Stream gradient information was not
available for the entire study area. There was, however,
stream gradient class information available for most of
the Alsea and parts of the Ocean Tributary and Siletz 6th
Field watersheds in the
USFS
densified streams layer (dens_str_final). In order
to prioritize 6th field watersheds, stream gradient information,
necessary for
channel
typing described in the Oregon Watershed Assessment
Manual, was developed for the entire study area using GIS.
The stream gradient data layer that was produced is a computer-generated
representation of stream gradient: it is meant to be used
as a study area wide surrogate for stream gradient information
until a better representation of stream gradient can be
produced.
| Class |
Slope (%) |
Length
(km)
|
Proportion
of All Streams |
| 0 |
0 |
458 |
7.3% |
| 1 |
1.8 |
497 |
7.9% |
| 2 |
3.5 |
814 |
12.9% |
| 3-5 |
5.3-8.8 |
1568 |
24.9% |
| 6-8 |
10.5-14.1 |
1,016 |
16.2% |
| >9 |
> 15.8 |
1,940 |
30.8% |
We used these data for
stream
channel typing and for multi-factor analyses such as
Winter Coho, Summer Coho, and Steelhead Habitat. This layer
could also be used to target
restoration
actions in low gradient streams.
Fields
MCWC_class and
Der_gradie in the shapefile
can be used to summarize stream lengths based on gradient.
A good use of this data layer would
be to guide field teams and to field verify where the layer
correctly represents stream gradient and where it does not.
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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