DRASTIC model results for Upper Floridan aquifer vulnerability to Bromacil and Ethylene Dibromide
This dataset includes DRASTIC (Aller and others, 1987) model results for Upper Floridan aquifer vulnerability to contamination. The DRASTIC value serves as an intrinsic vulnerability index for assessing the transport of contaminants from the surface. The DRASTIC model setup requires the input of raster data for depth to groundwater, aquifer recharge, aquifer media, soil media, topography, vadose zone media, and aquifer hydraulic conductivity. These variables were entered into the DRASTIC equation using the raster calculator tool in ArcGIS.
A downloadable version of the final dataset is provided in GeoTIFF file format with 10-meter resolution.
Douglas, Steven H., 20170828, DRASTIC model results for Upper Floridan aquifer vulnerability to Bromacil and Ethylene Dibromide: U.S. Geological Survey data release doi:10.5066/F7S46QTV, U.S. Geological Survey, St. Petersburg, FL.
Planar coordinates are encoded using row and column
Abscissae (x-coordinates) are specified to the nearest 10.0
Ordinates (y-coordinates) are specified to the nearest 10.0
Planar coordinates are specified in meters
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 1980.
The semi-major axis of the ellipsoid used is 6378137.0.
The flattening of the ellipsoid used is 1/298.257222101.
U.S. Geological Survey, 20111117, Potentiometric Surface of the Upper Floridan Aquifer in Florida and in Parts of Georgia, South Carolina, and Alabama, May – June 2010: U.S. Geological Survey, Orlando, FL.
U.S. Department of Agriculture, Natural Resources Conservation Service, 2015, USDA-NRCS Soil Survey Geographic (SSURGO 2.2): texdesc and ksat_r: USDA/NRCS - National Geospatial Center of Excellence, Fort Worth, TX.
Tabular and map Soil Survey Geographic Database SSURGO data for Florida were downloaded through the U.S. Department of Agriculture (USDA) Geospatial Data Gateway. Descriptions for the SSURGO classes are available at the Soil Survey website http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ref/?cid=nrcs142p2_054253. SSURGO metadata is available at: http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/home/?cid=nrcs142p2_053631. The polygon SSURGO shapefiles were joined to the tabular files within the file geodatabase. The first join to be made uses the “mukey” field as the common identifier to join the cokey field from the “component” table. The second join to be made uses the cokey field as the common identifier to join the ksat_r (Saturated Hydraulic Conductivity) field from the “CHorizon” table. Finally, the chtexturegrp join was made using the chorizon field as the common identifier to join the texdesc (Texture) field. The texture and rock type variables are expressed as descriptive text. They were reclassified as numerical values based on the methods described by Aller and others (1987). The final polygon shapefile was converted to a 10-meter raster GeoTiffs using the Polygon to Raster tool.
Person who carried out this activity:
Steven H. Douglas
Cherokee Nation Technologies contracted to the U.S. Geological Survey
600 4th St S
St Petersburg, FL
Date: 2015 (process 2 of 5)
SWFWMD Recharge converted to inches per year based on Aller and others (1987).
Date: 2015 (process 3 of 5)
Aquifer media reclassified based on Aller and others (1987).
Date: 2015 (process 4 of 5)
Topography converted to percent slope using the Slope tool in the Surface toolbox in ArcGIS based on Aller and others (1987).
Date: 2015 (process 5 of 5)
Impact of the vadose zone reclassified based on Aller and others (1987).
Aller, L., Bennet, T., Lehr, J. H., Petty, R., and Hackett, G., 198705, DRASTIC: A standardized system to evaluate groundwater pollution potential using hydrogeologic settings: National Water Well Association, U.S. Environmental Protection Agency, Dublin, OH.
Douglas, S., Dixon, B., and Griffin, D., Unknown, Assessing intrinsic and specific vulnerability models ability to indicate groundwater vulnerability to groups of similar pesticides: a comparative study: Physical Geography, Philadelphia, PA.
Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The data have been approved for release and publication by the U.S. Geological Survey (USGS). Although the data have been subjected to rigorous review and are substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, the data are released on the condition that neither the USGS nor the U.S. Government may be held liable for any damages resulting from authorized or unauthorized use. Although the data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described and/or contained herein. Users of the data are advised to read all metadata and associated documentation thoroughly to understand appropriate use and data limitations.