Template:SPU 7157

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 7157 is a 10.19 km long beach system containing 772 meters of barrier beach (8%) and 3 creek mouths, one of 121 beach sites located in the San Juan Sub-basin. Based on these attributes it ranks 67 out of 100 in terms of size and complexity among all Puget Sound Beach systems. Over five generations of beach development, 66 percent of beach length now has some indicator of sediment supply degradation, and 80 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 114 meters. Based on these metrics, this site ranks 68 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 D12, a small group of 6 unusual sites where parcel size is very large, but sediment supply degradation and nearshore impervious levels are well above 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 high 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 0.13 km, encompassing 0.3 hectares of tidal wetlands. This system is one among 89 barrier embayment complexes in the San Juan Sub-basin. Based on these metrics this site ranks 15 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 7157 currently has 0 embayment--1 less than under historical conditions. This has been accompanied by a 100 percent loss of 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 94 out of 100 and placed this site in Degradation Group D9, a medium group of 39 of the most degraded barrier embayment systems, with very high shoreline modification following extensive loss of length, in moderately to highly developed drift cells. Based on this grouping, the site is recommended for a enhancement-based approach, 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.