HR: 0800h
AN: H41F-0471    [Abstracts]
TI: Characterization of Vertical Distribution of Hydraulic Conductivity in a Heterogeneous Aquifer
AU: * Chia, Y
EM: ypc@ntu.edu.tw
AF: National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: Chen, J
EM: cjs@ntu.edu.tw
AF: National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: Lee, T
EM: gnt0926@so-net.net.tw
AF: National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: Chu, C
EM: jerry.chu@sgs.com
AF: National Taiwan University, No.1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AB: Delineation of the vertical distribution of hydraulic conductivity in a heterogeneous aquifer is a challenge to the characterization and remediation of groundwater contamination. Development of various flowmeters provides a direct technique for measuring the variation of vertical flow rate in a well. By performing a single-well recovery test and flow rate measurements at different depths in an aquifer at a constant pumping rate, a vertical profile of horizontal hydraulic conductivity could be obtained. The calibration process for a heat-pulse flowmeter was developed in the laboratory. After a standard operation procedure was established, we conducted a field measurement performed for every 25 cm along the screened interval of a monitoring well with known stratigraphic column and well logs. The heat-pulse flowmeter measurement results revealed that the flow rate is fluctuated with depth and groundwater is produced primarily through two thin layers with a total thickness of 2 m in a 10-m thick heterogeneous aquifer. The calculated hydraulic conductivities for these thin layers are 3 to 5 times greater than the averaged hydraulic conductivity in the aquifer. The impeller flowmeter measurement was also used to delineate the vertical distribution of flow rate, but its accuracy and precision were poor in low flow rate environment. The results of field test suggested that heat-pulse flowmeter is a promising tool for characterizing vertical distribution of hydraulic conductivity and the contaminant migration rate in a heterogeneous aquifer could be much faster than that calculated from the pumping test.
DE: 1829 Groundwater hydrology
DE: 1835 Hydrogeophysics
SC: Hydrology [H]
MN: Fall Meeting 2005