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Application of SLAMM 4.1 to Nine
Sites in Florida
For: National Wildlife Federation
Patty Glick
Climate Change Specialist
6 Nickerson Street, Suite 200
Seattle, WA 98109
February 16, 2006
Jonathan S. Clough, Warren Pinnacle Consulting, Inc
PO Box 253, Warren VT, 05674
(802)-496-3476
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Application of SLAMM 4.1 to Nine Sites in Florida
Project Background ................................................................................................................... 1
Model Summary ........................................................................................................................2
Sea Level Rise Scenarios.................................................................................................... 2
Model Results ............................................................................................................................ 4
All of Florida ......................................................................................................................................... 4
Pensacola: .............................................................................................................................................. 5
Apalachicola .......................................................................................................................................... 9
Tampa Bay...........................................................................................................................................11
Charlotte ..............................................................................................................................................13
Florida Bay ..........................................................................................................................................17
Biscayne Bay........................................................................................................................................19
Saint Lucie .................................................................................... 2Error! Bookmark not defined.
Indian River Lagoon ..........................................................................................................................23
Model Parameterization .......................................................................................................... 25
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Project Background
The SLAMM 4.1 model was applied to nine sites within Florida, comprising over 1.7 million
hectares (Figure 1). Funding for this model application was provided by the National Wildlife
Federation. Extensive data processing that made this application possible was provided by Brad
Nunley, NWF’s GIS expert.
Figure 1: Map of Sites Modeled within Florida
SLAMM Version 4.1 is the latest version of the SLAMM Model, developed in 2005 and based on
SLAMM 4.0. SLAMM 4.1 provides additional sea level rise scenarios based on the latest IPCC
findings (IPCC 2001) and additional data examination tools to ensure that data quality is acceptable.
1
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Model flexibility has been improved with respect to accretion rates, and the model now accepts data
from the USGS seamless data distribution tool (seamless.usgs.gov). To accurately model erosion in
larger sites, maximum fetch is now calculated on a cell-by-cell basis rather than being input as a site
characteristic. For more information on the development of the SLAMM model, please see the
model’s technical documentation (Clough and Park, 2005).
Model Summary
Within SLAMM, there are four primary processes that affect wetland fate under different scenarios
of sea level rise:

Inundation:
The rise of water levels and the salt boundary is tracked by reducing
elevations of each cell as sea levels rise, thus keeping MTL constant at
zero. The effects on each cell are calculated based on the minimum
elevation and slope of that cell.

Erosion:
Erosion is triggered based on a threshold of maximum fetch and the
proximity of the marsh to estuarine water or open ocean. When these
conditions are met, horizontal erosion occurs at a rate based on site
specific parameters.

Overwash:
Barrier islands of under 500 meter width are assumed to undergo
overwash during each 25 year time-step due to storms encountered.
Beach migration and transport of sediments are calculated.

Saturation:
Coastal swamps and fresh marshes can migrate onto adjacent uplands as a
response of the water table to rising sea level close to the coast.
For a thorough accounting of each of these processes and the underlying assumptions and
equations, please see the model’s technical documentation.
Sea Level Rise Scenarios
The model was run given the minimum, mean, and maximum estimates of each of the SRES
scenarios. A brief description of each of these scenarios can be found in the SLAMM 4.1 technical
documentation, more extensive descriptions are in the Intergovernmental Panel on Climate Change
report (IPCC 2001). For simplicity, this report will focus on the A1 scenario in which the future
world includes very rapid economic growth, global population that peaks in mid-century and
declines thereafter, and the rapid introduction of new and more efficient technologies. In particular,
the A1B scenario assumes that energy sources will be balanced across all sources.
