Grand Canyon High Flow Monitoring

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Detailed Description

The USGS monitors sediment loads during Grand Canyon's beach-building high flow releases.


Date Taken:

Length: 00:02:40

Location Taken: Tucson, AZ, US


The Colorado River is named for the Spanish
word for red, a reflection of the often muddy

waters in a river that has the capacity to
convey tremendous amounts of sediment.

Within the Grand Canyon, sediment carried
in the river is essential for the maintenance

of beaches and the ecosystems associated with
those beaches.

In 1963 Glen Canyon Dam began impounding the
waters of the Colorado to form Lake Powell,

and as an unintended consequence, also impounded
the sediments that had previously been carried

from higher in the watershed.

This resulted in a deficit of sediment in
the river, which caused erosion of the beaches.

In 1996, the Department of Interior authorized
the first of a series of experimental high-flow

releases from Glen Canyon Dam that are intended
to simulate some of the floods of the pre-dam


Although these high-flow releases don’t
add sediment to the system directly below

the dam, they do provide flows sufficiently
high to remobilize the sediment added to the

river from the many tributaries to the River
in Grand Canyon, that subsequently rebuild

the beaches.

The USGS has many roles in Grand Canyon science
and in studying the effects of high flows.

At the Arizona Water Science Center, we focus
on monitoring the flows in the river, both

during high flows and at other times, and
sediment loads during the high flow experiments.

Our data are combined with data collected
by other USGS researchers and others in the

research community to help determine the most
effective timing and execution of high-flows

to maximize their benefit.