estimating extreme groundwater levels 18 mars 2014 estimating extreme groundwater levels 1...
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ESTIMATING EXTREME GROUNDWATER LEVELS1
Estimating Extreme Groundwater Levels
18 MARS 2014
Hydrologidagarna, 18 mars 2014
Ezra Haaf
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ESTIMATING EXTREME GROUNDWATER LEVELS2 18 MARS 2014
Estimating extreme groundwater levelsHydrologidagarna, 18 Mars 2014
› Damage caused by:› Buoyancy
› Landslides
› In water resources management
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ESTIMATING EXTREME GROUNDWATER LEVELS3
› Unclear which distributions can be used
› Many long time series in SGU’s groundwater network available
› Parameter convergence vs time series length
What is interesting about this?
18 MARS 2014
Hydrologidagarna, 18 Mars 2014
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ESTIMATING EXTREME GROUNDWATER LEVELS4
Basic steps to estimation of return levels
18 MARS 2014
Hydrologidagarna, 18 Mars 2014
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ESTIMATING EXTREME GROUNDWATER LEVELS5
Distributions tested
18 MARS 2014
› Distributions tested:› Normal
› Generalized extreme value
› Log Pearson type 3
› …
Hydrologidagarna, 18 Mars 2014
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ESTIMATING EXTREME GROUNDWATER LEVELS6
Model-adequacy: Anderson-Darling
18 MARS 2014
› 8 series for normal distribution rejected
› GEV rejected for cases with far outliers and negative skewness
› LP3 rejected for far outliers
Hydrologidagarna, 18 Mars 2014
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ESTIMATING EXTREME GROUNDWATER LEVELS7
L-moment diagram with Anderson Darling: Normal distribution
18 MARS 2014
Hydrologidagarna, 18 Mars 2014
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ESTIMATING EXTREME GROUNDWATER LEVELS8
Convergence of mean of groundwater time series
18 MARS 2014
Hydrologidagarna, 18 Mars 2014
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ESTIMATING EXTREME GROUNDWATER LEVELS9
› Normal distribution often good model but not always adequate
› Good convergence of mean value after 12 years
› GEV and LP3 good alternatives
Conclusions
18 MARS 2014
Hydrologidagarna, 18 Mars 2014