patrickbdevaney/mia9 · Datasets at Hugging Face

text stringlengths 0 6.44k
-8.1 (2025)
11.4 (2050)
35.8 (2075)
62.4 (2100)
>62.4
Garden, Bush and Long Keys
(Low) 50th Percentile
1:17,000
Areas of interest
Dry Tortugas
National Park
Figure 8. Mean sea level elevation maps for Dry Tortugas National Park at Loggerhead, Garden, Bush
and Long Keys for the median (50th) and high (99th percentile) RCP 8.5 projections. Tides and storm
surges are not included in this projection.
3.1.1. General Influence of Sea Level Rise
Over the next ten years, represented by the 2025 estimates, dramatic change in sea level is not
anticipated with an expected sea level rise of 7 cm for the low scenario and 10 cm for the high
projection. These changes will result in more frequent tidal inundation along coastal regions although
the buttonwood ridge located along the southern peninsula and north shore of Florida Bay should
remain above mean sea level. This modest increase is not likely to impact the terrestrial portions of
South Florida or the Dry Tortugas.
By 2050, local sea levels are expected to increase between 26 and 41 cm. Overall, inundation
at mean sea level will produce similar impacts for both scenarios with a wider fringe of saltwater
inundation around the periphery of the peninsula under the high scenario. Expansion of the white zone,
a low productivity area influenced by the periodic flooding of saltwater [26], is expected to continue.
Under both projections, mean sea level is expected to reach the elevation of the land surrounding the
Florida Power and Light Turkey Point nuclear power plant cooling canal system (vertical lines along
the southwest corner of Biscayne National Park (BNP) in Figure 7).
By 2075, sea levels are anticipated to increase by 51 and 91 cm for the low and high projections,
respectively. At these elevations, significant portions of the buttonwood ridge separating Florida
Bay from the peninsula will be exceeded by mean sea level, and marine conditions can be expected
to expand into current-day areas of the Everglades that maintain fresh and brackish-water marshes.
This could signal an important tipping-point in the ecological response of freshwater marshes since
freshwater basins delineated by the ridge will no longer be viable. Low-lying suburban areas along
the southeastern peninsula will also be at mean sea level elevation resulting in perennial tidal flooding
with significantly reduced ability to discharge rain floodwaters by gravity from the urban areas into
J. Mar. Sci. Eng. 2017, 5, 31 11 of 26
the sea. Below ground, saltwater intrusion can be expected to reduce aquifer productivity along coastal
well fields [27].
In 2100, the projected sea level rise is 77 cm for the low projection and 161 cm for the high scenario.
Strikingly, in the high scenario, mean sea level can be expected to extend from the southwest peninsula
to the northeast corner of Everglades National Park along the topographical depression of Shark River
Slough. It is likely that widespread ecological changes will be evident around South Florida as Florida
Bay expands. Many of the low-lying islands of Biscayne and Dry Tortugas national parks can be
expected to become tidally submerged or dynamically redefined. Islands with coral substrate are
likely to submerge, while sand- or sediment-based islands will become increasingly mobile as tidal
influences trigger localized erosive and depositional dynamics.
3.1.2. Infrastructure Inundation
Figure 9 presents a comparison of projected mean sea level with land elevation surrounding
infrastructure at Flamingo in Everglades National Park and Fort Jefferson in Dry Tortugas National
Park where red indicates a building or infrastructure footprint. Conditions at Flamingo are mixed,
with the low projection forecasting the housing and visitors center to remain above mean sea level to
2100, but with mean sea levels reaching the boat basin, maintenance yard and water plant by 2100.
Under the high projection, the housing area is at mean sea level by 2100; the visitor center will be
partially inundated by 2050; and the maintenance yard and water plant by 2075.
At Fort Jefferson, the projections indicate that the north coal dock and campground remain above
mean sea level to 2100, while areas around the ferry dock and the isthmus to Bush and Long Keys
are expected to be at mean sea level by 2075 under the low sea level rise projection. Under the high
projection, much of the north coal dock and campground will be at mean sea level by 2075, as will
much of the land between the ferry dock and moat, although a portion of this will be at sea level by
2050. The isthmus to Bush Key is expected to be at mean sea level by 2050.
It is important to note that mean sea level in Florida Bay fluctuates by approximately 30–40 cm
(12–16 in) in a yearly oceanographic cycle, as well as up to 70 cm (2.3 ft) in daily and monthly tidal
cycles so that effects of tidal inundation will be observed during high tides several years before the
projected dates when mean sea level reaches a specific land elevation.
Figure 9. Sea level rise inundation maps at Flamingo in Everglades National Park (top row) and Fort
Jefferson in Dry Tortugas National Park (bottom row). Building and infrastructure footprints are
indicated in red.
J. Mar. Sci. Eng. 2017, 5, 31 12 of 26
3.2. Exceedances
As sea levels rise against a fixed elevation threshold near the mean high water tidal elevation,
exceedance rate changes will follow Equation (1) experiencing nonlinear growth regardless of whether
water levels are increasing at a steady or accelerated rate [22]. This is exemplified in Figure 10 at four
coastal stations across the southern peninsula suggesting a transition from linear exceedance growth
to exponential growth. Model parameters fit to the middle elevation threshold are shown in Table 4.
Exceedance model fits suggest a progression of exponential growth initiation times (TG) from
the eastern end of Florida Bay where freshwater marsh interaction with the coastal region is high, to
the western side of the Bay where marine conditions prevail with substantial water mass exchange
with the Gulf of Mexico. Generally, the transition of exceedances near the mean high water tidal
threshold suggest that the late 20th to early 21st century represents a change of coastal dynamics where
water level exceedances enter a growth phase. Interestingly, the model fits indicate that the doubling
times (τ) increase from one decade in the marine areas to two and half decades in the eastern coastal
region of Florida Bay, suggesting that environmental impacts from increased exceedances may be more
acute over the next few decades along the southwestern coastal region.
Figure 10. Yearly water level elevation exceedance data and fits to the model of Equation (1). Elevation
thresholds are with respect to the NGVD29 datum. Note that the MD station is located on a higher
land elevation than the other three stations. (a) MK; (b) LM; (c) LS; (d) MD.
Table 4. Exceedance model parameters at an elevation threshold of 35 cm NGVD29 at Murray Key
(MK), Little Madeira Bay (LM) and Long Sound (LS). Note that the South Dade (MD) station is located
on a higher land elevation and uses a threshold of 85 cm NGVD29.
Station Threshold (cm) E0 α TL TG r τ
Murray Key (MK) 35 42.38 2.46 2005.51 2007.63 381.40 10.32
Little Madeira (LM) 35 71.49 3.99 1996.77 2000.39 134.36 16.82
Long Sound (LS) 35 83.80 1.80 2008.45 1998.01 229.10 20.36
South Dade (MD) 85 66.55 2.59 1998.34 1992.00 208.87 26.12
J. Mar. Sci. Eng. 2017, 5, 31 13 of 26
Exceedance Projections
Application of the sea level rise projections to exceedance data has potential to provide a
meaningful environmental-change metric. For example, projection of exceedances at Little Madeira Bay
based on a mean local coastal ridge elevation threshold of 70 cm NGVD29 is shown in Figure 11. Several

