sea level rise integration in coastal structures safe … zomorodi, ph.d., p.e., cfm sea level rise...
TRANSCRIPT
Kaveh Zomorodi, Ph.D., P.E., CFM
Sea Level Rise Integration in
Coastal Structures Safe Design
NOAA Coastal Flood Exposure Mapper,SLR Map for Delaware City, DE
http://www.csc.noaa.gov/floodexposure/#/start
This map shows sea level rise scenarios of 0 to 6 feet, which represent a rise in
water above the average of the highest high tides (called mean higher high
water, or MHHW) for hydrologically connected areas. Areas that are lower in
elevation will be exposed to flooding from sea level rise first and are
represented by the darkest red.
From SLR in feet to change in
Design Elevation in feet
From SLR in feet to change in
Design Elevation in feetIf SLR is estimated to be 1.0 foot :
NOAA: Tide stations measure Local • NOAA: Tide stations measure Local Sea Level, which refers to the height of the water as measured along the coast relative to a specific point on land. Water level measurements at tide stations are referenced to stable vertical points (or bench marks) on the land and a known relationship is established. However, the measurements at any given tide station include both global sea level rise and vertical land motion, such as subsidence, glacial rebound, or large-scale tectonic motion.
• SLR trends project Local Sea Level into future.
How much should the 100-year flood elevation be raised?
Engineering design and planning • Engineering design and planning is based on probabilistic conceptual flood levels, not just Local Sea Level.
• How do you incorporate projected SLR into a design flood level?
Background to This StudyApril, 2013
April, 2013
FTA-HMCE Tool Version: 1.0Build Date: 1/16/2014
This tool may be used for benefit-cost analysis (BCA) of resilience projects submitted to FTA for consideration
for funding under the Public Transportation Emergency Relief Program and the Disaster Relief Appropriations
Act of 2013 (Pub. L 113-2) for States, local governmental authorities, tribal governments and other FTA
recipients impacted by Hurricane Sandy, which affected mid-Atlantic and northeastern states in October 2012.
Resilience projects are those hazard mitigation projects designed and built to address vulnerabilities to a public
transportation facility or system due to future recurrence of emergencies or major disasters that are likely to
occur in the geographic area in which the public transportation system is located; or projected changes in
development patterns, demographics, or extreme weather or other climate patterns. All proposed projects for
funding are required to provide a cost-effectiveness evaluation leading to a benefit-cost ratio (BCR) for the
proposed project. This information will be used by FTA to evaluate the cost-effectiveness of the proposed
project in reducing an asset’s and the public transportation system’s vulnerabilities to future disasters.
Consistent with Executive Order 12893, selection of projects for funding will be based in part on a systematic
analysis of benefits and costs. In general, a BCR of one or greater indicates a project is cost-effective.
However, there are additional considerations that may lead to some projects with a BCR of less than one to be
considered cost-effective.
Applicants should provide information about the qualitative benefits of the proposed project under Tab 5 of this
tool.
The tool provides a framework for applicants to submit quantitative information about the project and its cost-
effectiveness, including the estimated damage and losses from specifically identified hazards (recorded
historical and/or expected theoretical events) and the reduction in the anticipated losses after such an event as
a result of the proposed project. Quantitative information that applicants must submit includes the estimated
damage and losses from specifically identified hazards (recorded historical or expected theoretical events) and
the reduction in the anticipated damages and losses after such an event as a result of the proposed project.
FTA will review the explanations and justifications provided to determine the reasonableness of the submitted
information, as well as the source of the information.
TAB 2 - Project Information & Cost Estimate
TAB 3 - Pre-Resilience Damages
TAB 4 - Post-Resilience Damages
TAB 5 - Analysis Results & Qualitative Benefits
TAB 1 - Tool Information
Click on a tab title to go directly to it:
Disclaimer:
The results produced by this tool are not
conclusive evidence that a project proposal is or is
not cost-effective. Use of this tool does not
guarantee that a project is eligible for funding
under the FTA Public Transportation Emergency
Relief Program. The analysis conducted is
dependent upon the quality of the information
provided, and will be evaluated in the context of
both analysis results and sufficiency of
Relative Sea Level Change Curves (meters)T(t) = (E+M)t+bt2
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
19
92
19
95
20
00
20
05
20
10
20
15
20
20
20
25
20
30
20
35
20
40
20
45
20
50
20
55
20
60
20
65
20
70
20
75
20
80
20
85
20
90
20
95
21
00
21
05
21
10
21
15
21
20
21
25
21
30
21
35
21
40
21
45
21
50
21
55
21
60
21
65
Re
lati
ve
Se
a L
ev
el
Ch
an
ge
(M
ete
rs)
Year
8638610 - Sewells Point, VA: 4.31 (mm/yr)
USACE High Rate
USACE Intermediate Rate
USACE Low Rate (Current Rate)
Curves are computed using the global rate in cell [I4]/yr + the local
land movement rate in cell [K4], with the start date in cell [J4]
Start by Selecting
Project Location
Select Applicable NOAA Tidal Gage
from USACE Climate Change Adaption
Seal Level Change Curves
Select SLR Trend
Set Project Useful Life (SLR projection
duration) and starting Year
Obtain Parameters
from Coastal Study
Estimate from
FEMA FIS Data
Set baseline flood to which SLR applies
directly
Estimate Moving Average Linear Slope
of the Baseline Flood Elevation + SLR
Estimate Gumbel Revised Location
Revised Scale by multiplying with
Slope up to each year in future
Estimate Equiv. Elevation, Rise and
Year for required profiles: (10, 50, 100
(BFE), 500-years and BFE+1 ft)
Are Gumbel Distribution
Parameters (Location, Scale)
for coastal flood elevations
(including wave) available ?
