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I Ccolog"t Teclut a IXC Page 3 Groundwater Monitoring Report Project No 989 2 November 18,2004 ' not feasible Tlus unit is not assigned a capability classification or a vegetative soil group ' 1.3 Site-Specific Hydrogeolo y g ' A site map showing the locations of streets, structures, wells, and other site-related details is attached as Figure 2 ' 1.3.1 Lithology and Soil Characteristics The lithology of the site can be divided into 3 generalized sections, from the surface to 23- feet bgs, is primarily comprised of brown clays and silty-clay mixtures, from 23- to 31-feet bgs, is primarily comprised of brown sandy-clay, from 31- to 42-feet bgs, is comprised of a dense, plastic, "blue-grey" clay The Site Conceptual Model dated December 17, 2003 ' discusses the lithology and site characteristics in more detail 1.3.2 Groundwater Gradient and Bearing ' On October 13, 2004, the depth to groundwater was measured in all of the wells prior to purging The average depth to water was 8 96 feet below the top of casing and the average groundwater elevation at the site is 190 feet below mean sea level The wells are screened at 5 feet bgs and groundwater surface continues to be below the tops of the screens in the nine shallow monitoring wells ' Site-specific groundwater gradient was calculated using MW-3, MW-7 and MW-9, and found to be N44°W at 0 0039 ft/ft A groundwater elevation map is included as Figure 3 Previous groundwater gradient calculations show a consistent bearing of north-northwest, averaging ' N3?W at 0 0064 ft/ft A Rose Diagram is attached as Figure 4 Vertical groundwater gradients were calculated for the site using the MW-I/MW-101 well ' pair and found to be negative The site-specific vertical groundwater gradient is -0 0152 ft/ft The vertical groundwater gradients are generally one order of magnitude greater than the horizontal groundwater gradients MW-I is screened from 5 to 25 feet bgs and MW-101 is screened from 29 5 to 42 feet bgs Vertical groundwater gradient calculations have been performed at regular intervals since the installation of MW-101 on July 30, 2002 ' Historical groundwater bearing and slope are summarized in Table 1 and a summary of vertical groundwater is included as Table 2 of Appendix A As required under A132886, the depth to groundwater data was submitted electronically to GeoTracker on November 12, 2004, with confirmation number 5904911637 ' 1.3.3 Average Groundwater Velocity Hydraulic conductivity and porosity were calculated from three soil samples collected during the installation of MW-101 in March 2003 The soil samples were collected from 21, 26 and