7796

• UCREFRP Catalog Number: 7796
• Author: Burdick, B. D.
• Title: Conceptual Management Plan for Habitat Enhancement in Flooded Bottomlands, Escalante State Wildlife Area, Gunnison River Downstream of Delta, Colorado.
• USFW Year: 1994.
• USFW - Doc Type: \
• Copyright Material: NO

' of the lack of the right sizes of food organisms at the right time and in
sufficient quantity (Wydoski and Wick 1994).
Flooded bottomland habitats occur in broad valleys along low gradient
stream reaches. Bottomlands are off- or out-of-channel habitats that include
' oxbow lakes, former side channels in broad valley floodplains, ponds, and wetland
depressions. During high flow events, some of these off-channel features were
temporarily connected to the river. Re-establishing connectivity to the mainstem
river may provide off-channel habitats for endangered fishes which are essential
' for effective management of the riverine ecosystem and recovery of endangered
fishes. Former natural riverine features could be integrated back into the
historic floodplain by removing portions of man-made dikes or natural
' obstructions (e.g., gravel/sand bars).
Protection, restoration, and enhancement of inundated bottomland habitat
t along mainstem riparian corridors are believed to be important for recovery of
razorback sucker. Riparian enhancement in the upper Colorado River basin can be
accomplished by providing sufficient flow to inundate bottomlands in a manner
that approximates the natural hydrograph. If sufficient flows cannot be obtained
' regularly, dikes and levees should be breached at intervals to allow inundation
of lowlands during the spring high flow period. To reconnect floodplain habitat
where existing dikes occur, "set-back" dikes may have to be constructed to
' protect private property in bottomlands near population centers and agricultural
areas. Local government entities may resist removal of structures that have been
built, maintained, and reinforced after major flood events to protect private as
well as public property. Therefore, institutional and social constraints may
' limit the amount of floodplain that can be reclaimed near population centers.
The river reach adjacent to the Escalante State Wildlife Area (SWA) is
t important historical habitat for the razorback sucker and Colorado squawfish.
The area has been identified as occupied habitat and recently was designated
critical habitat for both razorback sucker and Colorado squawfish by the U. S.
' Fish and Wildlife Service ([USFWS] effective 20 April 1994; Federal Register,
Vol. 59, No. 54, 21 March 1994) under authority of the Endangered Species Act
(USFWS 1973). This system formerly contained substantial numbers of razorback
suckers downstream from the Black Canyon of the Gunnison but now contains no or
' few razorback sucker. In 1889, Jordan (1891) reported that razorback sucker were
very abundant in the rivers of the upper Colorado system, including both the
Gunnison and Uncompahgre rivers near Delta, Colorado. Chamberlain (1946) noted
' razorback sucker were common in the lower Gunnison River between Delta and Grand
Junction. However, the number of razorback sucker began to decline in the
Gunnison River near Delta in the 1950's (Quartarone 1993). The capture of four
t adult razorback sucker in the Delta area in 1981 was the last documented report
in the Gunnison River (Holden et al. 1981). The razorback sucker now appears to
be extirpated from the Gunnison River upstream from the Redlands Diversion Dam.
1 Ob.iectives/PurDOse
' Habitat development and enhancement is identified as one of the five
principal elements of the Recovery Program (USFWS 1987). The general objectives
of this plan are, 1) to restore razorback sucker and other endangered fishes in