Peat and Carbon Loss in the Everglades Using Historical Data and Geospatial Techniques

Abstract

Historical, spatially referenced data can provide an opportunity, to not only describe past conditions, but inform changes that have occurred through time to the present. We have had access to predrainage, early post-drainage, and other historical surveys, maps and other data sets and descriptions. These data sources as well as current spatial data, with the aid of geographic information systems (GIS) have allowed us to create topographic maps and analyze landscape-scale changes in topography and peat volumes over the course of over a century. Thus, we have quantified subsidence and CO2 evolution at the regional scale by calculating the changes in peat volume.
We determined the amount of peat that has been lost from the Everglades using these data and spatial analysis tools. The spatially referenced data used were peat surface data created for a Natural System Regional Simulation Model (NSRSM) using historical land surveys, data gathered within the Everglades for the South Florida Topography Project, a south Florida bedrock map created mid-20th century, land surveys made in the Everglades Agricultural Area, tree island topographic surveys from 1976 and 2009 and data from the USEPA RE-MAP program.
These data sets have allowed us to evaluate change in volume, mass and carbon on a whole-system, regional, down to a single tree island scale. The analyses will be discussed in relation to the impact on restoration of the Everglades and the effect on the regional and global carbon cycles.

Full text

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The Everglades Protection Area (EPA) and
Everglades Agricultural Area (EAA)
The Everglades Protection Area (EPA) and
Everglades Agricultural Area (EAA)
22
Project 1.
Evaluating
Peat Loss
From the
Entire
Everglades
System
Project 2.
Evaluating
Peat Loss
From the
Everglades
Agricultural
Area
Project 3.
Evaluating
Peat Loss
From a Tree
Island in
WCA-2A

Evaluating Everglades Peat Carbon
Loss Using Geospatial Techniques
Evaluating Everglades Peat Carbon
Loss Using Geospatial Techniques
33
Sources for the South Florida Topography Project
Predrainage Contours
from The NSRSM

The predrainage surface is a reconstruction using the
best available information from predrainage and early
post-drainage land surveys and canal construction
surveys
The current surface is a mosaic of data from various
sources having varying degrees of accuracy

The Parker bedrock map is referenced to earlier work of
Jones et al. (1948) who describes the sampling (probing)
to be to a 0.1 foot accuracy at intervals of 660 feet.
We used current EPA peat soils characteristics for both
the current and predrainage calculations
For the predrainage calculations, we screened the data
and restricted it to values that were reasonable for
predrainage peat, using the most unimpacted peat in the
region (from WCA-1) as a proxy for predrainage
44

Predrainage and Current Everglades Surfaces
(freshwater)
Predrainage and Current Everglades Surfaces
(freshwater)
55
Visualization of the contours of the peat surfaces used in the peat loss and carbon flux calculations for the Greater
Everglades. The upper surface represents the pre-drainage peat surface (NSRSM) and the lower surface the current
condition (USACE). As an example, the distance between the pre-drainage surface and the current surface of the
WCAs is approximately three to five feet (0.4 m to 0.9 m). Acronyms: WCA = Water Conservation Area, EAA =
Everglades Agricultural Area and ENP = Everglades National Park.

Everglades Peat and Carbon Loss
Results (Method 1)
Everglades Peat and Carbon Loss
Results (Method 1)
The difference between the reconstructed
peat surfaces provided an estimate of the
degree of soil loss and carbon dioxide
released that occurred during the period
following the construction of the early
drainage canals.
Specifically, for the EAA: 2.3 billion metric
tons; for WCA-1, 2A and 3B: 0.1 billion metric
tons; for WCA-3A: 0.6 billion metric tons; and
for WCA-2B and ENP: 50 and 60 million
metric tons of carbon dioxide respectively.
66

77

88

99

1010

1111

1212

Time Period Total Area
(m2)
Peat Volume
(m3)
Mass
(MT)
Carbon
(MT)
Predrainage Everglades
Totals 1.1 x 1010 2.0 x 1010 2.6 x 1099.4 x 108
Current EPA Totals 5.6 x 1094.7 x 1094.5 x 1081.8 x 108
Change (Loss) 5.4 x 1091.5 x 1010 2.2 x 1097.6 x 108
1313

USEPA R-EMAP Data Comparison
(Scheidt, Johnson, Scinto and Kalla, GEER 2015)
USEPA R-EMAP Data Comparison
(Scheidt, Johnson, Scinto and Kalla, GEER 2015)
1414

Estimating Soil Subsidence and Carbon Loss in
the Everglades Agricultural Area (EAA) using
Geospatial Techniques
Estimating Soil Subsidence and Carbon Loss in
the Everglades Agricultural Area (EAA) using
Geospatial Techniques
This study estimated the volume and mass of peat that
had been lost over the last 125 years within the EAA.
To offset limitations in the historical as well as current
data sets, we used two independent methods and sets
of data to estimate the volumes of peat lost. The first
method was based on historical and current estimates
of peat thickness. The second method was based on
estimates of the historical and current surface
topography.
We used a GIS to organize the historical data, to
interpolate, and to calculate volume differences.
The volumes were used, in combination with soil
characteristics to determine peat subsidence, peat
carbon loss and carbon dioxide emissions.
1515

Contour maps were
created and analyzed to
estimate peat loss (ft) in
the EAA:
Approach 1
Peat Thickness 1915;
Peat Thickness 2003
Approach 2
Bedrock (1955);
Peat Surface 1880;
Peat Surface 2000
Contour maps were
created and analyzed to
estimate peat loss (ft) in
the EAA:
Approach 1
Peat Thickness 1915;
Peat Thickness 2003
Approach 2
Bedrock (1955);
Peat Surface 1880;
Peat Surface 2000
1616

