Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPC.2 Physical SettingWMA 3 is located on the North Plateau. It is bounded to the west by WMA 10 and WMA 5, tothe north by WMA 5, to the east by WMA 5, and to the south by WMA 1.The surface of WMA 3 consists of building footprints and compacted surface cover with noappreciable vegetation. WMA 3 is relatively flat and is drained by storm sewer lines.The four waste storage tanks contained within WMA 3 are buried and extend to a depth of 50 to60 feet below grade, including foundations and footer material. This depth is well below thewater table and extends into the Lavery Till.WMA 3 is underlain by the sand and gravel unit, a relatively permeable layer. In generalgroundwater beneath WMA 3 flows to the east and northeast, following surface topography.Underneath the sand and gravel unit is the Lavery Till, a relatively impermeable layer that is apartial barrier to vertical groundwater flow. A limited amount of groundwater does flow verticallydownward through this unit, recharging the underlying Kent Recessional Sequence.There is believed to be a significant amount of buried infrastructure (piping, etc.) associated withthe WMA 3 facilities.C.3 Area HistoryThe WMA 3 area (and in particular its surface soils) has undergone significant reworking sincethe initiation of NFS activities.Figure C.3 shows WMA 3 in 1962 prior to WVDP site development. At this time WMA 3 wasfarmed.Figure C.4 shows WMA 3 in 1966. The footprints of waste tanks 8D-1 and 8D-2 are visible inthis photograph along with the condenser and equipment shelter footprints. The surface of WMA3 appears to be predominately exposed soils.Rev. 1 C-4