Name: ______________________ S.S. No. ________________ Grade: _________

1. List and explain three variables that influence the rate of biological degradation in an oxidation pond (Use the Wilhelm-Werner equation as an example).

2. 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?

3. 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). How can floods be good and bad at the same time? Are levees good or bad?

4. 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 is sustainable river architecture?

5. What causes eutrophication? Why is eutrophication generally regarded as bad for the environment? Under what circumstances can eutrophication be considered to be good? What is the latitudinal location of most reservoirs in the U.S? Why?

6. What are the five types of sanitation solutions around the world? Describe each, pointing advantages and disadvantages.

7. Why is the Salton Sea there? What are the four sources of salts entering the sea? Why is the proposed dike impoundment solution not likely to work as intended? Why is the Salton Sea a national (and state) problem?

8. 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?

9. 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. Provide en example.

10. 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?

11. Describe the plight of groundwater users in semiarid and arid environments, in both hydrogeologic, economic, and political terms.

12. What is the Tragedy of the Commons? When does it occur? How can we cope with it?