The San Bernardino Valley Water Conservation District (SBVWCD) contracted AECOM to produce an association-level vegetation classification and map of lands owned and/or managed by the District in the Upper Santa Ana River Wash. The classification is consistent with the Manual of California Vegetation (MCV) (CNPS 2018), and vegetation sampling methods followed National Park Service (NPS) Vegetation Index protocols. The mapping study area consists of approximately 2,200-acres near Mentone, in San Bernardino, California. Approximately 1,500-acres lie within the Preserve set aside for the Upper Santa Ana River Wash Habitat Conservation Plan. The primary purpose of this project was to provide the District a consistent system for the mapping of vegetation on its lands. Vegetation mapping is conducted periodically by the District to inform various environmental and species management initiatives.All plot data collection took place May 2-5, 2025. Four-band (RGB and color NIR) aerial imagery was collected May 4, 2022. All image acquisition, processing, and ortho-rectification were conducted by GeoTerra, Inc. Polygons were drawn using a minimum mapping unit (MMU) of 0.5 acre, and vegetation attributes assigned using the vegetation key provided in the newly created classification. Field reconnaissance was conducted by the photo-interpreter during the earliest stages of mapping to establish photo-signature recognition for each alliance and association. There were a total of 21 mapping classes. More information can be found in the project report, which is bundled with the vegetation map published for BIOS here: https://filelib.wildlife.ca.gov/Public/BDB/GIS/BIOS/Public_Datasets/3200_3299/ds3212.zip