CIV E 633-ENVIRONMENTAL HYDROLOGY
FALL 2010
MIDTERM EXAM
MONDAY, OCTOBER 18, 2010, 1900-2015

Name: __________________ S.S. No. ________________ Grade: _____

Instructions: Closed book, closed notes. Use engineering paper. Answer only 10 questions. When you are finished, staple your work in sequence, and return this sheet with your work.

  1. Plotting flood stage peak vs date of occurrence in the Ladario gage of the Pantanal of Mato Grosso leads to a boomerang-shaped curve. Why? Explain how could this happen. Why does the Pantanal not exhibit a double boomerang?

  2. What is the difference between the Leopold matrix and the Battelle Environmental Evaluation System?

  3. How does the additional conversion of runoff to evapotranspiration (by irrigation) increase the salinity of the land? What is the preferred way to reduce or eliminate the additional salinity?

  4. Why is the ocean salty? Why is river water generally higher in calcium than ocean water? Why is ocean water higher in sodium than river water?

  5. Why is it a fallacy to state that tropical rainforests such as the Amazon will help in sequestering excess carbon from fossil-fuel burning? Explain in detail.

  6. How long are global phosphate resources likely to last? Why is phosphorous important for the functioning of the biosphere?

  7. What processes take part in the nitrogen cycle? How does nitrogen enter the biosphere? How does nitrogen escape from the biosphere?

  8. Why is it necessary to have alternate periods of aerobiosis and anaerobiosis in a ATTZ ecosystem in order to close the nitrogen cycle? How did the early inhabitants of the Llanos de Mojos manage to interrupt this natural process?

  9. What is DO? What is a typical value of DO in clean waters? What is BOD? What are typical BOD values in domestic wastewaters? What is the DO sag curve? What two reaction parameters does it depend on? In what case does the Streeter-Phelps equation become undefined?

  10. What is redox potential? What does it describe? What redox potential (mV) describes aerobic conditions? What redox potential (mV) describes anoxic conditions? What redox potential (mV) describes anaerobic conditions? Describe the time sequence of oxidation-reduction in newly flooded wetland soils. What is methanogenesis?

  11. Bonus question: What is the difference between Hydrology and Environmental Hydrology? Be specific.