ARCHIVED REPORTS XR0000194 - Laserfiche WebLink

Home Browse Search

R10/71-51-IC 5 3 LOCAL GEOLOGY AND HYDR GEOLO Y 5 3 1 Local Geoloav The site consists of interbedded clay, silt, and fine sand The upper 60' is mainly clay and silt with lenses of fine sand (SP) whereas below 60 ft or 70 ft, there are fine sands with lenses of clay and silt A lens of dark gray/black, very stiff clay which has high plasticity is present within first 5 ft A well-graded clean (uncemented) sand lens of only 6" thickness was found at depth 40 ft in borehole of MW-13 Clay and silt are medium stiff with low to medium plasticity Fine sand is brown very uniform and medium dense with little or no silt and clay Location of geologic cross sections is presented in Figure 9 (see Appendix H) Cross sections A-A' and B-B' are ' presented in Figure 10 and Figure 11 (see Appendix 1), respectively 5 3 2 Local Hydrogeolociy In Shop 10, the depth to water table is approximately 68 ft Groundwater table elevation contour map is constructed based on the water level data collected on October 22, 1993 The depth to water was measured after the wells were developed and stabilized in the recently installed wells Depth to water and water elevation data are presented in Table ' 1 (see Appendix C) Based on the water level data collected on October 22, 1993, the groundwater elevation ' contour map is presented in Figure 29 (see Appendix K) The groundwater flow direction in the vicinity of monitoring well MW8 is to the west, in the vicinity of MW9 is to the east, and in the vicinity of MW1, MW2, MW3, MW4, MW1 0, MW1 4, and MW24 is to the north The groundwater flow gradient is calculated as ratio of vertical head difference to horizontal distance The groundwater gradient is presented as unit ft per ft (and as ' groundwater head change per mile of horizontal distance) The groundwater flow gradient ranges from 9 8 x 10-4 ft/ft (5 2 ft/mile) in the vicinity of monitoring well MW1 to 2 7 x 10-3 ft/ft (14 ft/mile) in the vicinity of monitoring well MW9) 1 18