UAS Monitoring of Ackerson Meadow Restoration in Yosemite National Park, CA

Over a three-year period, the U.S. Geological Survey (USGS) National Uncrewed Systems Office (NUSO), in partnership with the National Park Service (NPS), used drone-based lidar and photogrammetry to document the restoration of Ackerson Meadow in Yosemite National Park, CA. Beginning with pre-restoration surveys in 2023 and continuing through post-restoration monitoring in 2026, these repeated data collections captured changes in topography, hydrology, vegetation, and habitat. 

Ackerson Meadow is one of the largest mid-elevation meadows in the Sierra Nevada and provides important habitat for several sensitive wildlife species. Decades of land use and water management altered the meadow and contributed to extensive gully erosion that drained wetlands and threatened critical habitat. In response, project partners completed the largest wetland restoration project in Yosemite National Park's history, restoring 94 acres of former wetlands and protecting an additional 84 acres through large-scale gully filling and revegetation efforts. 

This video showcases aerial imagery and lidar visualizations collected before, during, and after restoration, highlighting both the transformation of the landscape and the role of uncrewed aircraft systems in supporting long-term environmental monitoring and ecosystem restoration. 

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.    

Time Stamps: 

00:05 UAS flying low over a field of purple, yellow, and white flowers at Ackerson Meadow, pre-restoration in June 2023.   

00:26 UAS flying high over the center of Ackerson Meadow, pre-restoration in June 2023.   

00:46 UAS flying high over Ackerson Meadow at dusk in November 2023.   

00:55 UAS flying over various parts of the meadow with fill areas visible during restoration efforts in November 2024.   

02:17 UAS footage over the meadow during restoration efforts in November 2024.  

03:07 UAS footage flying over Ackerson Meadow, vegetation growth visible post-restoration in July 2026.  

03:49 UAS footage flying over purple flowers, tall grasses, and revegetated areas in the meadow post-restoration in July 2026.  

05:00 UAS flying low over Ackerson Meadow post-restoration in July 2026.  

05:40 UAS footage flying high over Ackerson Meadow post-restoration in July 2026.