Efforts to monitor groundwater pumping for irrigation in the Western United States (Western US) are hindered by the lack of comprehensive pumping records. While previous studies have developed region-specific machine learning models using limited datasets, these models are often not transferable across regions, and a groundwater pumping dataset that goes beyond local and state boundaries remains missing. In this study, we develop a regional-scale, data-driven machine learning framework to address these limitations by integrating remote sensing datasets and in-situ pumping records from Arizona, Colorado, Kansas, and Nevada. Using gridded hydroclimatic and land use variables, including effective precipitation, fraction of irrigated croplands, and evapotranspiration, the model generates spatially continuous, high-resolution (2 km, annual) historical groundwater pumping estimates from 2000 to 2023 for groundwater-dominated basins of the Western US, while predicting total irrigation in conjunctive basins. The model demonstrates good predictive performance under randomized split, with an R2 = 0.62, NRMSE = 0.50, NMAE = 0.34, and PBIAS = 8.59% on the test set. Model evaluation over groundwater-dominated and conjunctive basins across the region shows satisfactory results. In addition, comparisons using spatial holdout analysis and power consumption-based pumping records in multiple basins indicate strong generalization capacity and spatial transferability within the study region. Our assessment identifies limited availability of in-situ pumping records and lack of surface water irrigation datasets as the primary constraints for further advancing such regional-scale frameworks. Overall, the findings highlight that regional transferability of machine learning models for predicting groundwater irrigation is achievable but contingent on holistic representation of the hydrologic system.

GEE asset - projects/ee-westus-pumping/assets/westus_pumping
GEE code example - https://code.earthengine.google.com/a439de4785b9123e7255c3471ff8ed15
GitHub repository - https://github.com/mdfahimhasan/WestUS_pumping