Surface Drainage, Field Ditches on Agricultural Land in the Conterminous United States, 1992: National Resource Inventory Conservation Practice 607

This data set represents the estimated percentage of the 1-km grid cell that is covered by or subject to the
agricultural conservation practice (CP607), Surface Drainage, Field Ditches (SDFD) on agricultural land by
county. Surface Drainage, Field Ditches are described as "a graded ditch for collecting excess water."
(U.S. Department of Agriculture, 1995) This data set was created with geographic information systems
(GIS) and database management tools. The acres on which SDFD's are applied were totaled at the county
level in the tabular NRI database and then apportioned to a raster coverage of agricultural land within the county
based on the Enhanced National Land Cover Dataset (NLCDe) 1-kilometer resolution land cover grids
(Nakagaki, 2003). Federal land is not considered in this analysis because NRI does not record information
on those lands.