Lecture 18 Potential Exam Questions

1. What are the three major axes of the fluvial system?
Answer: upstream-downstream, channel-margins, and surficial-underground

2. What type of classification is used for streams/rivers?
Answer: Order 1-10. The order tells you a lot about the size. Lower orders are smaller and higher orders are larger. There are a huge number of 1st order streams (small) and very few higher level (larger) rivers.

3. What is a HUC? What are they used for?
Answer: A HUC is the system used by the USGS to catalog watersheds at different scales. It stands for Hydrologic Unit Cataloging.

4. What is fluvial geomorphology and why is it important?
Answer: It is the study of landforms (specifically river channels and drainage networks). It is important because it helps one to understand the relationships between discharge, longitudinal changes, changes in morphology, and tributary size. This helps one to understand how rivers change over time and the impact on the habitats and ecosystems that exist within those areas.

5. What is an important function of rivers?
Answer: They move sediments from areas higher in the watershed to areas lower in the watershed. The amount of sediment that they move is dependent on the slope of the river and the amount of water flowing through the river (discharge). Sediment is often larger and rockier near the top of the watershed while the lower reaches primarily has finer, sandier material.

6. What is Lane's Law? What does it mean for the structure of a stream or river?
Answer: It says that equilibrium is reached when: sediment discharge*sediment particle size = stream discharge*stream slope. When these are in equilibrium, the channel will stay relatively unchanged. When these are out of balance (not at equilibrium), the channel structure will change.

7. What is the relationship between stream power and sediment movement?
Answer: Greater stream power (stream discharge * stream slope) results in greater movement of sediment. This relates to Lane's Law.

8. What is the difference between autotrophic and heterotrophic stream systems?
Answer: Heterotrophic systems get the majority of their energy from dead organic material (e.g. leaves falling into stream) while autotrophic systems get the majority of their energy from biofilm and algae.

9. What is CPOM?
Answer: It stands for coarse particulate organic matter. In the process of decomposition, organic matter (such as dead leaves) become increasingly fine. They go from being coarse particulate organic matter to fine particulate organic matter to dissolved particulate organic matter. In class Professor Allan used tea as an example of fine particulate organic matter leaching and becoming dissolved particulate organic matter.

10. What is in biofilm?
Answer: Biofilm is a mix of a large array of materials, including CPOM, FPOM, DPOM, microbes, and algae.

11. What are different types of functional feeding groups?
Answer: Functional feeding groups are also called guilds. Grazers, collector-gatherers, shredders, and predators are the visible functional feeding groups on which fish feed.

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