-8.1 (2025)

11.4 (2050)

35.8 (2075)

62.4 (2100)

>62.4

Garden, Bush and Long Keys

(Low) 50th Percentile

1:17,000

Areas of interest

Dry Tortugas

National Park

Figure 8. Mean sea level elevation maps for Dry Tortugas National Park at Loggerhead, Garden, Bush

and Long Keys for the median (50th) and high (99th percentile) RCP 8.5 projections. Tides and storm

surges are not included in this projection.

3.1.1. General Influence of Sea Level Rise

Over the next ten years, represented by the 2025 estimates, dramatic change in sea level is not

anticipated with an expected sea level rise of 7 cm for the low scenario and 10 cm for the high

projection. These changes will result in more frequent tidal inundation along coastal regions although

the buttonwood ridge located along the southern peninsula and north shore of Florida Bay should

remain above mean sea level. This modest increase is not likely to impact the terrestrial portions of

South Florida or the Dry Tortugas.

By 2050, local sea levels are expected to increase between 26 and 41 cm. Overall, inundation

at mean sea level will produce similar impacts for both scenarios with a wider fringe of saltwater

inundation around the periphery of the peninsula under the high scenario. Expansion of the white zone,

a low productivity area influenced by the periodic flooding of saltwater [26], is expected to continue.

Under both projections, mean sea level is expected to reach the elevation of the land surrounding the

Florida Power and Light Turkey Point nuclear power plant cooling canal system (vertical lines along

the southwest corner of Biscayne National Park (BNP) in Figure 7).

By 2075, sea levels are anticipated to increase by 51 and 91 cm for the low and high projections,

respectively. At these elevations, significant portions of the buttonwood ridge separating Florida

Bay from the peninsula will be exceeded by mean sea level, and marine conditions can be expected

to expand into current-day areas of the Everglades that maintain fresh and brackish-water marshes.

This could signal an important tipping-point in the ecological response of freshwater marshes since

freshwater basins delineated by the ridge will no longer be viable. Low-lying suburban areas along

the southeastern peninsula will also be at mean sea level elevation resulting in perennial tidal flooding

with significantly reduced ability to discharge rain floodwaters by gravity from the urban areas into

J. Mar. Sci. Eng. 2017, 5, 31 11 of 26

the sea. Below ground, saltwater intrusion can be expected to reduce aquifer productivity along coastal

well fields [27].

