Template:SPU 4112

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 4112 is a 9.56 km long beach system containing 1027 meters of barrier beach (11%) and 5 creek mouths, one of 145 beach sites located in the South Central Sub-basin. Based on these attributes it ranks 72 out of 100 in terms of size and complexity among all Puget Sound Beach systems. Over five generations of beach development, 63 percent of beach length now has some indicator of sediment supply degradation, and 21 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 36 meters. Based on these metrics, this site ranks 71 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 D15, a very large group of 247 sites with very high levels of sediment supply degradation and average to above average levels of shoreline development. Based on this grouping we recommend this site for a enhancement-based strategy, where due to extensive development and degradation, the likelihood of restoring ecosystem processes is low, and efforts should focus first on mitigating development impacts, and strategically protecting and restoration critical habitat functions for key species. The site faces no 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 1 barrier-type embayment, with an embayment shoreline of 0.19 km, encompassing 0 hectares of tidal wetlands. This system is one among 88 barrier embayment complexes in the South Central Sub-basin. Based on these metrics this site ranks 8 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 P2, a very large group of 232 sites where very small embayments occuring at a typical density.

Site 4112 currently has 0 embayment--1 less than under historical conditions. This has been accompanied by a 0 percent increase in wetland area and a 100 percent loss of embayment length, based on comparison to historic maps. 100 percent 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 81 out of 100 and placed this site in Degradation Group D5, a medium group of 50 barrier embayment systems where there has been large loss of embayment length and extensive development of embayment shorelines with moderate to low levels of urbanization or sediment supply degradation in the surrounding drift cell. 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.