Stream substrates are an important component of salmonid
habitat. Streams with substrates ranging in size from
gravel to boulder provide Steelhead habitat.
For the 6th field assessment, as requested by MCWC, we
summarized the composition of substrates from riffle units.
The analyses conducted were: length of riffle units with
gravel-sized substrate dominant; length of riffle units
with bedrock dominant; and length of riffle units with
gravel-to-boulder-sized substrate dominant. In each case,
"dominant" was defined as a particular particle size (or
range of particle sizes) occupying more than 50% of the
streambed. In the ODFW habitat-unit-level GIS layer we
summarized by reach to obtain total lengths dominated
by the different substrates, joined those reach averages
to the
ODFW reach-level
GIS shapefile, and finally, summarized by 6th field.
For the
USFS Region 6,
we calculated 6th field total lengths of all habitat units
(NSO's) with substrate dominated by each particle size
or range of particle sizes. For the ODFW data and
Lincoln
District data, we used substrate data from units classified
as "riffle" and "riffle with pockets" to determine lengths
of stream dominated by the various substrate categories.
Please address questions or comments
to:
Dr. Ralph Garono
Principal Investigator
Earth Design Consultants, Inc.
rgarono@earthdesign.com
Laura Brophy
Principal Investigator
Green Point Consulting
brophyl@peak.org |
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