In 2100, the projected sea level rise is 77 cm for the low projection and 161 cm for the high scenario.

Strikingly, in the high scenario, mean sea level can be expected to extend from the southwest peninsula

to the northeast corner of Everglades National Park along the topographical depression of Shark River

Slough. It is likely that widespread ecological changes will be evident around South Florida as Florida

Bay expands. Many of the low-lying islands of Biscayne and Dry Tortugas national parks can be

expected to become tidally submerged or dynamically redefined. Islands with coral substrate are

likely to submerge, while sand- or sediment-based islands will become increasingly mobile as tidal

influences trigger localized erosive and depositional dynamics.

3.1.2. Infrastructure Inundation

Figure 9 presents a comparison of projected mean sea level with land elevation surrounding

infrastructure at Flamingo in Everglades National Park and Fort Jefferson in Dry Tortugas National

Park where red indicates a building or infrastructure footprint. Conditions at Flamingo are mixed,

with the low projection forecasting the housing and visitors center to remain above mean sea level to

2100, but with mean sea levels reaching the boat basin, maintenance yard and water plant by 2100.

Under the high projection, the housing area is at mean sea level by 2100; the visitor center will be

partially inundated by 2050; and the maintenance yard and water plant by 2075.

At Fort Jefferson, the projections indicate that the north coal dock and campground remain above

mean sea level to 2100, while areas around the ferry dock and the isthmus to Bush and Long Keys

are expected to be at mean sea level by 2075 under the low sea level rise projection. Under the high

projection, much of the north coal dock and campground will be at mean sea level by 2075, as will

much of the land between the ferry dock and moat, although a portion of this will be at sea level by

2050. The isthmus to Bush Key is expected to be at mean sea level by 2050.

It is important to note that mean sea level in Florida Bay fluctuates by approximately 30–40 cm

(12–16 in) in a yearly oceanographic cycle, as well as up to 70 cm (2.3 ft) in daily and monthly tidal

cycles so that effects of tidal inundation will be observed during high tides several years before the

projected dates when mean sea level reaches a specific land elevation.

Figure 9. Sea level rise inundation maps at Flamingo in Everglades National Park (top row) and Fort

Jefferson in Dry Tortugas National Park (bottom row). Building and infrastructure footprints are

indicated in red.

J. Mar. Sci. Eng. 2017, 5, 31 12 of 26

3.2. Exceedances

As sea levels rise against a fixed elevation threshold near the mean high water tidal elevation,

exceedance rate changes will follow Equation (1) experiencing nonlinear growth regardless of whether

water levels are increasing at a steady or accelerated rate [22]. This is exemplified in Figure 10 at four

coastal stations across the southern peninsula suggesting a transition from linear exceedance growth

to exponential growth. Model parameters fit to the middle elevation threshold are shown in Table 4.

Exceedance model fits suggest a progression of exponential growth initiation times (TG) from

the eastern end of Florida Bay where freshwater marsh interaction with the coastal region is high, to

the western side of the Bay where marine conditions prevail with substantial water mass exchange

with the Gulf of Mexico. Generally, the transition of exceedances near the mean high water tidal

threshold suggest that the late 20th to early 21st century represents a change of coastal dynamics where

water level exceedances enter a growth phase. Interestingly, the model fits indicate that the doubling

times (τ) increase from one decade in the marine areas to two and half decades in the eastern coastal

region of Florida Bay, suggesting that environmental impacts from increased exceedances may be more

acute over the next few decades along the southwestern coastal region.

Figure 10. Yearly water level elevation exceedance data and fits to the model of Equation (1). Elevation

thresholds are with respect to the NGVD29 datum. Note that the MD station is located on a higher

land elevation than the other three stations. (a) MK; (b) LM; (c) LS; (d) MD.

Table 4. Exceedance model parameters at an elevation threshold of 35 cm NGVD29 at Murray Key

(MK), Little Madeira Bay (LM) and Long Sound (LS). Note that the South Dade (MD) station is located

on a higher land elevation and uses a threshold of 85 cm NGVD29.

Station Threshold (cm) E0 α TL TG r τ

Murray Key (MK) 35 42.38 2.46 2005.51 2007.63 381.40 10.32

Little Madeira (LM) 35 71.49 3.99 1996.77 2000.39 134.36 16.82

Long Sound (LS) 35 83.80 1.80 2008.45 1998.01 229.10 20.36

South Dade (MD) 85 66.55 2.59 1998.34 1992.00 208.87 26.12

J. Mar. Sci. Eng. 2017, 5, 31 13 of 26

Exceedance Projections

Application of the sea level rise projections to exceedance data has potential to provide a

meaningful environmental-change metric. For example, projection of exceedances at Little Madeira Bay

based on a mean local coastal ridge elevation threshold of 70 cm NGVD29 is shown in Figure 11. Several