QUESTION 1

1. Write an essay consisting of at least 500 words addressing ALL of the following topics (a. through i.):

   1. Mention two states in the U.S. that receive 50 to 75 inches of rain annually.
   2. Describe the hydrologic cycle.
   3. During a particular storm, 1.8 inches of rain fell over an area of 10 acres. What was the rainfall volume in acre-ft? Show your work.
   4. In the hyetograph in Figure 3-5 of our textbook, what is the rainfall intensity 15 minutes from the beginning of the storm in inch/hour?
   5. If a news service mentions that a 50-year storm caused recent flooding along the Mississippi River, what is the probability of that storm occurring in any given year (express your answer in percent)?
   6. Explain the concept of rainfall intensity-duration-frequency (IDF) curves including why they differ from location to location.
   7. Describe the watershed where you live.
   8. Perform an Internet search, and provide a website that shows a hydrograph for a river in the state of Iowa. What is the maximum flow (also known as discharge and flow rate) shown on the graph?
   9. Provide a typical permeability coefficient of salty sand. Why is it more permeable than clay?

QUESTION 2

1. Write an essay consisting of at least 500 words addressing ALL of the following topics (a. through i.):

   1. Describe alpha particles, beta particles, and gamma rays. Include a discussion of how far they travel and what stops them.
   2. If 200 grams of salt is dissolved in 8000 grams of water, what is the salt concentration in percent? Show your work.
   3. Why is dissolved oxygen an important water quality parameter? Are higher or lower values better for water quality? What is the saturation concentration (mg/L) of dissolved oxygen in freshwater at 20^oC?
   4. Describe how biochemical oxygen demand is measured?
   5. There is an error in the computation in Example 4-4. Nevertheless, what would be the correct 5-day BOD if the dissolved oxygen was measured as 0.9 mg/L after five days (all other numbers in the Example's statement are the same)? Show your work.
   6. Explain how the total dissolved solids concentration is determined?
   7. Why is hardness an important water quality parameter? What are the two primary cations (i.e., positive ions) that contribute to hardness?
   8. Explain total coliforms, fecal coliforms, and E. coli.
   9. Describe the difference between grab samples and composite samples.