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Figure 2: Summary of SRES Scenarios
Global average sea level rise for the SRES scenarios
Mean Estimates
1000
900
mm (mean)
800
700
A1B
600
A1T
500
A1FI
400
A2
B1
300
B2
200
100
0
1990
2010
2030
2050
2070
2090
2110
Global average sea level rise for the SRES scenarios
Minimum and Maximum Estimates
1000
900
A1B MIN
800
A1T MIN
A1FI MIN
700
A2 MIN
mm
600
B1 MIN
500
B2 MIN
400
A1B MAX
300
A1T MAX
A1FI MAX
200
A2 MAX
100
0
1990
B1 MAX
B2 MAX
2040
2090
3
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Model Results
All of Florida
Looking at the combined results of all modeled sites can be informative. At present we will focus
on the mean results of sea level rise for Scenario A1B. By the year 2100, dry land is predicted to
decrease by 14 percent over all sites, due to the processes of inundation and saturation. Hardwood
swamp loss is predicted to be 12%. Nearly 50% of salt marsh is predicted to be lost over all sites by
the year 2100. Due to the inundation of dry land, transitional salt marsh (brackish marsh) is
predicted to increase dramatically. The model also predicts roughly a 40% loss of ocean beaches
and that two thirds of estuarine beaches will disappear (primarily to erosion, but also due to
overwash, and inundation). As sea levels rise, open ocean and estuarine water is predicted to
increase. Mangroves are also expected to thrive under these conditions, gaining by 33%.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for all Sites Modeled in Florida
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond.
(ha)
496,043
175,319
2,955
56,129
1,915
684
19,328
104,462
3,530
80,458
1,292
21
15,055
493
508,769
261,355
1,727,807
Year 2100
(ha)
425,363
156,699
2,287
53,505
1,745
30,520
10,034
141,928
1,150
13,020
887
21
12,609
179
602,246
275,615
1,727,807
Initial Condition
Percent of Percent Loss
Percent
Init. Cond.
(mean)
Loss (max)
29%
14%
22%
10%
11%
20%
0%
23%
41%
3%
5%
24%
0%
9%
11%
0%
-4364%
-3690%
1%
48%
-75%
6%
-36%
-68%
0%
67%
72%
5%
84%
86%
0%
31%
-8%
0%
0%
0%
1%
16%
21%
0%
64%
71%
29%
-18%
-21%
15%
-5%
-6%
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
4
Open Ocean
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If we run the model using the “maximum” estimates for scenario A1B, loss of dry land increases to
22% (from 14%), but salt marsh actually increases by 75% as dry land is converted beyond
transitional marsh into pure salt marsh due to continuing inundation. Mangroves do even better
under scenarios of higher sea level rise, gaining by over 60% under the maximum scenario.
Pensacola:
Relatively steep slopes of dry land around Pensacola, FL result in a relatively low loss rate for dry
land (6-7%), the majority of dry-land loss is predicted due to saturation (increase of height of water
table leading to fresh marsh expansion) rather than inundation. Some migration of the barrier
islands are predicted with a two thirds loss of ocean beach under the mean scenario. Salt marsh in
this region is predicted to be quite vulnerable, however, with a loss of over 70% in both the mean
and maximum parameter set.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Pensacola, FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. (ha)
64,476
16,697
128
2,814
19
70
2,785
54
59
470
45
917
46,256
17,471
152,261
5
Year 2100 Percent of Percent Loss Percent
(ha)
Init. Cond.
(mean)
Loss (max)
60,580
42%
6%
7%
17,240
11%
-3%
1%
122
0%
5%
5%
2,931
2%
-4%
-1%
19
0%
0%
0%
536
0%
-668%
-1268%
753
2%
73%
77%
54
0%
0%
0%
38
0%
36%
-77%
449
0%
4%
23%
15
0%
67%
28%
0%
NA
NA
761
1%
17%
18%
0%
NA
NA
50,986
30%
-10%
-12%
17,778
11%
-2%
-2%
152,261
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SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Pensacola, FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Legend for All SLAMM ScreenCapture Maps:
6
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Pensacola, FL Current Condition
Pensacola, FL Year 2100, A1B Mean
7
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Detail of Elevational Map for Pensacola, FL Barrier Islands
8
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Apalachicola
Significant loss of hardwood swamp is predicted, particularly along the Apalachicola river where
swamp elevations are low relative to sea level. SLAMM predicts that 13-16 percent of these swamps
will convert to brackish (transitional) salt marsh. Inundation and saturation is also predicted to
convert over a quarter of the dry land on this site, again, particularly along the river basin.
Overwash is predicted to have significant effects on the barrier islands to the south of this site.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Apalachicola FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. (ha)
34,921
126,599
64
9,318
159
349
7,164
60
1,739
531
1
18
3,033
396
56,051
51,387
291,791
Year 2100
(ha)
25,218
110,640
38
6,787
38
22,193
2,828
60
222
3,787
131
18
1,937
103
64,640
53,150
291,791
Percent of Percent Loss Percent
Init. Cond.
