Frank Lavelle, Peter Vickery, Bo Yu, and Sudhan Banik
Applied Research Associates, Inc.
Raleigh, NC
(919) 582-3350
HAZUS Coastal Storm Surge Model
HAZUS User Conference
Indianapolis
August 24, 2010
2
Project Objectives
Implement a storm surge and wave hazard modeling capability in HAZUS-MH by coupling and integrating existing, publicly available models
Develop a new capability for combining currently available HAZUS-MH wind-only and flood-only loss estimates into an overall estimate of combined coastal wind and flood losses for a single hurricane event
3
Hurricane Wind Field Model
Goal is to use a single, consistent hurricane wind field model to drive: Storm surge (SLOSH)
Waves (SWAN)
Wind damage (Existing HAZUS Hurricane Model)
Options SLOSH Wind Field Model (NWS 48, 1992)
• Assumed wind speed profile:
ARA Wind Field Model (Vickery et al., 2009)• Assumed pressure profile:
• Wind field equations are numerically solved for the vertically averaged horizontal velocity, V, over open water and open land for 14,040 combinations of Δp, RMW, B (Holland, 1980), and translation speed
4
C-MANFCMP
ASOS
Buoy
Available Surface Wind Measurements
(1) ASOS Towers (Airports)(2) FCMP Towers (Mobile)(3) C-MAN Stations (Coastal)(4) Buoy Stations (Offshore)
Surface Wind Measuring Systems
5
Hurricane Wind Field Summary: Modeled vs. Measured 10-min. Wind Speeds
(Hurricanes Isabel, Ivan, Katrina, Ike & Gustav)ARA-TRK-SLOSH-WD:
y = 1.0505x, R² = 0.5674
ARA-TRK-ARA-WD: y = 1.0234x, R² = 0.7262
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100
Mod
eled
Mea
n W
ind
Spe
ed (m
ph)
Observed Mean Wind Speed (mph)
ARA-TRK-SLOSH-WD
ARA-TRK-ARA-WD
Linear (ARA-TRK-SLOSH-WD)
Linear (ARA-TRK-ARA-WD)
6
Incorporation of SLOSH Storm Surge Model into HAZUS
SLOSH produces reasonably accurate estimates of surge and runs quickly
Emergency management community is familiar with and comfortable with SLOSH
SLOSH does not include waves or tide • Waves to be modeled in HAZUS using SWAN
• Tide treated approximately as additive term
7
SLOSH Model Coupled with HAZUS Wind Field Model
• Wind field model used in HAZUS has been coupled into SLOSH
• Enables consistent modeling of damage and losses induced by wind and coastal flooding
8
Storm Tide RMS Analysis: Five HurricanesMean Std mean RMS mean RMS
0-3 3338 1.3 0.8 0.2 0.8 0.4 1.0
3-6 1575 4.3 0.9 -1.3 1.8 0.0 1.1
6-9 500 6.7 0.7 -3.3 3.8 -1.0 1.8
all 5413 2.7 2.0 -0.6 1.6 0.1 1.1
0-3 544 2.1 0.9 -0.4 1.9 0.1 1.5
3-6 1083 4.0 0.7 -0.9 1.2 -0.3 0.8
6-9 52 6.5 0.2 0.8 1.1 0.2 0.6
all 1679 3.5 1.3 -0.7 1.4 -0.2 1.1
0-3 65 2.8 0.1 1.1 1.1 1.3 1.4
3-6 357 4.2 0.7 0.5 1.0 0.8 1.3
6-9 30 7.0 0.8 -0.9 1.3 0.5 0.6
all 452 4.2 1.1 0.5 1.0 0.9 1.2
0-3 7085 1.7 0.7 0.6 1.6 0.9 1.8
3-6 5436 4.2 0.8 -0.7 1.8 -0.1 1.2
6-9 2366 7.3 0.9 -2.2 3.1 -1.9 2.3
9-12 993 10.5 0.9 -5.3 5.4 -4.0 4.0
12-15 560 13.3 0.8 -6.4 6.5 -5.2 5.2
all 16440 4.3 3.1 -0.8 2.6 -0.3 2.1
0-3 963 2.0 0.8 2.9 4.4 3.2 4.4
3-6 5429 4.9 0.8 -1.5 3.1 -1.2 3.1
6-9 11235 7.4 0.8 -1.3 3.0 -0.8 2.6
9-12 7871 10.3 0.8 -0.2 3.3 -0.5 3.1
12-15 3147 13.2 0.9 0.6 2.0 -0.4 1.7
15-18 766 15.6 0.5 0.1 2.2 -1.0 2.1
18-21 4 18.3 0.6 -6.3 6.3 -6.8 6.8
all 29415 8.4 3.1 -0.7 3.0 -0.6 2.8
SLOSH-Obs ARA-Obs Hurricane Unit
Isabel 2003
(ft NAVD)
Ike 2008
(ft NAVD)
Surge Range
Numer Data
Obs
Ivan 2004
Katrina 2005
Gustav 2008
(ft NGVD)
(ft NAVD)
(ft NGVD)
9
Storm Tide Summary
