Rivers and Streams Field Methods home page.
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How are these data used?

Observations are used to determine values for four physical habitat indicators.

Physical Indicators

Closeup of muddy water eroding bare soil. Photo by James River Association, Flickr, CC BY-SA 2.0

Streambed sediments are fine mineral deposits and silt on the stream bottom. Human activities that disturb the land can increase the amount
of fine sediment entering river and stream channels. In excess amounts, sediments can
fill in the spaces between streambed cobbles and boulders where organisms live and breed, suffocating the organisms, their habitat and
their eggs.

Where are streambed sediments observed?

Crews observe and record streambed
sediment characteristics through-
out the sample reach.
Schematic of stream segment showing 11 evenly spaced transects.

To learn more, see the
NRSA Field Operations Manual.