A capture zone analysis was performed to predict the possible impact of Well 44's future pumping on the TCE-contaminated side of the aquifer. The model was run on the EPA's MWCAP wellhead protection analysis software. The model was set up with an impermeable boundary along the edge of the Portneuf Lava field, and the following parameters:
Well discharge: 2000 gpm (constant)
Aquifer permeability: 800 - 3000 ft/day (equivalent to that estimated at PA-9 and -10)
Aquifer thickness: 70 ft/day (equivalent to that observed at PA-9 and -10)
Ambient flow: oriented parallel to the edge of the Portneuf Lava field
Time of travel: 90 days
CLICK HERE to look at a figure that summarizes the results of the capture zone analysis. Note: that if a low permeability equal to that measured in monitoring well PA-10 is used, then the predicted capture zone would extend much farther west than the high-permeability case and could draw existing TCE contamination eastward.