3060 CRSS(FORS) - Soils and Hydrology - Exam 3
1. (3 points) West Point Lake (near Columbus, GA) holds approximately 500,000 Acre-Feet of water when full. What is the average residence time of water in the reservoir if the ow into the lake is 1,000 cfs?
2. (3 points) What is the average depth of West Point Lake if the surface area of the lake is 41 mi2 ?
3. (3 points) What is the average runo depth (inches/yr) from the 3,440 mi2 watershed upstream of the reservoir corresponding to the inow?
4. (2 points) What kind of air mass was here in Athens on Sunday?
5. (2 points) Which kind of front yields precipitation with high intensity and short duration?
6. (2 points) Why is the wet air lapse rate less than the dry air lapse rate?
7. (3 points) Use the dry air lapse rate to nd the temperature at 3000 if the temperature on the coast is 45F.
8. (2 points) What rainfall mechanism caused the record rainfall in Charrapunji, India, from 1860-61?
9. (5 points) Using the rainfall intensity - duration plot for Atlanta, Georgia, in Chapter 10 of your notes, nd the total precipitation for the extreme 10-year precipitation event. Storm Duration 10 min Intensity (in/hr) Total Depth (in) 30 min 1 hour 6 hour
10. (3 points) What is the volume of a soil sample, in cm3 , collected in a metal ring (diameter = 4, height = 2)?
11. (3 points) What is the bulk density, g/cm3 , of the soil if the oven-dry weight is 21.8 ounces?
12. (3 points) What is the porosity of the soil?
13. (12 points) Complete the following table using the above information. Soil Condition soil Saturated mass, g water mass, g g v 14. (3 points) What is the maximum depth of available water (in inches) if the soil is 6 inches deep? Field Capacity Wilting Point 763 661 Air Dry 636 Oven Dry
15. (7 points) Soil tensions were measured at various depths in a soil prole. Complete the following table: Elevation Tension Total Head 100 95 90 85 80 75 0 100 90 60 50 50 50 0 Gradient
16. (3 points) At what depth is the water table?
17. (3 points) At what depth does the ow reverse direction?
18. (3 points) What might cause the upward water ow?
19. (3 points) Where is the hydraulic gradient largest?
20. (2 points) What are the dominant forces (sources of energy) that cause water to move in soils?
21. (2 points) Why is the subsurface humidity (soils, caves, basements, etc.) generally so high?
22. (2 points) Why do ne-textured soils (clays) generally hold water more strongly than coarse soils (sands)?
23. (6 poi...