Yes No
SLR Equivalent Coastal Flood Elevation
considering all of the modified flood levels for the future years an SLR
equivalent coastal flood elevation is calculated that would give the same
probability of failure for the duration of the Project Useful Life as provided
by the current design standards.
For example, a structure designed for the current 100-year flood elevation
has a probability of failure of 39.5% during the next 50 years. The Equiv.
100-year flood depth is found by trial&error that would make the sum of
the failure probability over the next 50 years the same. Failure probability
for each year is calculated by Gumbel Distribution with shifting Locatin
and Scale for each year.
Computational Flow ChartComputational Flow Chart
Method explained through a
Hypothetical Example of a Coastal
Levee at Hampton Roads, VA
currently designed with top-of-
levee elevation set at BFE+1 foot
Select nearby
NOAA Gauge:Select SLR Trend:
The magnitude of SLR is estimated following the USACE Climate Change Adaption Seal Level Change Curves:
http://corpsclimate.us/ccaceslcurves.cfm
select the closest NOAA coastal gauge to resilience project site from drop down list. To see a map of gauge locations visit the link
below and select East Coast and Zoom in to your project location: http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml
Estimated for Year 2064 based on Accelerated (Intermediate) trend
projection for NOAA Gauge: Sewells Point, VA.
Sewells Point, VAAccelerated (Intermediate)
0.00
0.20
0.40
0.60
0.80
1.00
1.20
2010 2020 2030 2040 2050 2060 2070
SLR
(ft
)
Year
Gumbel Distribution (EV Type I) fit to flood Elevation (including waveheight) Input (Green Cells)Current Design
Freeborad over BFE = 1.0 ft, FB input is optional
Tr
(Year)
Flood
Elev(including
waveheight)(ft) This method is used only when flood elev. data not available to estimate distribution parameters directly.
10 8.76 FIS data for flood including wave from Table 3, Transect 5, City of Norfolk, VA August 5, 2012
50 10.99
100 12.10
500 14.17
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.1 0.02 0.01 0.002
Gumbel fit
by equation
standard P
Location 5.600 Scale 1.401 Shape
P
Gumbel fit
by equation flood elev (ft) using NTGumbel Constant weight diff^2
0.1 0.0998 8.76 0.0998 10 0.00000030
0.02 0.0212 10.99 0.0212 20 0.00002923
0.01 0.0096 12.10 0.0096 100 0.00001357
0.002 0.0022 14.17 0.0022 20 0.00000086
sum sq= 0.000044
Define Baseline flood as the flood elevation to which SLR may be directly added. After trying several variations (i.e., 1.1-yr, etc.) the Mode was selected.
