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Geol/Geog 621: Fluvial Geomorphology Test 1 Distributed 21 Sept 2008

Due to Kite by 4:45 p.m. 2 October 1. Use Dave Rosgen’s (1994) classification stream to

determine the type of the following stream reach.• The following images are from a team in a former

restoration workshop, who for some reason decided not to plot the cross sections using Excel.

• Calculate Bankfull Width, Bankfull Depth, Width/Depth Ratio, Width of Flood-Prone Area, Entrenchment Ratio, D50, and Water-Surface Slope from the figures provided

• Given that Sinuosity = 1.83.

Does the channel classification yield a unique solution. If not, how did you deal with contradictory data?.

Unnamed Tributary of Muddy Run

May 2004 Sketch Map

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Unnamed tributary of Muddy Run

29 May 2003

Unnamed tributary of Muddy Run

29 May 2003

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Riffle Cross SectionUnnamed Tributary of Muddy RunMay 2004

Bankfull Stage

Longitudinal Profile Unnamed tributary of Muddy Run

May 2004

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Unnamed Tributary of Muddy RunMay 2004

Cumulative frequency plot of pebble count data

Raw pebble count data

Question 2

• 2. How would the stream in Question 1 be classified according to Montgomery and Buffington (1998)?

• Answer in 100 words or less.

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Question 3

• 3. What frequency of stream flow is most important at creating the hydraulic geometry (dimension, pattern, & profile) of most bedrock-bed or large-boulder-bed streams?

• Explain the conceptual basis for your answer in 250 words or less.

Question 4

• 4. Compare how bars develop on meandering streams with the development of bars in braided streams.

• Answer in 350 words or less.

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Question 5• 5a. Give a concise, but comprehensive

explanation of how is bedload material introduced into mountain streams in humid climates?

• Limit this part of your answer to 250 words or less.

• 5b. What field evidence would you look for to determine which of the processes described in 5a are active in a given watershed.

• Limit this part of your answer to 150 words or less.

Question 6• 6a. Why is heterogeneity desirable in freshwater

stream ecosystems?

• 6b. What geomorphological process in a watershed favor heterogeneity?

• 6c. What geomorphological process in a watershed reduce heterogeneity?

• Limit your answers to no more than 125 words per each part of this question.

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Question 7• Devise your own stream classification systems that will

best differentiate rivers according to what properties and process are most important to YOU!

• Your classification will have to yield unique solutions, be reproducible by multiple operators with diverse backgrounds, and not require undue amounts of data collection in order to deal with individual streams.

• Your answer should be in a table or flowchart form, but include a concise explanation of how the classification works (no more than 150 words).

• BWEARE. like a bad penny, this exercise will come back to you later in the semester!!!