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�.- Program SESOIL requires the input of a soil's intrinsic permeability (k) instead of the better ' know saturated hydraulic conductivity (K). The intrinsic permeability of a soil is related to its w- saturated hydraulic conductivity as follows: k = (K) (viscosity of water)/((density of water)(gravity constant)), or k (cm2) = 1 x 10-5 (K)(cm/sec) SESOIL allows the input of separate permeabilities for each of the 4 layers but it then calculates a single depth-weighted average permeability for internal calculations. An overall L. intrinsic permeability of 5 x 10-11 cm2 (equivalent to a hydraulic conductivity of 5 x 10-6 cm/sec) is considered conservative since the soil type, CH, in the critical area below the residual chemicals indicates a much lower permeability. Furthermore, the silt below the fat +- clay is very dense as indicated by the blow counts measured during standard penetration tests. The standard penetration tests were performed while drilling the monitoring well boring MW- 1. Blow counts varied from 18 to 47 which indicates Very Stiff to Hard soils. The disconnectedness index for silt and clay, 12, is specified as recommended by the SESOIL documentation. This index is a dimensionless number, generally ranging from 3.7 to 12. ` Higher values indicate less-connected pore space and hence greater resistance to flow. The effective porosity for silt, 0.27, is specified as recommended by the SESOIL documentation. The effective porosity is defined as the ratio of the pore space through which r flow can occur to the total volume. Cation exchange capacity is specified as zero. SESOIL determines retardation based on } organic carbon content alone when the cation exchange capacity is specified as zero. Cation • exchange modeling is typically utilized for heavy metal transport. SESOIL employs the general Freundlich equation to model soil sorption processes. The equation includes an exponent know as the Freundlich exponent. In the absence of chemical specific data, a value of 1.0 is recommended in the SESOIL user manual for the Freundlich exponent. With the Freundlich exponent input as 1.0, the Freundlich equation then defines a +" linear partitioning isotherm. �. 5.3.5 Chemical Properties The SESOIL software package from General Science Corporation includes chemical data files for eight common contaminants of concern including benzene, toluene, and ethylbenzene. The recommended values were compared to values found in multiple references (see the Reference wA943681reports\sesoi1.doc 8 SMTH