ENVS469 Lecture Notes - Lecture 6: Longshore Drift, Groyne, Cyanobacteria
25 Feb 2020
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Document Summary
Week 6b marine ecology and restoration (dynamic environments) Coastal population density: +51 million in usa since 1970, 2011: 160 million in coastal communities (50% of total pop"n, same growth rate as rest of country, but only 20% of surface. Structural changes to coastlines: land reclamation: ag in floodplain. Industry: proximity to trade routes, labour markets, waste disposal: transportation: building of new land for ports, etc, residential: high pop"n density + low land availability. Waves & sediment movement: longshore current: moving sediment parallel to the beach shoreline, ripshore current: moving sediment up and away from the beach shoreline. Changes of saltwater & freshwater gradient stronger, more extreme gradient; inhabitable for some species. Barrier structures and erosion, wave amplification, and hardening. Changed erosion and deposition patterns at groyne: reduced erosion up-current by stopping longshore current, leads to increased erosion down- current, changed sedimentation patterns.
