Location of irrigated land classified from satellite imagery - High Plains Area, nominal date 1992

Potential climate change effects on groundwater recharge in the High Plains Aquifer, USA

“…Development of the area began with dryland agriculture in the late 1800s followed by rapid expansion of irrigated agriculture in the 1950s [Colaizzi et al, 2009]; irrigated land now covers $12% of the region [Qi et al, 2002]. Water for irrigation is sourced from groundwater in the south and central regions and from a combination of groundwater (86%) and surface water (16%) in the north (2005 data, [Kenny et al, 2009]).…”

“…The historical baseline rainfall raster was obtained from PRISM (PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu/), the soils raster was derived from the STATSGO map [NRCS, 2006], and the vegetation raster was reclassified from National Land Cover Data (NLCD 2001) [Homer et al, 2007] with irrigated land coverage from Qi et al [2002] spliced in. These disparate data sets have been rescaled to a common grid size of 1 km from 1:250,000 for the soils, 4 km for rainfall, and 30 m for vegetation and irrigation.…”

A multi-scale accuracy assessment of the MODIS irrigated agriculture data-set (MIrAD) for the state of Nebraska, USA

“…Multispectral image data from the early Landsat multispectral scanner and the more recent Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) systems are appropriate for classifying spatial cropping patterns across the landscape (Bauer et al 1978;Odenweller and Johnson 1984;Price et al 1997;Oetter et al 2001;Dappen et al 2007;Maxwell et al 2004;Craig 2001) given their high spatial resolution (79 m and 30 m, respectively) relative to typical field sizes throughout the United States (Ozdogan and Woodcock 2006). However, these Landsat-based irrigated crop mapping efforts have not been national in scope, but rather conducted at local (Keene and Conley 1980;Egbert and Mercier 2000), state (Dappen et al 2007), and regional (Thelin and Heimes 1987;Qi et al 2002) scales. As a result, a patchwork of Landsat-derived irrigation maps has been generated for selected locations and time periods across the country, but no national-level mapping effort like the National Land Cover Data-set (NLCD) (Vogelmann et al 2001;Homer et al 2004) has been undertaken to provide a spatially and temporally consistent classification of irrigated agricultural land.…”

“…Satellite-based remote sensing has been increasingly used for irrigation mapping in the United States, with the majority of these efforts having utilized data from the series of Landsat instruments (Keene and Conley 1980;Thelin and Heimes 1987;Egbert and Mercier 2000;Qi et al 2002;Dappen et al 2007). Multispectral image data from the early Landsat multispectral scanner and the more recent Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) systems are appropriate for classifying spatial cropping patterns across the landscape (Bauer et al 1978;Odenweller and Johnson 1984;Price et al 1997;Oetter et al 2001;Dappen et al 2007;Maxwell et al 2004;Craig 2001) given their high spatial resolution (79 m and 30 m, respectively) relative to typical field sizes throughout the United States (Ozdogan and Woodcock 2006).…”

“…A seasonal classification approach using multiple dates (ranging from 2-5 dates) of Landsat imagery collected during key periods of the growing season has often been used for irrigated crop mapping (Egbert and Mercier 2000;Qi et al 2002) to capitalize on phenology-related spectral differences to discriminate irrigated and nonirrigated crops, which would result in 576 B.D. Wardlow and K. Callahan hundreds of Landsat images being required if such a method was implemented at a national scale.…”