Oceans and Coasts

The oceans are the last major part of the global environmental systems for our discussion.  They are the result of plate tectonic processes, the storage for most water for the hydrologic cycle, a buffer for carbon dioxide in the atmosphere, and a sink for weathered material from the continents as they feed the lithosphere at subduction zones.  They are also a giant solar collector and metronome for global weather and climate at scales from waterspouts to glaciations.

Problems:

1. Consider the problem of coastal erosion.  The USGS Coastal Erosion Home Page is helpful - note long-term, low frequency, and El Nino issues.  The San Mateo, CA El Niņo Web page has a selection of detailed maps of the coast of San Mateo county (seaward and south of San Francisco) with abundant information.
   1. What materials are least susceptible to coastal erosion?  What materials are most susceptible? 
   2. What coastline geometries are least susceptible to coastal erosion?   What geometries are most susceptible?  Does that change with time?
   3. What geological activities are important to coastal erosion.   Consider the information from the Coalition to Restore Coastal Louisiana.  Consider Houston, TX and the coast of Alaska as well.
   4. What timescales are important to coastal erosion?  As with river floods, areas of coastal hazard can be identified, but may not be continuously active.   Consider El Niņo (above), hurricanes and typhoons, and global change.
2. So why does it matter? 
   1. Consider what might happen if you owned shoreline property on an ocean, a Great Lake, or Flathead Lake.   How might you prepare yourself and your property?  The Natural Hazards Center at the University of Colorado is an international clearinghouse of hazard information.  They have a long Hurricane Damage to Residential Property Report - use the Table of Contents to look for relevant information!
   2. You might build well back from a bluff, but suppose your neighbor, who has inherited a family cabin just up-drift (into the prevailing wind and waves) from you, feels that her house is under attack by the elements and proposes to rip-rap the cliff, build a sand-trapping groinfield, and/or nourish her beach.  What fears might you have, and how might you respond?