Improving Flash Food Prediction
in Multiple Environments
1
Using a Continuous Hydrologic Model
in Support of Flash Flood Predictions
Patrick D. Broxton
Peter A. Troch, Michael Schaffner, Carl Unkrich, David Goodrich, Hoshin Gupta, Thorsten Wagener,
Soni Yatheendradas
1
Motivation: Considerations for
Modeling Extreme Streamflow Events
• What is a catchment’s ability to absorb precipitation?
Precipitation
Runoff
Infiltration
Baseflow
High Potential ET
Warm
More Water in Storage
Wet
Dry
Cool
Low Potential ET
Less Water in Storage
2
Motivation: Considerations for
Modeling Extreme Streamflow Events
• What is the “true” precipitation input?
Rain Gauges
More Accurate
Less Coverage
Radar
Satellite Observations
Less Accurate
More Coverage
Large Scale
Small Scale
• What about Snow?
3
SM-hsB Overview
4
Soil Moisture – hillslope Bousinesq Model
Land Surface Module
- Water and energy balance at the land surface
- Incorporates Snow
Subsurface Module
- Root zone water balance
- Lateral transport of soil water
ET
Infiltration
Root Zone
Transmission Zone
hsB Aquifer
Deep Aquifer
1) Keep track of the hydrologic state between flood model runs
2) Distributed so that it can account for spatial variability of terrain and
atmospheric forcing
5
Study Sites
5
Study Sites – New York Watersheds
- Five watersheds in New York’s Catskill Mountains:
- Humid catchments that are focus of current efforts
a) W. Branch Delaware River
(332 sq mi)
b) W. Branch Delaware River
(134 sq mi)
c) Platte Kill
(35 sq mi)
d) East Brook
(25 sq mi)
e) Town Brook
(14 sq mi)
6
Study Sites – Arizona Watersheds
- Three watersheds in southeastern Arizona:
- Semi-arid catchments to compliment humid catchments
a) Sabino Canyon
(35.5 sq mi)
b) Rincon Creek
(44.8 sq mi)
c) Walnut Gulch
(57.7 sq mi)
7
Hydrology of New York Watersheds
New York Basins
8
Arizona Basins
1150
42.3
1100
42.4
31.8
800
700
32
600
32.2
500
400
32.4
1.2
-74.6
-111
Delaware River (Walton)
Delaware River (Delhi)
East Brook
Town Brook
Plate Kill
0.8
0.4
0
Month
-110.6
-110.2
-109.8
Longitude (degrees)
Runoff Coefficient (Q/P)
1.6
-75
-74.8
Longitude (degrees)
0.8
0.6
Sabino Canyon
Rincon Creek
Walnut Gulch
0.4
0.2
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
75.2
Oct
Nov
Dec
Runoff Coefficient (Q/P)
42.5
1050
900
Latitude (degrees)
1200
42.2
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Latitude (degrees)
PRISM – Average Yearly Precipitation (mm)
Month
Date
300
9
Modeling
with
SM-hsB
9
Land Surface Module - Overview
Atmospheric Inputs:
Shortwave Radiation
Longwave Radiation Wet Canopy Evaporation/
Snow Interception
Precipitation
Trees
Temperature
Pressure
Humidity Long Wave Radiation
Shortwave
Radiation
Wintertime
Snowpack
Near-Surface
Soil Layer
10
Precipitation
Infiltration/Runoff
Variable Canopy Cover
Stream
Fully distributed, runs on hourly timesteps (diurnal cycle is important)
Based on energy balance principles – similar to Utah Energy Balance Model
Land Surface Module - Calibration
11
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
Photo courtesy Jim Porter at NYCDEP
120
120
80
80
40
40
0
1/1/2007
0
4/1/2007 1/1/2008
140
