View in Vital Signs- Functioning Habitat
- Beaches and Marine Vegetation
- Indicator
- Feeder bluffs in functional condition
- Vital Sign Indicator
- Mile (miles)
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No targets are currently set for this indicator.
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Kenna Kuhn
- Contributing Partners
- Last Updated
- 12/19/2022 10:26:33
This indicator measures the amount (length and percent) of Puget Sound feeder bluff shorelines that have been armored. Feeder bluffs are eroding coastal bluffs that deliver the sand and gravel to maintain Puget Sound’s beaches and spits. Beaches and bluffs provide critical habitat for the region’s fish and wildlife, including spawning beaches for forage fish and rearing habitat for juvenile salmon. Shoreline armor disrupts the natural supply of sediment and can lead to the loss of beaches and degraded nearshore habitat.
Extent of feeder bluff shorelines where armor is present (orange) or not present (blue) by Puget Sound Local Area. The 11 Local Area geographies are derived from the Puget Sound Partnership Action Areas to represent local communities working to advance the Partnership’s Action Agenda.
Beaches, sustained by the ongoing supply of sand and gravel from feeder bluffs, are a key element in the Puget Sound nearshore ecosystem. Beaches and bluffs provide critical habitat for the region’s fish and wildlife, including spawning beaches for forage fish and rearing habitat for juvenile salmon.
Shoreline armoring is the practice of using physical structures, such as seawalls and riprap, to stabilize shorelines and prevent coastal erosion. People construct armor on feeder bluffs because they fear bluff erosion and landslides. Unfortunately, there are unintended consequences of shoreline armor on nearshore habitats and species (Dethier et al. 2016). The impacts are strongly related to the coastal processes that shape the shoreline; namely that armor disrupts the sediment supply and transport processes that form and maintain beaches (Shipman 2010). By reducing the natural supply of sediment, armor can actually increase overall erosion and lead to the loss of beaches and degradation of nearshore habitat.
- Feeder bluffs stretch along 656 miles (27%) of Puget Sound’s total 2,460 marine shoreline miles. 34% (224 miles) of the feeder bluff shoreline is armored.
- Feeder bluffs are present throughout the Puget Sound region; however, their relative length and the extent of armor varies by Local Area. We see higher rates of armor on feeder bluffs in the more developed parts of Puget Sound, including the Puyallup/White, South Central, and Snohomish/Stillaguamish Local Areas. See the indicator’s Interpretation of Results for details.
- Shoreline armor on feeder bluffs negatively impacts several ecosystem processes, including reducing the supply, transport, and deposition of both sediment and large wood. These impacts extend to nearshore and marine habitats beyond the location of the armor.
- We do not have comprehensive data to describe changes in feeder bluff armoring over time. However, the Friends of the San Juans Armor Mapping Project provides a good example of how one Local Area quantified changes in armor and then linked those results to permit records.
- Friends of the San Juans mapped changes in shoreline armor between 2009 and 2019. They found that more armor was installed than removed on San Juan County shorelines over the 10-year period. 1.8 miles of new hard armor was installed (0.26 miles on feeder bluffs), while just 0.3 miles of armor was removed (257 feet on feeder bluffs).
- Friends of the San Juans also reviewed permit records for the waterfront sites where new armor was installed. They found that a significant amount of shoreline armoring is occurring without legal authorization or in sizes greater than permitted.
- Monitoring Program
Washington Department of Fish and Wildlife Estuary and Salmon Restoration Program (ESRP)
- Data Source
Beach Strategies Phase 1. Estuary and Salmon Restoration Program Learning Project #14-2308. Prepared by Coastal Geologic Services (2017).
Changes in Shoreline Armoring in San Juan County, WA 2009-2019: Mapping, Analysis and Regulatory Review. NTA 2018-0828. Friends of the San Juans (2022).
Coastal Geologic Services (CGS) developed standard methodology for mapping feeder bluffs in Puget Sound (MacLennan et al. 2013). This approach uses criteria to classify bluffs into several categories based on the bluff face, bluff vegetation, signs of landslides, beach substrate, sediment transport indicators, and driftwood age and abundance. Feeder bluff categories include feeder bluffs, exceptional feeder bluffs, and feeder bluffs-talus. Exceptional feeder bluffs are coastal bluffs with active erosion that periodically supplies substantial volumes of sediment to the nearshore. Feeder bluff-talus shorelines are more slowly eroding rocky (bedrock) cliffs and slopes (MacLennan et al 2013).
CGS completed the most comprehensive and current armor spatial data for Puget Sound as part of the Beach Strategies for Nearshore Restoration and Protection in Puget Sound Project. CGS developed the Beach Strategies Geodatabase (2017) to provide nearshore managers the best available information to assist decision-making and nearshore recovery. Even though it was compiled over multiple years (between 2003 and 2013), the dataset describes the extent of armor in Puget Sound, not the change in shoreline armor over time. CGS derived armor status from field and remotely mapped collection methods. A summary report is available which describes the database components, including compilation and assessment of source data, tabulation of shore armor and historical feeder bluffs extent, and suggestions for future efforts.
