Using a Continuous Hydrologic Model in Support of Flash Flood Predictions
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Improving Flash Food Prediction in Multiple Environments
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Patrick D. Broxton
Peter A. Troch, Michael Schaffner, Carl Unkrich, David Goodrich, Hoshin Gupta, Thorsten Wagener, Soni Yatheendradas
Motivation: Considerations for Modeling Extreme Streamflow Events
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Wet DryWarm
CoolLow Potential ET
Less Water in StorageMore Water in Storage
High Potential ET
• What is a catchment’s ability to absorb precipitation?
Precipitation
Runoff
BaseflowInfiltration
Motivation: Considerations for Modeling Extreme Streamflow Events
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• What is the “true” precipitation input?Rain Gauges Radar Satellite Observations
More Accurate Less AccurateLess Coverage More Coverage
• What about Snow?
Large Scale
Small Scale
SM-hsB Overview 4
1) Keep track of the hydrologic state between flood model runs2) Distributed so that it can account for spatial variability of terrain and atmospheric forcing
Soil Moisture – hillslope Bousinesq Model
- Water and energy balance at the land surfaceLand Surface Module
- Incorporates Snow
Transmission Zone
Root Zone
hsB Aquifer
Deep Aquifer
Infiltration
ET
Subsurface Module- Root zone water balance- Lateral transport of soil water
Study Sites
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- Five watersheds in New York’s Catskill Mountains:- Humid catchments that are focus of current efforts
Study Sites – New York Watersheds 6
a) W. Branch Delaware River (332 sq mi)
b) W. Branch Delaware River (134 sq mi)
d) East Brook (25 sq mi)
c) Platte Kill (35 sq mi)
e) Town Brook (14 sq mi)
- Three watersheds in southeastern Arizona:- Semi-arid catchments to compliment humid catchments
Study Sites – Arizona Watersheds 7
a) Sabino Canyon (35.5 sq mi)
b) Rincon Creek (44.8 sq mi)
c) Walnut Gulch (57.7 sq mi)
Date
Hydrology of New York Watersheds 8
Month
0
0.4
0.8
1.6
1.2
Delaware River (Walton)Delaware River (Delhi)East BrookTown BrookPlate Kill
Longitude (degrees)
42.2
42.3
42.4
42.575.2 -75 -74.8 -74.6
1050
1100
1150
1200
New York Basins
Longitude (degrees)
31.8
32
32.2
32.4
-111 -110.6 -110.2 -109.8
PRISM – Average Yearly Precipitation (mm)
300
400
600
500
700
800
900
Month
0
0.2
0.6
0.4
0.8 Sabino CanyonRincon CreekWalnut Gulch
Arizona Basins
Modeling with
SM-hsB
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Fully distributed, runs on hourly timesteps (diurnal cycle is important)
Based on energy balance principles – similar to Utah Energy Balance Model
Wet Canopy Evaporation/Snow Interception
Long Wave Radiation
Trees
Precipitation
Infiltration/Runoff
Variable Canopy Cover
Stream
WintertimeSnowpack
ShortwaveRadiation
Near-SurfaceSoil Layer
Atmospheric Inputs:Shortwave RadiationLongwave RadiationPrecipitationTemperaturePressureHumidity
Land Surface Module - Overview 10
Can be run at a point:e.g. Calibrate to a point measurement such as a snow pillow
...or over an area:e.g. Calibrate over an area to remotely sensed data or to a data assimilation system
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SNODAS SWE (mm)
R2 = 0.81
0
20
4060
80
100120
140
0 20 40 60 80 100 120 140
Land Surface Module - Calibration
1/1/2007 4/1/2007 1/1/2008 4/1/20080
40
80
120
0
40
80
120
Photo courtesy Jim Porter at NYCDEP
Over a multi-year span, it is generally tuned to compare well with SNODAS, but for specific years, it can be refined using other measurements
Preliminary results for 2009-2010 Snow Season in W. Branch Delaware River Watershed
