Sediment Transport II Warm-Up

Your Name

Essay Question

(This essay question is based upon lecture material from last class, together with bits and pieces from the readings in the text.)

Transport of sediment depends directly upon the shear stress acting on the bed of sediment. But together with shear stress, sediment transport is also dependent upon the viscous sublayer (or boundary layer), in which no shear stress operates on the bed. Discuss the concept of grain roughness and its role in breaking down the viscous sublayer, resulting in drag forces operating on the sediment to move it downcurrent.

Multiple Choice Questions

Use figure 6.8 in the handout to answer this question.

For a mean sediment size of 0.6 mm, and a mean flow velocity of 80 cm/sec, which sedimentary structure will appear in the bottom sediment?

no structure will form

ripples

sand waves

dunes

antidunes

Use your answer in the preceding multiple choice question to answer the following

How would you recognize the existence of the bedform you selected in the previous answer, if it resulted in stratification in a preserved vertical sequence of sediment?

parallel stratification

planar cross bedding

trough cross bedding

no stratification

flaser bedding