Piner Point Shoreline Stabilization

King County acquired a former gravel mine adjacent to the Piner Point Natural Area on the shoreline near the south end of Maury Island. The property originally had a small home, parking area, access road, a creosote-treated timber bulkhead and a series of reinforced benches remnant from original mining. King County sought to remove the creosote-treated revetment, but required a shoreline stability assessment of the subject property. They also sought design guidance to revetment removal process.

King County contracted with Herrera to provide the shoreline stability assessment and design guidance. After a site visit and a review of available information, Herrera determined that there would be little risk to adjacent landowners from the removal of the bulkhead because the shoreline in front of the bulkhead was accreting sediment. This was determined from a range of geomorphic indicators.

In the process of researching the site, Herrera confirmed that the site was used as a gravel pit, which explained some of the unusual landforms on the property. The presence of the gravel pit and mounded spoils meant that some of the road infrastructure found on site had to remain in place to ensure that adjacent properties would not be at risk from the restoration project.