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| Titel |
A flume experiment on the effect of constriction shape on the formation of forced pools |
| VerfasserIn |
D. M. Thompson, C. R. McCarrick |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 14, no. 7 ; Nr. 14, no. 7 (2010-07-20), S.1321-1330 |
| Datensatznummer |
250012372
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| Publikation (Nr.) |
 copernicus.org/hess-14-1321-2010.pdf |
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| Zusammenfassung |
| A series of 18 flume runs were conducted in a 6-m long, 0.5-m wide
recirculating flume with a bed gradient of 0.8% to determine the
influence of obstruction shape on the formation and characteristics of
forced pools. Six different-shaped obstructions were added to the flume with
the maximum width of the obstruction held constant at 20 cm, which equaled a
40% constriction of flow. The obstruction shapes used included a square,
a rectangle, a right triangle with the hypotenuse-facing upstream, a right
triangle with the hypotenuse-facing downstream, a combination of a square
and triangle with the hypotenuse-facing upstream, and a rectangle and
semi-circle shape. Three flume runs were conducted with each obstruction
shape. A profile of the flume bed was taken after each experiment and a grid
measurement of bed elevations for the last run were conducted to create
topographic maps of the flume bed to compare pool-riffle morphologies. ANOVA
results indicate pool depth, pool location, and the distance between the
pool center and the riffle crest all vary with the obstruction shape.
Obstructions with a more blunt upstream face created deeper pools, more
total scour and longer pool-riffle sequence lengths than pools formed by
obstructions with a more gradual narrowing of flow. The increased volume of
scour associated with obstructions that rapidly narrow flow also creates
larger volume riffles that cover a greater extent of the channel bed. |
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