The Colorado River system

Stanford, Jack A.; Ward, J. V.; Zimmermann, Helmut; Cline, L. D.

doi:10.1007/978-94-017-3290-1_9

Cited by 38 publications

(27 citation statements)

References 20 publications

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“…Diel fluctuations in pH during the latter part of summer and early autumn, absent from the two near-dam sites, were partially responsible for this pattern. All chemical variables were within normal levels for similar high-elevation Rocky Mountain streams (Pennak 1977;Ward 1986). The substratum at each site consisted predominantly of cobble and pebble ( Table 2 ) .…”

Section: Physical-chemical Gradientmentioning

confidence: 98%

Biotic Responses along the Recovery Gradient of a Regulated Stream

Voelz¹,

Ward²

1991

Can. J. Fish. Aquat. Sci.

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Voeln, N. J., and I. V. Ward. 1991. Biotic responses along the recovery gradient of a regulated stream. Can. J. Fish. Aquat. Sci. 48: 2477-2490 Samples were collected year-round over a I-yr period at six sites located downstream from a reservoir with a hyplirnnetic release on the upper Colorado River to examine the longitudinal patterns of macroinvertebrates along an environmental gradient induced by river regulation. The impoundment had only minimal effects on river chemistry, and chemical variables did not exhibit a distinct downstream gradient. Macroinvertebrate density was highest at sites near the Granby Reservoir dam, but diversity increased with distance from the impoundment. A percentage similarity matrix identified two areas sf rapid transition in macroinvertebrate assemblages along the regulated river gradient. Detrended correspondence analyses (DCAB showed a sequential faunal gradient with the most rapid change occurring within the first 3.0 km below the impoundment. Detrended canonical correspondence analysis (DCCA) suggested that downstream decreases in periphyton standing crop and minimum temperatures and downstream increases in most food resources and maximum temperatures were major variables structuring faunal assemblages. The results of this study, when compared with research conducted in free-flowing and other impounded rivers, indicated the predictability of some longitudinal patterns and the recovery potential of regulated iotic systems.Des echantiilons ont ete prklev6s pendant toute une ann6e en six endroits situes en aval d'un reservoir 2 dkcharge hypolimnetique sur le cours superieur du Colorado, dans le but d'exarniner Jes tendances longitudinales des macroinvertebres le long d'un gradient envirionnemental dir 3 la regularisation du cours d'eau. Le reservoir n'a eu que des effets minirnes sur la chirnie du cours d'eau, et les variables chimiques n'ont present6 aucun gradient distinct en aval. La densit6 de macrovertebr6s etait la plus forte aux endroits proches du barrage de Granby Reservoir, mais la diversite augmente en s'eioignant du reservoir. Une matrice de pourcentages de similarit4 a permis de reperer deux zones de transition rapide dans les assemblages de macroinvept6br$s le long du gradient du cours regularis& Des analyses de correspondances d6compos6es ont r$vel& la pr6sence d'e~n gradient faunistique s6quentiel avec la variation la plus forte se produisant dans les 3'0 premiers km en aval du reservoir.Une analyse de correspondances canoniques d6composees a indiqu6 que les principales variables de structure des asserrkblages faunistiques etaient les diminutions en aval de la biomasse de periphyton et des temperatures minimaies, ainsi que les augmentations en aval de la pluparts des ressources de nourriture et des temperatures maximales. les rksarltats de cette etude, une fois comparkes 3 celles de la recherche menee des eaux vives et d'autres r6servoirs, ont montre que certaines tendances longitudinales ktaient previsibles et que les syst&r=i es lotiques regularises pouvaient &re...

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Section: Physical-chemical Gradientmentioning

confidence: 98%

Biotic Responses along the Recovery Gradient of a Regulated Stream

Voelz¹,

Ward²

1991

Can. J. Fish. Aquat. Sci.

