GUT in the Asotin

Context of the Asotin

The maps to the left and right show where the Asotin drainage is, showing the 10 digit huc codes. The left map shows the general context, it is at the Idaho, Oregon, Washington juncture. The map to right shows a little bit of the finer scale context, which rivers are near it with some topography and nearby towns.

The map on the left shows the general vegetation of the drainage, The green is closed canopy conifer, the brown is grassland, and the blue is the major river flowing through.

It is difficult to show exactly where the fish sites are since they are so small, but they are in HUC 1706010302, Site 4 is in thee more grassland dominated system while Site 6 is upstream in the transition from closed canopy to grassland.

The survey years were chosen to be 2012 and 2017 simply because 2017 was the newest and 2012 was a enough years prior to potentially show some geomorphic change.

North Fork Fish Site 4 P1

2012

The in channel geomorphology can be quickly shown with the image to the right, overall it is a straight not very complex system

The T2 forms are in the pie chart to the right. It is dominated by mound, planar, and trough forms. Overall it is fairly uniform

The map to the right is a T3 map showing where GU's are within the reach. It is overall mostly glide-run and chute. There is a distinct lack of riffles

This map on the right is zoomed in, where we can see glide-run, pool, pocket pool, margin attached bars, and rapids. There really isn't anything else. Nothing is standing out as completely wrong

2017

The in channel geomorphology in 2017 is slightly more variable, the thalweg actually contacts the bank, but overall, still straight and boring

The diagram to the right shows that in 2017 the reach was still dominated by mounds, troughs, and planar features but now there are some saddle forms showing up

The T3 map to the right shows the GU's and now we are seeing a predominantly glide-run system rather than a rapid system, there are also some riffles appearing

In the zoomed in form, we see predominatly margin attatched bars, glid-run, pools, pocket pools, and I'm noting the thalweg hits the bank and a pool is right there, so there are likely some good processes working on that bank and creating some complexity. Nothing stands out as wrong

Distinguishing Features

There is clearly a pool there in that location to the right.

Forcing: bar forcing constriction Orientation: Streamwise

Position: Mid channel Slope likely low

Roughness likely low T3 name bar forced pool.

Discriminating features differences with GUT

orientation and forcing Gut calls it a pool, it can go more detailed with what kind of pool

There is clearly a Bar there in that location to the right.

Forcing Planform, straight Orientation Streamwise

Position Bank attached Slope varies

Roughness varies T3 name Lateral bar

Discriminating features differences with GUT

forcing position and orientation GUT calls it a margin attached bar, while true, could do a bit more to call it specifically what it was

There is clearly a planar feature there in that location to the right.

Forcing nor forcing Orientation Streamwise

Position varies Slope Low-moderate

Roughness Low-moderate T3 name Glide or Run

Discriminating features differences with GUT

the slope and roughness GUT seems to get these very well

Test

Looking at the detrended DEM on the right, this looks to be an in channel, slightly less steep planar feature without structural forcing and is streamwise. Best guess is rapid or run, more on run

The T2 Shows a trough and bowl transition, that seems about right, although where exactly to draw the line between bowl transition and trough without a convexity is likely a bit dubious.

The T3 shows a glide-run sandwiched between rapids, That is in line with what I was seeing. The biggest problem is its hard to see roughness at the DEM resolution of this level, especially WS roughness. I marked the sequence I wanted well, but the T2 didn't match well, so that's strange.

Comparisons

Overall both reaches were very similar. 2017 had the introduction of some riffles but they weren't a major component. As far as GUT is concerned, I do believe they do planar features well, but the issues I'm finding are in it's delineation of pools and bars and transitions between planar features. It seems weird to have a rapid run sequence (2012) without any convexities. Some of the concavities are also a bit iffy with where they draw the line. Like I had a bowl transition into a trough but somehow there wasnt a convexity or any other feature, it was all glide-run out of a rapid.

North Fork Fish Site 6 P2

2012

The in channel geomorphology can be quickly shown with the image to the right, overall it is straight but has this large chicane in it and some evidence of diffluence

The T2 forms are in the pie chart to the right. It is dominated by mound, trough and planar features but contains quite an array of forms

The map to the right is a T3 map showing where GU's are within the reach. It is overall mostly glide-run and chute. There are major pools, some good point bars and eddy bars. There are also a fair few riffles

This map on the right is zoomed in, where we can see glide-run, pool, pocket pool, margin attached bars, and rapids. There is a chute on one of the margin attached bars and a mid channel bar

2017

The in channel geomorphology in 2017 is slightly more variable,. There appears to be some side channels and mid channel bars

The diagram to the right shows that in 2017 the reach was still dominated by mounds, troughs, and planar features and overall the relative area of these features didn't change too much

The T3 map to the right shows the GU's and there is a very major riffe right in the center along with some variance in the bars, glide-run, pools, margin attached bars, etc.

