Advanced Tensiometer for Shallow or Deep Soil Water Potential Measurements

Hubbell, Joel M.; Sisson, J. B.

doi:10.1097/00010694-199804000-00002

Cited by 56 publications

(32 citation statements)

References 16 publications

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“…As indicated in section 2, The tensiometers were placed in stacked profiles near existing steel-cased wells (F2, A3, H2, H4, and H6). The basic features of the tensiometers units deployed in augur holes near wells H2, H4 and H6 can be found in Hubbell and Sisson (1998) and in Gee et al (2001). Tensiometers deployed by direct push using cone penetrometer technology (CPT) are shown in The pressure values obtained from the tensiometers were used to determine direction and flow of water during the course of the testing.…”

Section: Tensiometry Data Summarymentioning

confidence: 99%

Vadose Zone Transport Field Study: Status Report

Gee¹,

Ward²

2001

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SummaryStudies were initiated at the Hanford Site to evaluate the process controlling the transport of fluids in the vadose zone and to develop a reliable database for testing vadose-zone transport models. These models are needed to evaluate contaminant migration through the vadose zone to underlying groundwater at Hanford. A study site that had previously been extensively characterized using geophysical monitoring techniques was selected in the 200 E Area. Techniques used previously included neutron probe for water content, spectral gamma logging for radionuclide tracers, and gamma scattering for wet bulk density. Building on the characterization efforts of the past 20 years, the site was instrumented to facilitate the comparison of nine vadose-zone characterization methods: advanced tensiometers, neutron probe, electrical resistance tomography (ERT), high-resolution resistivity (HRR), electromagnetic induction imaging (EMI), cross-borehole radar (XBR), and cross-borehole seismic (XBS). Soil coring was used to obtain soil samples for analyzing ionic and isotopic tracers.Laboratory-scale experiments with hypersaline fluids in Hanford sediments suggest that fluid properties may influence transport behavior, to the extent of finger formation, through an interaction between fluid and hydraulic properties. Yet, the importance of these mechanisms to field-scale transport is largely unknown, thereby limiting the accuracy of contaminant-transport predictions. To assess the importance of these interactions in field-scale solute transport, tank leaks were simulated by performing a series of injections with dilute fluids in late spring and early summer of FY 2000 and with hypersaline fluids (36 wt% sodium thiosulfate) during the spring of 2001. In both tests, a suite of isotopic and ionic tracers was included in the injected fluids. The test in FY 2000 consisted of injecting to ground a series of five 3875 L (1000 gal) pulses of water and tracers, weekly, for five weeks. The FY 2001 test, which was designed partly to evaluate the effects of fluid properties and transport processes, involved the injection of 19,000 L (5000 gal) of hypersaline fluid over the course of 5 weeks. This was followed by 11,400 L (3000 gal) of solute-free water applied in a 2-week period. In FY 2000, infiltration and redistribution were monitored using the nine characterization methods over the course of the injections and for 2 months after the last injection. In FY 2001, all methods except EMI were used to monitor the infiltration and redistribution of the 30,000 L (7925 gal) plume over the course of 3 months.Thus far, field-measured distributions of soil water content have been analyzed using threedimensional spatial-moment analysis. Results clearly show that the subsurface distributions of both the dilute and hypersaline fluids are controlled by an interaction between small-scale horizontal stratification and fluid properties. The centers of mass for the two plumes were similar in the lateral and transverse directions, but were significantly d...

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Section: Tensiometry Data Summarymentioning

confidence: 99%

Vadose Zone Transport Field Study: Status Report

Gee¹,

Ward²

2001

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“…Temperature-induced fluctuations in soil tension measurements were apparent in tensiometer responses. These could be avoided by using an advanced tensiometer design (Hubbell and Sisson, 1998).…”

Section: Resultsmentioning

confidence: 99%

An Automated Vacuum Extraction Control System for Soil Water Percolation Samplers

Lentz

Kincaid

2003

Soil Science Soc of Amer J

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A vacuum applied to soil water percolation samplers permits collection of both macro-and matrix-pore liquids. Performance of these field samplers is improved when the extraction vacuum is adjusted in accordance with the tension in the surrounding soil. This is particularly important when monitoring a network of spatially distributed samplers and for samplers installed in medium to fine textured soils. We designed a vacuum extraction system to more efficiently collect vadosezone soil solution samples. A single vacuum pump, vacuum tank, and air dryer provided a vacuum supply for 12 soil water sampling sites via a branching polyethylene pipe network. A vacuum controller containing two inexpensive pressure transducers, a voltage regulator, relay, and solenoid valve was developed and tested for field installation. Data loggers operated the controllers, monitored extraction vacuum and ambient soil water potential, and adjusted relative vacuum at each percolation sampling site. The automated vacuum controllers successfully maintained sampler extraction pressures at levels proportional to ambient soil water potential and provided the added benefit of recording the pressure values for use in subsequent data interpretation.

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“…In general, the data ranges from -300 to +50 cm H 2 O for the monitored period. Small fluctuations in water potential data were observed in the tensiometer data are attributed to changes in barometric pressure (Hubbell and Sisson 1998).…”

Section: Using Deep Tensiometers To Interrogate and Validate Numeric mentioning

confidence: 86%

Environmental Systems Research, FY-99 Annual Report

Miller¹

2000

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The Environmental Systems Research (ESR) Program, a part of the Environmental Systems Research and Analysis (ESRA) Program, was implemented to enhance and augment the technical capabilities of the INEEL. The program has now completed its second year. The purpose for strengthening technical capabilities of the INEEL is to provide the technical base to serve effectively as the Environmental Management Laboratory for the Office of Environmental Management (EM). The program is starting into its third year of the initial three-year program content cycle. The original portfolio of research activities was assembled after an analysis of the EM technology development and science needs as gathered by the Site Technology Coordination Groups (STCGs) complex-wide. Current EM investments in science and technology throughout the research community were also included in this analysis to avoid duplication of efforts. The content of the portfolio was modified at the end of the first year to respond to comments from external review panels brought in to help strengthen the program. This is a progress report for the second year of the ESR Program (Fiscal Year 99).

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Advanced Tensiometer for Shallow or Deep Soil Water Potential Measurements

Cited by 56 publications

References 16 publications

Vadose Zone Transport Field Study: Status Report

Vadose Zone Transport Field Study: Status Report

An Automated Vacuum Extraction Control System for Soil Water Percolation Samplers

Environmental Systems Research, FY-99 Annual Report

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