Template:SPU 6042

Nearshore Strategies Data Report

Cereghino et al 2012 completed a soundwide analysis to identify and describe beach sites in Puget Sounds as part of a nearshore ecosystem restoration strategy (using remote sensing data c. 2000-2006). The following narrative was developed to support distribution and use of analysis results:

Beach Site 6042 is a 22.31 km long beach system containing 4803 meters of barrier beach (22%) and 17 creek mouths, one of 59 beach sites located in the Whidbey Sub-basin. Based on these attributes it ranks 85 out of 100 in terms of size and complexity among all Puget Sound Beach systems. Over five generations of beach development, 39 percent of beach length now has some indicator of sediment supply degradation, and 41 percent of the nearshore zone has estimated impervious levels higher than 10 percent. Property boundaries now legally segment the shoreline with an average of one property every 33 meters. Based on these metrics, this site ranks 78 out of 100 in terms of estimated degradation among all beach sites in Puget Sound. The PSNERP Strategy Analysis places this site in Degradation Group D13, a large group of 116 sites where parcel size, nearshore impervious and sediment supply degradation all approach or exceed the Puget Sound average. Based on this grouping we recommend this site for a restoration-based strategy, where there may be the opportunity through a combination of protection and restoration efforts to recover the full operation of ecosystem processes thereby recovering ecosystem services that are either degraded or at risk. The site faces a moderate risk from jetty development impounding sediment, has no impacts from active shoreline railroad, and faces a slight risk from predicted future population growth.

This site is among 518 littoral cells that contained barrier-type embayments. Historically this system contained 6 barrier-type embayments, , one of which occurs on the overlap with an adjacent drift cell, with an embayment shoreline of 4.96 km, encompassing 24 hectares of tidal wetlands - considering the length of beach this is the equivelent of one embayment every 3.7 km. This system is one among 46 barrier embayment complexes in the Whidbey Sub-basin. Based on these metrics this site ranks 73 out of 100 in terms of size and complexity among all Puget Sound barrier embayment systems. The PSNERP Strategy Analysis placed this site in Potential Group P9, a large group of 69 sites with large embayments and wetlands at a typical density, identified as noteworthy sites for their high potential to provide ecosystem services.

Site 6042 currently has 1 embayment--5 less than under historical conditions. This has been accompanied by a 99 percent loss of wetland area and a 65 percent loss of embayment length, based on comparison to historic maps. None of the remaining embayment shoreline length has evidence of shoreline modification. Based on these metrics, and the general development status of the drift cell, the PSNERP Strategy Analysis ranked this system 58 out of 100 and placed this site in Degradation Group D3, a very large group of 107 barrier embayment systems with high levels of armoring along the supporting drift cell, but othewise moderate to low levels of degradation within embayments. Based on this grouping, the site is recommended for a restoration-based approach, where there may be the opportunity through a combination of protection and restoration efforts to recover the full operation of ecosystem processes thereby recovering ecosystem services that are either degraded or at risk.