7799

• UCREFRP Catalog Number: 7799
• Author: Modde, T. and D. Irving.
• Title: Conceptual Management Plan for Habitat Enhancement In Old Charley Wash.
• USFW Year: 1994.
• USFW - Doc Type: \
• Copyright Material: NO

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barriers to historic bottomlands, and by providing sufficient flow to inundate bottomlands in a manner that
approximates the natural hydrograph. Because the peaks and duration of high flows have decreased in the
post-water development era, it will be necessary to regain connectivity of wetlands at the lower flows and
maintain water in these sites as long as possible. Management (Le. draining, water elevation control, etc.)
of flooded bottomlands may be needed during the early phases of the recovery process to reduce the
abundance of exotic predators and allow for the marking of razorback sucker produced in these nursery
sites. The marking of fish produced in rehabilitated bottomlands is necessary to monitor the importance of

these sites to recovery. Specific bottomland management strategies have yet to be developed which would

maximize recruitment. In isolated coves in Lake Mohave, Mueller et a!. (1993) have been successful in

rearing razorback sucker to nearly adult size in a single growing season. In the Upper Colorado River Basin,

two growing seasons may be required before razorback sucker would be impervious to piscivorous

predation.

PROPOSED DEVELOPMENT

Old Charley Wash is encircled by both natural and man-made dikes and has been developed and

managed as a waterfowl production site by the U.S. Fish and Wildlife Service since 1961. As such, the

wetland has inlet and outlet structures that control water entry and release. Options available for

management of the wetland include passive management which allows periodic flooding, but, does not

reconnect the wetland to the river at the end of the growing season. This strategy has been in effect for

over thirty years with little perceived benefit to endangered fishes. The second option is to actively manage

the bottomland to maintain water levels, restrict. potential fish predators and allowing the capture of fish

produced at the end of the growing season.

Inflow into Old Charley Wash can be controlled until river elevations approach 14,000 cfs, at which

time water flows over the downstream dike and into the wetland. During October 1993, a fish access control

structure was constructed at the outlet to Old Charley Wash at a cost of $87K (Appendix 2, Figures 1 and