Estimates of Subsurface Tile Drainage Extent for the Conterminous United States, early 1990s

This dataset is a 30-meter resolution national-scale raster of estimated subsurface tile drainage extent that was developed using 1) county-level estimates of subsurface tile drained acres for the early 1990s (Sugg, 2007); 2) the extent of cultivated cropland from the National Land Cover Dataset (NLCD) 2011; 3) the extent of poorly drained soils from the State Soil Geographic Database (STATSGO) database Version 2; 4) the extent of federally-owned land, and 5) county administrative boundaries. The extent of estimated subsurface tile drains within each county was evenly allocated by using a geographic information system (GIS) to identify areas of potentially drained land - cropland with poorly drained soils. The estimated extent of subsurface tile drains in each cell is expressed in square meters. 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 http://www.wri.org/publication/assessing-us-farm-drainage.