Source Terms Constant Concentration Injection Well Recharge May be introduced at the boundary or in the interior of the model

Q Constant Concentration (Z&B, p. 283) cscs at boundary e.g., NAPL source area

Injection Well Qc s well

Recharge R, c s Mass Flux = R (  x  y) c s

Problem Set #3 Source Terms and Chemical Reactions Constant Concentration Injection Well Recharge retardation 1 st order decay

Problem Set #3 Two Layers This screen shows a constant concentration source. Contours of head are also shown. Confined layers

Note the water table Flow field for an unconfined upper layer with areal recharge and a recharge source cell.

Problem Set #3 Parts 1 and 2: Produce breakthrough curves under different assumptions about the source term and chemical reactions.

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

Central Finite Difference Solution

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

Courant Number Cr < 1 Peclet Number P e < 4

Pumping well is represented by 4 nodes 50 m grid

100 m grid spacing Peclet number = 5 50 m grid spacing upper left node in the pumping complex Peclet number = 2.5 TVD solution

100 m grid 50 m grid – near center of pumping compex TVD Solution