FIGURE 4-1

Some fate and transport processes in the subsurface and atmospheric environment.

FIGURE 4-2

Some fate and transport processes in the aquatic environment.

FIGURE 4-3

Contaminant transfer through soil-water-air interfaces.

FIGURE 4-4

Sources of fluids for the generation of landfill leachate.

FIGURE 4-5

Water balance variables in the HELP model.

FIGURE 4-6

Hydrologic cycle.

FIGURE 4-7

Darcy’s experiment.

FIGURE 4-8

Schematic of saturated flow in laboratory experiment.

FIGURE 4-9

Bernoulli’s equation for flow through a pipe.

FIGURE 4-10

Hydraulic heads in Darcy’s experiment.

FIGURE 4-11

Darcy’s experiment revisited.

FIGURE 4-12

Flow lines and equipotentials.

FIGURE 4-13

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

FIGURE 4-14

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

FIGURE 4-15

Schematic of mechanical dispersion.

FIGURE 4-16

Effect of dispersion on contaminant transport.

FIGURE 4-17

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

FIGURE 4-18Effect of diffusion oncontaminant transport with noadvective transport.

FIGURE 4-19

Schematic of fractured flow.

FIGURE 4-20

Effect of high-permeability zone on contaminant transport.

FIGURE 4-21

Movement of NAPL.

FIGURE 4-22

Two-dimensional control volume.

FIGURE 4-23

Finite difference.

FIGURE 4-24

Simplified flow diagram representing general process of developing a transport model.

FIGURE 4-25

Soil aggregates in subsurface domain.

FIGURE

4-26

Partitioningof sorbate betweensolventand sorbent.

FIGURE 4-27

Two-stage sorption model.

FIGURE 4-28

Desorption of sorbate.

FIGURE 4-29

Sorption of lindane by unstripped and stripped soil.

FIGURE 4-30

Variable sorption of trichloroethene on glacial till.

FIGURE 4-31

Solubilities of metal hydroxides as a function of pH.

FIGURE 4-32

Biological transformation of PCE under anaerobic conditions.

FIGURE 4-33

Hydrolysis of chlorinated alkyl compounds.

FIGURE 4-34

Reduction of sorption by cosolvation.

FIGURE 4-35

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

FIGURE 4-36

A simplified, expanding box model.

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.

FIGURE 4-38

Stable and unstable lapse rates.

FIGURE 4-39

A gaussian distribution.

FIGURE 4-40

Bivariate plume and plume cross section.

FIGURE 4-41

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

FIGURE 4-42

PGT vertical dispersion coefficient as a function of stability category and downwind distance.

FIGURE 4-43

Two steps of estimating dispersion.

FIGURE 4-44Relative ground level concentration versus distance.

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

FIGURE 4-46

Relative ground level concentrationversus distance for various effective stack heights.

EXAMPLE 4-7. FLOWNETFORAWATERTABLEAQUIFER.

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

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

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

4-3.

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

4-4.

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

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

4-20.

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

4-21.

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