Estimates of subsurface tile drainage extent for the conterminous United States, early 1990s

Metadata Updated: January 29, 2020

This dataset is a 30-meter resolution national-scale raster of estimated subsurface tile drainage extent based on early 1990s county areas of subsurface tile drains and geospatial datasets of cropland and poorly drained soil. Specifically, it was developed using 1) county-level acres of subsurface tile drain extents from Sugg (2007); 2) the extent of cultivated cropland from the National Land Cover Database (NLCD) 2011; 3) the extent of poorly drained soil from the State Soil Geographic (STATSGO) database Version 2; 4) the extent of federally-owned land, and 5) county administrative boundaries. Sugg's (2007) area of subsurface tile drains within each county was evenly allocated to potentially drained land -- cropland with poorly drained soil. The estimated area of subsurface tile drains in each cell is expressed in square meters. In most cases, the estimated subsurface drainage extent in each cell is less than the actual area of the cell in the raster. Sugg, Zachary, 2007, Assessing U.S. farm drainage: can GIS lead to better estimates of subsurface drainage extent?: World Resources Institute, Washington D.C., accessed December 2013, at

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License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Date April 21, 2016
Metadata Created Date January 29, 2020
Metadata Updated Date January 29, 2020
Reference Date(s) April 1, 2016 (publication)
Frequency Of Update notPlanned

Metadata Source

Harvested from DOI Open Data

Additional Metadata

Resource Type Dataset
Metadata Date April 21, 2016
Metadata Created Date January 29, 2020
Metadata Updated Date January 29, 2020
Reference Date(s) April 1, 2016 (publication)
Responsible Party U.S. Geological Survey, PACIFIC REGION (Point of Contact)
Contact Email
Access Constraints Use Constraints: 1) This dataset was created by allocating Sugg's (2007) county tabular areas of subsurface tile drainage extent to poorly drained cropland. But because subsurface tile drains are presumably not exclusively found on poorly drained cropland, nor evenly distributed in poorly drained cropland within a county, there is considerable uncertainty in this data set. 2) There are 108 counties (3.5 percent of all counties in the conterminous US) for which the subsurface tile drainage extent could not be represented in this dataset due to the absence of mapped cropland with poorly drained soil in these counties. The county areas of unaccounted subsurface tile drainage extent range from 2 to 181,200 acres, with an average of 4,629 acres (19 square kilometers). The 4 counties with the highest acreages are: a) Imperial County, CA - county FIPS (Federal Information Processing Standard) code 6025 - 181,200 acres (733 square kilometers); b) Riverside County, CA - county FIPS code 6065 - 37,200 acres (151 square kilometers); c) Hidalgo County, TX - county FIPS code 48215- 32,000 acres (129 square kilometers); and d) Kiowa County, OK - county FIPS code 40075 - 8,300 acres (33 square kilometers) 3) This dataset does not reflect non-cropland areas where subsurface tile drains may be installed. 4) This dataset is based on Sugg's (2007) county tabular data, and the revised estimates for counties in the Midwest states have not been validated (Sugg, 2007). In addition, Sugg's (2007) subsurface drainage area for over 80 percent of conterminous US counties were obtained from the 1992 NRI (U.S. Department of Agriculture, 1995). The NRI is a survey program, and limitations to their survey methods, protocols, and sample design should all be considered before using this dataset. 5) Although the cells in this raster are 30-by-30 meter in size and accordingly 900 square meters in area, cell values greater than 900 exist in 206 counties. These grid cells represent a greater area of subsurface tile drainage extent than the area of land they represent. Estimating subsurface tile drainage extent within a study area derived by clipping this raster to a study boundary and summing the cell values from the resultant raster could potentially result in a total estimated area of subsurface tile drainage extent greater than the total area of cropland, for example, within the study area. 6) As described in the Supplemental_Information section, Sugg (2007) used the NLCD 1992 (Vogelmann and others, 2001) for the source of mapped cropland whereas the NLCD 2011 (Homer and others, 2015; U.S. Geological Survey, 2014) was used to develop this dataset. One difference between the two NLCD products is the classification of cropland: the 2011 version has a single classification, cultivated crops whereas the NLCD 1992 has 4 classes: row crops, small grains,fallow, and orchards/vineyards/other. Nonetheless, nationally, the NLCD 1992 row crops represents 74 percent of the total area of the 4 cropland classifications; for the 12 Midwest states, 98 percent of the total cropland area is represented by row crops. Therefore, the classification differences between the NLCD 1992 and 2001 did not play a major role in introducing inconsistencies in the 12 Midwest states, but did to some degree elsewhere. 7) The replacement of the original STATSGO (U.S. Department of Agriculture, 1994) which is what Sugg (2007) used, with STATSGO2 (U.S. Department of Agriculture, 2006), likely contributed to spatial and attribute inconsistencies because of potential differences in soil-map-unit boundaries and soil-property quantifications between the two versions. 8) Please refer to the Horizontal_Positional_Accuracy section for information regarding the accuracy limitations of the NLCD (source for mapped cropland) and STATSGO2 (source for mapped soils) datasets. 9) State-level comparisons in the Midwest between Sugg's (2007) estimated areas of subsurface tile drains and the 2012 Census of Agriculture (U.S. Department of Agriculture, 2015) acres of land drained by tile showed that in Indiana, the areas were nearly identical; but for Illinois and Ohio, the Census 2012 areas were unexpectedly smaller than Sugg's by 8 and 13 percent respectively; for Michigan, the Census 2012 areas were larger by 10 percent; for Wisconsin, Kentucky, Missouri, Minnesota, and Iowa, the Census 2012 areas were larger by 24 to 43 percent; and for South Dakota, Kansas, and Nebraska, the Census of 2012 areas were immensely larger. Hence, based on this state-level comparison, within the Midwest states, the subsurface tile drainage extents in the western states (Iowa, Minnesota, Wisconsin, Missouri, South Dakota, Nebraska, and Kansas) increased substantially from the early 1990s to 2012, whereas subsurface drainage area in the eastern states (Illinois, Michigan, Indiana, and Ohio) remained about the same. 10) There were two (1990) counties (FIPS 12025, Dade, FL and FIPS 30113, Yellowstone National Park) in Sugg's (2007) data file that were not found in the 2010 county boundaries geospatial dataset. Sugg's (2007) data file showed zero acreage of subsurface tile drainage area for these counties. 11) See "Distribution_Liability"., Access Constraints: None. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data.
Bbox East Long -65.254952344
Bbox North Lat 50.627609837
Bbox South Lat 22.768624251
Bbox West Long -127.977086659
Coupled Resource
Frequency Of Update notPlanned
Harvest Object Id eb30ebc6-af36-4460-b55e-2e409fc03585
Harvest Source Id 5b7e4031-1e2d-428b-92e2-56554bbd7371
Harvest Source Title DOI Open Data
Licence Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner whenever applicable. 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 U.S. Geological Survey, 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 U.S. Geological Survey 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.
Metadata Language
Metadata Type geospatial
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester true

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