20th Annual South Florida GIS Expo
SUSAN M. HOHNER
AND
October 10th - 11th, 2013 Palm Beach County Convention Center, West Palm Beach, FL
THOMAS W. DRESCHEL
Everglades Systems Assessment, South Florida Water Management District, West Palm Beach, Florida
The Florida Everglades is a patterned peatland which once covered about 1.1 X 1010 m2 (2.7 X 106 acres) of south Florida and now covers approximately 6.1 X 109 m2 (1.5 X 106 acres). The peat of the Everglades is formed from sawgrass or other aquatic plant material that has accumulated over millennia, with decomposition limited by inundation. Since the late 1800s, urban and agricultural development have strongly influenced the loss of peat within the Everglades. In this study, we utilized spatial data sets developed for the Everglades peat and bedrock surfaces. We used these surfaces to calculate the original volume of peat present in the Everglades and the current volume of peat in the Everglades. We then projected regional soils values for bulk density and carbon content to calculate the mass and carbon content of the predrainage and current volumes of peat in the Everglades.
Procedures and Calculations
Data Sets for Evaluating Peat Volumes
The total Everglades peat volumes were determined by subtracting the bedrock surface elevations (feet, NGVD) from the predrainage and current surface elevations (feet, NGVD) for each region, which were then converted to cubic meters.
Predrainage Contours (NSRSM)
Parker Bedrock Map
Sources for the South Florida Topography Project
The peat volumes (cubic meters) were then converted to mass by multiplying by the peat bulk density (megagrams or metric tons per cubic meter) for the region; The amount of carbon in the peat (metric tons) was determined by multiplying the peat mass by the carbon content (metric tons carbon per metric ton of peat) for the region.
Region
Total Area (m2)
Peat Carbon Volume Mass (MT) (MT) (m3)
Region
Total Area (m2)
Peat Volume (m3)
5.6 x 108
1.8 x 109
4.2 x 108
6.9 x 108
1.1 x 108
1.1 x 108
7.2 x 108
2.2 x 108
1.3 x 109
1.1x 109
4.0 x 108
4.6 x 108
3.8 x 108
9.2x 106
7.7 x 108
2.8 x 108
9.9 x 108
1.2 x 107
Total EPA
Total EPA
5.6 x 109
4.7 x 109
Mass (MT)
Carbon (MT)
Total EPA
Total EPA
Current WCA1
Predrainag 5.7 x 108 8.2 x 106 2.3 x 106 4.4 x 105 e Ochopee Marl Marsh
Current WCA2A
Current WCA2B
Predrainag 8.9 x 109 2.0 x 1010 2.5 x 109 9.3 x 108 e Ridge and Slough
Current WCA3AN
Current WCA3AS
Predrainag e Eastern 1.6 x 109 2.0 x 108 8.9 x 107 8.8 x 106 Marls & Taylor Slough
Current WCA3B Current ENP Ochopee Marl Marsh Current ENP Shark River Slough Current ENP Eastern Marls & Taylor Slough
Total
Total
Total
Total
1.1 x 1010 2.0 x 1010 2.6 x 109 9.4 x 108
Conclusions The total predrainage Everglades area was 1.1 x 1010 m2 with a peat volume of about 2.0 x 1010 m3 and a mass of X.X x 10X metric tons; The total current Everglades area is 5.6 x 109 m2 with a peat volume estimated to be about 4.7 x 109 m3 and a mass of X.X x 10X metric tons; The predrainage Everglades was about 11 billion m2 in size with an average depth of peat of about 2 meters. The current Everglades Protection Area is about 6 billion m2 in size with an average depth of peat of about ¾ of a meter. Thus, the current Everglades is about one-half of the area, but less than one-fourth of the volume of the predrainage. REFERENCES: • 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., 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. • 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. • Parker G.G., Ferguson, G.E., Love, S.K., et al., 1955. Water Resources of Southeastern Florida. Geological Survey Water-Supply Paper 1255, United States Government Printing Office, Washington, DC. • 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.
AUTHORS’ CONTACT INFORMATION 3301 Gun Club Road, MSC 4440 West Palm Beach, FL 33406 Susan M. Hohner: Senior Geographer, (561) 682-6801,
[email protected] Thomas W. Dreschel: Section Leader, (561) 682-6686,
[email protected]
