Irrigation Dynamics Inside and Outside Official Irrigation Systems in Galați County, Romania: A Satellite-Based Assessment (2017–2025)

In order to ensure agricultural productivity and, implicitly, food security, irrigation is indispensable in regions with extensive agricultural areas subject to water stress. In such areas, approaches are needed to optimize water resources and better understand irrigation needs, aspects that cannot be captured exclusively through administrative reporting. This study analyzed the annual dynamics of irrigation in Galați County, Romania, during 2017–2025 using satellite data, spatial analysis techniques, and public administrative records. Using a Random Forest classifier applied to multitemporal Sentinel-2 and Landsat data, annual maps of irrigated areas were generated and their distribution inside and outside official irrigation systems was analyzed. Satellite-detected irrigated area varied from 19.1 thousand ha in 2017 to 41.8 thousand ha in 2023, broadly consistent with hydroclimatic variability. Agreement between satellite data and official reports was moderate at the aggregate level (r = 0.782, R2 = 0.612), but strong at the irrigation-scheme level (r = 0.907, R2 = 0.822). Spatial analysis further showed that 60.1% of the cropland-filtered outside-system irrigated area was located within 500 m of the nearest potential surface water source. The results indicate that satellite-based analysis can serve as a useful complementary tool for irrigation monitoring, spatial assessment, and county-scale irrigation auditing.