Coastal Impacts: Beaches, Sand Spits, and Bluffs Amber Moore University of Washington School of Marine Affairs 12 February 2009 Amber Moore University of Washington School of Marine Affairs 12 February 2009

Impacts on Beaches and Sand Spits  Puget Sound’s shoreline is estimated at 2411km (1477mi) in length  SLR will cause the landward migration of the shoreline  Coastal development could be threatened by increased vulnerability of coastal property  Puget Sound’s shoreline is estimated at 2411km (1477mi) in length  SLR will cause the landward migration of the shoreline  Coastal development could be threatened by increased vulnerability of coastal property

Impacts on Beaches and Sand Spits  Beaches protected by sea walls, riprap, or revetments are likely to be less stable than unprotected shores  The beaches of Puget Sound act as critical habitat  Beaches protected by sea walls, riprap, or revetments are likely to be less stable than unprotected shores  The beaches of Puget Sound act as critical habitat

Bainbridge Island  Contains 85.2km (53.3mi) of shoreline  82% currently in residential, recreational, commercial, or industrial use  48% is armored  Uplifted beach terraces, bays, and coves are most susceptible to inundation  Contains 85.2km (53.3mi) of shoreline  82% currently in residential, recreational, commercial, or industrial use  48% is armored  Uplifted beach terraces, bays, and coves are most susceptible to inundation

Southwest Washington  Ocean Shores has been actively eroding  Shorelines are relatively well protected within the shallow bays  Willapa Bay and Grays Harbor  Ocean Shores has been actively eroding  Shorelines are relatively well protected within the shallow bays  Willapa Bay and Grays Harbor

Bluff Erosion in Puget Sound  Feeds sediment for beach formation but also threatens property and human lives  The steepening of bluff slopes increases the probability of bluff failure  Key factors are storms with large waves, especially when combined with high tides or elevated sea levels  Feeds sediment for beach formation but also threatens property and human lives  The steepening of bluff slopes increases the probability of bluff failure  Key factors are storms with large waves, especially when combined with high tides or elevated sea levels

Western Whidbey Island  Erosion rates have been measured from 1cm to more than 61cm (2ft) per year  Whidbey Is. bluffs are frequently sites for residential development  Erosion rates have been measured from 1cm to more than 61cm (2ft) per year  Whidbey Is. bluffs are frequently sites for residential development

Western Whidbey Island  Many homes built on Whidbey Island were placed on artificial fill at the base of landslide prone bluffs  Along a 1 mile stretch of road, as much as $32 million worth of property could be involved  Many homes built on Whidbey Island were placed on artificial fill at the base of landslide prone bluffs  Along a 1 mile stretch of road, as much as $32 million worth of property could be involved

Bainbridge Island  Bainbridge Island has 394km (246mi) of shoreline, 20% of which is classified as “unstable”  Bluff erosion rates average between 5.1cm (2in) and 15.2cm (6in) per year  Bainbridge Island has 394km (246mi) of shoreline, 20% of which is classified as “unstable”  Bluff erosion rates average between 5.1cm (2in) and 15.2cm (6in) per year

San Juan Islands  Presently very little bluff erosion  The islands are composed mainly of exposed bedrock coast  Unlikely that an increase in SLR will affect the bluff erosion patterns  Presently very little bluff erosion  The islands are composed mainly of exposed bedrock coast  Unlikely that an increase in SLR will affect the bluff erosion patterns

Adaptation Options  Accommodation  Protection  Sea walls, dikes, raising docks  Retreat  Moving or building on higher ground & further from bluffs  Accommodation  Protection  Sea walls, dikes, raising docks  Retreat  Moving or building on higher ground & further from bluffs

Research Gaps  Incorporate additional sites into a future study  Applied and basic research into movement of sediments and shifts in beach and bluff profiles  How auxiliary structures will be and are being threatened by beach and bluff erosion  Representation of more ports  More research into the effects of increased SSTs and ocean acidification on shellfish  Incorporate additional sites into a future study  Applied and basic research into movement of sediments and shifts in beach and bluff profiles  How auxiliary structures will be and are being threatened by beach and bluff erosion  Representation of more ports  More research into the effects of increased SSTs and ocean acidification on shellfish

Conclusion  Global Climate Change is happening  Will impact humans and coastal ecosystems  Effective adaptive actions can enhance the resilience of vulnerable systems  Global Climate Change is happening  Will impact humans and coastal ecosystems  Effective adaptive actions can enhance the resilience of vulnerable systems