Irrigation Water Conveyance by Ditch and Canal on Agricultural Land in the Conterminous United States, 1992: National Resource Inventory Conservation Practice 428

This data set represents the estimated percentage of the 1-km grid cell that is covered by or subject to the agricultural conservation practice (CP428), Irrigation Water Conveyance by Ditch and Canal (IWCDC) on agricultural land by county. Irrigation Water Conveyance by Ditch and Canal is described as "a fixed lining of impervious material installed in an existing or newly constructed irrigation field ditch or irrigation canal or lateral." (U.S. Department of Agriculture, 1995) This data set was created with geographic information systems (GIS) and database management tools. The acres on which IWCDC'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.