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• ~ ~' <br />For the record, BMG should submit a revised narrative nr at least <br />acknowledge the errors. <br />RESPONSE: The Division's comments are accurate and the revised figures are <br />presented Herein as Figures 1 and 2, with Figure 1 being the porosity <br />sensitivity analysis and Figure 2 being the dispersivity sensitivity analysis. <br />We have also corrected the legend on Figure 1 so 4hat the correct <br />porosities are reflected. <br />It should be noted that the narrative in the original submittal is correct <br />insofar as it discusses the effect of the change of porosity on the shape of <br />the plume and the movement of the plume. <br />COMMENT 3. Bath sensitivity analyses employed constant contan:inattt Source strengt)ts <br />of 2.5 N/day and a period of 20 years. Tl~e reasons for these input <br />pa.ranreters were, however, not explained in the response. <br />BMG should explain irs selection of 2.SN source strength and 20 year <br />period of rime employed in the sensitivity analyses. <br />RESPONSE: The purpose of the sensitivity analysis was [o show what the shape of a <br />hypothetical plume would look like given the hydrog8ologic data that we <br />have for the Santa Fe aquifer, and to predict movement of the hypothetical <br />plume through the aquifer. <br />A source strength of 2.5 ]bs/day was selected as a realistic possible source <br />strength value, although the 2.5 Ibs/day value has no special significance. <br />Other values could have been used and the plume would have had the <br />exact same shape, only with different concentration contours. The exact <br />source strength used in the analysis does not affect the cogclusions drawn <br />from the analysis. <br />Likewise, the time period of 20 years was chosen to demonstrate the <br />relative movement of the plume in the sensitivity analysis. With a longer <br />time frame, distinct plumes could be shown due to the disparate distances <br />travelled for each case. Again, this value has no special significance. <br />The demonstration of the sensitivity of porosity and dispersivity to the <br />movement of the plume would be similar for other time Rrames as well. <br />-2- <br />