About this indicator: King County's Shorelines Index is derived from two main groupings of results describing the conditions of shoreline along marine and freshwater environments. Wetland conditions do not factor into the index at this time because of inadequate data.
Status: A high percentage of shoreline has been armored with bulkheads and other structures. Countywide, stream riparian areas in rural areas have higher forest coverage than urban areas.
Influencing factors: Bulkheads impede natural erosion and cut off the supply of sand, rocks and other natural features that are home to native plant and animal species. Less forests along stream riparian corridors result in less stormwater control, less habitat for forest species, and aquatic systems that are less-healthy for fish.
What you can do:
- Consider alternatives to bulkheads and other artificial barriers to marine shorelines.
- Encourage your local city or town to make tree protection regulations stronger.
More information about King County's Shoreline Index is available by continuing below for these measures:
Marine Shoreline armoring
About this indicator: King County's Shorelines Marine Environment Index includes information about the conditions of marine shorelines. Our weighting system applies 50 percent towards unincorporated/Vashon Island armoring and 50 percent toward incorporated area shoreline armoring.
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 delivery 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: King County's Shoreline Master Program update was adopted by the County Council in late 2010 and was approved by The Washington Department of Ecology in January 2013.
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.
In 2014, King County completed the WRIA 9 Marine Shoreline Monitoring and Compliance Pilot Project report on behalf of Watershed Resource Inventory Area 9 (WRIA 9), that assessed changes in shoreline armoring and other shoreline infrastructure that has occurred since the last marine shoreline survey in 2005. Changes noted will be incorporated into King Stat in the future.
Marine Shoreline armoring
Download the PDF version.
Data source: The data source for this indicator comes from the King County WLRD Science, Monitoring and Data Management Section.
Collection frequency: This is the first time comprehensive data has been available to develop this environmental indicator. Now that a baseline has been established, follow up surveys every 5 years will provide useful analysis in the future.
Methods for analysis: Aerial photography and limited ground truthing was used to conduct this survey. The aerial photography collection was conducted in 2005.
Berry, H.D., J.R. Harper, T.F. Mumford, Jr., B.E. Bookheim, A.T. Sewell, and L.J. Tamayo. 2001. The Washington State ShoreZone Inventory User's Manual. Nearshore Habitat Program, Washington State Department of Natural Resources, Olympia, WA.
Higgins, K. F., Schlenger, P., and Hall J., 2005. Spatial Relationships between Beneficial and Detrimental Nearshore Habitat Parameters in WRIA 9 and the City of Seattle, 2005 Puget Sound Georgia Basin Research Conference Proceedings.
Johannessen, J.W., MacLennan, A., and McBride, A, 2005. Inventory and Assessment of Current and Historic Beach Feeding Sources/Erosion and Accretion Areas for the Marine Shorelines of Water Resource Inventory Areas 8 & 9, Prepared by Coastal Geologic Services, Prepared for King County Department of Natural Resources and Parks, Seattle, WA.
Rice, Casimir, A. 2006. Effects of Shoreline Modification on a Northern Puget Sound Beach: Microclimate and Embryo Mortality in Surf Smelt (Hypomesus pretiosus). Estuaries and Coasts, Vol. 29, No. 1, p 63-71.
Stream Riparian Habitat
About this indicator: King County's Shorelines Freshwater Environment Index includes information about the conditions of stream riparian habitats. There is no program for Lakes and River Floodplain Habitats.
Increased population and development have substantially altered the landscape in King County over the past two centuries. This indicator reflects landscape changes that protect forest and aquatic habitats along streamside, or riparian, corridors.
Forest data were derived from a 2001 Landsat image, and impervious area data were derived from 2000 multispectral images. The width of riparian areas along stream banks varied between a minimum 165-foot buffer on each side and expanded to include wetland and steep slope areas. Possible landslide areas that extend past this buffer were also included. This approach to defining "riparian areas" is intended to encompass functional features of adjacent lands that could have been missed if a simple buffer width were used.
Status: Stream riparian land cover was categorized by urban vs. rural areas. Countywide, stream riparian areas in rural areas (71percent) have higher forest coverage than urban areas (39 percent), as shown in Chart 1 and Figure 1. Impervious coverage along the riparian corridor in urban areas (26 percent) was almost seven times more than in rural areas (4 percent).
Influencing factors: Forests naturally regulate stormwater runoff, protect water quality, provide habitat for many species, and maintain healthy streams and rivers for salmon and other fish. Less forests result in less stormwater control, less habitat for forest species, and aquatic systems that are less-healthy for fish. Increases in impervious surfaces are generally associated with the highest rates of stormwater runoff, the highest degradation in water quality, and the most impacts on forest and aquatic species.
Existing DNRP response: Land-use regulations, which were updated as part of the Critical Areas Ordinance in 2004, attempt to maintain a minimum of 65 percent forest cover and limit impervious areas to less than 10 percent in rural, unincorporated King County. They also provide extra protection for aquatic riparian areas. King County DNRP intends to monitor forest cover and impervious area within riparian zones.
The county works with landowners to restore streamside parcels that have important benefits as aquatic resources. In addition, the King County Water and Land Resources Division's capital projects program builds small and large stream and wetland enhancement projects while protecting public safety. Habitat restoration projects include streamside and wetland planting and in-stream habitat improvements.
Priority new actions: King County is in the midst of updating its 30-year old Shoreline Master Program, which guides land-use activities along shorelines of marine areas and most lakes and streams in unincorporated King County. The first step in this effort is to review current shoreline conditions, including ecology, public access, land use and historic resources. The program update, which is expected to be completed in mid 2010, will include changes that will have an effect on this indicator.
Stream Riparian Habitat
Download the PDF version.
Data source: The data source for this indicator comes from the King County DNRP/WLRD Science, Monitoring and Data Management Section.
Collection frequency: This is a first time review of percent landscape maintained as forest and the percent that has been converted to impervious area. At the time this indicator was developed, the data available was from different time periods. Forest data percentages were derived from a 2001 Landsat image. Impervious area percentages were derived from 2000 multispectral images.
Methods for analysis: This indicator reflects landscape changes that protect forest and aquatic habitats along streamside, or riparian, corridors. The width of riparian areas along stream banks varied between a minimum 165-foot buffer on each side and expanded to include wetland and steep slope areas. Possible landslide areas that extend past this buffer were also included. This approach to defining "riparian areas" is intended to encompass functional features of adjacent lands that could have been missed if a simple buffer width were used.
What can you do?