Observed migration of a controlled DNAPL release by geophysical methods

Journal Article · Wed Nov 01 04:00:00 EST 1995 · Ground Water

DOI:https://doi.org/10.1111/j.1745-6584.1995.tb00043.x· OSTI ID:128863

Brewster, M L ^[1]; Annan, A P; Greenhouse, J P; Redman, J D ^[1]; Kueper, B H ^[2]; Olhoeft, G R ^[3]; Sander, K A ^[3]

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1. Univ. of Waterloo, Ontario (Canada). Waterloo Centre for Groundwater Research
2. Queen`s Univ., Kingston, Ontario (Canada). Dept. of Civil Engineering
3. Geological Survey, Denver, CO (United States)

Seven hundred seventy liters of a dense nonaqueous phase liquid (DNAPL), tetrachloroethylene (PCE), were released into an isolated volume of a completely saturated natural sandy aquifer. The release was monitored over a period of 984 hours with a variety of geophysical methods including ground penetrating radar, time domain reflectometry, in situ resistivity, and a neutron soil moisture probe. The PCE formed a pool on a low permeability layer at approximately 1 m depth and spread over an area exceeding 32 m{sup 2}. In its course of downward migration, the PCE subsequently formed eight smaller pools. At the end of the experiment an estimated 41% of the total PCE volume remained trapped in the upper pool. The PCE mass and its spatial moments were calculated from radar reflection amplitudes. Between 48 and 100% of the PCE mass was accounted for by radar measurements. The center of mass moved a total of 0.5 m south southeast and 1.3 m downward. Spatial variances showed that the greatest lateral spreading occurred in the east-west direction. The results demonstrate that natural heterogeneities, even in a relatively homogeneous aquifer, can cause DNAPLs to spread laterally over large areas in the subsurface. This experiment also demonstrated that while the ability of geophysics to uniquely measure the presence of DNAPL is limited, certain techniques are well-suited to monitoring changes in DNAPL saturation.

• Sponsoring Organization: USDOE
• OSTI ID: 128863
• Journal Information: Ground Water, Journal Name: Ground Water Journal Issue: 6 Vol. 33; ISSN GRWAAP; ISSN 0017-467X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AQUIFERS
CHLORINATED ALIPHATIC HYDROCARBONS
ENVIRONMENTAL TRANSPORT
GEOPHYSICAL SURVEYS
WATER POLLUTION