Environment Canada Modelling Systems and the 2013 Alberta Floods Calgary, Alberta February 19, 2014 Bruce Davison (EC) Al Pietroniro (EC) Nick Kouwen (UW) Anthony Liu (EC) Muluneh Mekonnen (AB) Ron Goodison (EC) EC Montreal (CMC, RPN, National Lab) 2/24/2014 Page 1
Overview EC Numerical Weather Prediction Systems Precipitation Forecasts and Analysis During the Flood Hydrological Modelling Systems Streamflow Hindcasts of the Flood 2/24/2014 Page 2
Existing EC Products The CMC Numerical Output Database CaPA HRDPS RDPS REPS GEPS NAEFS Seasonal forecasting system
Observations at Calgary and Banff during the 2013 Southern Alberta Floods Daily precipitation amounts (from noon the previous day to noon the current day) at two measurement sites
Published precipitation map http://en.wikipedia.org/wiki/2013_alberta_floods Max. precip: over 300 mm CaPA precipitation map June 16 June 30, 2013 Max. precip.: 221 mm
NAEFS 24H QPF Ending at 00Z 21 June 2013
Performance of Forecasting Systems during the 2013 Southern Alberta Floods At the medium-range (7-day lead time) The North American Ensemble Forecasting System (NAEFS) unambiguously forecasted strong precipitation over the area of interest Calgary June 2013
Performance of Forecasting Systems during the 2013 Southern Alberta Floods At the medium-range (5- to 10-day lead time) The experimental Extreme Forecast Index (EFI) calculated from the Global Ensemble Prediction System clearly indicated the possibility of extreme precipitation
Performance of Forecasting Systems during the 2013 Southern Alberta Floods At the short-range (3-day lead time) The Regional Ensemble Prediction System (REPS) indicated the probability of heavy precipitation (regions with 90% chances of at least 40 mm in 24 hours)
Performance of Forecasting Systems during the 2013 Southern Alberta Floods At the short-range (1-day lead time) The Regional Deterministic Prediction System (10-km grid spacing) forecasted extreme precipitations over significant areas Precipitation accumulation from 19 June 12Z to 22 June 12Z
Performance of Forecasting Systems during the 2013 Southern Alberta Floods At the short-range (1-day lead time) The High-Resolution Deterministic Prediction System (2.5-km grid spacing) forecasted extreme precipitations over significant areas Precipitation accumulation from 19 June 12Z to 22 June 12Z
Performance of Forecasting Systems during the 2013 Southern Alberta Floods Difference (HRDPS RDPS)
Hydrologic Modelling Systems Second Generation Land Surface Scheme SENSIBLE EXCHANGE Aerodynamic resistance ( r a ) Wind Leaf Drip T g Surface Soil Temperature Lower Soil Temperature Root Distribution Fn ( vegetation type) T gb CLASS WATFLOOD MESH RADIATIVE MOISTURE EXCHANGE EXCHANGE IR up r a Ponded Water Evaporation Infiltration Overland Flow α veg Interception Layer 1 Transpiration Leaves LAI Stomata T c Canopy Percolation Temperature and humidity r s ( light sensitivity Layer 2 changes r s ) Fraction vegetation cover & LAI IR down Fn ( temperature & season) IR up Stems SAI Infiltration Surface α soil Runoff Snow Fn ( soil wetness) Upper layer Upper soil layer wetness Full soil column Full column wetness CLASS WATFLOOD Layer 3 UZS Drainage LZS Interflow Base Flow Sellers et al. 1997 Subsurface Runoff Sub-grid Variability Grid Square Computational Unit = Grid Square a c Individual Pixels Computational Unit = GRU Mixture of 4 sub-areas CS C GS G b Kouwen et al. 1993 Mixture of 4 sub-areas CS C GS G Blend of 5 vegetation groups Blend of 5 vegetation groups
The MESH Modelling Platform 2/24/2014 Page 14
The approach - WATFLOOD Use existing watershed Manitoba Hydro WATFLOOD model for the headwaters of the North & South Saskatchewan rivers Convert CaPA precipitation and temperature data form its native format to Green Kenue (GK) r2c formats Re-calibrate the model parameters for the CaPA met data for 2002 2009 Model the 2013 Calgary flood
Model calibration approach The usual approach to calibrating WATFLOOD is to first obtain the proper overall volume using only those parameters that affect evapotranspiration, sublimation and lake evaporation The nest step is to adjust the timing of the hydrographs The next slides show the result of 10 Dynamically Dimensioned Search (DDS) runs with WATFLOOD
800 Computed Flow Observed Flow 33-05BH004 BOW RIVER AT CALGARY 7868 km^2 Dv = -11.4 % 600 cms 400 200 02 03 04 05 06 07 08 09 10 300 27-05BB001 BOW RIVER AT BANFF 2210 km^2 200 cms 100 Dv = -26.7 % 0 2002 2003 2004 2005 2006 2007 2008 2009 2010
1000 Computed Flow Observed Flow 33-05BH004 BOW RIVER AT CALGARY 7868 km^2 Dv = -24.3 % 800 600 cms 400 200 10 11 12 13 14 250 27-05BB001 BOW RIVER AT BANFF 2210 km^2 200 cms 150 100 Dv = -42.2 % 50 0 2010 2011 2012 2013 2014
Computed Flow Observed Flow 2000 Dv = -1.9 % 33-05BH004 BOW RIVER AT CALGARY 7868 km^2 1600 cms 1200 800 400 2012 500 2013 2014 27-05BB001 BOW RIVER AT BANFF 2210 km^2 400 cms 300 Dv = -26.3 % 200 100 0 2012 2013 2014
Dv = -11.1 % Qlz SIM OBS 2000 1600 33-05BH004 BOW RIVER AT CALGARY 7868 km^2 cms 1200 800 400 2012 600 2014 2013 27-05BB001 BOW RIVER AT BANFF 2210 km^2 cms 400 Dv = -31.1 % 200 0 2012 2013 2014
The approach - MESH Use existing watershed MESH model for the South Saskatchewan River Convert CaPA precipitation and temperature data form its native format to Green Kenue (GK) r2c formats Calibrated the model parameters for the CaPA met data for Oct 2004 Oct 2006 Calibrated the model on other sub-basins Model the 2013 Calgary flood
Standalone MESH run Really a spatial validation