Fishes.
• Copyright Material: NO

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Figure 1-4: Habitat Types

80
70
60
.!! 50
c:
fl 40
~ 30
20
10
o

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Colorado & Gunnison Rlver5

. Terraeel . Oo.rrqf,ur\J
. Sid. Chann.11 . 'Other Habitats

along the Gunnison River are estimated at 774
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acres primarily in a 25-mile reach from River Miles
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50 and 75 (Nelson 1996, 1997). A remnant
population of Colorado s4uawfish is still found in
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the Gunnison River but razorback suckers
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apparently no longer inhabit the river (Burdick

Green River

The Gmn jlvor S"tem

MAP LOCATlOM

j----l
i lr'_' .-.-.-.----.
. ......_ I
!UTAH COlORAOO i
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1__. ____._____.1

Figure 1-5. General map of the Green River System
MlI,jor Floodplain Areas Along the Green River.

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1995) except for those that have been recently
stocked. The Gunnison mver between Austin and
Delta, Colorado, histohcally contained large
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numbers of razorback suckers (Quartarone 1993),

Bottomland habitats allng the Colorado and
Gunnison rivers consisted of 48% floodplain
terraces, 18% gravel-pit ponds (depressions), 15%
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side channels, and a 19% mix of other types of

habitat. Levees isolate 49,5 miles of habitat from
the river (Irving and Burdick 1995).

Along the Green River, floodplain habitats that
meet the above criteria are estimated at 11,428
acres on privately-owned properties and 6,000
acres on Tribal lands, primarily concentrated in the
80-mile reach from the boundary of Dinosaur
National Monument at River Mile 318 downstream
to Pariette Draw at River Mile 238 (Irving and
Burdick 1995; Nelson 1996, 1997). Floodplain
habitat in this area consists of 75% terraces and
25% depressions. Approximately 15% of the 132
potential bottomland sites along the Green River
are isolated from the river by levees, preventing
approximately 20 miles of the Green River
floodplains from connecting to the river during high
stream flows (Irving and Burdick 1995).
Razorback suckers spawn during high spring flows
upstream of this reach and newly hatched larvae
drift downstream. Survival of these larvae is
expected to increase with increased access to
productive floodplain habitats. This reach of the
Green River is especially important to recovery of
the razorback sucker because it contains the largest
number of adult razorbacks known to occur in the
Upper Basin and the largest natural riverine
population in the entire Colorado River system
(Tyus 1997).

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Related Projects.

The Recovery Program has initiated various actions
to support recovery of the endangered Colorado
River fishes (Recovery Program 1997a, 1997b)
including studies to determine the ecological
requirements of the fish, studies to determine the
instream flow requirements of the fish, acquisition
of water to meet the instream needs of these fish,
construction of propagation facilities, development
of brood stock for captive propagation and
stocking, construction of experimental fish
passageways to allow fish migration to river
reaches above barriers, studies to determine the
effects of selenium on endangered fishes, activities

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