Correlation Analysis between Variations of Groundwater Level and Ground Elevation－A Case Study of Chou-Shui River Alluvial Fan
Date Issued
2015
Date
2015
Author(s)
Dai, Yu-Xuan
Abstract
The purpose of this study is to establish an analytical method which includes filter and spectral analysis for investigating correlation between variation of groundwater level and recoverable ground fluctuation. With this analytical method we can compute efficiency coefficient and delay time of effect on recoverable ground fluctuation caused by change of groundwater level at different area. Chou-Shui River Alluvial Fan is chosen as an actual case for this analytical method. First, we use signal analysis method to separate annual periodic signal from original signal of groundwater level as well as ground elevation. And then we apply cross correlation analysis on two periodic signals for finding the correlation and delay time between these signals. At last, we can use the spectral analysis to find amplitudes of the two periodic signals and compute ratio of the two. We define this ratio as efficiency coefficient of water-level variation and with this coefficient we can understand how intensively variation of groundwater level affects recoverable ground fluctuation. From the analysis results on Chou-Shui River Alluvial Fan, the conclusion can be inferred as follows: (a) the correlation between the annual periodic variation of groundwater level and recoverable ground fluctuation is positive; (b) the average delay time is longer around Fan-top area than other areas; (c) the delay time of deeper aquifer is shorter than shallow aquifer at same station; (d) variation of groundwater level affects less to the recoverable ground fluctuation at head area where the efficiency coefficient of water-level variation is the smallest.
Subjects
Chou-Shui River Alluvial Fan
filter analysis
spectral analysis
groundwater level
ground elevation
Type
thesis
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