Oregon hydrologic area agricultural field boundaries and field level and hydrologic unit water-use data

The data was developed for the USGS Water-Use and Data Research program grant opportunities G20AS00053 and G21AS00258, combined with fundnig from Oregon Water Resources Department to improve estimates of water use from irrigated lands in Oregon. These data contain attributes of irrigation status, irrigation source type, crop type, irrigation method, assumed irrigation efficiency, irrigation water source, evapotranspiration (ET) data from OpenET, and effective precipitation developed using the USBR ET Demands model. Thee data were aggregated in order to further the development of estimates of applied water at the field-scale.

NOTICE:

This dataset is superseded by an expanded and updated release and report, “Crop Evapotranspiration, Consumptive Use, and Open-Water Evaporation for Oregon” (Huntington et al., 2025). Please download and cite the new version hosted at https://www.dri.edu/project/owrd-et/. This record is retained for transparency but should not be used for new analyses.

Methods
A single set of draft field boundaries for all agricultural lands were developed to represent the maximum extent of irrigated lands from 1985-2020 (digitized at the 1:5,000 scale). The approach used for this task was relatively straight forward yet time consuming and required careful attention to detail to avoid numerous potential pitfalls. Agricultural field boundaries were developed within a GIS system by modifying existing 2007 USDA Common Land Unit (CLU) data, OWRD drawn field boundaries (e.g., Malheur Lake Basin) and developing field boundaries from scratch where needed. This entailed: 1) using Common Land Unit (CLU) as-is where the quality and representativeness of the linework was deemed suitable; 2) modifying the CLU data to eliminate duplicates, overlaps, and slivers within the linework, and make representative of maximum agricultural extent; 3) manually digitizing new field boundaries where they do not currently exist; and 4) QAQC all results.

Crop type and irrigation status rasters and field-level summaries were derived from the USDA Cropland Data Layer (CDL) (USDA, 2019) and the open-source IrrMapper model (Ketchum et al., 2020). IrrMapper uses a Random Forest (RF) modeling approach to predict four land classes of irrigated agriculture, dryland agriculture, uncultivated lands, and wetlands at an annual time step, and at 30 m spatial resolution across the Western U.S. IrrMapper was used in this project to produce rasters of these classes for 2016-2022. For the attribution of agricultural field boundaries, the native IrrMapper values were aggregated into 2 classifications; a value of ‘1’ representing irrigated conditions and ‘0’ representing non-irrigated conditions. For each year, mapped field polygons were included in HUC-12 ET and irrigated acreage summaries if the irrigation status value was greater than 0.4 (40% of IrrMapper pixels in polygon are classified as irrigated). Crop type classification was based on the mode (i.e., majority) of CDL crop type pixels contained by the individual field geometry.

Irrigation system type was determined based on available data including OWRD place of use, water right, and water source information, high-resolution aerial images, and expert knowledge of agricultural practices in Oregon. The primary sources of imagery used for irrigation system type attribution was sourced from OSIP acquired in 2017 and 2018 at ~0.3m (1 ft pixel resolution) (State of Oregon: Oregon Geospatial Enterprise Office - Oregon Statewide Imagery Program, n.d.) and the 2020 series of aerial imagery from the National Agriculture Imagery Program (NAIP) (National Agriculture Imagery Program (NAIP), 2019) acquired at 60 cm (2 ft pixel resolution). Fields were attributed using the following irrigation system types: 0 - Developed/No longer irrigated; 1 - Sprinkler-Pivot-Linear; 2 - Sprinkler-Other (Wheel Line, Hand Line, Solid Set, Big Gun, Travelling Gun, Pods); 3 - Flood-Uncontrolled (Wild Flood) and No Apparent Irrigation Equipment; 4 - Flood-Controlled (Land Leveling, Borders, Basins, Furrows); 5 - Micro (Micro Sprinklers, Drip Lines, Subsurface Drip).

