An assessment of post-restoration trajectories of geomorphological and vegetative change in the Nisqually River Delta, Washington
June 2021 - June 2023
- Nisqually Indian Tribe
The Nisqually River Delta provides important feeding and rearing habitat for a variety of fish and wildlife. Between 1996 and 2009, the Nisqually Tribe and Billy Frank Jr. Nisqually National Wildlife Refuge collaborated to restore over 365 ha of estuarine habitat to tidal influence in the Delta for the benefit of juvenile Chinook salmon and other estuary-dependent species. Pre- and post-restoration monitoring datasets have highlighted clear increases in connectivity between the Nisqually River mainstem and the restored estuary, especially at mid-to-high tide; however, low-elevation areas in the most recent (2009) and most subsided restoration area have experienced relatively slow vegetation colonization and growth. In light of the decadal anniversary of the 2009 restoration, the Tribe, the Refuge, and USGS have collaborated to collect new data, including LIDAR imagery (2020), aerial photography (2019), SET (Surface Elevation Table) readings (2019, 2021), and vegetation surveys (2019, 2021) to supplement 2009-2015 monitoring datasets. These new data will facilitate a full evaluation of restoration progress using metrics of habitat connectivity, spatial analyses of sediment deposition and erosion, and vegetation colonization and growth. Results will inform future habitat management decisions to preserve and enhance habitat for sensitive fish and wildlife species.