Key Concepts in Geomorphology – ideas for revision
Chapter 5 – Hillslopes
Please add your comments about how to improve Chapter 5 here.
29 thoughts on “Chapter 5 – Hillslopes”
Why is there a jump in the figures between Fig. 5.9 and 5.19 (p. 165 – 165) and in other parts of the chapter?
Fig. 5.9, p.164 Could you inverse the colour scheme here? It is more logical to have convex (channels, drainage lines) in blue and concave (ridges etc) in brown.
could figure 5.11 move to chapter 14 since it’s about evolution of slopes…would lighten this already heavy chapter.
Photograph 5.10b – The movement direction (left or down?) of the inactive landslide is unclear – get a better photograph. The ancient ones near the Oso Slide would be much better.
Why lead soil creep discussion with tree throws? Isn’t heave (both wetting & drying(!) and frozen ground) more important/more recognized? I would reorder the presentation.
Consider putting Diffusive Processes after Slope Stability, so the the chapter would flow from Rock Strength to Mass Movements and Slope Stability
The last paragraph of Applications (p. 173) leads with something that should be included in the slope stability section – how would the equations be modified to include these variables?
Fig 5.3 – replace – Lavaka is unnecessary jargon, replace with badlands – NM, Utah, or SD have great examples
Photograph 5.5 – Weak depiction of sheetwash – find better one or eliminate
Fig 5.10b pg 154 I have trouble seeing the orientation
p. 149 Note that the weight of water is also important (in addition to the buoyancy) in increasing driving forces
Consider adding a section on how to map and investigate mass movements: what features are mappable? (headscarps, side scarps, pressure ridges, etc.) in an investigation.
The “Applications” section could be reworked to be more specific; while mentioning LIDAR, you are missing true “Applications”; consider including diagrams of rockfall netting?
No significant inclusion of mitigation strategies
Short shrift on Topples (p. 158); The reasons for these failures can be different than for falls, and modeling of the failures are quite different.
mentioning of mass movement examples without a map or photograph is frustrating (Love Creek slide & Canyonlands lateral spreads on p. 155 & Turnagain Heights on p. 156)
no mention of how Shear strength is measured – a photo of a simple direct shear test device and its output would help
No mention of Sackung as lateral spreading phenomena – a discussion with a cross section or 3D diagram comparing driving vs resisting forces and features for mass movements early in the chapter would help
No inclusion of Aspect-related slopes in presentation of weathering-limited & transport limited hillslopes (and the topic comes in on page 146 & 165 – try to reorganize them)
I would re-iterate it in the alluvial fan section. It would be nice to have some indication of how landslides disrupt contours and how they may look on maps, what features to look for on landscapes Mudflows don’t seem to be mentioned? The slope stability models may be a bit much for some students Perhaps add more on rills, gullies and gully evolution
As defined in Box 5.1, which has equations whose units need to balance, q_s is a mass flux rate with units of kg m^-1 s^-1 , but it is referred to as a volumetric flux rate four lines above eq. 5.9, on page 165.
Per Figure P5.6 (“Tree throw can move large amounts of material downslope. Here, in the Nahanni Karst region of northern Canada, a tip up moves the shallow layer of soil downslope. Lens cap for scale on the top of the rootwad.”)
Paul Sanborn noted regarding his image caption:
“The proposed caption refers to the role of treethrow in downslope soil movement. However, in this case, the site shown was almost perfectly level, so the treethrow wouldn’t be contributing to any downslope movement.”
In Fig 5.4 rotational and translational slumps are illustrated as different processes but the text explains that rotational slumps can form from one slump, or many. If there is a key different between rotational and translational it could be mentioned.
Figure 5.3 (pg 152) illustrates soil creep and interactions with other landscape features. Could be beneficial to see some of the interactions explained for heave in the heave component of the figure
A figure showing the components of shear strength acting on a single grain would be helpful in understanding the relationship and equation further in Figure 5.2 (pg 148). A question on tenile verses compressive strength or on shallow mass movements (page 147; 153). If the end of the chapter questions followed the reading progression it would help a lot. I found myself answering questions found at the end of the chapter but located towards the top of the questions.
Fig 5.11–photo of “slope replacement” is actually an example of “parallel retreat.” For slope replacement, the material below the resistant sandstone cap should be talus, not more bedrock. The photo of parallel retreat is not demonstrably parallel retreat because the viewer cannot tell if the lowest slopes are bedrock or talus. We need to see bedding planes for students to understand the difference. For that reason the erroneous slope replacement photo would be excellent to illustrate parallel retreat.
In the same figure, make the cartoon part actually mimic the profile of the photo, so there is a one to one correspondence between theory and example.
The figure in question was a draft figure I’ve been using as a handout. Sorry. The actual text book is correct.
can you give us a figure number and location on the figure to correct? thanks PRB
There is an error in the equations for the infinite slope model in the figure. It is missing the soil thickness term.