R2 = 0.81
120
SM-hsB SWE (mm)
SWE (mm)
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
100
80
60
40
20
0
0
4/1/2008
20
40
60 80 100 120 140
SNODAS SWE (mm)
Land Surface Module - Simulation
12
Preliminary results for 2009-2010 Snow Season in W. Branch Delaware River Watershed
All precipitation inputs are derived from the MPE
January 15,2010
200
100 mm
SWE (mm)
160
120
80
50 mm
40
0
12/1/2009
1/1/2010
2/1/2010
3/1/2010
4/1/2010
0
Date
January 25,2010
February 15,2010
February 28,2010
Subsurface Module - Overview
13
Root Zone Water Balance / Baseflow
ET
Infiltration
Runoff
Root Zone
Streamflow Routing
Transmission Zone
hsB Aquifer
Deep Aquifer
hsB Aq. Baseflow
Deep Aq. Baseflow
Semi distributed, runs on daily or hourly timesteps
Subsurface Module - Calibration
14
Calibration procedure relies on a baseflow separation
Log(Streamflow-mm)
Portions of the model are reconstructed from the steamflow signatures
(hydrology backwards)
Streamflow/Baseflow/Runoff (mm)
70
Streamflow
Baseflow
Runoff
60
50
40
2
HSB Aquifer
1
0
Deep Aquifer
-1
30
0
5
10
15
20
25
30
35
Effective Time (days)
20
10
0
1/1/2005
4/2/2006
7/3/2007
10/1/2008
12/31/2009
Date
Calibration procedure based on that developed by Gustavo Carrillo and Peter Troch at the University of Arizona
Subsurface Module - Simulation
15
101
100
10-1
0
20
Normalized Streamflow
Generation
Baseflow (mm/day)
log(Streamflow – mm/day)
Simulation for Delaware River (Walton) using MPE as input
Data
Model
15
10
5
0
1/1/2005
20
40
4/2/2006
60
80
100
1
0.6
0.4
Streamflow (mm/day)
40
NSE Baseflow
Data
Model
0.2
7/3/2007
0
0
Probability
of Exeedance
60
Catchment
Model
Data
0.8
10/1/2008
0.2
0.4
12/31/2009
0.6
0.8
1
Normalized Water Year Precipitation
NSE Streamflow
Catchment
Model
Data
NSE Baseflow NSE Streamflow
Delaware River (Walton)
20
Delaware River (Delhi)
0.61
0.34
Sabino Canyon
0.10
0.41
0.62
0.10
Rincon Creek
-3.34
-0.96
East Brook
0.58
0.48
Walnut Gulch
0.65
4/2/2006
0.61
0.41
7/3/2007
0.34
Town Brook
Platte Kill
0
1/1/2005
10/1/2008
No Baseflow
12/31/2009
Benefits of Modeling With SM-hsB
16
BF (mm/day)
Yields many useful modeled quantities for flood forecasting
Baseflow
20
Model
Data
10
0
1/1/2005 4/2/2006
7/3/2007
10/1/2008 12/31/2009
Transp.
(mm/day)
SM (%)
Modeled Soil Moisture
30
5
0
1/1/2005 4/2/2006
7/3/2007
Modeled soil moisture
Modeled water storage
40
20
1/1/2005 4/2/2006
Initial Conditions
10/1/2008 12/31/2009
Potential and actual
evapotranspiration
Modeled Transpiration
Aquifer depth
7/3/2007
10/1/2008 12/31/2009
hsB Aquifer Storage
Storage (mm)
Modeled SWE
30
Precipitaiton Estimates
Snow and Snowmelt
20
10
0
0
5
10
15
Discharge (mm)
20
Storage-discharge relationships
that can be inverted to estimate
precipitation from streamflow
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
Correlation with Flood Size - Top 10 Events
Deleware River (Walton)
Deleware River (Delhi)
East Brook
Town Brook
Platte Kill
AVERAGE
Total Precip
Soil Moisture
Combined
0.80
0.65
0.02
0.68
0.48
0.52
0.43
0.59
0.00
0.01
0.05
0.22
0.88
0.82
0.06
0.82
0.72
0.66
18
Acknowlegements
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
19
Questions