A GEOGRAPHICAL SURVEY OF CENTER PIVOT IRRIGATION SYSTEMS IN THE CENTRAL AND SOUTHERN HIGH PLAINS AQUIFER REGION OF THE UNITED STATES

With the declines in water levels of the Central and Southern High Plains Aquifer, there is a critical need to accurately map the irrigated agriculture in this region as it is the largest user of groundwater resources. The goal of this study was to develop a geospatial database of all areas under the most dominant irrigation system in the region: center pivots. The borders of all center pivots (50,116) were manually digitized using high spatial resolution satellite imagery, delineating the area that can be potentially irrigated by these systems. Most center pivots were comparable in size (ca. 50 ha), with a range of 1 to >230 ha. The areas of digitized center pivots at the state and study area levels were relatively close to estimates of two actual irrigated area products based on automatic land classification. The new layer was also used to extract available data on groundwater level changes since predevelopment (before 1950). Aquifer regions under center pivots in Colorado and Texas had the smallest and largest declines in water level, respectively. The new layer offers advantages in terms of accurately identifying the area covered by center pivots and has potential research and practical applications such as studying adopted practices in response to water level declines, assessing field-scale irrigation uniformity, and extracting distributed soil, weather, and crop data to be used in various precision agriculture applications. The new layer is freely available to the public as supplemental information of this article (https://doi.org/10.13031/14707284).