Baseline Moisture Monitoring at the INEEL Vadose Zone Research Parka

摘要

The Vadose Zone Research Park was developed at the Idaho National Engineering and EnvironmentalrnLaboratory to address mission-critical issues related to operations, waste management, and environmentalrnrestoration at U. S. Department of Energy sites located over thick vadose zones. The Vadose Zone Research Park isrnstrategically located along the Big Lost River, an intermittent river, and around a recently constructed percolationrnpond. This location is ideal to study variable recharge from the river, continuous recharge from the ponds, and therninteractions between the two sources that will contribute to the study of the effects of infiltration ponds and naturalrnriver infiltration on subsurface water and contaminant movement. In addition, this location’s subsurface conditionsrnare comparable to those at INEEL facilities with subsurface contamination, such as the Idaho Nuclear Technologyrnand Engineering Center and the Radioactive Waste Management Complex. Between September 2000 and Junern2001, twenty-eight wells and instrumented boreholes were installed at the Vadose Zone Research Park to monitorrnperched water, measure moisture movement, collect water and gas samples, and study intra-well geophysicalrnproperties. Nine of the boreholes, ranging in depth from 150 ft to 504 ft, are instrumented to monitor moisture in thernvadose zone. Instruments include: tensiometers, moisture content sensors, suction lysimeters, temperature sensors,rnand gas ports. We monitored baseline water content and matric potential before the pond is operational and whenrnthe river had been dry for the previous 18 months. Our results indicate wet conditions at depths up to 150 ft near thernriver. In addition, our results show perched water zones remain on top of sedimentary interbeds, indicating that thernbeds form impediments to vertical flow.