(mean)
Loss (max)
12%
28%
33%
43%
13%
16%
0%
41%
56%
3%
27%
34%
0%
76%
91%
0%
-6264%
-1301%
2%
61%
-234%
0%
0%
6%
1%
87%
89%
0%
-613%
-382%
0%
-8978%
-10597%
0%
0%
0%
1%
36%
42%
0%
74%
82%
19%
-15%
-24%
18%
-3%
-4%
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Apalachicola , FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
9
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Apalachicola, FL Current Condition
Apalachicola, FL Year 2100, A1B Mean
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Tampa Bay
Tidal flats around Tampa bay are predicted to nearly disappear by the year 2100. The barrier islands
around Tampa bay are also predicted to be hit hard, with a resulting loss of 10% to 16% of dry lands
for the site. Some cypress swamp saturation is also predicted to occur. Mangroves are predicted to
roughly double or triple at the site depending on whether the mean or maximum scenario is
evaluated.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Tampa Bay, FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. (ha)
147,401
8,882
897
2,196
16
59
1,200
7,533
331
17,973
59
0
2,189
23
85,010
49,557
323,326
Year 2100
(ha)
133,362
8,264
969
2,073
7
81
167
20,055
317
690
125
0
2,072
3
102,722
52,421
323,326
Percent of Percent Loss Percent
Init. Cond.
(mean)
Loss (max)
46%
10%
16%
3%
7%
15%
0%
-8%
-9%
1%
6%
12%
0%
59%
93%
0%
-36%
-186%
0%
86%
90%
2%
-166%
-294%
0%
4%
37%
6%
96%
98%
0%
-112%
-148%
0%
0%
0%
1%
5%
8%
0%
87%
92%
26%
-21%
-22%
15%
-6%
-7%
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Tampa Bay, FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
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Tampa Bay, FL Current Condition
Tampa Bay, FL Year 2100, A1B Mean
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Charlotte
Like Tampa Bay, significant overwash is predicted for the barrier islands around Charlotte resulting
in much dry land loss. Saturation and inundation also take their toll with dry land predicted to drop
a whopping 35-55% depending on whether the mean or maximum scenario is run. Tidal flats are
also predicted to be decimated by sea level rise. Mangroves thrive under these scenarios, though,
increasing by 75% to 120%. Results in this region are similar to Tampa Bay, though lower
elevations of dry land result in more significant predicted impacts here.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Charlotte, FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. Year 2100 Percent of Percent Loss Percent
(ha)
(ha)
Init. Cond.
(mean)
Loss (max)
37,805
24,468
23%
35%
55%
5,000
3,196
3%
36%
51%
31
32
0%
-5%
-5%
1,261
1,036
1%
18%
55%
0%
NA
NA
73
15
0%
80%
-167%
1,384
151
1%
89%
98%
18,577
32,535
11%
-75%
-119%
492
143
0%
71%
76%
22,835
612
14%
97%
99%
97
70
0%
27%
-133%
3
3
0%
0%
0%
517
212
0%
59%
73%
0%
NA
NA
50,921
74,501
31%
-46%
-48%
22,691
24,711
14%
-9%
-11%
161,685
161,685
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Charlotte, FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
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Charlotte, FL Current Condition
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Charlotte, FL Year 2100, A1B Mean
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Ten Thousand Islands
What little dry land is at this site is predicted to be lost under these sea level rise scenarios (or at least
80-90% of it). Tidal flats are predicted to migrate further inland while Mangroves, which are already
dominant at this site increase from 16% to 26%. Mangrove migration takes its toll on inland fresh
marsh which decreases by 44% to 79% depending on the scenario evaluated. Over half of salt
marsh also is lost in both scenarios. Some fresh marsh is also predicted to be converted to
transitional (brackish) salt marsh, which was not initially present at the site.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Ten Thousand Islands, FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. (ha)
3,274
5,744
1,198
7,485
3,667
32,500
84
2,337
10
91
16,865
33,073
106,328
Year 2100 Percent of Percent Loss Percent
(ha)
Init. Cond.