Estimated values of soil parameters for
predrainage and current soil profiles in the
EAA
Estimated values of soil parameters for
predrainage and current soil profiles in the
EAA
1717

EAA Analysis ResultsEAA Analysis Results
Approximately two-thirds of the peat volume
from the EAA has been lost during the last
century, decreasing from about 7 x 109m3to
about 2.5 x 109m3.
This corresponds to a loss of about 2.5 x 108
metric tons of peat and a release of about 5 x
108metric tons of CO2.
This CO2 is similar to the annual carbon
emissions of approximately 1 x 105American
households, assuming emissions of 48 metric
tons per year per household.
1818

3. Geospatial Quantification of Peat Loss
from an Everglades Tree Island
3. Geospatial Quantification of Peat Loss
from an Everglades Tree Island
This study estimates changes on a tree
island in Water Conservation Area-2A
over a 36-year period.
The data sources used were land
surveys of the surface of the island
conducted in 1973 and 2009. The more
recent survey included the collection of
soil/sediment cores for analysis.
1919

Ghost Tree Islands and Dineen IslandGhost Tree Islands and Dineen Island
2020
2009

1973 Survey of Dineen Island1973 Survey of Dineen Island
2121
Map courtesy of Kenneth Rutchey

1973 and 2009 Peat Surface Transects1973 and 2009 Peat Surface Transects
2222
Rutchey 2009).

Topographic InterpolationsTopographic Interpolations
2323

Core Analysis ResultsCore Analysis Results
2424

Tree Island Change ResultsTree Island Change Results
The average peat subsidence on the island
in 36 years was about 0.14 m, which is
equivalent to 0.40 cm yr-1. This compares
well with our result from Project 1 that the
average peat subsidence calculated for the
entire landscape of WCA-2A of
approximately 0.42 cm yr-1 over 130 years.
The changes in the island resulted in a net
loss of roughly 8,000 metric tons of peat,
3,600 metric tons of carbon, 2.5 metric tons
of total phosphorus and 230 metric tons of
total nitrogen.
2525

Overall SummaryOverall Summary
Using GIS and a variety of spatial data
sources, we calculated the volume of peat
loss from various regions of the historical
Everglades.
In addition, from analyses performed on
collected peat cores and values found in
the literature, we were able to estimate the
masses of peat, carbon and other mineral
constituents lost.
Although many uncertainties exist with
the data and the techniques, we believe
that this approach can provide insight into
the amount of change that the Everglades
has experienced over more than a century.
2626

Sources:Sources:
Aich, S. and T. W. Dreschel. 2011. Evaluating Everglades Peat
Carbon Loss Using Geospatial Techniques. Florida Scientist
74(1):63-71.
Aich, S., C.W. McVoy, T.W. Dreschel and F. Santamaria. 2013.
Estimating Soil Subsidence and Carbon Loss in the Everglades
Agricultural Area, Florida using Geospatial Techniques.
Agriculture, Ecosystems & Environment 171 (2013) 124-133.
Aich, S., S. M. L. Ewe, B. Gu and T. W. Dreschel. 2014. An
evaluation of peat loss from an Everglades tree island, Florida,
USA. Mires and Peat, 14(2):1-15.
Aich, S., C. W. McVoy, F. Santamaria and T. W. Dreschel. 2008.
Early Post-Drainage Aspects of the Everglades Agricultural Area
Based on Historic Land and Canal Surveys. Poster presented at the
15th Annual South Florida GIS Expo, West Palm Beach, FL.
Central and Southern Florida (C&SF) Flood Control District. 1973.
Island in Conservation Area 2A. Survey Drawing Number CA-25,
sheet 1 of 1, Drawn by B.R., 6/7/1973, Engineering Division, West
Palm Beach, FL.
Ecology and Environment, inc. 2009. Final Report: Survey of
Living and Ghost Tree Islands in Water Conservation Area 2A:
Assessment of Island Microtopography, Soil Bulk Density, and
Vegetation Patterns. Contractor Report to the South Florida
Water Management District, West Palm Beach, FL.
2727

Sources (continued) :Sources (continued) :
Hohner, S.M. and T.W. Dreschel. 2015. Everglades peats: using
historical and recent data to estimate predrainage and current
volumes, masses and carbon contents. Mires and Peat 16(1) 1-15.
Holt, P. R., R. J. Sutton and D. Vogler. 2006. South Florida Digital
Elevation Model, Version 1.1. U. S. Army Corps of Engineers,
Jacksonville District, Jacksonville, FL
McVoy, Christopher W., Winifred Park Said, Jayantha Obeysekera,
Joel A. VanArman and Thomas W. Dreschel. 2011. Landscapes and
Hydrology of the Predrainage Everglades. University Press of
Florida, Gainesville, FL. 342 pp. + 297 pp. on DVD.
Said, W.P. and M. C. Brown. 2011. Hydrologic Simulation of the
Predrainage Greater Everglades Using the Natural System Regional
Simulation Model v3.3. South Florida Water Management District,
Hydrologic and Environmental Systems Modeling Section, West
Palm Beach, FL, 532 pp.
2828

Questions or Comments?Questions or Comments?
3030
From Snyder, G. H. (2004) EVERGLADES AGRICULTURAL AREA SOIL SUBSIDENCE AND
LAND USE PROJECTIONS. Contractor Report to the South Florida Water Management
District, University of Florida, IFAS. 26 pp.