Recirculating flow and sedimentation in the Colorado River in Grand Canyon, Arizona

Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Journal of Geology; (USA)

DOI:https://doi.org/10.1086/629435· OSTI ID:6292665

Schmidt, J C ^[1]

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1. Middlebury College, VT (USA)

Debris fans debouching into the bottom of Grand Canyon create rapids and flow separation in the Colorado River. The patterns of flow and the behavior of recirculation zones formed by flow separation are consistent throughout the Canyon's length. Zones of recirculating flow occur along the margin of channel expansions. Recirculation zones are comprised of one primary eddy; secondary eddies and areas of unorganized low velocity may exist upstream from the primary eddy. The longest recirculation zones are formed by channel constrictions of low width-to-depth ratio. Recirculation zones increase in length with increasing discharge. Sand bars form beneath recirculation zones, especially near separation and reattachment points. Reattachment bars project upstream from the reattachment point and underlie primary eddies. Separation bars mantle the downstream parts of the debris fans and form beneath secondary eddies and low-velocity areas. Sediment that forms reattachment bars is dominated by sizes characteristic of suspended load, while sediment that forms separation bars is finer. Reattachment bars are more common than separation bars, and both occur more frequently and are larger in wide reaches. The form and location of these bars is consistent with the location and behavior of stagnation points; however, the locations of these stagnation points change. Although velocity increases in the main channel at high discharges, velocities near the separation and reattachment points remain low. Sedimentation can occur in a bedrock gorge at high discharges and low transport rates, although the location of high-discharge sand bars may differ from those deposited at lower flows.

• OSTI ID: 6292665
• Journal Information: Journal of Geology; (USA), Vol. 98:5; ISSN 0022-1376
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ARIZONA
COLORADO RIVER
SEDIMENTATION
ENVIRONMENTAL TRANSPORT
FLOW RATE
FLUID FLOW
FLUID MECHANICS
HYDROLOGY
RECYCLING
SAND
SEDIMENTS
STAGNATION POINT
WATER CURRENTS
CURRENTS
FEDERAL REGION IX
MASS TRANSFER
MECHANICS
NORTH AMERICA
RIVERS
STREAMS
SURFACE WATERS
USA
540310* - Environment
Aquatic- Basic Studies- (1990-)