SLOSH model runs with ARA wind field result in lower overall mean and RMS errors for 4 of 5 validation events• Only exception is Hurricane Katrina, for which we have only one complete
record tide gauge record and three partial records
Decision is to use SLOSH storm tide model with ARA wind field model• Better overall results
• Ensures consistency between HAZUS wind loss model and HAZUS coastal surge methodology
10
Wave Modeling Objectives
Hazard modeling• Include wave stresses in storm surge model
• Wave set-up increases still water depths produced by SLOSH
Damage modeling• Near-Term: Determination of V-zone and Coastal A-zone (CA-zone) 3 ft < Wave height V-zone
1.5 ft < Wave height < 3 ft CA-zone (use V-zone damage functions)
Wave height < 1.5 ft A-zone
• Longer-Term: Supports move towards direct use of wave height in damage modeling
11
Grids Used in SWAN Runs
-120 -110 -100 -90 -80 -70 -60 -500
5
10
15
20
25
30
35
40
45
50
SLOSH grid
Coarse grid boundary
12
Significant Wave Heights: Katrina, New Orleans Basin
0
1
2
3
4
5
6
8/25/2005 0:00 8/27/2005 0:00 8/29/2005 0:00 8/31/2005 0:00
Sign
ifica
nt W
ave
heig
ht (
m)
Time
Buoy: 42007
Observed
SLOSH_grid_No BC
SLOSH_grid_WW3_BC
SLOSH_grid_SWAN_BC
0
1
2
3
4
5
6
7
8
9
10
8/25/2005 0:00 8/27/2005 0:00 8/29/2005 0:00 8/31/2005 0:00
Sign
ifica
nt W
ave
heig
ht (
m)
Time
Buoy: 42039
Observed
SLOSH_grid_No BC
SLOSH_grid_WW3_ BC
SLOSH_grid_SWAN_BC
-1
1
3
5
7
9
11
13
15
8/25/2005 0:00 8/27/2005 0:00 8/29/2005 0:00 8/31/2005 0:00
Sign
ifica
nt W
ave
heig
ht (
m)
Time
Buoy: 42040
Observed
SLOSH_Grid_No BC
SLOSH_grid_WW3_BC
SLOSH_grid_SWAN_BC
-94 -92 -90 -88 -86 -84
26
27
28
29
30
31
42039
42040
42007
Gulf of Mexico
13
Significant Wave Heights: Ike, Galveston Basin
0
1
2
3
4
5
6
7
8
9/11/2008 0:00 9/12/2008 0:00 9/13/2008 0:00 9/14/2008 0:00
Sign
ifica
nt W
ave
heig
ht (
m)
Time
Observed
SLOSH_grid_No BC
SLOSH_grid_SWAN_BC
Buoy: 42019
0
1
2
3
4
5
6
7
9/11/2008 0:00 9/12/2008 0:00 9/13/2008 0:00 9/14/2008 0:00
Sign
ifica
nt W
ave
heig
ht (
m)
Time
Observed
SLOSH_grid_No BC
SLOSH_grid_SWAN_BC
Buoy: 42035
-98 -97 -96 -95 -94 -93 -92 -9126
27
28
29
30
31
42019
42035
Gulf of Mexico
14
Overland Waves
Use existing 1-D transects and simplified WHAFIS methodology implemented in HAZUS coastal flood model
Where each transect intersects the coastline, use the modeled significant wave height from SWAN to estimate the controlling wave height, Hc = min(0.78 ds, 1.6 Hs) where ds = still water depth at the coast line
Wave crest elevation = SWEL + 0.7 Hc
Neglect• Wave regeneration and wave dissipation
• Wave run-up and dune erosion
Interpolate between transects to develop flood depth grid
Use V-zone damage functions where Hc ≥ 1.5 ft
15
Hurricane Ike: USGS SSS-TX-GAL-001 Gauge Location
16
Before and After Hurricane Ike
17
Hurricane Ike USGS SSS-TX-GAL-001 Gauge
~ 6 feet
Observations are instantaneous samples at 1 minute intervals
18
Hurricane Ike: USGS SSS-TX-GAL-002 Gauge Location
Transect
19
12
12.5
13
13.5
14
9/13/08 12:00 AM 9/13/08 2:00 AM 9/13/08 4:00 AM 9/13/08 6:00 AM
Wat
er E
leva
tion
(ft
NA
VD
88)
Local Time (CDT)
Hurricane Ike USGS SSS-TX-GAL-002 Gauge
~ 0.3 feet
20
Elevation Profile Along the GAL-002 Transect
-15
-10
-5
0
5
10
15
0 1000 2000 3000 4000 5000 6000 7000 8000
Elev
atio
n (f
t)
Distance from starting point of a Transect (ft)
21
WHAFIS vs. HAZUS Results: Controlling Wave Height
-Hsig=2.0 m at coastline-SWEL=12.0 ft (assumed to be 100-year RP)-All of the results from HAZUS except first point are “instantaneous” depth limited waves
