1:
The two sites that will be discussed for this assignment are located in the southwest corner of Washington in the North Fork Asotin Creek, which is a northwest sub-watershed of the Asotin Watershed. The ecoregions description of the study sites are North American desert and the dominant vegetation is a dry-mesic mixed conifer forest.
2.1:
The in-channel geomorphology of the North Fork Asotin F4 site is comprised of a relatively straight channel that has little variation in width throughout the reach.
2.2:
The two surveys that will be analyzed are the 2012 and 2014. These surveys were chosen to illustrate variations in geomorphic units within the same river reach in a relatively short time span.
2.3:
In both surveys all 3 types of Tier 2 forms are present. These forms include concavities, convexities and planar forms. Although all the forms are present in the both surveys they assemblages of these forms differ from 2012 to 2014.
2.4:
The Tier 2 forms are fairly mixed in both surveys although the major difference is that in 2012 the Tier 2 forms are smaller in size and more variable, compared to 2014 where the forms are large and pretty consistent throughout the reach. This show how quickly the channel can change form in just to years.
2.5:
The Tier 3 geomorphic units that are present in the 2012 survey include margin attached bars, glide-runs, chutes, transitions and pool/ pocket-pools.
In 2014 the geomorphic units include margin attached bars, glide-runs, transitions and pools/pocket-pools.
2.6:
GUT does a good job at the arrangement of geomorphic units such as having transition zones between margin attached bars and glide-runs.
2.7:
Although GUT is good at the arrangement of geomorphic units as previously discussed, I believe GUT does a below average job at actually discriminating the geomorphic units. For example, there are large areas that are described as being concavities in the tier 2 form but are marked as glide-runs in the tier 3 units. One of the key properties of a glide-run is that it is a planar feature. The algorithm that GUT uses may have a size requirement to denote a feature as separate from its surroundings, this is one area of concern for smaller geomorphic units that may be nestled in larger units.
2.7A: Pool 2012
2.7 A1:
The GU forcing is from flow width constriction due to margin attached bars.
2.7 A2:
The GU orientation of the pool is streamwise.
2.7 A3:
The GU position is mid-channel.
2.7 A4:
The Low Flow Water Surface Slope is shallow.
2.7 A5:
The Low Flow Relative Roughness is low, but the GUT Bed material is listed as boulders. This is a downfall of GUT.
2.7 A6:
Structurally-forced pool from a flow constriction due to margin attached bars.
2.7 A7:
Surrounding geomorphic units that could be forcing also the GU position.
2.7 A8:
GUT described the bed material as boulders throughout this entire reach, which many of the GU would not form in this environment. I'm assuming the bed material is contrived from valley setting and what zone the reach is in (source, transfer, accumulation).
2.7 B Bar
2.7 B1:
The GU Forcing is from planform.
2.7 B2:
The GU Orientation is streamwise.
2.7 B3:
The GU Position is bank-attached.