1. Problem Set #3 – Part 3 - Remediation
Numerical error caused
by high Peclet number
TVD Solution

2. There is a source of error in Part 3 of PS#3
owing to approximate representation of the
removal of the source.

3. PS#3: Part 3. Remediation simulation
t = 1 year (last time step in first stress period
Concentration distribution around
the constant concentration source cell

4. t = 1.020141 yr; 1st time step in the 2nd stress period
Note: Some mass is flowing into the constant
concentration cell and is removed from the model.

6. t = 1 yr
Before removal of the source

7. t = yr
After removal of the source
During remediation the model removes contaminant via
--the pumping well
--flow out the lower boundary
-- through the constant concentration cell
In the field, mass is removed only through the well &
the lower boundary

8. t = 3 years
In the model, around 1.3% of the total mass removed is
erroneously removed through the constant concentration cell.

9. A better way to represent the removal of the source
would be to change the constant concentration cell
to an active cell at the end of the 1st stress period.
This would require re-starting the simulation with
new initial concentrations. That is, we would need
two GWV simulations.

10. 2 runs; constant conc.
cell is active
during 2nd stress period
Constant concentration cell has
zero concentration during 2nd stress period.