Exercise 24
Suppose that a source of contaminant is introduced to the up-gradient end of a column filled with sand in a hydrogeology laboratory. If the source is maintained at a continuous concentration of 1000 mg/L, the hydraulic conductivity is 0.1 cm/sec, effective porosity is 0.2, the dispersivity in the x direction is 5 cm, dispersivity in the y direction is 1/5 of the dispersivity in the x direction, dispersivity in the z direction is 1/10 of the dispersivity in the x direction, and the head drop across the 100 cm long cylinder is 10 cm.
What will the concentration be at:
(a) 25 cm after 1000sec?
(b) 50 cm after 1000sec?
(c) 75 cm after 1000sec?
- Do the answers you obtained make sense? Why, or why not?
- Would you expect measurements of concentrations in plumes in a field setting to produce the values you calculated? Why, or why not?