0
2
4
6
8
10
12
0 1000 2000 3000 4000 5000 6000 7000 8000
Cont
rolli
ng W
ave
Hei
ght
(ft)
Distance from starting point of a Transect (ft)
WHAFIS
HAZUS
HAZUS_DL
Depth-LimitedWave with noRegenerationand no Dissipation
22
Coupled Surge and Wave Modeling
SLOSH and SWAN codes have been coupled together
Each code is advanced in 15 minute steps• SLOSH is run first to update water elevations SWAN uses water elevations produced by SLOSH
Result is larger modeled wave heights in areas where waves are depth-limited
• SWAN is run to update wave stresses Wave stresses are added to wind stress in SLOSH
Result is increased modeled storm surge due to wave setup
23
Coupled Storm Tide for Hurricane Ike (2008): Galveston Bay Basin
Difference of Peak Storm Tide (ft)
(coupling – no coupling)
24
Modeled Coupled Storm Tide vs. Observations
25
SLOSH+SWAN Two-Way Coupling Wave Results
26
Study Regions Spanning Multiple SLOSH Basins
27
Hurricane Katrina: Multi-Basin Approach
28
Hurricane Katrina: Maximum Storm Surge (ft. NAVD)
29
Hurricane Katrina: Maximum Significant Wave Height (ft)
30
Combined Wind and Flood Loss Approach
Use existing HAZUS methodologies to compute the “flood-only” and “wind-only” losses
Use USACE New Orleans District (NOD) methodology to apportion HAZUS flood-only building losses to building sub-assemblies
Use HAZUS wind loss methodology to apportion HAZUS wind-only building losses to building sub-assemblies
Sum losses by sub-assemblies: Assume wind and flood losses within a sub-assembly are independent
Cap combined sub-assembly loss at total replacement value of the sub-assembly
Populate combined wind and flood loss matrix
31
Combined Wind and Flood Loss Example
Building• Single family, one-story house (no garage)
• Flood characteristics No basement
• Wind characteristics Wood frame, gable roof shape, shingle roof covering
Medium roof deck attachment (8d nails @ 6/12 spacing)
Strapped roof-to-wall connection
No opening protection, no secondary water resistance
Hazard• Flood: Still water, short duration (1 day or less), saltwater flooding,
negligible waves
• Wind: Suburban surface roughness (z0=0.35 m)
32
Allocation of Flood-Only Losses (NOD Methodology)
“Foundation” includes site work, footings, and slab
“Roof Covering” includes flashing, roofing paper, and shingles
“Roof Framing” includes roof trusses (or rafters) and sheathing
“Exterior Wall” includes siding, insulation, windows, and exterior doors
“Interiors” includes drywall, trim, paint, interior doors, floor coverings, cabinets, counter tops, HVAC, plumbing, and electrical
Building Loss Foundation Roof Covering Roof Framing Exterior Walls Interiors10% 0.0% 0.0% 0.0% 1.0% 9.0%20% 0.0% 0.0% 0.0% 2.5% 17.5%30% 0.0% 0.0% 0.0% 6.7% 23.3%40% 0.0% 0.0% 0.0% 9.6% 30.4%50% 0.0% 1.2% 0.2% 11.2% 37.5%60% 0.0% 1.4% 0.2% 13.4% 44.9%70% 0.0% 1.7% 0.3% 15.7% 52.4%80% 0.0% 1.9% 0.3% 17.9% 59.9%90% 0.0% 2.1% 0.3% 20.1% 67.4%
33
Allocation of Wind-Only Losses (HAZUS Methodology)1 Story, Wood Frame, Gable, 8d@6/12, Straps, No Shutters, No SWR, No Garage, z0=0.03m
“Foundation” includes site work, footings, and slab
“Roof Covering” includes flashing, roofing paper, and shingles
“Roof Framing” includes roof trusses (or rafters) and sheathing
“Exterior Wall” includes siding, insulation, windows, and exterior doors
“Interiors” includes drywall, trim, paint, interior doors, floor coverings, cabinets, counter tops, HVAC, plumbing, and electrical
