7387

• UCREFRP Catalog Number: 7387
• Author: U.S. Bureau of Reclamation.
• Title: Glen Canyon Environmental Studies Executive Summaries of Technical Reports.
• USFW Year: 1988.
• USFW - Doc Type: \
• Copyright Material: NO

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through the darn can be predicted. The objective of
this study was to obtain data on the configuration of
the channel of the Colorado River in the vicinity of
the rapids and on the hydraulics of the river in the
rapids.

METHODS

Twel ve maj or rapids were selected for study: House
Rock, 24.5 Mile, Hance, cremation2, Bright Ange12, Horn
Creek, Granite, Hermit, Crystal, Deubendorff, Lava, and
209 Mile. These rapids include the largest on the
river, and are of interest for hydraulic, sediment
transport, beach stability, and recreational safety
studies. 209 Mile Rapid was not studied in detail, and
Cremation Rapid and Bright Angel Rapid are treated as a
single reach of the river; therefore, ten rapids were
studied in detail and mapped.

Two river trips of 16-18 days duration were conducted
for the purposes of: (a) filming time-lapse
photography of the rapids as discharge varied during
fluctuating flow from about 7,000 cubic feet per second
(cfs) to about 20,000 cfs, (b) surveying control points
to provide data for constructing topographic maps by
cartographic methods, (c) recording fathometer data
across the channel above the rapids, (d) launching
floats and filming their trajectories through the
rapids for analysis of streamlines and velocity, and
(e) obtaining preliminary data on the size distribution
of the large boulders lining the channel of the river.
Because travel time between the rapids is substantial,
even in a motor boat, the average time spent at each of
the ten sites was only two days.

RESULTS

Most data obtained in this study are presented on ten
hydraulic maps of the rapids (USGS Miscellaneous
Investigations Map 1-1897, parts A-J). The maps are at
a scale of 1:1,000 (except for the map of the river in
the vicinity of the Grand Canyon gaging station for
which a scale of 1:2,000 was used because of the large

2 These two rapids do not have formal names. The
names in this report are used informally to indicate
the two rapids in the vicinity of the USGS's Grand
Canyon gaging station.