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The partitioning interwell tracer test (PITT) was introduced into the practice of contaminant hydrogeology in 1994, since which time about 50 PITTs have been conducted in the field. Confirmation of results of vadose-zone and ground-water zone PITTs by subsequent field testing of aquifers in Utah and New Mexico have demonstrated the reliability of the technique for operational purposes, i.e., th...

The vadose zone beneath the USDOE’s Hanford Site in southeastern Washington State (Fig. 1) received approximately 1 trillion liters (450 billion gallons) of liquid waste, some contaminated with radioactive and hazardous contaminants. Today, Hanford is engaged in the world’s largest environmentalcleanup project, and a variety of conceptual and mathematical vadose zone models have been developed ...

Aquifer drainage was numerically simulated by a coupled, unsaturated-saturated flow equation. The effect of the vadose zone on aquifer parameter predictions of classical hydraulic theory was investigated. Saturated-zone hydraulic theory was shown to be fairly robust in estimating the saturated hydraulic conductivity but less so in estimating drainable porosity, mainly because of the much tighte...

While ERT surveys are useful, Yeh et al. (2002) showed that uncertainties in tracking moisture movement in the Electrical resistivity tomography (ERT), during the past few years, vadose zone on the basis of ERT surveys alone can has emerged as a potentially cost-effective, noninvasive tool for imaging changes of moisture content in the vadose zone. The accuracy be quite significant. They report...

Anaerobic ammonium oxidation (anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S ...

Leaking underground concrete sumps used to store produced water have contaminated groundwater with gas condensate hydrocarbons at a gas production site near Ft. Lupton, Colorado. The source of contamination has been removed; however, a plume of hydrocarbon contamination extends some 46 m from the original source location. This is an agricultural area and the water table is rather shallow (about...

Geophysical site characterization investigations at fuel spill sites have been generally guided by a working hypothesis Ž . which assumes that the light non-aqueous phase liquids LNAPL are a fully saturating phase of intrinsically very high electrical resistivity. Using observations from other related sciences, and contrary geophysical observations, a different model is developed which treats t...