Dr. Daniel Huppert School of Marine Affairs, UW Climate Impacts on Washington’s Coasts

Organization of Talk Overview of Sea Level Rise Erosion of beaches and bluffs Impacts on Shellfish Impacts on Ports

WA has 5000km of coast (3085 mi.), including Puget Sound, 300 islands, & 2 major bays

Projected SLR - Mote, et al. 2008

Beaches, Sand Spits & Bluffs The most prevalent shore type in Puget Sound is the bluff-backed beach – coastal bluffs fronted by narrow mixed sand and gravel beaches. (Johannsssen and MacLennan 2007)

Sea walls, riprap, or revetments protecting beaches reflect wave energy, causing increased erosion of adjacent beach

Bainbridge Island (Pt Munroe) 82% of shoreline is residential, commercial, or industrial use 48% is armored How to accommodate SLR?

Shorelines are relatively well protected within the SW Wash. bays –Willapa Bay and Grays Harbor

Gig 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

Western Whidbey Island Erosion rates range from 1cm to more than 61cm (2ft) per year CC will increase the rate of erosion

San Juan Islands Very little bluff erosion Composed mainly of exposed bedrock coast Unlikely that an increase in SLR will affect the bluff erosion patterns

Adaptation Options Accommodation - raise docks Protection - Sea walls, dikes Retreat –Moving or building on higher ground –rolling easements

Impacts on Ports Shoreline facilities susceptible to inundation with SLR. Both Tacoma and Seattle ports have some plans to raise docks & piers Broader problem is flooding of neighboring lands and transportation routes - highways and rail lines. Solutions require broad planning

Temperature & HABs A positive relationship between harmful algae blooms and sea surface temperature (Moore et al.) HABs cause paralytic and amnesiac shellfish poisoning (PSP and ASP). During HAB outbreaks recreational and commercial harvests are halted.

Ocean Acidification 30% of recent CO 2 emissions absorbed in the ocean. Projected to increase to 90% ultimately. CO 2 lowers system pH and saturation of carbonate minerals that form skeletal structures in marine organisms. Kleypas, J.A., R.A. Feely, V.J. Fabry, C. Langdon, C.L. Sabine, and L.L. Robbins, Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifiers: A Guide for Future Research, report of a workshop held 18–20 April 2005, St. Petersburg, FL, sponsored by NSF, NOAA, and the U.S. Geological Survey, 88 pp.