9508

• UCREFRP Catalog Number: 9508
• Author: Valdez, R. A. and P. Nelson.
• Title: Green River Subbasin Floodplain Management Plan.
• USFW Year: 2004.
• USFW - Doc Type: Lakewood, Colorado.
• Copyright Material: NO

Executive Summary

April 2004

These areas are either under private ownership unwilling to allow easement access or are small
depressions and pockets that collectively constitute a large area. These floodplains are considered
a buffer to estimated fish production and recruitment.

This Plan will be implemented in three phases. Phase I prioritizes two additional
floodplain sites for restoration and management that can provide an additional 900 acres of
floodplain depressions for a total of 1,389 acres available at seven sites located 5-60 miles
downstream ofthe razorback sucker spawning bar. These sites include: (1) Thunder Ranch, 330
acres, and (2) Stewart Lake, 570 acres. An easement agreement to access, flood, and manage the
Thunder Ranch floodplain was acquired by the Recovery Program in 2003, and levee breaches
are identified as restoration under this Plan. Stewart Lake is managed by the Utah Division of
Wildlife Resources (UDWR) as the principal feature ofthe Stewart Lake Waterfowl
Management Area. This Plan calls for cooperative and coordinated management of Stewart Lake
as a nursery and rearing area to benefit razorback sucker consistent with the primary purpose of
the management area.

Phase II ofthis Plan identifies two floodplain sites in the Ouray National Wildlife Refuge
(ONWR) as additional restoration sites: (1) Leota Ponds, 1,016 acres, and (2) Johnson Bottom,
146 acres, for a total of 1,162 acres. Some restoration has taken place at Johnson Bottom and
Leota Ponds, including levee breaches and installation of water control gates and fish kettles by
the Recovery Program, and removal or breaches of internal dikes by ONWR. The need for
additional restoration of these sites will be determined following restoration and evaluation of
Thunder Ranch and Stewart Lake and response by the razorback sucker and bonytail populations
to all floodplain management actions. If a need for additional restoration is identified, the
Recovery Program will establish a partnership with the ONWR to develop restoration and
management strategies compatible with program and refuge goals and objectives. Restoration of
the two sites on the ONWR would result in an additional 1,162 acres of floodplain depressions,
for a total of2,551 acres (i.e., 1,389 + 1,162) in 9 sites located 5-60 miles downstream from the
known razorback sucker spawning bar.

Phase III involves restoration of five sites, including (1) Sheppard Bottom, 300 acres, (2)
Wyasket Lake, 850 acres, (3) Sportsman's Lake, 132 acres, (4) Horseshoe Bend, 22 acres, and
(5) Old Charlie-Diked, 81 acres, for a total of 1,385 acres. Restoration of these floodplain sites
would result in a total of 3,936 acres. These sites will require substantial mechanical excavation
of floodplain basins for costs that may be substantial, but have not been computed. Sportsman's
Lake is under private ownership and would require purchase of a property easement as well as
structural modification to the inlet and levees, and possible excavation of an outlet. These
actions could be expensive and may not be necessary if other floodplain sites are suitable for
speCIes recovery.

A mathematical Floodplain Model estimates that an average of 2,032 acres of floodplain
depressions are necessary as nursery and rearing habitat to support a self-sustaining population of

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