(mean)
Loss (max)
654
3%
80%
90%
3,963
5%
31%
83%
988
1%
18%
56%
4,225
7%
44%
79%
0%
NA
NA
1,946
0%
NA
NA
898
3%
76%
51%
37,857
31%
-16%
-26%
58
0%
30%
76%
3,117
2%
-33%
-18%
53
0%
-424%
-408%
0%
NA
NA
48
0%
48%
91%
0%
NA
NA
17,388
16%
-3%
-11%
35,133
31%
-6%
-7%
106,328
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Ten Thousand Islands, FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
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Ten Thousand Islands, Current Condition
Ten Thousand Islands, FL Year 2100, A1B Mean
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Florida Bay
In Florida Bay, the most significant prediction is the loss of tidal flats which are currently dominant.
Under both scenarios, 99% of tidal flats are predicted to be lost. Mangroves, on the other hand,
hang tough with losses of only 3% to 6% due to inundation. At least half of the small amount of
dry land at this site is predicted to be lost under the A1B mean and maximum scenarios.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Florida Bay, FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. (ha)
1,269
8
13
1,232
33,402
485
32,561
226
118,336
3,959
191,489
Year 2100
(ha)
616
5
9
839
32,294
52
484
54
152,477
4,660
191,489
Percent of Percent Loss Percent
Init. Cond.
(mean)
Loss (max)
1%
51%
70%
0%
34%
50%
0%
NA
NA
0%
NA
NA
0%
NA
NA
0%
30%
100%
1%
32%
100%
17%
3%
6%
0%
89%
95%
17%
99%
99%
0%
76%
71%
0%
NA
NA
0%
NA
NA
0%
NA
NA
62%
-29%
-31%
2%
-18%
-19%
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Florida Bay, FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
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Florida Bay, Current Condition
Florida Bay, FL Year 2100, A1B Mean
18
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Biscayne Bay
In Biscayne Bay, the most heavily developed areas in the northwest portion of the study map are not
predicted to suffer extensive losses from sea level rise as these developments are built on relatively
high land elevations. Further south, however, lesser developed low lying dry land and freshwater
wetlands are predicted to suffer significant inundation effects. The barrier islands at the south of the
map are also predicted to undergo inundation and subsequent mangrove expansion, especially under
the maximum scenario. The resulting prediction is a loss of dry-land that ranges from 13-30%
depending on whether the mean or maximum scenario is evaluated.
Given land elevations at this site, a potential exists for expansion of hardwood swamps as the overall
water-table rises. However, this potential is likely to be thwarted due to the extent of developed
land. The model also predicts that such potential would be short-lived; as the salt level rises, these
freshwater swamps are converted into transitional salt marsh under the maximum scenario. Fresh
water marshes suffer a 33% to 89% loss under the two scenarios.
As is often the case, transitional salt marsh and mangrove stands have the potential to increase
significantly under these two scenarios of sea level rise as dry lands and fresh marshes undergo
inundation. Beach erosion is predicted to claim roughly one third of existing beaches on these sites.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Biscayne Bay, FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. (ha)
57,841
3,993
589
7,846
119
1,387
8,556
225
3,340
1,815
80,428
5,794
171,934
19
Year 2100 Percent of Percent Loss
Percent
(ha)
Init. Cond.
(mean)
Loss (max)
50,278
34%
13%
30%
5,656
2%
-42%
86%
86
0%
85%
100%
5,224
5%
33%
89%
0%
NA
NA
1,642
0%
-1278%
-4310%
639
1%
54%
-32%
14,654
5%
-71%
-230%
47
0%
79%
69%
702
2%
79%
87%
94
0%
NA
NA
0%
NA
NA
1,326
1%
27%
38%
0%
NA
NA
82,758
47%
-3%
-4%
8,828
3%
-52%
-54%
171,934
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SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Biscayne Bay, FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Biscayne Bay, Current Condition
Biscayne Bay, FL Year 2100, A1B Mean
20
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INTERNAL USE ONLY
Saint Lucie
The two dominant processes predicted to affect Saint Lucie are overwash of the barrier islands and
saturation of dry land. Inland elevations of dry land are low, especially in relation to the inland fresh
marsh that occurs close to the bay. This results in significant predictions of saturation and a loss of
10 to 12% of dry land (which is comprises more than 50% of this site). Because this part of Saint
Lucie is heavily developed, this prediction should probably be considered the “potential” for
saturation as this process is likely to be offset by landowners bringing in fill when required. Beach
erosion and overwash is predicted to result in the loss of roughly half of the ocean beach at this site.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Saint Lucie, FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. Year 2100 Percent of Percent Loss Percent
(ha)
(ha)
Init. Cond.
