Shorelines

Shoreline armoring

About this indicator: Shoreline armoring can take the form of a bulkhead, sea wall, riprap, or any other built impediment to naturally advancing tidewaters. The amount of shoreline that has been armored can be used as a general indicator of the condition of marine shorelines.

When armoring is present, the health of habitats decline in the nearshore area (the water, shoreline and adjacent upland areas). The nearshore area is an important feeding, nesting and resting ground for many fish and wildlife species, including young salmon as they migrate from the stream of their birth to marine rearing areas.

Status: Conclusions from a baseline survey for shoreline armoring in 2005 show that many beach-feeding sediment sources have been locked up behind armoring. Much of King County's mainland shoreline has been armored — in stark contrast to the relatively natural shorelines along Vashon-Maury Islands.

The Central Puget Sound Basin is one of the most heavily urbanized areas within Puget Sound, and King County's armored marine shoreline is indicative of this.

Influencing factors: Property owners build bulkheads to protect their homes and businesses from erosion.

Existing DNRP response: King County is working to decrease the rate of new and currently existing shoreline armoring in unincorporated areas. Recognizing that not all armoring has the same impacts, these reductions will be focused where sediment movement is restricted and most important. Removing or preventing armoring in deeper, inter-tidal waters is also a priority.

Many Vashon Island waterfront property owners who are applying for flexibility to critical areas regulations through the Rural Stewardship Planning process are being provided with alternatives to bulkhead construction.

Priority new actions: With a baseline in place, follow-up surveys of new armoring every five years will provide useful information. This will allow for a more realistic review of changes that occur naturally and the results of those initiated by King County. Additionally, creating better guidance on the appropriate location and the type of new shoreline armoring is expected in the King County's Shoreline Master Program update.

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Fecal bacteria at marine beaches

About this indicator: Fecal coliforms are one of many groups of bacteria that indicate the presence of fecal contamination at swimming beaches. The State of Washington's water regulatory standards indicate that organism counts should not exceed a geometric mean value of 14 colony-forming units per 100 ml, and not more than 10 percent of the samples used to calculate the geometric mean should exceed 43 colony-forming units per 100 ml. These standards are known as the geo-mean standard and the peak standard, respectively.

For this indicator, comparison to both the geo-mean and peak standard are made for each beach site monitored (13 sites in 2006) using fecal coliform counts from samples collected on a monthly basis during the year. The geo-mean value reflects the typical fecal coliform count at a given site, while the peak value is used to determine whether pulses of high fecal coliform counts may be present at a site.

Status: During 2006, four of the 13 sites tested (30 percent) met both the geo-mean and peak standards for all 12 sampling events. Eight of the 13 sites (62 percent) met the geo-mean standard for all 12 sampling events, but did not meet the peak standard one or more times. One of the 13 sites (8 percent) did not meet either the geo-mean or peak standards one or more times. Sites with any type of standard failure are shown on the map by the red circled X.

Influencing factors: Fecal coliform concentrations measured at marine beach sites are highly influenced by proximity to fresh water inputs, especially during rainfall events. During 2006, the majority of peak standard exceedances at all stations occurred following significant rainfall events during either or both January and December. The one station that failed both the geomean and peak standards one or more times is located offshore of Gorsuch Creek on Vashon Island. This station failed the peak standard only once, in April 2006. It failed the geomean standard three of the 12 months monitored and exceeded the standard only slightly with geomean values of 15, 15, and 16 colony-forming units per 100 ml.

Existing DNRP response: Past and on-going efforts by King County have reduced fecal contamination from most outfalls to the point that contributions from non point sources in the area are more significant than the outfalls themselves. DNRP has little control on improving current levels of fecal coliforms near most outfall sites. An exception to this is the Vashon outfall where recent improved maintenance and operations have reduced bacteria entering the environment and an upgrade to the outfall itself (moving it further out into deeper water) should further reduce fecal contamination on nearby beaches.

Priority new actions: DNRP will pursue efforts to determine sources of non-point source contributions of fecal coliforms. These efforts will include evaluating emerging technologies in microbial source tracking, and the continued application of fecal coliform survey projects, such as the one performed at Alki Point. King County has added an additional 13 new beach monitoring stations for 2007.

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