Friends of the San Juans recently completed the San Juan County Armor Change Analysis and Regulatory Review Project. The project mapped all hard armor on San Juan County shorelines in 2009 and 2019 using primarily boat-based field surveys. Using the 2009 survey as a baseline, Friends of the San Juans completed a change analysis to identify all new, existing, and removed armor for the ten-year period. Please see the summary report for project methods and analysis as well as key findings and implications.
This Vital Sign indicator summarizes data on feeder bluff locations and presence of armor by Local Area. Local Area geographies are derived from the Puget Sound Partnership Action Areas to represent local communities working to advance the Partnership’s Action Agenda. We used the Friends of San Juans 2019 data for San Juan County/Local Area shorelines and the CGS circa 2013 data for all other Puget Sound shorelines. We grouped all feeder bluff shorelines together in the summary.
Indicator reporting plan for 2024-2025 study of shoreline armor trends
- Critical Definitions
The extent and character of feeder bluffs varies throughout the region (Table 1). Many miles of feeder bluffs exist in the Hood Canal, Island, and South Sound areas. Other Local Areas have fewer feeder bluffs because they have a greater proportion of other shoreline types. For example, rocky bedrock shorelines dominate in San Juan and delta shorelines dominate in Skagit/Samish and Snohomish/Stillaguamish.
Feeder bluff exceptional (FBE) shorelines are primarily located in northern and western Puget Sound where wave exposure is higher and bluff erosion is more rapid.
| Local Area |
Total Shoreline Length |
Feeder Bluff Length |
% Feeder Bluff Shoreline |
Feeder Bluff Armor Length |
% Feeder Bluff Armored |
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|---|---|---|---|---|---|---|---|---|
| FBE | FB | FB-T | Total | |||||
| Strait of Juan de Fuca | 193.5 | 14.1 | 33.3 | 13.0 | 60.4 | 31% | 10.4 | 17% |
| Hood Canal | 315.4 | 5.2 | 107.0 | 3.1 | 115.2 | 37% | 27.7 | 24% |
| West Sound | 203.8 | 1.5 | 63.0 | 64.4 | 32% | 30.4 | 47% | |
| South Sound | 445.5 | 3.4 | 144.7 | 148.1 | 33% | 60.3 | 41% | |
| Puyallup / White | 48.0 | 0.3 | 10.0 | 10.3 | 22% | 6.5 | 63% | |
| South Central | 130.7 | 3.9 | 51.0 | 54.9 | 42% | 34.9 | 64% | |
| Snohomish / Stillaguamish | 118.4 | 0.9 | 18.1 | 19.0 | 16% | 11.5 | 61% | |
| Island | 216.2 | 15.4 | 78.8 | 94.2 | 44% | 21.3 | 23% | |
| Skagit / Samish | 225.0 | 1.9 | 26.8 | 1.3 | 30.0 | 13% | 9.0 | 30% |
| Whatcom | 155.0 | 2.0 | 26.6 | 1.5 | 30.1 | 19% | 6.2 | 21% |
| San Juan | 408.0 | 2.7 | 25.4 | 1.5 | 29.5 | 7% | 6.33 | 21% |
San Juan Change Analysis and Regulatory Review
The 2019 Armor Mapping and Change Analysis Project (Friends of the San Juans 2022) directly measures changing conditions in on-the-ground shoreline armor. The project describes characteristics of the new, existing, and removed armor, including elevation, material, condition, and association with priority shoreline types. They found that only 9% of all sites with new armor had the required authorization from local and state regulators prior to construction of the shoreline armor (10 of 108 sites). While some sites had at least one permit (local shoreline or WDFW Hydraulic Project Approval (HPA)), most (80 sites, 74%) had no permits. For feeder bluffs, a priority shoreline type, more armor was installed than removed between 2009 and 2019.
The San Juan change analysis results are concerning and point to some key findings and implications:
- San Juan County is not meeting no net loss standards when it comes to shoreline armor.
- Shoreline armor continues to be installed on priority shorelines, like feeder bluffs and pocket beaches, despite a strong understanding of their importance to juvenile salmon and forage fish.
- Few people comply with or participate in the permit process. We need to improve methods for engaging with property owners and contractors around shoreline infrastructure.
- For sites that did receive permits, there was little, to no, review of habitat impacts or post-project inspection.
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This indicator describes the extent of armor on feeder bluffs in Puget Sound, not the change over time. To understand change in on-the-ground armor, we need a comprehensive dataset with armor mapped at two or more time periods following consistent methodology. This type of effort takes significant resources and should be driven by clear monitoring objectives.
The San Juan County Armor Mapping and Change Analysis Project provides a good example of how one Local Area quantified changes in armor and then linked those results to permit records. The project addresses objectives around both ecosystem monitoring and regulation and permitting compliance. We list in the section above several important lessons the Puget Sound recovery community can glean from the San Juan project.
