8215

• UCREFRP Catalog Number: 8215
• Author: U.S. Fish and Wildlife Service.
• Title: Final Environmental Assessment
• USFW Year: 1997.
• USFW - Doc Type: Management and Control of Noonative Fish Species in Floodplain Ponds of the Upper Colorado and Gunnison Rivers.
• Copyright Material: NO

occupations such as agriculture, mining, personal services, professional
services, and retired individuals. Tourism, hunting, and mining are the
important industries in Garfield County (Rifle Area Chamber of Commerce
Undated). Fuels such as natural gas, coal, oil shale, and nacholite have
been mined or developed within close proximity of Rifle. The population of
Garfield County in 1992 was estimated at 29,974 (Rifle Area Chamber of
Commerce Undated). Outdoor recreation by tourists is pursued on over a
million acres of public lands surrounding Rifle and on private lands.
Delta, Colorado is the upstream end of the critical habitat for the
endangered fishes in the Gunnison River. Floodplain ponds are primarily
confined to the broad valley both upstream and downstream of Delta.
Agriculture dominates the Delta valley. The population in Delta County in
1994 was 24,179 persons and is expected to grow to about 35,888 by the Year
2000 (City of Delta 1996). The population of the City of Delta is
approximately 4,000 with another 4,000 persons within a 5-mile radius of the -_
city. The ethnicity of the county residents in 1990 (City of Delta 1996)
was primarily white (89.8%), hispanic (9.1%), native American (0.5%), black
(0.28%), and Asian (0.23%). The per capita income of Delta County in 1993
was about $16,000. Delta, Colorado was rated in the top one-third of
retirement communities in the United States by the 'Rand McNally's Places
Rated Retirement Guide, based on climate, housing, health care, personal
safety, economics, and recreation.
B. Vegetation and Land Use. Much of Delta, Garfield, and Mesa Counties is
rural and remains primarily an agricultural area with hay for livestock the
primary crop. The Grand Valley between Clifton and Palisade is dominated
by orchards and vineyards. The riparian vegetation in the floodplain
consists primarily of cottonwood (Populus fremontii), willows (Salix sp.),
tamarisk (Tamarix parviflora), and Russian olive (Elaeagnus angustifolia).
In unaltered floodplains, broadleaf cattail (Typha latifolia), some hardstem
bulrush (Schoenoplectus acustus), and sedges are the dominant non-woody
plants. Low vegetation of adjacent uplands consists of various grasses,
fortis, and sagebrush.
Numerous ponds are the dominant feature in altered areas of the broad
floodplain areas of the Colorado and Gunnison rivers. Some are natural
floodplain depressions. Gravel mining in the floodplain of the Colorado and
Gunnison rivers in construction of Interstate Highway 70 and in commercial
and residential construction resulted in depressions that are filled by
groundwater and by irrigation return flows. Because of their close
proximity to the rivers, many floodplain ponds become connected to the
rivers during years with high streamflows during the spring runoff
(Osmundson 1986). In addition, some of the ponds have outlets that connect
directly to the rivers. In either case, chronic escapement of the nonnative
fishes into the rivers occurs regularly. Some of the nonnative fishes do
not fare well in the riverine environment. However, the river serves as a
conduit for these nonnative fishes to occupy other suitable habitats such
as backwaters, embayments, and floodplain ponds.
Mitchell (1995) identified 308 ponds (both public and private) representing
878 surface acres along the Colorado and Gunnison rivers (Table 1).
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