(a) Why do natural streams carry sediments? What mechanical process enables sediment entrainment and transport? What are typical values of bed material sediment concentration in natural streams? (b) What is wash load?

(a) Describe the criterion describing initiation of motion in natural streams. State the variables in the equations. (b) What is the typical value of Froude number that guarantees initiation of motion?

What parameter describes the relation between critical bottom shear stress and critical mean velocity?

(a) What is autodredging? Where does it occur? How does it occur? What is the depth of autodredging in the Upper Paraguay river? (b) What is the ecological benefit of autodredging?

(a) How may a river profile (bottom slope profile) be used as an indication of changes in sediment transport capacity? (b) In the absence of geologic controls, what is the typical shape of a stream/river profile? Why?

How does tectonism and the enduring presence of the oceans combine to assure the process of soil sedimentation and, consequently, of valley formation?

(a) Explain the relation between the existence of forests, floods, and springs. (b) What was Humboldt's major contribution to science in the early 1900s?

(a) Explain the factors that lead to the meandering of rivers. To what did Albert Einstein attribute the cause of meandering? (b) Is river straightening a solution to river meandering? What is the role of time engineering in river engineering?

(a) What distinctive geologic event led to the formation of the Colorado Desert, later renamed Imperial Valley? Describe the sequence of events. (b) What geologic feature assured the existence of the Salton Depression, which in the past century has been used as a repository for agricultural drainage (the Salton Sea)?

(a) Why is a clearwater stream/river hungry for sediment? Explain in detail. (b) Which parameter (or parameters) in the Modified Lane relation are the only ones to be determined empirically? In practice, how does the value of the sediment rating exponent affect the value of the coefficient?

Bonus question (may be used to replace any of the above): 11. (a) In sand-and-gravel mining of streambeds. Will the negative bed perturbation move upstream or downstream? Explain. (b) What equation is used in sediment routing? What is the limitation of sediment routing as it is practiced?