Coastal Processes and Tides
Coastal Processes Topic outline:
A. Wave action
- Wave refraction
- Longshore current
- Longshore drift (transport)
- Littoral cells (beach compartments)
B. Coastline classifications and features
- Erosional – wave-cut bench, marine terrace, sea cave, stack, arch
- Depositional – delta, spit, tombolo, barrier islands
C. Human influence on coastal processes
- groins, breakwaters, and jetties
Tides Topic outline:
A. Equilibrium theory of tides
- Gravitational force
- Daily recurrence of tides – tidal bulges
- Lunar day
- Solar bulges
- Monthly tidal cycle
- Neap tide
- Spring tide
- Other factors
- Declination of sun and moon
B. Dynamic theory of tides
- Shape of ocean basin - amphidromic point
- Tidal patterns
- Tidal datum - mean sea – MLLW - MLW
Interesting places to visit:
Great photos of America's coastlines: http://www.photolib.noaa.gov/coastline/
Clear explanation of tidal bulges: http://csep10.phys.utk.edu/astr161/lect/time/tides.html
Tides charts for U.S.: http://www.tidesonline.com/
Tidal animation: http://www.sfgate.com/getoutside/1996/jun/tides.html
When you are finished with this topic, you should be able to answer the following questions:
- Distinguish between a summertime and wintertime beach. Why do these differences occur?
- How are longshore currents formed? How is longshore drift (transport) related to longshore current?
- Distinguish between groins, jetties, and breakwaters.
- What are some coastal features associated with erosional coastlines? With depositional coastlines?
- What are the parts of a beach compartment (littoral cell)?
- Why is a lunar day 24 hours and 50 minutes long, while a solar day is only 24 hours long?
- What causes the recurrence of high and low tides at a given location each day?
- How are the tidal bulges on each side of the earth generated?
- What causes the differences between neap and spring tides and what are those differences?
