Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPAPPENDIX KWMA 12 (NORTHERN PORTION) PRE-REMEDIATION DATA COLLECTIONK.1 BackgroundThe northern portion of Waste Management Area 12 (WMA 12 North) is approximately 7 acresin size (see Figure K.1 for map).K.2 Physical SettingWMA 12 North is located on the North Plateau. It is bounded to the west, north, and east by theWVDP fence line and to the south by WMA 4.WMA 12 North is vegetated. A significant portion of its surface is a wetland that is orientedalong a southwest to northeast axis and is approximately 1.6 acres in size. A portion of this areahas standing water for most of the year. Surface drainage is towards the southwest through theNP-1 gully into Quarry Creek.The subsurface of WMA 12 North is comprised of the sand and gravel unit, a relativelypermeable unit that carries groundwater, which overlays the Lavery Till, a relatively impermeableunit that is a barrier to vertical groundwater flow. Because there has been no intrusive samplingwithin the boundaries of WMA 12 North, the thickness of the sand and gravel unit in this area isnot known. Groundwater likely flows to the northwest, north, and northeast following surfacetopography, discharging to seeps along Quarry Creek to the north, Franks Creek to the east,and/or to the wetlands/surface drainage features within WMA 12 North.There are no facilities in WMA 12 North.K.3 Area HistoryWMA 12 North was not used for any structural purposes during the lifespan of the NFSreprocessing activities on-site or for any known WVDP-related activities. As will be discussedRev. 1 K-1