Eroding soils can contribute sediments to streams and
can alter salmonid habitat quality.
To create a "soils at risk of erosion" layer,
we merged the soils GIS coverages obtained from
NRCS
and OSU Soil Science Department websites to create a single
soils coverage for the entire study area. We then intersected
this soils layer with the 6th fields layer to attribute
each soils polygon with the appropriate 6th field identifier.
There are more than 350 soils types in the study area.
The data tables for the available soils coverages did
not contain information on erosion risk. Therefore, we
entered erosion risk information (
er_risk) in to
the data table that we acquired from downloaded Map Unit
Interpretations Record (MUIR) Tables. We used the field
"
wderos" from the MUIR tables. This is
a value which ranks erosion hazard in wood management
areas. Although erosion risk categories were not found
for all soil types in the study area, 300 (86%) soil types
were designated as having "slight", "moderate"
or "severe" risk.
Over 95% of the study area was classified for soil erosion
risk with available data. We found that most of the study
area is at risk of soil erosion (Table 1).
Erodible soils can be used to identify
areas at risk for contribution of sediments to streams.
In addition, erodible soils information can be combined
with information on areas susceptible to shallow land slides
to identify areas that may represent both chronic and acute
sediment sources.Click
here
for a map showing 6th field watershed ranked by proportion
of erodible soils.
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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