Puget Sound Shorelines. Waves and coastal processes. Puget Sound shorelines: Effects of beach armoring

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1 Puget Sound Shorelines Puget Sound shorelines: Effects of beach armoring Waves and coastal processes Factors affecting wave energy hitting the coast Processes transporting sediment along coastlines What parts of Puget Sound are most at risk of erosion due to storm waves? Common types of shorelines in Puget Sound: Sand and gravel Sandy beach/dunes Sediment-starved beach Beach w/ bulkheads Mudflats Deltas 1

2 Armoring of Puget Sound shorelines Natural shoreline with development Shoreline development and armoring: 32% of historic intertidal wetlands lost 73% historic subaerial wetlands lost 30% of shorelines stabilized by structures t 1.7 miles armored each year King County: ~ 80% of shorelines armored Shoreline with bulkhead modified from Griggs, et al Importance of nearshore zone High productivity Erosion control Water-quality control (nutrient cycling, bioreactivity) Wildlife habitat Habitat mosaic enhances biodiversity Natural resources Asthetics 2

3 Primary productivity biomass (g dry m-2) productivity (g dry m-2 yr-1) NEARSHORE ESTIMATED TOTAL ANNUAL NET PRODUCTION OF PRIMARY PRODUCERS IN HOOD CANAL brackish marsh macroalgae eelgrass & epiphytes benthic microalgae salt marsh phytoplankton From Simenstad 2004 (Simenstad and Wissmar 1985) Sediment supply to Puget Sound beaches Most beaches sediment starved > 80% of sediment delivered to the Sound by streamflow comes from the 3 rivers: the Skagit, the Puyallup, and the Snohomish. Deltas in protected embayments trap the sediment. Sediment in much of Puget Sound is delivered by coastline erosion and landslides Coarse-grained sediment remains. Fine-grained sand (important for seagrass beds) is more easily eroded. Shoreline concerns Wetland diking and filling Shoreline armoring Dredging Water regulation (dams) Nutrient loading / eutrophication Fish migration (barriers) Exotic species (e.g., Spartina) Extraction/Harvest Contaminants Sea level rise Boat wakes Sediment loading? Nearshore habitat usage Forage fish for salmon and rockfish: Pacific herring, surf smelt and Pacific sand lance Depend on nearshore marine habitats for spawning and rearing. WDFW enforces No Net Loss regulations for the protection of known forage fish spawning sites Nearshore habitat usage Sand lance: spawn on sand beaches Surf Smelt: Spawn in upper intertidal zone on sand and gravel beaches at high tide Herring: Spawn in lower intertidal tid and upper subtidal regions of bays and sheltered beaches Longfin smelt (Spirinchus thaleichthys) is present but less common in Puget Sound 3

4 Surf smelt spawning beaches Sand lance spawning beaches Herring spawning grounds Shoreline factors affecting spawning success Riparian habitat: Shading, detritus and debris increase spawning success. Riparian vegetation affects nearshore sediment supply Freshwater seeps thought to help spawning Stormwater outfall pipes Bulkheads and seawalls: bury upper intertidal zone, reduce sedimentation, increase erosion, leading to beach armoring and reduced spawning habitat Forage fish spawning grounds in Bellingham Bay Surf smelt spawn in upper intertidal zone In Bellingham Bay, they spawn only in a few spots All other shorelines in the bay have bulkheads or seawalls Surf smelt and sand lance spawning areas in Bellingham Bay 4

5 Shoreline modification & salmon Nearshore use by salmon species Function Nursery Juvenile Food Production & Feeding Adult Food Production Residence Physiological Transition Potential Effects of Shoreline Modification Migration Corridors of movement blocked Connections between habitats fragmented Critical habitats in the landscape are eliminated Shallow water areas reduced Vegetation cover lost Habitats that produce prey are lost or degraded Access to prey resources are blocked Drift material accumulation areas are lost Habitats that produce prey are lost or degraded Access to prey resources are blocked Baitfish spawning habitat degraded Refuge habitats are lost or fragmented Hydrological changes alter/restrict location of physiological adjustment (Williams and Thom 2001) Pacific Salmon habitat usage Species-LH Type Freshwater Downstream Estuarine Estuary- Ocean Possible Residence Migration Residence Ocean Residence Life Transition History Types Nearshore use by salmon species PINK Virtually none Immediate & rapid, as fry Short; ~2 weeks Rapid Fixed; 2 years 1 CHUM Virtually none Immediate, as fry Short-moderate, 2-3 weeks Rapid Variable; 1-5 years 10 SOCKEYE-lake type Extensive, 1-3 years Relatively rapid, as in lakes smolts; I-2 weeks Short; few days Highly variable Variable; 1-3 years 9 -ocean type Short Rapid, as fry Often extensive; 1 week-5 months Unknown Fixed; 1 years 1 COHO-stream type Extensive; 1-4 years Relatively rapid, as smolts; 1-2 weeks Short; few days Highly variable Variable; 1-5 years 11 -ocean type Virtually none Rapid, as fry Long? May involve protracted overwintering, and return upstream to rear? Unknown? Fixed; 1 year 1 CHINOOK-stream type Variable; 1-2 years Variable; few days to months Short; few days Highly variable Variable; <1 to 6 years >13 -ocean type Variable; few days to months Variable; rapid as fry, longer as fingerlings Highly variable; days to 6 months Highly variable; often prolonged Variable; <1 to 6 years 36 (Simenstad and Fresh, unpubl.) (Williams and Thom 2001) Nearshore use by other fish species Eelgrass (Zostera marina) and Hood Canal chum salmon Migratory corridor Predation refuge Foraging habitat NearPRISM (Williams and Thom 2001) 5

6 Alternatives to bulkheads Bay Delta alterations Puyallup River delta (Commencement Bay) not recognizable Land (Downing 1983) Costal areas at risk Puget Sound Shorelines Bellingham Bay Erosion risk highest at headlands Contamination risk highest in embayments 6