The San Juan data connects new and existing armor with development, especially residential development. WDFW HPA permits also show that most new armor is for single family residential properties. The reasons for armor removal, however, are not always clear. Restoration activities account for roughly one-third of the removed armor in San Juan County, and a few large wood structures were known or were likely to have washed away. However, the reason armor was removed at other sites remains unexplained.
Previous Vital Sign reporting pointed to positive trends in the amount of armor permitted for removal compared to installation (WDFW HPA permitted more armor for removal than construction between 2011 to 2020). However, the PSEMP Nearshore Work Group, among others, raised concerns that the HPA permit data is not an accurate reflection of projects on the ground. The San Juan County Armor Project confirms these concerns: more armor was constructed than removed and very few of the new armor sites had the required permits.
Strategic Restoration
Shipman (2017) reports on progress related to the strategic attention feeder bluffs now receive and a broad understanding of their environmental value. The importance of feeder bluffs on Puget Sound has been recognized since the 1970s, but interest in protecting them has increased in recent years as awareness of their environmental role has grown. As a result, feeder bluffs receive attention in state and local regulations, in outreach and education programs, among the scientific community, and in restoration programs.
Process-based restoration is a primary objective of the WDFW Estuary and Salmon Restoration Program (ESRP). Process-based restoration aims to restore the dynamic processes that generate and sustain ecosystem structure and function (Coastal Geologic Services 2020). ESRP works to identify areas where there is the greatest potential to restore or protect nearshore processes to their historical extent and enhance nearshore ecosystem resilience while benefiting salmonid habitat. Phase 2 of the Beach Strategies for Puget Sound project identifies sediment supply processes as a priority for restoration and protection of beach systems (Coastal Geologic Services 2020). The project identifies feeder bluffs that would provide the greatest potential benefit from protection and restoration. Sites with the least sediment supply degradation and greatest potential benefit to ecosystem functions were of the highest priority for protection. Sites with low to moderate degradation were the highest priorities for restoration and moderate priorities for protection.
Washington Department of Ecology Puget Sound Feeder Bluffs
Action Agenda | Healthy Shorelines
References:
Coastal Geologic Services, 2017. Beach Strategies for Puget Sound, Phase 1 Summary Report. Prepared for the Estuary and Salmon Restoration Program of the Washington Department of Fish and Wildlife. Bellingham, Washington. 38 pp.
Coastal Geologic Services, 2020. Beach Strategies for Puget Sound, Phase 2 Summary Report. Prepared for the Estuary and Salmon Restoration Program of the Washington Department of Fish and Wildlife. Bellingham, Washington. 79 pp.
Dethier, M., W. Raymond, A. McBride, J. Toft, J . Cordell, A. Ogston, S. Heerhatz and H. Berry. 2016. Multiscale impacts of armoring on Puget Sound shorelines: evidence for cumulative and threshold effects. Estuarine, Coast and Shelf Science. 175 (2016) 106-117.
Friends of the San Juans. 2022. Changes in Shoreline Armoring in San Juan County, WA 2009-2019: Mapping, Analysis and Regulatory Review. Prepared by Tina Whitman. Funded by the National Estuary Program and the Puget Sound Partnership NTA 2018-0828. Friday Harbor, WA. pdf
Johannessen, J., A. MacLennan, A. Blue, J. Waggoner, S. Williams, W. Gerstel, R. Barnard, R. Carman, and H. Shipman, 2014. Marine Shoreline Design Guidelines. Washington Department of Fish and Wildlife, Olympia, Washington. pdf
MacLennan. A., J.W. Johannessen, S.A. Williams, W. Gerstel, J.F. Waggoner, and A. Bailey. 2013. Feeder Bluff Mapping of Puget Sound, prepared by Coastal Geologic Services, Bellingham, for Washington Department of Ecology, Olympia WA.
MacLennan, A., B. Rishel, J. Johannessen, A. Lubeck, L. Ode. 2017. Beach strategies phase 1 summary report - identifying target beaches to restore and protect. Estuary and Salmon Restoration Program Learning Project #14-2308. Prepared by Coastal Geologic Services October 25, 2017. pp.39. pdf
Shipman, H., 2010, The geomorphic setting of Puget Sound: implications for shoreline erosion and the impacts of erosion control structures, in Shipman, H., Dethier, M.N., Gelfenbaum, G., Fresh, K.L., and Dinicola, R.S., eds., 2010, Puget Sound Shorelines and the Impacts of Armoring—Proceedings of a State of the Science Workshop, May 2009: U.S. Geological Survey Scientific Investigations Report 2010-5254, p. 19-34.
Shipman, H. 2017. Armoring on Puget Sound Feeder Bluffs: Implications for the Vital Sign. Prepared for the Puget Sound Partnership. 33 pp.
No datasets uploaded.
- Reporting Instructions
| Name | |
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| Shoreline Length |
Armor, No Armor
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