行政院國家科學委員會專題研究計畫期中進度報告:濁水溪沖積扇三維水文地質特性受集集地震影響之研究(1/3)
Date Issued
2004
Date
2004
Author(s)
DOI
922313B002104
Abstract
The spatial distribution of natural aquifer properties, such as hydraulic conductivity (K),
often exhibits extreme heterogeneity and anisotropy. However, a field investigation can only
survey and analyze a small fraction of in-situ data, due to limitations of time and cost. Therefore,
the sparsely measured data contain considerable levels of uncertainty. Hydraulic conductivity is
an important parameter for the investigations of the hydrogeology, groundwater flow and
contaminant transport. Soil structures and hydraulic conductivities maybe vary due to the 1999
Chi-Chi earthquake in the Choushui River alluvial fan.
In this study, the changes of groundwater level induced by the Chi-Chi earthquake are
regarded as the water-level fluctuations of a slug test made by nature. At first we analyze the
relationship of coseismic water-level change versus the distance from epicenter and
transmisivity of wells in unconfined, confined aquifer and mountain region. We also analyze the
recovery of water level in selected observation wells. The results indicate that there is no
definite relationship can be drawn among the water-level change versus distance from epicenter
and transmisivity. The groundwater model MODFLOW, coupled with the automatical
calibration model, UCODE are thus adopted to simulate the recovery of coseismic water-level
changes to determine the changes of K caused by the Chi-Chi earthquake.
Subjects
Coseismic water-level change
hydrogeology
groundwater model
parameter identification
Publisher
臺北市：國立臺灣大學生物環境系統工程學系暨研究所
Type
report
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