In the zoomed in form, we see A major pool follwed by a major riffle into mid channel bars and glide-run features with a slight rapid feature. There are some margin attached bars too.

Distinguishing Features

There is clearly a pool there in that location to the right. *

Forcing: bar forcing constriction Orientation: Streamwise

Position: Mid channel Slope likely low

Roughness likely low T3 name bar forced pool.

Discriminating features differences with GUT

orientation and forcing Gut calls it a pool, it can go more detailed with what kind of pool

*I initially did the test before seeing the Tiers, so I am double dipping into this pool feature but I didn't know GUT called it a pool when I did the test.

There is clearly a Bar there in that location to the right.

Forcing Planform, bend Orientation Streamwise

Position Bank attached Slope varies

Roughness varies T3 name point bar

Discriminating features differences with GUT

forcing position and orientation GUT calls it a margin attached bar, while true, could do a bit more to call it specifically what it was since there is a noticeable planform control indicating point bar

There is clearly a planar feature there in that location to the right.

Forcing planform, low sinuosity Orientation Streamwise

Position varies Slope Low-moderate

Roughness Low-moderate T3 name Glide or Run

Discriminating features differences with GUT

the slope and roughness GUT seems to get these very well but I would add here that it is difficult to be sure on this since there is higher complexity in the system, so it could be a rapid or some other planar feature

Test

Looking at the detrended DEM on the right, this looks to be an in channel, significantly deeper portion right past a higher margin attached bar feature. It is streamwise. It's position is pretty close to margin attached, so it's likely a bar forced pool

The T2 Shows a noticeable bowl right next to mounds, so that adds further evidence this is a pool

The T3 shows a pool right next to a bank attached bar. This thing is a textbook bar forced pool, so that's good that GUT picked it up.

Comparisons

Both time frames have interesting geomorphology. It appears in 2017 there is development of mid channel and diagonal bars, which is quite interesting, especially concerning GUT. GUT seemed to really struggle on identifying the bars in this reach. Like in the top right of my test images, it shows two bank attached bar, one with a chute, and then a mid channel bar, when likely, all of that is point bar forming into a diagonal bar. It got the textbook pool, so that's good. The big picture I'm getting is that GUT seems to struggle with dynamics within a geomorphic unit. Compound histories, transition zones, etc. It would call some eddy bars mid channel bars since they form kinda strangely. It's a really useful tool, especially for planar features, but definitely needs the user to understand it's limits. Transition zones are generally a pain, so it's understandable why GUT struggles with them.

Differences

The major differences in exploring GUT between the two sites are that 1. the sites are genuinely different but that 2. GUT seems to have different limitations depending on the morphology of the area. So for F4 it's limits were in concavities and convexities while in F6 it was properly assigning bar features and planar features. It does give enough visual data to give some inferences on the processes. F4 was straight bowling alley stream that is slowly building some diversity while F6 has a major bend and some overbank flows (and likely some structures) that are adding complexity to the system to make for a more interconnected floodplain. Having one snapshot would definitely impact the confidence in conclusions. If I only had 2012 F4 then I wouldn't have a good measure of what features are actually there, but with 2017 I can see that there are some riffles that just weren't picked up in the 2012 GUT.

Synthesis

The forms are pretty similar, but in GUT they also measure transitions. In T3, they lump the fluvial taxonomy we learned into similar groups. It is not quite so detailed and I believe it is lumped in that way because finding those specific taxonomic definitions can be difficult. Measuring stream orientation and position along with forcing is a little bit more abstract and probably hard to identify using algorithms. T4 would be quite difficult to do without high resolution vegetation surveys, grain sized DEM's, or field studies to measure and map the T4 features. I honestly am more confident in my field mapping of GU's because it's nice to see where I can actually critique a WIP tool based on the data given, let alone when comparing to a field survey. I do believe there is a nice place for both in research.

Appendix

T1 legend T2 legend T3 legend

Page updated

Google Sites

Report abuse