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Record Nr. |
UNINA9910696708203321 |
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Autore |
Blevins Dale W |
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Titolo |
The response of suspended sediment, turbidity, and velocity to historical alterations of the Missouri River [[electronic resource] /] / by Dale W. Blevins |
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Pubbl/distr/stampa |
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Reston, Va. : , : U.S. Dept. of the Interior, U.S. Geological Survey, , 2007 |
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Descrizione fisica |
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iv, 8 pages : digital, PDF file |
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Collana |
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Soggetti |
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Sediment transport - Missouri River |
River engineering - Environmental aspects - Missouri River Watershed |
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Lingua di pubblicazione |
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Formato |
Materiale a stampa |
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Livello bibliografico |
Monografia |
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Note generali |
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"Prepared in cooperation with the U.S. Environmental Protection Agency." |
Title from Web page (viewed on Sept. 28, 2007). |
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Nota di bibliografia |
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Includes bibliographical references (page 8). |
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Sommario/riassunto |
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"Median suspended-sediment concentrations in the lower Missouri River appear to have decreased by at least 70 to 80 percent from predevelopment conditions, although two semiquantitative sediment-settling observations made by William Clark and Edward Harris indicate even larger reductions in maximum concentrations. Regardless of the amount of reliability that might be ascribed to the Clark and Harris measurements, the decrease in suspended-sediment concentrations and increase in water clarity of the Missouri River is remarkable. Most of this decrease occurred after the closure of dams and massive bank stabilization activities that occured in the 1950s and 1960s. The ecological change that may have resulted from the decrease in suspended-sediment and turbidity has not been documented. However, numerous ecological changes can be postulated from fundamental principles of aquatic ecology (Horne and Goldman, 1994). For example, the greater range in velocities likely resulted in a greater range in turbidity and a greater variety of fish habitat. Also, increased water clarity may permit algal photosynthesis at low river stages providing a new energy source for the food chain and a niche for nonnative |
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planktivorus fish. Increased water clarity should benefit sight-feeding fish, perhaps at the expense of native fish such as catfish, drum, and the endangered pallid sturgeon, that need little light to find food. Thus, the top end of the food chain also may be altered with a potential trophic cascade that could substantially alter the food chain and populations of many species. Conversely, drinking-water suppliers and other users who must remove river sediments benefit from the decrease in suspended material."--Conclusions and implications. |
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