Chapter 19 Shorelines and Coastal Processes Coastal Processes ...
Chapter 19 Shorelines and Coastal Processes Coastal Processes ...
Chapter 19 Shorelines and Coastal Processes Coastal Processes ...
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<strong>19</strong>.7 What are the consequences ofrising sea level?Low-lying isl<strong>and</strong>s such as theFlorida Keys would all butdisappear with a two-meterincrease of sea level.<strong>19</strong>.7 What are the consequences ofrising sea level?Sea-level rise would cause a net loss of beach area due to erosion.On average, 1 cm of rise equals 1.5 meters of l<strong>and</strong>ward incursion.Fig <strong>19</strong>.47Fig <strong>19</strong>.46Fig 11.29<strong>19</strong>.7 What are the consequences of risingsea level?• Barrier isl<strong>and</strong> effects– Higher waves from risingseas wash s<strong>and</strong> acrossisl<strong>and</strong>.– Isl<strong>and</strong> migrates shoreward.– Isl<strong>and</strong>s merge with shoreafter filling lagoon.– Full wave effects arethereafter felt on shore.– Geologists find lagoondeposits indicating this hasoccurred in the past.<strong>19</strong>.7 What are the consequences ofrising sea level?Fig <strong>19</strong>.49• Estuary effects– For an estuary to persist,sea-level rise must exceedsedimentation from river.– Submergence of wetl<strong>and</strong>s(pictured 50 years apart)– In a natural system, tidalflats <strong>and</strong> salt marsheswould move inl<strong>and</strong>. Withhumans in the environmentthis does not occur.Fig 11.29 Fig <strong>19</strong>.48Fig <strong>19</strong>.52• What do we do? Thereare three generalresponses.– Armor the shoreline(seawalls, rip-rap, boulders,various deflectors)– Add sediment to erodingbeaches to maintain them– Ab<strong>and</strong>on the coastNote that armoring, suchas seawalls, protectsspecific property but doesnot save the beach or stoperosion.