jang cheng-shing and cheng-wuing liu, hydrol. process. 18, 1333-1350(2004) adviser : jui-sheng chen...
TRANSCRIPT
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Geostatistical analysis and conditional simulation for estimating the spatial variability of hydraulic conductivity in the Choushui River alluvial fan, Taiwan
Jang Cheng-Shing and Cheng-Wuing Liu,Hydrol. Process. 18, 1333-1350(2004)
Adviser : Jui-Sheng Chen and Cheng-Shing Jang Presenter : Wei-Jie Wang
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OUTLINE
INTRODUCTION STUDY AREA METHODS RESULTS SUMMARY AND CONCLUSIONS
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INTRODUCTION
Why? For establishing a sound water
management plan to prevent further drawdown of groundwater levels, land subsidence and aquifer contamination in the Choushui River alluvial fan, Taiwan.
How? Ordinary Kriging (OK) Sequential Gaussion simulation (SGS) MODFLOW
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STUDY AREA
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STUDY AREA
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METHODS
Establishing baseline flow
model
Inverse calibration(pumping and recharge
rate)
Flow simulation
Calculating global simulation errors(SAMSE)
Calculating local simulation
errors(SAMSE) along flow paths
Assessing the different spatial
variability of various
estimated K fields
Heterogeneous K fields by
geostatistical methods (OK,
mean SGS, individual SGS)
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METHODS
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METHODS
In a baseline flow model, a K field within each zone was constructed by determining a geometrical average of local measured data (Wen and Gómez-Hernández, 1996).
The pumping and recharge rates were inversely adjusted to reduce the difference between simulated and measured heads, and the calibrated errors were expected to fall within a tolerance of 1.5 m for each monitoring well (Gau et al., 1998).
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METHODS
SAMSE=17.6M
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METHODS
Ordinary Kriging (OK)： Best：
Linear：
Unbiased Estimate：
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METHODS
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METHODS
Semivariances:
h
h a
c
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METHODS
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METHODS
Conditional simulation：
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METHODS
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RESULTS
SAMSE=15.1M
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RESULTS
SAMSE=15.5m
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RESULTS
SAMSE=18.4 to 38.4mMean=27.1M
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RESULTS
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RESULTS
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SUMMARY AND CONCLUSIONS
The OK realization had the smallest sum of SAMSE and the SGS realizations preserved the spatial variability of the measured K fields.
The OK realization yields small local SAMSE in the measured K field of moderate magnitude,whereas the SGS realizations have small local SAMSE in the measured K fields, with high and low values.
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Thanks for your attention……