Observations are used to determine values for four physical habitat indicators.
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.
To learn more, see the
NRSA Field Operations Manual.