University of Vermont
Why is there a jump in the figures between Fig. 5.9 and 5.19 (p. 165 – 165) and in other parts of the chapter?
Fig. 5.9, p.164 Could you inverse the colour scheme here? It is more logical to have convex (channels, drainage lines) in blue and concave (ridges etc) in brown.
could figure 5.11 move to chapter 14 since it’s about evolution of slopes…would lighten this already heavy chapter.
Photograph 5.10b – The movement direction (left or down?) of the inactive landslide is unclear – get a better photograph. The ancient ones near the Oso Slide would be much better.
Why lead soil creep discussion with tree throws? Isn’t heave (both wetting & drying(!) and frozen ground) more important/more recognized? I would reorder the presentation.
Consider putting Diffusive Processes after Slope Stability, so the the chapter would flow from Rock Strength to Mass Movements and Slope Stability
The last paragraph of Applications (p. 173) leads with something that should be included in the slope stability section – how would the equations be modified to include these variables?
Fig 5.3 – replace – Lavaka is unnecessary jargon, replace with badlands – NM, Utah, or SD have great examples
Photograph 5.5 – Weak depiction of sheetwash – find better one or eliminate
Fig 5.10b pg 154 I have trouble seeing the orientation
p. 149 Note that the weight of water is also important (in addition to the buoyancy) in increasing driving forces
Consider adding a section on how to map and investigate mass movements: what features are mappable? (headscarps, side scarps, pressure ridges, etc.) in an investigation.
The “Applications” section could be reworked to be more specific; while mentioning LIDAR, you are missing true “Applications”; consider including diagrams of rockfall netting?
No significant inclusion of mitigation strategies
Short shrift on Topples (p. 158); The reasons for these failures can be different than for falls, and modeling of the failures are quite different.
mentioning of mass movement examples without a map or photograph is frustrating (Love Creek slide & Canyonlands lateral spreads on p. 155 & Turnagain Heights on p. 156)
no mention of how Shear strength is measured – a photo of a simple direct shear test device and its output would help
No mention of Sackung as lateral spreading phenomena – a discussion with a cross section or 3D diagram comparing driving vs resisting forces and features for mass movements early in the chapter would help
No inclusion of Aspect-related slopes in presentation of weathering-limited & transport limited hillslopes (and the topic comes in on page 146 & 165 – try to reorganize them)
I would re-iterate it in the alluvial fan section. It would be nice to have some indication of how landslides disrupt contours and how they may look on maps, what features to look for on landscapes Mudflows don’t seem to be mentioned? The slope stability models may be a bit much for some students Perhaps add more on rills, gullies and gully evolution
As defined in Box 5.1, which has equations whose units need to balance, q_s is a mass flux rate with units of kg m^-1 s^-1 , but it is referred to as a volumetric flux rate four lines above eq. 5.9, on page 165.
Per Figure P5.6 (“Tree throw can move large amounts of material downslope. Here, in the Nahanni Karst region of northern Canada, a tip up moves the shallow layer of soil downslope. Lens cap for scale on the top of the rootwad.”)
Paul Sanborn noted regarding his image caption:
“The proposed caption refers to the role of treethrow in downslope soil movement. However, in this case, the site shown was almost perfectly level, so the treethrow wouldn’t be contributing to any downslope movement.”
In Fig 5.4 rotational and translational slumps are illustrated as different processes but the text explains that rotational slumps can form from one slump, or many. If there is a key different between rotational and translational it could be mentioned.
Figure 5.3 (pg 152) illustrates soil creep and interactions with other landscape features. Could be beneficial to see some of the interactions explained for heave in the heave component of the figure
A figure showing the components of shear strength acting on a single grain would be helpful in understanding the relationship and equation further in Figure 5.2 (pg 148). A question on tenile verses compressive strength or on shallow mass movements (page 147; 153). If the end of the chapter questions followed the reading progression it would help a lot. I found myself answering questions found at the end of the chapter but located towards the top of the questions.
Fig 5.11–photo of “slope replacement” is actually an example of “parallel retreat.” For slope replacement, the material below the resistant sandstone cap should be talus, not more bedrock. The photo of parallel retreat is not demonstrably parallel retreat because the viewer cannot tell if the lowest slopes are bedrock or talus. We need to see bedding planes for students to understand the difference. For that reason the erroneous slope replacement photo would be excellent to illustrate parallel retreat.
In the same figure, make the cartoon part actually mimic the profile of the photo, so there is a one to one correspondence between theory and example.
The figure in question was a draft figure I’ve been using as a handout. Sorry. The actual text book is correct.
can you give us a figure number and location on the figure to correct? thanks PRB
There is an error in the equations for the infinite slope model in the figure. It is missing the soil thickness term.