Limited Data, Complex Coastline
and Successful Wave Modeling
Challenges, Solutions and Lessons Learned
Paula Kulis, PhD
Nader Mahmoudpour, PhD
Lauren Klonsky
June 11, 2013
Purpose
• Objectives
• Wave Modeling Procedure
• Challenges
– Model configuration
– Model validation
• Solutions
• Lessons Learned
Limited Data, Complex Coastline and Successful Wave
Modeling
2
Study Objective
• Coastal Flood Hazard Analysis of
Maine Coast
– York
– Cumberland
– Sagadahoc
– Lincoln
– Knox
– Waldo
– Hancock
• 1-Percent-Annual-Chance Wave
Conditions
– Region 1: Event-based study
– Develop model of wave energy
• Nor’easter
Limited Data, Complex Coastline and Successful Wave
Modeling
3
Features of Study
• STWAVE v. 6 Halfplane
• Large Area (200 miles alongshore)
• Irregular coastline
– Rocky
– Islands, Peninsula features
– Different areas have
different dominating risks
• Offshore waves
• Surge
• Near-shore wave data
limitations
http://www.noaa.gov/features/03_protecting/noreasters.html
http://en.wikipedia.org/wiki/Nor'easter
Limited Data, Complex Coastline and Successful Wave
Modeling
4
Original Plan: Use WIS
http://chl.erdc.usace.army.mil/wis
• Identify key representative
buoys
–
–
–
–
Boundary conditions
validation
Local bathymetry
Distribution in study area
• Identify storms with large H
– 1980-1999
– Use Extremal Plots
• Obtain full wave spectrum
Limited Data, Complex Coastline and Successful Wave
Modeling
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Original Plan: Use WIS
http://chl.erdc.usace.army.mil/wis
Bob Jensen at ERDC
• Identify key representative
buoys
–
–
–
–
Boundary conditions
validation
Local bathymetry
Distribution in study area
• Identify storms with large H
– 1980-1999
– Use Extremal Plots
• Obtain full wave spectrum
Limited Data, Complex Coastline and Successful Wave
Modeling
6
Validation Troubles
Storm
Observed Wave
Height
Modeled Wave
Height
WIS Modeled
Height
December 1992
6.1 m
4.4 m
5-5.5 m
January 1996
5.5 m
5.3 m
5.5 m
October 1996
7m
4.9 m
5-5.5 m
Modeled H is off by ~ 2 m!!
Limited Data, Complex Coastline and Successful Wave
Modeling
7
WIS Validation Troubles
Limited Data, Complex Coastline and Successful Wave
Modeling
8
Limited Data
• Have off-shore NDBC buoy
data:
– 44005 is most
comprehensive
• NDBC data includes:
– Total energy (H)
– Limited spectral data
• No direction data
– Wind speed/direction
Limited Data, Complex Coastline and Successful Wave
Modeling
9
Complex Coastline
• Multiple scales in same model
– Large scale: Offshore buoys
driving model Boundary
conditions
– Small scale: bathy and
coastline curvature on order
of tens of meters
• Solution: Nested grids
Limited Data, Complex Coastline and Successful Wave
Modeling
10
Methods
• STWAVE v 6
–
–
–
–
–
half-plane
Regular grid
USACE, SMS GUI
Wave action equation
Steady State
• Nesting
– 3 levels
– 500 m  10-20 m
Limited Data, Complex Coastline and Successful Wave
Modeling
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Validation Data Used: Wave Energy Spectrum
• 12/17/2007
• 12/9/2009
– Wave height from buoy
• Standard JONSWAP
spectrum
– Wave direction from wind
record
Limited Data, Complex Coastline and Successful Wave
Modeling
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300
18
250
16
14
200
12
10
150
8
Degree
– Focus on 2 storm events
(based on validation data
availability)
Wind Speed (m/s) and Wave Height (m)
• NDBC 44005: 2000-2011
100
6
4
50
2
0
12/9/09 12:00
44005 Obs
12/10/09 0:00
Wind Speed
12
0
12/10/09 12:00
Wind Direction
Data Used: Tide, Wind
• Wind: Buoy 44005, time
of peak wave height
• Tide: Tide gages
averaged
Elevation
Data
Point
– Only applied in nested
grids
Limited Data, Complex Coastline and Successful Wave
Modeling
13
Validation Results: 2009
7
Wave Height (m)
6
5
4
44007 Obs
3
44007 Model
2
1
0
12/9/09 12:00
12/10/09 0:00
12/10/09 12:00
44007
validation
44005
Boundary Condition
Limited Data, Complex Coastline and Successful Wave
Modeling
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Validation Results: 2007
Limited Data, Complex Coastline and Successful Wave
Modeling
Station
H Observed
H Modeled
Assessment
44005
7.4
7.5
Close
44032
6.7
6.4
Close
44033
3.2
2.9
Close
44034
6.7
6.7
Close
44030
6.5
6.3
Close
44031
6.4
6.0
Low
15
Uncertainty: Wave Direction
2007 Storm: all within 0.4 meters
15 Degrees
Plus
10 Degrees
Plus
5 Degrees
Plus
Observed
No
adjustment
5 Degrees
Minus
10
Degrees
Minus
15
Degrees
Minus
Modeled
44005
7.4
7.5
7.5
7.5
7.5
7.6
7.6
7.6
44030
6.5
6.1
6.2
6.2
6.3
6.3
6.3
6.3
44031
6.4
6.1
6.1
6.0
6.0
6.0
6.0
6.0
44032
6.7
6.4
6.4
6.4
6.4
6.4
6.3
6.3
44033
3.2
4.5
4.5
4.5
4.5
4.6
4.4
4.3
44034
6.7
6.7
6.7
6.7
6.7
6.7
6.7
6.6
Limited Data, Complex Coastline and Successful Wave
Modeling
16
1-Percent-Annual-Chance Event
• Model validated successfully
• Define 1-percent-annualchance conditions
– Tide from 2012 New England
Tide Report
– Wind from Buoy 44005 time
history (1979-2011)
– Wave height from Buoy
44005 time history (19792011)
Limited Data, Complex Coastline and Successful Wave
Modeling
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1-Percent-Annual-Chance
• Outer Boundary Waves
– Extremal analysis on 44005 data:
10.6 meters
– Direction in line with model grid
• Wind
– Extremal analysis on 44005 data:
25.1 m/s
– Direction in line with model grid
• Tide
– Applied per 2012 New England
Tide Report (2.9 meters north,
3.1 meters south)
Limited Data, Complex Coastline and Successful Wave
Modeling
18
Next Steps
• Wave Heights at Transects
• Propagate onshore
– Wave setup/runup
• Mapping
Limited Data, Complex Coastline and Successful Wave
Modeling
19
Lessons Learned
• Flexibility in Approach
• Carefully Evaluate All BC/Validation Data – “sanity check”
– Observations
– Model Results
• Consider spatial scales in approach
Limited Data, Complex Coastline and Successful Wave
Modeling
20
Questions?
• Project Team:
–
–
–
–
–
–
–
Paula Kulis
Nader Mahmoudpour
Lauren Klonsky
Brian Caufield
Frannie Bui
Ted Schultz
Karen Kelley
Limited Data, Complex Coastline and Successful Wave
Modeling
Paula Kulis
[email protected]
614-847-6879
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