NUCLEAR MAGNETIC RESONANCE IMAGING OF WATER CONTENT IN THE SUBSURFACE
This report contains the experimental, theoretical and numerical studies performed under Department of Energy (DOE) Agreement Number DE-FG07-96ER14732 entitled ''Surface Nuclear Magnetic Resonance for Imaging Subsurface Water.'' DOE and Department of Defense (DOD) complexes and test ranges are situated in widely varying climatic conditions from the desert southwest to the humid east. The mission of the Office of Environmental Restoration and Waste Management (EM) is to clean up the inventory of inactive DOE sites and facilities, and the goal of the EM Office of Technology Development (OTD) is to deliver technologies to make environmental restoration more efficient and cost effective. In the western United States, where a number of DOE facilities are located, the water table can occur several hundred feet below the surface. The zone between surface and water table is called the vadose zone or unsaturated zone. A characteristic of that zone is that mobility of water and contaminants is greatly reduced compared to rate of movement in the saturated zone. A thick vadose zone lowers the risk and, at least, increases the time before contaminants enter drinking water supplies. The assessment of risk is often performed by modeling of ground water flow and contaminant migration by analytical methods or unsaturated flow models (e.g. Hendrickx et al 1991). Necessary inputs for these models are the hydraulic properties of the different geological formations (e.g. Hendrickx 1990) and the water content distribution in the vadose zone (Freeze and Cherry 1979). Accurate risk assessments for ground water contamination cannot be conducted without actual measurements of the water content distribution in the vadose zone. To date, very few techniques have been developed to provide such information at an acceptable speed and cost. Because soil water contents exhibit a large spatial and temporal variability, the costs of conventional measurement techniques, such as gravimetric sampling, gypsum blocks, and neutron probes, are high. Only non-intrusive tests with a cost factor much lower than that of an intrusive test will offer acceptable alternatives. Therefore, a definite need exists for a non-intrusive water content measurement method. The surface nuclear magnetic resonance (NMR) technique applied to imaging of ground water was first developed by Russian scientists from the Institute of Chemical and Combustion in Novosibirsk, Russia. Over the last two decades they have published a series of papers and reports describing the theory of the method, along with experimental measurements from the surface to a depth of about 100 m. Preliminary evaluation of the concepts and results merited further investigations, particularly because of the critical technical need for cost-effective water content measurements in environmental restoration.
- Research Organization:
- New Mexico Institute of Mining and Technology,Socorro, New Mexico (US)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM) (US)
- DOE Contract Number:
- FG07-96ER14732
- OSTI ID:
- 827242
- Report Number(s):
- EMSP-54857; R&D Project: EMSP 54857; TRN: US200425%%524
- Resource Relation:
- Other Information: PBD: 31 Dec 1999
- Country of Publication:
- United States
- Language:
- English
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