Fuller et al 2014 port susan monitoring report

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Fuller, R., S. Thomas, J. McArdle, J. Lesser. 2014. Stillaguamish estuary monitoring report summary, September 2013 to July 2014. Produced by Western Washington University.

Notes[edit]

  • Provides summary and discussion of observations at the Stillaguamish Delta following the Port Susan Restoration.
  • Includes SET monitoring of sediment accretion.
  • Sampling methods are provided in appendices including Systematic Qualitative Monitoring (SQM) protocols
  • Indicates that there are differences in slope among delta regions. The restoration site is flatter than natural delta, potentially changing development over time.
  • The Stillaguamish is affected by a very long storm fetch compared to other Puget Sound estuaries.
  • Observations suggest that there may be interaction between elevation, sediment density, and goose herbivory, that sets the stage for erosion patterns in areas less connected to the river. Geese focus grazing on middle elevation areas with soft sediment, resulting in reduced vegetative cover, loose soil and greater erosion. The marsh face appears to erode, even as the high marsh is accreting (perhaps further nourished by lower marsh erosion). This suggests that goose herivory combined with wave energy may be more responsible for lost marsh area than insufficient sediment accretion.
  • Suggests that tracking marsh boundaries at edge of elevation ranges may provide the most robust tool for observing multiple factors affecting marsh resilience.
  • The restoration site forms a subsided basin with only two excavated connections to the adjacent slough. While tidal inundation is full, drainage in slower than natural sites both due to the channel size, and inhibition of scour from compacted layers formed during agricultural development.