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<br />.
<br />Infact, the water has been so cold that trout do not reproduce and in-
<br />
<br />well as transfers of pollutants from water to land, have significant im-
<br />
<br />
<br />~
<br />.
<br />~
<br />$
<br />,
<br />~
<br />
<br />44
<br />
<br />vertebrate populations, a major food source, are minimal. Fish reproduc-
<br />
<br />pacts on environmental quality in the basin. Especially, the localized
<br />
<br />f
<br />~
<br />. f
<br />
<br />tion and growth have been seriously retarded in reaches below Flaming
<br />
<br />Gorge and Lake Powell, and these reaches require continual stocking to
<br />maintain the trout fishery.
<br />
<br />water quality problems previously noted in table 2 could have serious
<br />
<br />impacts on rare and endangered floral and faunal species and recrea-
<br />
<br />~
<br />~
<br />
<br />tional pursuits. Development of natural resources in the Upper Colo-
<br />
<br />The impact on flow of reservoir releases is an especially important
<br />
<br />rado River Basin will accentuate already significant economic and eco-
<br />
<br />constraint on the maintenance of aquatic ecosystems. In turn, the pres-
<br />
<br />ence of specific aquatic ecosystems such as marsh areas (Topock Marsh,
<br />
<br />
<br />Brown Wildlife Refuge, Moab, and other marsh habitats, particularly along
<br />
<br />
<br />the Green River) have an impact on the river by increasing phreatophyte
<br />
<br />logic damages; in particular, (1) impacts of salinity on beneficial uses
<br />
<br />of the water and (2) impacts of water depletions on Btreamflows and on
<br />
<br />the aquatic ecosystem.
<br />
<br />Introduction of Alien Species. Many species of fish and some macro-
<br />
<br />evapotranspiration, increasing stream surface area for evaporation, and
<br />
<br />exposing greater substrate to continuous water contact.
<br />
<br />invertebrates have been introduced into the Colorado River system, some
<br />
<br />Water development has also led to an increase in agriculture, indus-
<br />
<br />dentally. These fish and other organisms may have ecological niches simi-
<br />
<br />-
<br />~
<br />~
<br />~
<br />,
<br />
<br />deliberately (through state and federal hatchery systems) and others acci-
<br />
<br />try, recreation, mining, and energy activities, as well as urbanization of
<br />
<br />lar to the native organisms, or may be more tolerant to changed or changing
<br />
<br />~
<br />~
<br />-
<br />-
<br />,
<br />
<br />the basin, all of which increase the pollutant loads in the river. Many,
<br />
<br />if not all, of these effects have had an influence on the maintenance of
<br />
<br />conditions than native species. For various reasons, such as physical
<br />
<br />-
<br />
<br />changes in the river, niche competition, greater tolerance to poorer
<br />
<br />they are compounded by interactions with other environmental changes are
<br />poorly understood.
<br />
<br />some of the introduced species have replaced or reduced native fish
<br />
<br />-
<br />~
<br />-
<br />-
<br />~
<br />>
<br />~
<br />-
<br />~
<br />
<br />native biota in the aquatic system. At this time these effects and how
<br />
<br />quality water, changes in the food web, predation, and hybridization,
<br />
<br />populations. Examples of introduced species to the intermountain region
<br />
<br />Land Use. Land may be used for a variety of purposes and each use
<br />
<br />include rainbow trout and brown trout, both of which were introduced to
<br />
<br />can affect water quality. Examples of land uses include: (1) human
<br />
<br />habitation and related activities, (2) recreational pursuits, (3) agri-
<br />
<br />culture, and (4) industrial-mining-energy activities. Salinity, nutri-
<br />
<br />the region during the last century (ca. 1890, 1880, respectively). In
<br />
<br />suitable habitats, these fish have replaced the native cutthroat trout,
<br />
<br />and in the case of the rainbow, it has hybridized with the cutthroat.
<br />
<br />ents, sediments, BOD and coliforms, heavy metals, and toxic organics all
<br />
<br />result from these activities, and certain problem areas in the basin can
<br />
<br />The rainbow trout and brown trout are not in themselves indicators of
<br />
<br />pollution, but are competitors that have more general niche requirements.
<br />
<br />be linked to these activities. pollutants generated by land activity, as
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