90 likes | 221 Views
Hydrologidagarna , 18 mars 2014. Ezra Haaf ezha@cowi.se. Estimating Extreme Groundwater Levels. Hydrologidagarna , 18 Mars 2014. Estimating extreme groundwater levels. Damage caused by: Buoyancy Landslides In water resources management . Hydrologidagarna , 18 Mars 2014.
E N D
Hydrologidagarna, 18 mars 2014 Ezra Haaf ezha@cowi.se Estimating Extreme Groundwater Levels Estimating Extreme Groundwater Levels
Hydrologidagarna, 18 Mars 2014 Estimating extreme groundwater levels • Damage caused by: • Buoyancy • Landslides • In water resources management Estimating Extreme Groundwater Levels
Hydrologidagarna, 18 Mars 2014 What is interesting about this? • Unclear which distributions can be used • Many long time series in SGU’s groundwater network available • Parameter convergencevs time serieslength Estimating Extreme Groundwater Levels
Hydrologidagarna, 18 Mars 2014 Basic steps to estimation of return levels Estimating Extreme Groundwater Levels
Hydrologidagarna, 18 Mars 2014 Distributions tested • Distributions tested: • Normal • Generalized extreme value • Log Pearson type 3 • … Estimating Extreme Groundwater Levels
Hydrologidagarna, 18 Mars 2014 Model-adequacy: Anderson-Darling • 8 series for normal distribution rejected • GEV rejected for cases with far outliers and negative skewness • LP3 rejected for far outliers Estimating Extreme Groundwater Levels
Hydrologidagarna, 18 Mars 2014 L-moment diagram with Anderson Darling: Normal distribution Estimating Extreme Groundwater Levels
Hydrologidagarna, 18 Mars 2014 Convergence of mean of groundwater time series Estimating Extreme Groundwater Levels
Hydrologidagarna, 18 Mars 2014 Conclusions • Normal distribution often good model but not always adequate • Good convergence of mean value after 12 years • GEV and LP3 good alternatives Estimating Extreme Groundwater Levels