Building Loss Foundation Roof Covering Roof Framing Exterior Walls Interiors10% 0.0% 4.3% 0.0% 0.8% 4.9%20% 0.0% 4.7% 0.0% 1.5% 13.8%30% 0.0% 4.7% 0.0% 2.3% 23.0%40% 0.0% 4.8% 0.0% 2.9% 32.4%50% 0.0% 4.8% 0.0% 3.0% 42.2%60% 0.0% 4.9% 0.0% 3.8% 51.3%70% 0.0% 4.9% 0.1% 4.9% 60.1%80% 0.0% 5.2% 0.3% 14.3% 60.2%90% 0.0% 5.2% 0.8% 23.8% 60.2%
34
Combined Losses
Assume wind and flood losses within a sub-assembly are independent Ci = Wi + Fi – Wi*Fi i=1,5
Cap the combined sub-assembly loss at the replacement value of the sub-assembly Ci ≤ Ri i=1,5
Add the sub-assembly losses C = ∑ Ci
35
Combined Overall Loss Method (Without Sub-Assemblies)
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%0% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
10% 10% 19.0% 28.0% 37.0% 46.0% 55.0% 64.0% 73.0% 82.0% 91.0% 100%20% 20% 28.0% 36.0% 44.0% 52.0% 60.0% 68.0% 76.0% 84.0% 92.0% 100%30% 30% 37.0% 44.0% 51.0% 58.0% 65.0% 72.0% 79.0% 86.0% 93.0% 100%40% 40% 46.0% 52.0% 58.0% 64.0% 70.0% 76.0% 82.0% 88.0% 94.0% 100%50% 50% 55.0% 60.0% 65.0% 70.0% 75.0% 80.0% 85.0% 90.0% 95.0% 100%60% 60% 64.0% 68.0% 72.0% 76.0% 80.0% 84.0% 88.0% 92.0% 96.0% 100%70% 70% 73.0% 76.0% 79.0% 82.0% 85.0% 88.0% 91.0% 94.0% 97.0% 100%80% 80% 82.0% 84.0% 86.0% 88.0% 90.0% 92.0% 94.0% 96.0% 98.0% 100%90% 90% 91.0% 92.0% 93.0% 94.0% 95.0% 96.0% 97.0% 98.0% 99.0% 100%
100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%
Wind-Only Building Loss
Floo
d-O
nly
Build
ing
Loss
C = W + F – W*F
36
Differences
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%
10% 0% 0.5% 0.7% 0.9% 1.1% 1.2% 1.3% 1.5% 2.4% 3.3% 0%20% 0% 1.1% 1.5% 1.9% 2.3% 2.5% 2.9% 3.4% 5.1% 6.9% 0%30% 0% 1.8% 2.7% 3.5% 4.3% 5.0% 5.8% 6.7% 9.0% 7.0% 0%40% 0% 2.4% 3.7% 4.8% 5.9% 6.9% 8.0% 9.2% 12.0% 6.0% 0%50% 0% 3.0% 4.6% 6.1% 7.5% 8.8% 10.3% 11.9% 10.0% 5.0% 0%60% 0% 3.6% 5.5% 7.3% 9.0% 10.6% 12.4% 12.0% 8.0% 4.0% 0%70% 0% 4.2% 6.4% 8.5% 10.5% 12.3% 12.0% 9.0% 6.0% 3.0% 0%80% 0% 4.8% 7.4% 9.7% 12.0% 10.0% 8.0% 6.0% 4.0% 2.0% 0%90% 0% 5.4% 8.0% 7.0% 6.0% 5.0% 4.0% 3.0% 2.0% 1.0% 0%
100% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0% 0%
Floo
d-O
nly
Build
ing
Loss
Wind-Only Building Loss
37
Combined Wind and Flood Loss Methodology
Compatible with existing wind-only and flood-only loss methodologies
Losses combined at the building sub-assembly loss level
Addresses order in which losses accumulate• Wind and flood losses are not independent Wind Top-down
Flood Bottom-up
Makes use of available sub-assembly loss data• HAZUS wind loss simulation data
• USACE NOD flood loss expert opinion
Relative contributions of foundation and exterior wall sub-assembly flood losses relative to interiors is higher when wave action is present (V-zone or CA-zone)
38
HAZUS Coastal Storm Surge Methodology Summary
Development of coastal surge methodology is nearing completion Links existing HAZUS Hurricane and Coastal Flood models
Uses a single hurricane wind field model to drive storm surge (SLOSH), waves (SWAN), and wind damage (HAZUS Hurricane)
Surge and wave models are coupled
Combined loss methodology implemented to combine wind-only and flood-only losses across five building sub-assemblies
Functional prototype to be completed by end of September
End-to-end hurricane wind and flood scenario analysis capability in HAZUS-MH Maintenance Release 6 (March 2011)
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