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FIELD EVALUATION OF DIPOLE METHOD TO MEASURE AQUIFER ANISOTROPY
Citation:
Simon*, M A., B. Hough, T. Li, AND Z. J. Kabala. FIELD EVALUATION OF DIPOLE METHOD TO MEASURE AQUIFER ANISOTROPY. The Second International Conference on Remediation of Chlorinated & Recalcitrant Compounds, Monterey, CA, 5/22-25/00.
Description:
The ultimate size of a three-dimensional groundwater circulation cell surrounding a vertical circulation well (VCW) is a strong function of the aquifer hydraulic anisotropy, the ratio of the hydraulic conductivity in the horizontal direction to that in the vertical direction. In designing a VCW, a given aquifer's anisotropy was either assumed or estimated by matching pump test curves. This paper presents results from a field-scale project designed to directly measure the aquifer's anisotropy. A VCW well was installed at the Naval Air Station North Island (NASNI) near San Digo, CA, in a sandy aquifer contaminated with chlorinated compounds. An extensive aquifer hydraulic test, including a dipole test, was conducted in 8/98. The interpretation of the dipole test data had to account for the tidal effects from San Diego Bay on the aquifer. The dipole extraction/injection rates were 1.89, 3.79, 5.68, 7.57, and 9.46 x 10(-2) cubic meters per minute (5, 10, 15, 20, and 25 gallons/min). Drawdown and drawup were monitored in the extraction and injection chambers of the VCW and in the surrounding monitoring wells for each step. However, the recovery data of the dipole test proved to be the most consistent and reliable for estimating the aquifer anisotropy. The anisotropic ratio for this aquifer is estimated to be 5:1.