CH^{2}M-Hill's (1994) ground water flux
estimate from their computer model for the portion of the aquifer immediately south of
Mink Creek is 1.35 x 10^{6} cu. ft./day. This model flux represents conditions for
November, 1993, and is equivalent to 3.69 x 10^{9} gal/year or approximately 70%
of the 5.3 x 10^{9} gal/yr flux past Red Hill independently estimated by Welhan et
al. (1996) for the April-November 1993 water balance period. At 28.32 liters/gallon, the
CH^{2}M-Hill model flux represents 14 x 10^{9} liters/year.

For a conservative average TCE concentration over the
LDS ballfield cross-section of 5 parts per billion (ppb) or 5 x 10^{-9} grams TCE
per liter of ground water, this flux equates to 70 kg of TCE/year. At a specific gravity
of 1.46, this represents 48 liters per year or about 13 gallons of equivalent liquid TCE
flowing past the LDS ballfield per year. Therefore, since 1992 when recorded TCE
concentrations first exceeded 5 ppb in Well 33, the equivalent of at least 90 gallons (335
liters) of liquid TCE have entered the aquifer and flowed past the LDS ballfield. If the
ground water flux computed by Welhan et al. (1996) is used, at least 18 gallons (69
liters) of TCE per year or 130 gallons (480 liters) of liquid TCE have entered the aquifer
and flowed past the LDS Ballfield since 1992.

In either case, these estimates are conservative because the average TCE concentration across the LDS ballfield is greater than 5 ppb. From the large amount of liquid TCE already accounted for that has entered the flow system, it is almost certain that a large amount remains suspended between soil particles at the source(s), and will continue to "bleed" dissolved TCE into the aquifer for a very long time to come. Thus, the likelihood that concentrations will decrease soon is extremely low.