Dames & Moore, 1999 - USDA Forest Service

VelocityDepth - influences benthic macroinvertebrate and fish assemblages
Channel Shape - identifies dominance of undercut banks and/or overhanging vegetation
Width to Depth Ratio - ratio of the wetted channel width divided by the wetted channel
depth
Bank Vegetation Protection - indicates bank stability and potential sedimentation
Lower Bank Stability - identifies potential for detachment of soils from the lower
streambank and its potential movement into the stream
Disruptive Pressure - estimates the amount of plant biomass that remains in the vegetated
area immediately adjacent to the stream
Zone of Influence - estimates the extent of human influence within the area adjacent to
the stream
These parameters were qualitatively assessed at five transects established to represent equal subreaches
within each sampling location. The scores for each transect were then averaged for the parameter score
for a particular sampling location.
In addition to the rapid bioassessment procedures, coarse substrate composition was determined by
applying the pebble count method developed by Wolman (1954) at ten points along each transect within
each sampling location. At each point, a "pebble" was identified randomly. The intermediate axis of
each pebble was measured or estimated and recorded. Therefore, a total of 50 data on coarse substrate
was acquired from each sampling location.
Benthic Macroinvertebrates
Benthic macroinvertebrates were sampled at all locations during September and early-October 1997.
Benthic macroinvertebrates were collected using a modified Hess (500-pm mesh) stream bottom sampler.
Eight replicate samples were collected from riffle areas at each location. All benthic macroinvertebrate
samples were preserved in 70 percent ethyl alcohol (ethanol) solution and transported to the laboratory for
processing, identification, and enumeration.
The following field information was also collected at each benthic macroinvertebrate sample location
whenever a sample was collected:
Semi-quantitative particle size characterization (percent sand, gravel, and cobble)
Current velocity
Water depth
Replicate location (a sketch depicting where replicates were collected within a given
sample location)
Benthic macroinvertebrates retained were identified to the lowest practical taxon using appropriate
taxonomic references and enumerated. A project-specific reference collection (vouchered reference
collection) was established in the event that identifications needed to be reconfirmed or in situations
where the taxonomic nomenclature changes or, for example, if there is a future need to separate a genus
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17693-005-OI9Uuly 19. 1999;2:07 PM:DRAFT FlNAL RI REPORT