Explain the relationship between stream velocity and erosion. ...

[yoroshambo]

Explain the relationship between stream velocity and erosion.
  What will be an ideal response?

Question 2

You are attempting to build a house in a valley bottom, but before you break ground on your new project, you want to make sure that the area is not in danger of experiencing a debris flow. What sort of evidence would you look for to ensure that you would be safe building in that location?
  What will be an ideal response?

[ally]

Answer to Question 1

ANSWER: In general, a higher stream velocity indicates the stream is likely to erode, while lower velocity streams are more likely to transport and deposit sediment. Particle size plays a role as well. Higher velocities are required to erode very fine and very coarse particles, while moderate velocities can erode mid-size particles such as sand. A low-velocity stream will transport fine particles such as clay and silt, and deposit large particles such as gravel.

Answer to Question 2

ANSWER: You would not want to see any of the following evidence of a debris flow: large boulders strewn across the valley floor that could not have been carried by the modern stream in the valley; boulders perched on top of finer-grained deposits; levees of coarse, angular material next to the stream; deep, narrow channels cut in the levees; fan-shaped deposits forming rounded lobes with coarser material at their outer edges; rocks lodged against trees or embedded in bark or branches; scars on tree bark; a drainage basin with large, actively eroding areas; or active faulting.

[yoroshambo]

Gracias!

[LVPMS]

Excellent