- List and explain three variables that influence the rate of biological degradation in an oxidation pond.
(Use the Wilhelm-Werner equation as an example).
- Describe the solution for cleaning the Tlaxiaco river. Why is the proposed solution better than
conventional wastewater treatment? Why is there a need for both oxidation pond and constructed wetland?
- From a climatological perspective, explain the controversy between the two paradigms of river ecology:
the river continuum concept (RCC) and the flood pulse concept (FPC).
- What is rationale behind the recent interest in stream restoration? What natural services are provided by streams and rivers?
Why is concrete lining no longer a sensible
solution for flood control?
- What causes eutrophication? Why is eutrophication generally regarded as bad for the environment?
Under what circumstances can eutrophication be considered to be good?
- Why is erosion and sediment transport at a maximum at an annual precipitation of 300 mm, or annual runoff of 50 mm?
- Why is the Salton Sea there? What are the four sources of salts entering the sea?
What are three most important issues in the perceived need to restore the sea?
- Why is sodium chloride considered a waste in the functioning of the biosphere?
What is the main use of bulk sodium chloride in industry?
What is the natural purpose of rivers?
- Explain the resource availability (light, water, nutrients, biota) across the climatic spectrum.
Discuss the rationale for the tendency of humans to concentrate on the drier side of the spectrum.
- Explain why irrigated agriculture can become nonsustainable. Give one specific example in California.
Why is the leaching fraction necessary in the irrigation of arid and semiarid lands?
- Describe the plight of groundwater users in semiarid and arid environments, in both hydrogeologic, economic, and political terms.
- What is the Tragedy of the Commons? When does it occur? How can we cope with it?
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