[en] A treatability study is being performed to investigate the practicability of using passive, in situ treatment systems to remove contaminants from the Bear Creek Valley (BCV) Characterization Area (CA). This draft document is a report of the site characterization results and is part of Phase 1 of this study. Field activities performed are outlined in Bear Creek Valley Passive Surface Water Treatment Technology Demonstrations, Phase 1, Site Characterization. The focus of the characterization was to obtain sufficient site-specific data on hydrogeology of NT-1, NT-2, and upper Bear Creek (above its confluence with NT-1) to support selection of groundwater capture and treatment systems in Phases 2 and 3. Groundwater samples from the S-3 Site and NT-1 area were also collected for the principal investigators to test during Phase 1 laboratory work. Three contaminant migration pathways were delineated in the S-3 Area. Each is described and briefly characterized by field observations and analysis of surface and groundwater collected within each pathway