February 28,2010
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February 15,2010January 25,2010
4/1/201012/1/2009 1/1/2010 2/1/2010 3/1/20100
Date
40
80
120
160
200 January 15,2010100 mm
0
50 mm
Land Surface Module - Simulation
All precipitation inputs are derived from the MPE
Transmission Zone
Root Zone
hsB Aquifer
Deep Aquifer
hsB Aq. Baseflow
Deep Aq. Baseflow
Infiltration
Runoff
ET
Streamflow Routing
Semi distributed, runs on daily or hourly timesteps
Subsurface Module - Overview 13
Root Zone Water Balance / Baseflow
Deep Aquifer
HSB AquiferBaseflowStreamflow
Runoff
1/1/2005 4/2/2006 7/3/20070
0 5 10 15
10/1/2008 12/31/2009
10
20
30
40
50
60
70
Effective Time (days)
Date
35
0
1
2
-1
20 25 30
Calibration procedure relies on a baseflow separationPortions of the model are reconstructed from the steamflow signatures (hydrology backwards)
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Calibration procedure based on that developed by Gustavo Carrillo and Peter Troch at the University of Arizona
Subsurface Module - Calibration
Catchment NSE Baseflow NSE Streamflow
Delaware River (Walton) 0.61 0.34
Delaware River (Delhi) 0.62 0.10
East Brook 0.58 0.48
Town Brook 0.65 0.41
Platte Kill 0.61 0.34
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Catchment NSE Baseflow NSE Streamflow
Sabino Canyon 0.10 0.41
Rincon Creek -3.34 -0.96
Walnut Gulch No Baseflow
Normalized Water Year Precipitation0 0.2 0.4 0.6 0.8 1
0
0.2
0.4
0.6
0.8
1
DataModel
0 20 40 60 80 10010-1
100
101
Probability of Exeedance
DataModel
Subsurface Module - Simulation
ModelData
ModelData
1/1/2005 4/2/2006 7/3/2007 10/1/2008 12/31/20090
20
40
60
0
5
10
15
20
1/1/2005 4/2/2006 7/3/2007 10/1/2008 12/31/2009
Simulation for Delaware River (Walton) using MPE as input
Modeled soil moisture
Modeled water storage
Aquifer depth
Storage-discharge relationships that can be inverted to estimate precipitation from streamflow
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Yields many useful modeled quantities for flood forecastingBaseflow
ModelData
Modeled Soil Moisture
Modeled Transpiration
1/1/2005 4/2/2006 7/3/2007 10/1/2008 12/31/2009
1/1/2005 4/2/2006 7/3/2007 10/1/2008 12/31/2009
1/1/2005 4/2/2006 7/3/2007 10/1/2008 12/31/2009
20
10
0
20
30
40
0
5
hsB Aquifer Storage
Discharge (mm)
0
10
20
30
0 5 10 15 20
Benefits of Modeling With SM-hsB
Potential and actual evapotranspiration
Precipitaiton Estimates
Initial Conditions
Snow and SnowmeltModeled SWE
Summary 17
hsB-SM has been implemented in all NY watersheds, most AZ watersheds
Snow module reproduces wintertime snowpacks; subsurface module works well in the W. Branch Delaware River Basin
Model yields useful information such as snowmelt rates, estimates of catchment “wetness”, and can be useful for estimating rainfall/snowmelt from streamflow response
Although it has not yet been coupled with a flash flood model (KINEROS2), statistical combinations of rainfall and e.g. soil moisture suggest that there is information to be gained from using model data
Total Precip Soil Moisture Combined
Deleware River (Walton) 0.80 0.43 0.88Deleware River (Delhi) 0.65 0.59 0.82East Brook 0.02 0.00 0.06Town Brook 0.68 0.01 0.82Platte Kill 0.48 0.05 0.72AVERAGE 0.52 0.22 0.66
Correlation with Flood Size - Top 10 Events
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Acknowlegements
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Funding comes from a COMET grant (UCAR Award S09-75794)Special thanks to Mike Schaffner, Peter Troch, Gustavo Carrillo, Jim Porter, Glenn Horton, and others
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Questions
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