(mean)
Loss (max)
74,677
67,169
54%
10%
12%
2,275
2,312
2%
-2%
5%
0%
NA
NA
8,425
13,465
6%
-60%
-66%
0%
NA
NA
0
0%
NA
NA
405
3
0%
99%
100%
3,231
3,871
2%
-20%
-43%
97
232
0%
-139%
-88%
216
252
0%
-16%
32%
301
62
0%
80%
47%
0%
NA
NA
1,025
1,048
1%
-2%
-2%
73
73
0%
0%
3%
15,864
17,134
12%
-8%
-10%
30,738
31,706
22%
-3%
-3%
137,328
137,328
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Saint Lucie, FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
21
DRAFT
NOT FOR RELEASE
Saint Lucie, FL Current Condition
INTERNAL USE ONLY
Saint Lucie, FL Year 2100, A1B Mean
22
DRAFT
NOT FOR RELEASE
INTERNAL USE ONLY
Indian River Lagoon
As was the case in Saint Lucie, saturation is again an important process at this east coast site
resulting in a loss of 15% to 25% of dry land (depending on scenario). Again, as this is a heavily
developed site this may be more a prediction of costs to be imposed on landowners rather than an
actual loss of dry land. Under the maximum scenario, some of the fresh marsh at the site is
converted into transitional salt marsh by the year 2100. Overwash is not predicted to be important
at this site, but beach erosion does claim roughly 50% of ocean beach under both scenarios.
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean (Max) for Indian River Lagoon, FL
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
Sum of Categories (ha)
Init. Cond. (ha)
74,380
6,121
48
16,784
1,720
1
104
549
18
195
554
5,468
39,039
46,685
191,665
Year 2100 Percent of Percent Loss Percent
(ha)
Init. Cond.
(mean)
Loss (max)
63,019
39%
15%
25%
5,422
3%
11%
25%
53
0%
-9%
-8%
17,764
9%
-6%
11%
1,681
1%
2%
3%
4,098
0%
-569031% -1515643%
3,755
0%
-3512%
-5135%
548
0%
0%
0%
41
0%
-128%
-264%
2,927
0%
-1398%
-2117%
284
0%
49%
50%
0%
NA
NA
5,205
3%
5%
7%
0%
NA
NA
39,640
20%
-2%
-4%
47,229
24%
-1%
-2%
191,665
SLAMM Predictions of Marsh Fate under Scenario A1B, Mean for Indian River Lagoon, FL
Initial Condition
Year 2100
Dry Land
Hardwood Swamp
Cypress Swamp
Inland Fresh Marsh
Tidal Fresh Marsh
Transitional Salt Marsh
Saltmarsh
Mangrove
Estuarine Beach
Tidal Flat
Ocean Beach
Rocky Intertidal
Inland Open Water
Riverine Tidal
Estuarine Open Water
Open Ocean
23
DRAFT
NOT FOR RELEASE
Indian River Lagoon, FL Current Condition
INTERNAL USE ONLY
Indian River Lagoon, FL Year 2100, A1B Mean
24
DRAFT
NOT FOR RELEASE
INTERNAL USE ONLY
Model Parameterization

Digital Elevation Maps were downloaded using the USGS seamless data distribution tool
(http://seamless.usgs.gov).

NWI maps were downloaded as polygons and converted to rasters with the appropriate
SLAMM category (http://www.nwi.fws.gov/).

NOAA data were gathered from 35 sites (Figure 1) to parameterize the model for tidal
range, inland tidal range, and “NGVD88 to Mean Tide Level” corrections. See the table
below for a summary of NOAA data used to derive parameters.
