Nearshore Strategies Data Report
Cereghino et al 2012 completed a soundwide analysis to identify and describe river delta sites in Puget Sounds as part of a nearshore ecosystem restoration strategy (using remote sensing data c. 2000-2006). The following narrative of this delta site was developed to support distribution and use of analysis results:
- The Duwamish Delta in the South Central Sub-basin historically contained 1,532 acres of vegetated wetland along a 32 km shoreline. The delta receives flow from a 124,268 square kilometer watershed. These characteristics make this system the 9th largest delta out of 16 systems in Puget Sound.
- Simenstad et al 2011 found that this system had lost 100% of its vegetated tidal wetlands, and 100% of its shoreline length. Of the remaining shoreline, 100% shows some evidence of infrastructure development. In the surrounding uplands, 100% of land is estimated to have greater than 10% impervious surface. Across the watershed, 100% of land is estimated to have greater than 10% impervious surface. Based on these paramters, the site was given a degradation score of 76 out of 100, making it the 1th most degraded delta in Puget Sound. It faces a medium risk of future development locally, and a high risk of development across the watershed. Approximately 52% of the watershed is currently impounded behind dams.
- A population of restoration efforts have been completed under NRDA authorities.