baseline flood elev (ft)
5.60 for Gumbel distribution Mode= Location
Updating each year’s parametersUpdating each year’s parameters
n Year rise
baseline flood
+SLR (ft) slope, m= constant, b=
revised
location revised scale
Revised 100-yr
flood El Simple BFE+SLR
Rise in theoretical
BFE Current BFE's P
0 2014 0.00 5.60 1.0000 0 5.60 1.4015 12.0471 12.10 0.00 0.9904
1 2015 0.02 5.62 1.0032 0 5.62 1.4060 12.0862 12.12 0.04 0.9901
2 2016 0.04 5.64 1.0065 0 5.64 1.4106 12.1256 12.14 0.08 0.9898
3 2017 0.05 5.66 1.0098 0 5.66 1.4152 12.1654 12.15 0.12 0.9895
4 2018 0.07 5.67 1.0131 0 5.67 1.4199 12.2055 12.17 0.16 0.9892
5 2019 0.09 5.69 1.0165 0 5.69 1.4246 12.2461 12.19 0.20 0.9889
6 2020 0.11 5.71 1.0199 0 5.71 1.4294 12.2870 12.21 0.24 0.9886
7 2021 0.13 5.73 1.0233 0 5.73 1.4342 12.3284 12.23 0.28 0.9883
8 2022 0.15 5.75 1.0268 0 5.75 1.4390 12.3701 12.25 0.32 0.9879
9 2023 0.17 5.77 1.0303 0 5.77 1.4439 12.4121 12.27 0.37 0.9876
10 2024 0.19 5.79 1.0338 0 5.79 1.4489 12.4546 12.29 0.41 0.9872
11 2025 0.21 5.81 1.0374 0 5.81 1.4538 12.4975 12.31 0.45 0.9869
12 2026 0.23 5.83 1.0410 0 5.83 1.4589 12.5407 12.33 0.49 0.9865
13 2027 0.25 5.85 1.0446 0 5.85 1.4639 12.5843 12.35 0.54 0.9861
14 2028 0.27 5.87 1.0482 0 5.87 1.4691 12.6283 12.37 0.58 0.9857
15 2029 0.29 5.89 1.0519 0 5.89 1.4742 12.6727 12.39 0.63 0.9853
Calculations carried out for number of years = PUL
Evaluating Equivalent Flood ElevationsEvaluating Equivalent Flood Elevations
change Equiv El to make Equiv Balance zero
need to optimize these values RI of BFE+FB
Tr: 10 50 100 500 211
current values: 8.76 10.99 12.10 14.17 13.10
Equiv EL 9.65 12.23 13.32 15.86 14.50Equiv Balance 0.000000000 0.000000003 0.000000002 0.000000001 0.000000000
Current BFE's P 10-yr 50-yr 100-yr 500-yr BFE+FB
0.9904 P (NF) equiv El P (NF) equiv El P (NF) equiv El P (NF) equiv El P (NF) equiv El
0.9901 0.9448 0.9910 0.9958 0.9993 0.9982
0.9898 0.9435 0.9907 0.9957 0.9993 0.9981
0.9895 0.9423 0.9904 0.9956 0.9993 0.9981
0.9892 0.9410 0.9902 0.9954 0.9992 0.9980
0.9889 0.9397 0.9899 0.9953 0.9992 0.9979
0.9886 0.9384 0.9896 0.9951 0.9992 0.9979
0.9883 0.9370 0.9893 0.9950 0.9991 0.9978
0.9879 0.9356 0.9890 0.9948 0.9991 0.9977
0.9876 0.9342 0.9887 0.9947 0.9991 0.9976
0.9872 0.9327 0.9883 0.9945 0.9990 0.9976
0.9869 0.9312 0.9880 0.9943 0.9990 0.9975
Simple Addition vs. Statistical ApproachSimple Addition vs. Statistical Approach
Recurrence
Interval
(yr)
Percent
Annual
Chance
(%)
Year 0 (2014)
flood Elevation
(including
Wavehight)
FIS Data
Year end (2054)
flood Elevation
(including
Wavehight)
Simple addition
of SLR
Year end (2054)
flood Elevation
(including
Wavehight)
Statistical Method
Equiv Year
flood Elevation
(including
Wavehight)
Data
Equiv
Year
Equiv
Rise
(fT)
10 10.00% 8.76 9.88 10.51 9.65 27 0.89
50 2.00% 10.99 12.11 13.29 12.23 28 1.24100 1.00% 12.10 13.22 14.47 13.32 28 1.22
500 0.20% 14.17 15.29 17.18 15.86 29 1.69
BFE+FB 0.47% 13.10 14.22 15.73 14.50 29 1.40
baseline flood N/A 5.60 6.73 N/A N/A 50 N/A
BFE Increase in Future YearsBFE Increase in Future Years
12.0
12.5
13.0
13.5
14.0
14.5
15.0
2010 2020 2030 2040 2050 2060 2070
10
0-y
r F
loo
d E
lev
., in
clu
din
g w
av
eh
eig
ht
(ft)
Year
Revised (Statistical) BFE Trend
SLR+ BFE
Equiv. BFE
0.0
50.0
100.0
150.0
200.0
250.0
2010 2020 2030 2040 2050 2060 2070
Re
cu
rre
nce
In
terv
al (Y
ea
rs)
Year
Tr current BFE
w/current parameters or revised BFE
w/ moving paramters
Tr current BFE
w/ moving parameters
Tr BFE+SLR
w/current parameters
Tr BFE+SLR
w/ moving parameters
Tr Equiv. BFE
w/ moving parameters
Tr at Equiv. Year
Changes in Recurrence Interval of Current BFEChanges in Recurrence Interval of Current BFE
Method Applied to Six East Coast Locations
Location
NOAA Station
for SLR Sea
Gumbel
Location
Gumbel
Scale
BFE
(ft)
50-yr
SLR
(ft)
BFE Rise
Statistical
(ft)
BFE Rise
Equiv.
