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1 <br />1 <br />I 1 5 Analysis of Groundwater Level Changes <br />Monthly groundwater level measurements have been made at the Stegner Farm property since <br />I 1 April 1999, one year prior to the construction of the shiny wall in April 2000, as required by the <br />state and county permits. Groundwater level monitoring is conducted at eight (8) well locations <br />1 (designated S-1 through S-8) that are located adjacent to the perimeter of the slurry wall. The <br />initial groundwater level measurements were made at two existing well locations (S-7 and S-8) <br />1 starting in April 1999 and subsequently supplemented with 6 monitoring wells (S-1 through S-6) <br />starting in August 1999. The locations of these wells are shown on Figure 1. <br />I Slurry wall construction was initiated on April 15, 2000, and completed on June 30, 2000. An <br />approximate outline of the slurry wall is also shown on Figure 1. Groundwater levels measured <br />' at the Stegner property between April 1999 and April 2000 are assumed to represent "pre-slurry <br />wall" conditions, a 13-month period. Groundwater levels measured after April 2000 are <br />' considered representative of "post-slurry wall" conditions. <br />In July 2001, six (6) additional monitoring locations (S-9 through S-14) were established in the <br />1 area southeast of Stegner Farm in the area of the Roe and Martin properties (Figure 1) to further <br />evaluate groundwater level changes. Groundwater levels have been measured monthly at these <br />~ six wells since August 2001. <br />In addition to the Stegner Farm monitoring wells, LaFarge, Inc., another aggregate producer in <br />the area, has also measured groundwater levels adjacent to their Home Office Pit property. Four <br />(4) LaFarge monitoring wells, (L-1, L-2, L-3, and L-5) located in the area south and east of the <br />Roe and Martin properties, were also used to assess groundwater Ievel changes since the slurry <br />wall was installed. Groundwater levels at these wells have been monitored monthly since <br />February 1998 and have continued until present. The LaFarge monitoring wells provide about 27 <br />months ofpre-slurry wall groundwater level data. <br />One of the LaFarge monitoring wells, L-2, is located about 120 feet south of Dr. Martin's pond <br />and about 1,400 feet south-southeast of the slung wall. Since the fall and winter pond water <br />levels are not affected by imgation seepage, the pond water level would reasonably be <br />represented by the groundwater level at this nearby monitoring well. Therefore, well L-2 is <br />expected to provide a historical record of groundwater levels representative of the Martin pond <br />levels prior to and after construction of the Stegner Fann slurry wall. Of the wells evaluated in <br />this report, well L-1 is located the furthest downgradient, approximately 2,600 feet, from the <br />7 <br />