NOAA Stations, Tide Range, and MTL Corrections
8729840
8729824
8729831
8729808
PENSACOLA, PENSACOLA BAY , FL
FLORIDATOWN, ESCAMBIA BAY , FL
FERRY PASS, ESCAMBIA BAY , FL
LITTLE SABINE BAY , FL
8728711 APALACHICOLA RIVER , FL
8728694 WHITE BEACH, EAST BAY , FL
8728690 APALACHICOLA, AP. RIVER , FL
0.383
0.442
0.421
0.392
towards water BG1732
most inland
inland
most ocean
0.094
0.412
0.601
0.492
inland
inland
most ocean
AS0240
NA
NA
0.061
AG7403
-0.131
AG7535
-0.098
AD7844
-0.225
AC3180
-0.18
AC3180
AA0428
AA0300
-0.18
-0.213
-0.308
AF3181
-0.311
AF3186
AF6971
-0.253
-0.298
AK3003
-0.326
AC2177
-0.271
AC2055
-0.256
AC1173
-0.256
8726364
8726428
8726277
8726573
MULLET KEY, TAMPA BAY , FL
TIERRA VERDE, FL
FORT HAMER, FL
GADSDEN POINT, TAMPA BAY , FL
0.634
0.659
0.686
0.75
ocean
ocean
inland
inland
8725781
8725685
8725665
8725366
SHELL CREEK, PEACE RIVER, FL
CUTOFF SOUTH
LITTLE GASPARILLA ISLAND
ESTERO ISLAND
0.668
0.454
0.464
inland
ocean
ocean
8724992 ADDISON BAY, FL
8724951 PANTHER KEY, FL
8724919 CHOKOLOSKEE , FL
0.884
1.286
0.968
inland
ocean
inland
8724919 CHOKOLOSKEE , FL
8723797 ISLAMORADA
0.968
0.462
0.322
ocean
0.353
0.367
0.908
0.329
0.476
inland
most inland
inland
inland
ocean
1.209
1.214
1.211
ocean
ocean
ocean
0.723
0.654
0.649
0.511
0.77
0.543
estuarine
ocean
most inland
ocean
ocean
inland
8724008 KNIGHT KEY CHANNEL , FL
8722371
8722334
8722212
8722357
8722414
SEWALL POINT. ST. LUCIE RIVER , FL
NORTH FORK, ST. LUCIE RIVER , FL
FORT PIERCE, SOUTH JETTY , FL
STUART, ST. LUCIE RIVER , FL
GOMEZ , FL
8721604 TRIDENT PIER, PORT CANAVERAL , FL
8721804 CANOVA, FL
8721649 COCOA BEACH, ATLANTIC OCEAN , FL
8723165
8723232
8723289
8723355
8723393
8723423
MIAMI, BISCAYNE BAY , FL
KEY BISCAYNE YACHT CLUB , FL
CUTLER, BISCAYNE BAY , FL
RAGGED KEY NO. 5, BISCAYNE BAY , FL
ELLIOTT KEY (OUTSIDE) , FL
TURKEY POINT, BISCAYNE BAY , FL
25
DRAFT
INTERNAL USE ONLY
Historic sea level rise trend data were downloaded from NOAA and spatially interpolated as
necessary. Variation in historic trends were relatively minor (figure below)
Historic Sea Level Rise Trends Measured at NOAA Stations
3
2.5
2
1.5
1
0.5
Vaca Key, Florida
Mayport, Florida
Miami Beach,
Florida
Key West, Florida
Naples, Florida
Fort Myers, Florida
St. Petersburg,
Florida
Apalachicola,
Florida
0
Pensacola, Florida
mm per year

NOT FOR RELEASE
.
26
DRAFT
NOT FOR RELEASE
INTERNAL USE ONLY

Erosion rates were set to SLAMM defaults. Default erosion rates are 2.0 horizontal meters
per year for marshes, 1.0 meter per year for swamps, and 0.5 meters per year for tidal flats.
These rates are based on a combination of professional judgment and a brief literature
survey. (Note also that these erosion rates presume that a threshold for erosion has been
exceeded prior to the incidence of horizontal erosion. See the technical documentation for
more information.)

Accretion rates were set to 2.25 mm/year for salt marshes, 3.75 mm/year for brackish
marsh, and 4.0 mm/year for tidal flats. These data were based on measurements from the
Altamaha River in Georgia (Personal Communication, Dr. Christopher Craft.) However a
literature review of accretion rates, including several measurements from Florida sites,
indicate that the above rates are comfortably in-line with measurements taken throughout
Florida (D. R. Cahoon, J. W. Day, Jr., and D. J. Reed, 1999. The influence of surface and
shallow subsurface soil processes on wetland elevation: A synthesis. Current Topics in Wetland
Biogeochemistry, 3, 72-88. ) (D. R. Cahoon, D. J. Reed, J. W. Day, Jr., 1995. Estimating
shallow subsidence in microtidal salt marshes of the southeastern United States: Kaye and
Barghoorn revisited. Marine Geology, 128, 1-9.)
27