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“…The White River was one of the few remaining freeflowing tributaries in the entire Colorado River Basin (Stanford & Ward 1986a). A major tributary in the Green River subbasin (Fig.…”

Section: Study Areamentioning

confidence: 99%

“…Dams and reservoirs have had profound effects on the ecology of the Colorado River system (Mullan et al 1976, Stanford & Ward 1986a. Its endemic fishes have been negatively affected by modifications resulting from impoundments (Behnke & Benson, ' Hickman 1983, Holden & Stalnaker 1975, Miller 1946,1961, Minckley & Deacon 1968, lyus et al 1982, Vanicek et al 1970.…”

Section: Introductionmentioning

confidence: 99%

“…Its endemic fishes have been negatively affected by modifications resulting from impoundments (Behnke & Benson, ' Hickman 1983, Holden & Stalnaker 1975, Miller 1946,1961, Minckley & Deacon 1968, lyus et al 1982, Vanicek et al 1970. Further, competition with non-native fish species, many of which thrived in the modified environments within and downstream from reservoirs, may also have contributed to the decline of native species (Stanford & Ward 1986~). Effects of damming a river have been classified as immediate and delayed (Holden 1979).…”

Section: Introductionmentioning

confidence: 99%

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Fish species composition before and after construction of a main stem reservoir on the White River, Colorado

et al. 1994

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SynopsisThe completion in the fall of 1984 of Taylor Draw Dam on the White River, Colorado, formed Kenney Reservoir -thus impounding the last significant free-flowing tributary in the Upper Colorado River Basin. Fishes were sampled above and below the dam axis prior to closure of the dam and in the reservoir and river downstream following impoundment. While immediate effects of the dam to the ichthyofauna included blockage of upstream migration to 80 km of documented range for endangered Colorado squawfish, the reservoir also proved to have profound delayed effects on the river's species composition. Pre-impoundment investigations in 1983-1984 showed strong domination by native species above, within, and below the reservoir basin. By 1989-1990, non-native species comprised roughly 90% of the fishes collected in the reservoir and 80% of the fishes collected in the river below the dam. Initially, fathead minnow, whose numbers quickly increased in the new reservoir, dominated all post-impoundment collections, but red shiner became the most abundant fish collected in the river below the dam by [1989][1990]. While agency stocking programs for the reservoir sought to emphasize a sport fishery for salmonids, primarily rainbow trout, local enthusiasm for warmwater sport fishes resulted in illicit transfers of these species from nearby impoundments. Several species, formerly rare or unreported in the White River in Colorado, including white sucker, northern pike, green sunfish, bluegill, largemouth bass and black crappie, were present in the river following impoundment. Our investigation indicates smaller-scale, main-stem impoundments that do not radically alter hydrologic or thermal regimes can still have a profound influence on native ichthyofauna by facilitating establishment and proliferation of nonnative species. 228

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“…Even in the absence of human disturbance, some rivers in the Middle East (Krinsley, 1970) and Australia (Australian Water Research Council, 1976) may be somewhat saline in certain reaches, while human-induced salinization is a perennial problem in many arid areas of North America (see, for example, Stanford & Ward 1986), Austrialia (Australian Water Research Commission, 1976) and southern Africa (Williams et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

Physical and chemical conditions in an hypersaline spring in the Namib Desert

Day

Seely

1988

Hydrobiologia

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Hosabes is a small mineralized spring lying in a gypsous crust in the central Namib Desert on the south-western coast of Africa. It is fed by virtually fresh groundwater that wells to the surface at this and other similar fracture lines. The extremely high rates of evaporation and solar radiation result in intense concentration of the salts and the formation of strong salinity and therefore density gradients in the deeper parts of the system. These in turn produce a "solar pond" effect with a reversed temperature gradient; temperatures reach 50 °C within the water column. The deeper parts of the system appear to be monomictic. Although the surrounding crust is largely gypsous, the water in the spring is dominated by NaCl as a result of precipitation of CaSO 4 in the highly concentrated water.

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The Colorado River system

Cited by 38 publications

References 20 publications

Biotic Responses along the Recovery Gradient of a Regulated Stream

Biotic Responses along the Recovery Gradient of a Regulated Stream

Fish species composition before and after construction of a main stem reservoir on the White River, Colorado

Physical and chemical conditions in an hypersaline spring in the Namib Desert

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