We obtained tabular stream inventory
data from the
U.S. Forest
Service Region 6 office. We used lookup functions, pivot
tables and conditional formulas in Excel to manipulate these
data and produce average values for each aquatic habitat
parameter for each 6th field. We then joined the table of
average values to the
6th field GIS
layer, allowing us to color code 6th fields by average
aquatic habitat characteristics. The numeric value shown
in each 6th field is the "survey extent", calculated by
dividing the total length of streams surveyed by USFS Region
6 in each 6th field by the length of streams mapped in the
1:100k streams coverage.
Due to the limited number of streams shown in the 1:100k
layer, this value may be more than 100%.
The colors show what proportion of total
stream area consists of pools. You could change the ranges
used to color code the 6th fields, to bring out differences
in a particular portion of the study area.
The USFS stream inventory methods are
different from the ODFW aquatic habitat inventory methods,
so the two datasets must be interpreted separately and can
not be presented in the same image. Also, USFS data should
not be analyzed using the ODFW habitat benchmarks, because
the distribution of the data is different (see frequency
charts).
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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