Field-Scale In Situ Measurements of Vadose Zone Flow and Transport Using Multiple Tracers at INEEL Vadose Zone Research Park (VZRP)

This study is aimed at obtaining a better understanding of vadose zone flow and transport processes at the field scale and establishing defensible links between laboratory- and field-derived transport parameters for conservative and reactive elements in the vadose zone. The study site (Vadose Zone Research Park [VZRP] at INEEL) provides a three dimensional instrumentation array strategically surrounding a new infiltration pond slated for initial use in the upcoming year, and the Big Lost River, and intermittent stream proximal to the infiltration ponds. The proposed research will utilize the infiltration ponds and the Big Lost River to study the effects of fluid flux, water chemistry and degree of saturation on contaminant transport in the vadose zone. Our research plan has four major objectives: (1) determine the transport of conservative and reactive solute and colloid tracers through the vadose zone and local perched water zones; (2) examine isotopic variations of U and Sr and compare these to introduced sorbing and non-sorbing tracers; (3) develop and calibrate a conceptual flow and transport model, and (4) examine the effects of flow and geochemical transients on tracer transport