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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management of Old Charley Wash allows larvae to drift into the wetland and rear until October. During the

initial years of operation larvae also will be collected with light traps from the Green River locally and

transferred into Old Charley Wash. In the fall the wetland would be drained and age 0 fish collected. Age

o fish would then be collected, given a permanent mark, sampled for genetic analysis and either released

into the river or retained in the hatchery if growth was not sufficient to reduce vulnerability to most predators.

Fish held in the hatchery overwinter would be replaced into Old Charley Wash the following spring. Water

level management may be necessary to maintain sufficient dissolved oxygen, adequate vegetative cover,

or invertebrate production. The information necessary to optimize the above and other necessary variables

will have to be determined from research activities.

The operation of Old Charley Wash as endangered fish habitat will be most effective as a nursery

site to age 0 razorback sucker when peak flows are less than 14,000 cfs. At this elevation large predacious

fish can be excluded, which could dramatically reduce the Intensity of predation on newly hatched larvae.

In addition, water quality may be improved by excluding large carp, Cyprinus carpio, which increase turbidity

and reduce primary production. Based on the exceedance predictions from the Bureau of Reclamation

(Figure 4, provided by Thomas Ryan, Bureau of Reclamation, Salt Lake City) the Yampa River would be

expected to peak at less than 13,000 cfs two of every five years. Thus, forty percent of the time Old Charley

Wash could be managed in an optimum manner (Le. restricting the discharge from Aaming Gorge Dam to

1,000 cfs during peak Yampa flow). During the alternate years when flows are expected to Inundate the

wetland, Old Charley Wash can still be managed to provide quality habitat and collect razorback sucker

produced, however, predacious fish will have access to the wetland. Despite the presence of predacious

fish, high water years may allow greater access for larval fish and provide greater water volume, both

enhancing the probability of recovering razorback sucker at the end of the growing season.

The plan described above is linked with the logistical success of reducing access by larger

predators, accomplishing a near complete draining of Old Charley Wash and the successful collection of

fish during the draining operation. The success of each of these operations is uncertain at this time and will

be evaluated during the spring and summer months of 1994 and 1995.