(ft)
(BFE Rise
Equiv.) / (50-yr
SLR)
BFE Rise
Equiv. - 50-
yr SLR
(ft)
Equiv.
Year
Transect 177, Woods
Hole,
Barnstable County,
Massachusetts
Woods Hole, MA Buzzards Bay 2.797 2.870 16.00 0.86 4.90 2.48 2.90 1.62 28
Transect 30, City of
Norwalk,
Fairfield County,
Connecticut
Bridgeport, CT Long Island Sound 8.531 1.407 15.00 0.82 1.45 0.73 0.89 -0.09 28
Transect NY-14,
New York, NYThe Battery, NY East River 3.533 2.273 14.00 0.90 3.54 1.80 2.01 0.90 28
Transect 22, Atlantic
County, NJ,Atlantic City, NJ Atlantic Ocean 5.375 1.871 14.00 1.05 2.72 1.39 1.32 0.34 28
Elk River,
Transect 29
Cecil County
Maryland
Chesapeake
CityChesapeake Bay 4.083 1.285 10.00 0.91 2.23 1.15 1.26 0.24 28
Transect 5,
City of Norfolk, VirginiaSewells Point, VA Chesapeake Bay 5.600 1.401 12.10 1.12 2.37 1.22 1.08 0.10 28
Results for Six East Coast LocationsResults for Six East Coast Locations
Regression Equation for Six East Coast LocationsRegression Equation for Six East Coast Locations
MA
CT
NY
NJ
MDVA
y = 0.0281e2.6576x
R² = 0.9931
0.70
1.20
1.70
2.20
2.70
3.20
3.70
4.20
1.25 1.35 1.45 1.55 1.65 1.75
(BF
E R
ise
Eq
uiv
.) /
(5
0-y
r S
LR)
BFE/10yr WSE
Evaluated Points Expon. (Evaluated Points)
50-yr BFE Rise Equiv. = (0.0281 e(2.6576 (BFE/100yr WSE))
) (50-yr SLR)
Regression fit for Six East Coast LocationsRegression fit for Six East Coast Locations
MA
CT
NY
NJ
MDVA
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
2.20
2.40
2.60
0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60
Re
gre
ssio
n E
va
lua
ted
BFE
Ris
e E
qu
iv.
Evaluated BFE Rise Equiv.
perfect fit line
Ratio Exponential Fit
Application Example
Problem: A coastal structure near Norfolk, VA is considered for mitigation against
coastal floods by elevating it to BFE+1 (considering SLR during the next 30-years which
is FEMA’s default mitigation PUL for elevation projects). How much does the structure
need to be elevated to? What is the equivalent flood elevation for each R.I. that can
be used in a BCA analysis? Accelerated (Intermediate) non-linear 30-year SLR at this
location is 0.62 ft.
Solution: As seen in results table BFE+FB (12.1’+1’) increases from 13.10 ft to 13.72 ft
(simple additions) or 14.55 ft (statistical method). The equivalent value is 13.87 ft
which shows a rise of 0.77’ (0.15’ more than simple 30-year SLR). The equiv. rise for
each R.I. is different and is not the same as the rise by the equiv. year (16 years).
Recurrence
Interval
(yr)
Percent
Annual
Chance
(%)
Year 0 (2014)
flood
Elevation
(including
Wavehight)
FIS Data
Year end (2034)
flood Elevation
(including
Wavehight)
Simple addition
of SLR
Year end (2034)
flood Elevation
(including
Wavehight)
Statistical Method
Equiv Year
flood
Elevation
(including
Wavehight)
Data
Equiv
Year
Equiv
Rise
(fT)
Rise
by
Equiv
Year
(ft)
Added
to
Current
Value
(ft)
10 10.00% 8.76 9.38 9.73 9.25 16 0.50 0.31 9.07
50 2.00% 10.99 11.61 12.30 11.71 16 0.72 0.31 11.30100 1.00% 12.10 12.72 13.38 12.75 16 0.65 0.31 12.41500 0.20% 14.17 14.79 15.90 15.15 16 0.98 0.31 14.48
BFE+FB 0.47% 13.10 13.72 14.55 13.87 16 0.77 0.31 13.41
Questions?
• Kaveh Zomorodi, Ph.D., P.E., CFM
Sea Level Rise Integration in Coastal Structures Safe Design