1. FIGURE 4-1
Some fate and transport processes in the subsurface and atmospheric environment.

2. FIGURE 4-2
Some fate and transport processes in the aquatic environment.

3. FIGURE 4-3
Contaminant transfer through soil-water-air interfaces.

4. FIGURE 4-4
Sources of fluids for the generation of landfill leachate.

5. FIGURE 4-5
Water balance variables in the HELP model.

6. FIGURE 4-6
Hydrologic cycle.

7. FIGURE 4-7
Darcy’s experiment.

8. FIGURE 4-8
Schematic of saturated flow in laboratory experiment.

9. FIGURE 4-9
Bernoulli’s equation for flow through a pipe.

10. FIGURE 4-10
Hydraulic heads in Darcy’s experiment.

11. FIGURE 4-11
Darcy’s experiment revisited.

12. FIGURE 4-12
Flow lines and equipotentials.

13. FIGURE 4-13
Flow net for steady-state flow through a homogeneous embankment.

14. FIGURE 4-14
Characteristic curves relating hydraulic conductivity and moisture content to pressure head for a naturally occurring sand soil.

15. FIGURE 4-15
Schematic of mechanical dispersion.

16. FIGURE 4-16
Effect of dispersion on contaminant transport.

17. FIGURE 4-17
Plume migration affected by dispersion and source type. The arker the area, the higher the contaminant concentration.

18. FIGURE 4-18
Effect of diffusion on
contaminant transport with no
advective transport.

19. FIGURE 4-19
Schematic of fractured flow.

20. FIGURE 4-20
Effect of high-permeability zone on contaminant transport.

21. FIGURE 4-21
Movement of NAPL.

22. FIGURE 4-22
Two-dimensional control volume.

23. FIGURE 4-23
Finite difference.

24. FIGURE 4-24
Simplified flow diagram representing general process of developing a transport model.

25. FIGURE 4-25
Soil aggregates in subsurface domain.

26. FIGURE
4-26
Partitioning
of sorbate between
solvent
and sorbent.

27. FIGURE 4-27
Two-stage sorption model.

28. FIGURE 4-28
Desorption of sorbate.

29. FIGURE 4-29
Sorption of lindane by unstripped and stripped soil.

30. FIGURE 4-30
Variable sorption of trichloroethene on glacial till.

31. FIGURE 4-31
Solubilities of metal hydroxides as a function of pH.

32. FIGURE 4-32
Biological transformation of PCE under anaerobic conditions.

33. FIGURE 4-33
Hydrolysis of chlorinated alkyl compounds.

34. FIGURE 4-34
Reduction of sorption by cosolvation.

35. FIGURE 4-35
Effect of the distribution coefficient on contaminant retardation during transport in a shallow groundwater flow system.

36. FIGURE 4-36
A simplified, expanding box model.

37. FIGURE 4-37
The effect of turbulent eddies on plumes (after Pendergast, 1984).124 (a) A large cloud in a uniform field of small eddies, (b) a small cloud in a uniform field of large eddies, (c) a cloud in a field of eddies of the same size as the cloud.

38. FIGURE 4-38
Stable and unstable lapse rates.

39. FIGURE 4-39
A gaussian distribution.

40. FIGURE 4-40
Bivariate plume and plume cross section.

41. FIGURE 4-41
PGT horizontal (crosswind) dispersion coefficient as a function of stability category and downwind distance.

42. FIGURE 4-42
PGT vertical dispersion coefficient as a function of stability category and downwind distance.

43. FIGURE 4-43
Two steps of estimating dispersion.

44. FIGURE 4-44
Relative ground level concentration versus distance.

45. FIGURE 4-45
Relative ground level concentration versus
distance for various stability classes.

46. FIGURE 4-46
Relative ground level concentration
versus distance for various effective stack heights.

47. EXAMPLE 4-7. FLOWNETFORAWATERTABLEAQUIFER.

48. EXAMPLE 4-8.
FINITE DIFFERENCE SOLUTION FOR DARCY’S EXPERIMENT.

49. Hydrolysis of chlo-rinated organics involves exchange of the hydroxyl group with an anionic X on a carbon atom.

50. 4-3.
The groundwater contours are spaced at intervals of about 50 m.

51. 4-4.
The groundwater contours are spaced at intervals of about 50 m.

52. 4-9. A laboratory experiment similar to the one conducted by Darcy is shown in Figure P-3.

53. 4-10.
The boundary conditions and material properties for a flow regime are shown in Figure P-4.

54. 4-20.
Determine the pressure, elevation, and total heads at points a , b , and c in Figure P-5.

55. 4-21.
Determine the pressure, elevation, and total heads at points A , B , and C in Figure P-6.