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24 Cards in this Set
- Front
- Back
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Define Beach |
extending from Mean-Lower-Water to dunes/cliff |
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Define Shoreline |
where land and water meet |
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Barrier Island or Spit |
Linear extension of shoreline, due to accumulation of sediment
seaward of land, usually ~parallel to trend of land |
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Define Troughs and Bars |
seabed features in surf zone |
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Define Berm |
relatively flat region of beach, behind shoreline |
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Define Foreshore |
seaward sloping surface, located seaward of berm |
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Define Backshore |
berm and dunes |
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Define Inlet/Washover |
means to transport beach sediment landward, due to tides and storms
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Longshore Transport |
littoral drift water and sediment movement parallel to the beach |
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Three Factors of Wind Formation |
Factors controlling wave formation -Duration wind blows -Wind Speed -Distance over which wind blows (fetch) |
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Wave Terminology T H L
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T=Time period ~ proportionate to wavelength L= Wavelength H= Wave height = amplitude is half of H |
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Define Wave Base |
No motion at a water depth >½ wavelength of wave |
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Describe Waves in Shallow Water |
As waves move towards shore they sort themselves out In shallow water, currents move back and forth at seabed More transportation under crest than trough Wave speeds decrease as depth decreases Wave height Increases, wavelength decreases
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Wave Refraction |
Occurs when the wave begins to feel carrying depths of the seabed in shallow water and the crests begin to refract/bend
CRESTS BEND IN WAVES AS THEY REACH SHALLOW WATER AND SLOW DOWN |
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Define Wave Rays |
On irregular shoreline, are perpendicular to wave crests
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Define Surf |
When H/L >1/7 wave becomes unstable and breaks |
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Define Swash and Backwash |
Wave hits beach as Swash and comes back down as Backwash |
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Define 3 Kinds of Waves |
Spilling Breaker: found on fine sand beaches, nearly flat beach Plunging Breaker: coarse sand beach, steep beach Surging Breaker: gravel beach, very steep beach |
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Define Rip Tide |
Strong current seaward |
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Define Undertow |
weak flow near seabed |
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Define Berm |
less sediment goes in backwash then swash creating flat are on beach |
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Define Storm Surge |
Strong winds push ocean water against coast Erode coast |
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Washington Wind Patters |
Winter: Low-pressure systems generate winds from S and SW, which push water against coast – causing storm surge, sea level ~.5m higher, ~4m waves Summer: High-pressure systems generate winds from N and NE, which pull water away from coast – causing deep water to upwell with nutrients, ~1m waves |
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WA Waves |
Increased ~1m over past 30yr -less sediment supply -higher energy -erosion |
