In 2015, agricultural irrigation withdrawals accounted for about 42 percent of the total freshwater withdrawals in the United States (Dieter and others, 2018). Consistent and accurate designations of irrigated agricultural lands, irrigation system type, conveyance systems, and water source (groundwater or surface water) are essential for the determination of irrigation water use and ultimately the sound management of our nation’s water resources. Several local, state, and federal agencies compile data (crops, irrigation, irrigation system type, etc.) that can be used to estimate irrigation withdrawals for agricultural. The format of these data varies from data tables, typically compiled at the county level, to spatial Geographic Information System (GIS) polygon layers of agricultural lands. These data sources are often incomplete, out of date, or inconsistently compiled.
The USGS and the University of Wisconsin-Madison developed annual Landsat-based Irrigation Dataset (LANID), which consists of irrigation maps, derivative products, and manually collected ground reference data covering the conterminous US (CONUS) for the period of 1997–2017 (Xie and Lark, 2021a). These maps were developed using verified irrigated-lands GIS datasets (i.e. training data) coupled with remotely-sensed, 30-meter resolution Landsat-derived data. The current and future availability of verified field-level data is required to train and validate this and other models.