An irrigation efficiency value, assumed to represent the ratio of ET of applied water divided by the total applied water, was assigned to each agricultural field based on the system type attribute. Average values of irrigation efficiency for each system type category were based on values in the Washington Department of Ecology Report “Determining Irrigation Efficiency and Consumptive Use” (Washington State Department of Ecology, 2005).

Fields digitized by the DRI team were attributed by OWRD staff with one of the following irrigation source types: groundwater irrigated (GW), surface water irrigated (SW), or a combination of groundwater and surface water (GW&SW). The geometries represented in the shapefile are attributed using the following categories: 1 =GW irrigated, 2 = SW irrigated, and 3 = Combination.

Estimates of irrigation application rates were developed using spatially averaged field-scale OpenET ensemble ET estimates, effective precipitation developed from ET Demands, and irrigation efficiency attributes collected by OWRD. Application rates were estimated as: Application Rate = (ET – effective precipitation) / irrigation efficiency) 

This approach resulted in many timesteps where effective precipitation was greater than ET, which resulted in negative Net ET. This negative Net ET was interpreted as a surplus of water contained within the represented unit of soil. As vegetation response lags irrigation activity, it is a certainty that irrigation or precipitation events occur during one calendar month, with a corresponding increase in ET and vegetation vigor observed in the following month. To account for this asynchronous relationship, negative Net ET was carried over to the following calendar month. This carry-over was repeated until positive Net ET values accounted for the surplus water condition. The applied water calculation was initialized using data developed prior to the 2016 water year, therefore all data associated with 2016 is considered valid.

Citations:

Beamer, J., & Hoskinson, M. (2021). Historical Irrigation Water Use and Groundwater Pumpage Estimates in the Harney Basin, Oregon, 1991-2018. State of Oregon Water Resources Department.

Bromley, M.; Minor, B. A.; Pearson, C.; Beamer, J.; Dunkerly, C. W.; Ott, T.; Huntington, J. L.; Hoskinson, M. (2023). Evapotranspiration, Net Irrigation Water Requirements, and Reservoir Evaporation Estimates for Oregon. Desert Research Institute – Draft report prepared for Oregon Water Resources Department.

Huntington, J., Minor, B., Bromley, M., Pearson, C., Beamer, J., Ingwersen, K., Carrara, K., Atkin, J., Brito, J., Morton, C., Dunkerly, C., Volk, J., Ott, T., ReVelle, P., Fellows, A., and Hoskinson, M. (2025). Crop evapotranspiration, consumptive use, and open water evaporation for Oregon. Division of Hydrologic Sciences, Desert Research Institute report 41306, 94 p., 10 appendices.

Melton, F. S., Huntington, J. L., Grimm, R., Herring, J., Rollison, D., Erickson, T., Allen, R., Anderson, M., Fisher, J. B., Kilic, A., Senay, G. B., Volk, J., Hain, C., Johnson, L., Ruhoff, A., Blankenau, P., Bromley, M., Carrara, W., Daudert, B., Doherty, C., Dunkerly, C., Friedrichs, M., Guzman, A., Halverson, G., Hansen, J., Harding, J., Kang, Y., Ketchum, D., Minor, B., Morton, C., Ortega-Salazar, S., Ott, T., Ozdogan, M., ReVelle, P. M., Schull, M., Wang, C., Yang, Y., & Anderson, R. G. (2021). OpenET: Filling a critical data gap in water management for the western United States. JAWRA Journal of the American Water Resources Association, 58(6): 971-994. https://doi.org/10.1111/1752-1688.12956

National Agriculture Imagery Program (NAIP). (2020). [Data set]. DOI/USGS/EROS. https://catalog.data.gov/dataset/national-agriculture-imagery-program-naip

State of Oregon: Oregon Geospatial Enterprise Office - Oregon Statewide Imagery Program. (n.d.). https://www.oregon.gov/geo/Pages/imagery.aspx

USDA NRCS. (1993). Part 623 National Engineering Handbook, Chapter 2, Irrigation Water Requirements.

Washington State Department of Ecology, 2005, Determining Irrigation Efficiency and Consumptive Use: Washington State Department of Ecology GUID-1210.