Verification Dataset of Irrigation Status of Agricultural Lands in Montana

Science Center Objects

The Wyoming-Montana Water Science Center (WY-MT WSC) is currently (2019-2020) developing field and data management methods to collect and manage field-verified spatial datasets of irrigated lands in an effort to improve estimates of irrigation water use throughout the nation.  The USGS is currently (2019) working with the University of Wisconsin to develop datasets to describe the spatial extent of irrigated agricultural lands across the United States on an annual basis for the period 1997-2017. These digital datasets (maps), called the Landsat Irrigation Dataset (LANID), are being developed using verified irrigated-lands GIS datasets (i.e. training data) coupled with remotely-sensed, 30-meter resolution Landsat-sourced data. The LANID project will be designed to add new datasets in order to create maps of irrigated lands throughout the United States in the future. The current and future availability of verified field-level data as provided by this project is required to train and validate the model.

Objectives:

  • Provide verified spatial datasets of the irrigation status (irrigated or non-irrigated) agricultural lands throughout areas of interest (example by watershed) on a revolving basis. Datasets are not intended to be extensive datasets of the irrigation status of all agricultural lands in an area, but rather a sample set of verified conditions (examples: irrigated or not, system type, crop type) to be incorporated in models developed to produce annual national maps of irrigated lands. A list of priority areas to be mapped will be developed by both the WY-MT WSC and the Montana Department of Natural Resources and Conservation (MTDNRC).

  • Create a shapefile of irrigation status of agricultural lands (by individual fields) of selected areas including attributes such as irrigated/non-irrigated, crop type, irrigation system type, water conveyance system, and water source (groundwater or surface water) being used for the current growing season.

  • Develop standardized field data-collection methodology and data processing guidance that can be used nationally within the USGS.

Benefits:

Natural color Landsat 8 image of center pivot irrigated crops in Washington state

The 11 bands of Landsat 8 can be combined in different ways to produce unique maps.  This image uses bands 4, 3, and 2 to produce a natural color image, which allows for the classification of irrigated fields.

  • Methodology and data collection efforts could be expanded to include area-wide assessments. For example, rather than just surveying a subset of fields in an area, an entire county or watershed could be mapped to meet project or cooperator needs.
  • On-site field visits promote increased understanding of the complexities and variability of agricultural irrigation. It is important for scientists and water-resource managers to physically observe actual delivery (examples: pipelines, ditches, etc.) and application systems (examples: variations in flood and sprinkler systems) as well as the processes that occur during irrigation such as excess watering and run-off.
  • Verification/ground truth datasets for models and remote sensing are in tremendous need both locally and nationally.
  • Scientists from several USGS WSCs have expressed interest in conducting field-verification projects in their states. Similar efforts could be conducted concurrently within several states allowing for collaboration to develop consistent methodology and nomenclature throughout the nation.

Products:

  • A series of digitized, field-verified maps (in a pdf and GIS shapefile) and summary tables (in spreadsheets or as attribute tables) representing a time-series of 2 to 6 observations over the course of 2 growing seasons within each of the selected areas recording the irrigation status of the assessed fields as well as observed crop type, irrigation system type, conveyance type, and source of irrigation water for the period between June 2019 and September 2020 will be generated. All data and files will be released through an USGS data release and will be considered the final product for deliverable. The GIS shapefile, metadata, and tabular data will be accessible on the USGS ScienceBase-Catalog web site. All maps, tables, and shapefile will be reviewed and approved by the USGS before being released. 
  • A guidance document describing methodology for the field and map development, data sources, field verification, crop delineation, digitizing, acreage limitations, assumptions, details on selected crops, and idle or vacant lands will be generated. This document is envisioned to support other WSCs to consistently and expediently complete similar efforts in other areas of the nation for future years.