Presentation Abstract
Protection programs are not holding the line against the incremental impacts of shoreline development. Habitat of the beach-spawning surf smelt (Hypomesus pretiosus), a forage fish critical to marine food webs, is vulnerable to the impacts of armoring and sea level rise (Simenstad et al 1979, Thom et al 1994, Krueger et al 2009). Scientists in San Juan County, Washington recently completed research on the tidal distribution of surf smelt eggs; the cumulative impacts of armoring on forage fish spawning habitat; and sea level rise vulnerability. To determine the tidal distribution of surf smelt eggs, samples were collected at 26 transects across the vertical beach profile of active spawn events in five regions of the County. Results show that 35% of incubating surf smelt eggs are located above Mean Higher High Water. ArcGIS was used to evaluate the cumulative impacts of armoring on forage fish spawning habitat, including direct burial, indirect impacts such as disruptions to sediment processes and shoreline development patterns. Findings show that shoreline armoring buries just over 10 acres of known surf smelt spawning habitat in the County. Armored feeder bluffs and armor located below mean sea level occur in drift cells with known surf smelt spawning habitat, disrupting sediment supply and transport. A strong relationship between residential home setback distances and the likelihood of armoring was also documented; 74% of armored sites have a house located closer than 100 feet from the marine shoreline. Sea level rise vulnerability models were applied across moderate and high projection scenarios and two planning horizons (2050 and 2100). Results indicate that forage fish spawning beaches will likely be threatened by sea level rise in the short term, especially at the 16% of sites where existing armor will constrain the landward translation of upper beach habitat (Griggs et al 1994, Krueger et al 2009). Results have implications for improved management of shorelines across the Salish Sea, including both protection and restoration strategies.
Session Title
Session S-06H: Puget Sound Shorelines and the Impacts of Armoring: State of the Science 2014
Conference Track
Shorelines
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
1-5-2014 1:30 PM
End Date
1-5-2014 3:00 PM
Location
Room 607
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Smelts--Spawning--Washington (State)--San Juan County; Smelts--Effect of habitat modification on--Washington (State)--San Juan County; Shore protection--Environmental aspects--Washington (State)--San Juan County
Geographic Coverage
Salish Sea (B.C. and Wash.); San Juan County (Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Included in
The Cumulative Impacts of Shoreline Armoring on Forage Fish Spawning Habitat in San Juan County, Washington
Room 607
Protection programs are not holding the line against the incremental impacts of shoreline development. Habitat of the beach-spawning surf smelt (Hypomesus pretiosus), a forage fish critical to marine food webs, is vulnerable to the impacts of armoring and sea level rise (Simenstad et al 1979, Thom et al 1994, Krueger et al 2009). Scientists in San Juan County, Washington recently completed research on the tidal distribution of surf smelt eggs; the cumulative impacts of armoring on forage fish spawning habitat; and sea level rise vulnerability. To determine the tidal distribution of surf smelt eggs, samples were collected at 26 transects across the vertical beach profile of active spawn events in five regions of the County. Results show that 35% of incubating surf smelt eggs are located above Mean Higher High Water. ArcGIS was used to evaluate the cumulative impacts of armoring on forage fish spawning habitat, including direct burial, indirect impacts such as disruptions to sediment processes and shoreline development patterns. Findings show that shoreline armoring buries just over 10 acres of known surf smelt spawning habitat in the County. Armored feeder bluffs and armor located below mean sea level occur in drift cells with known surf smelt spawning habitat, disrupting sediment supply and transport. A strong relationship between residential home setback distances and the likelihood of armoring was also documented; 74% of armored sites have a house located closer than 100 feet from the marine shoreline. Sea level rise vulnerability models were applied across moderate and high projection scenarios and two planning horizons (2050 and 2100). Results indicate that forage fish spawning beaches will likely be threatened by sea level rise in the short term, especially at the 16% of sites where existing armor will constrain the landward translation of upper beach habitat (Griggs et al 1994, Krueger et al 2009). Results have implications for improved management of shorelines across the Salish Sea, including both protection and restoration strategies.
