Source Zone Delineation Demonstration Report - Triad Resource ...

Figure 5-4. Soil samples collected from U12-1807 (30 to 33 feet bgs) containing LNAPL.Modeling of TCE contamination in soil was performed within the region illustrated in Figure 5-1. Thefigure also includes the approximate location of several drums excavated during trenching activities justprior to the start of the field investigation. The region depicted in Figure 5-1 is the areal extent of themodeling domain for the third and final iteration of the TCE contamination model. Earlier models ofTCE contamination utilized domains of smaller areal and vertical extent; however, all of the variousmodeling domains share consistent areal and vertical discretization increments. All iterations of themodel are presented within the final modeling domain in order to describe how the modeling was used toaid the selection of new wireline boring locations, and to illustrate how the understanding of soilcontamination evolved as newly acquired data were used to revise the model. The geometry anddiscretization of the modeling domain is summarized in Table 5-2.Table 5-2. Modeling Domain for TCE Contamination and Combined Soil/TCE ModelingCoordinateDirectionMinimum 4 Maximum DiscretizationInterval(ft)Number ofGrid Blocks 5Length(ft)x 1 1,856,000 1,856,168 Δ x =4 N x = 42 168y 2 298,200 298,400 Δ y =4 N y = 50 200z 3 4,515 4,600 Δ z =1 N z = 85 851 Easting (feet)2 Northing (feet)3 Elevation (feet above mean sea level)4 Corresponds to the model origin (lower left corner of the model)5 There are N x N y N z = 178,500 grid blocks in the modelMarch 2003 5-7 OU 12 Demonstration ReportFinal