Monday, August 22, 2011

Protecting the coastline and our city

including solutions other than "managed retreat". 

Can you believe it, of all the coastal erosion protection management choices, our Pacifica environmentalists and supportive city council majority favor "managed retreat"?  With their promotion of "we can do nothing", eventually we will lose Highway 1 and our entire city.  Does that sound reasonable to you? 

From BBC UK Schools "GCSE Bitesize".  Geography, coastal management strategies.  "Physical management of the coast attempts to control natural processes such as erosion and longshore drift."  Hard and soft management strategy choices below:  

A.  Hard engineering - Hard engineering options tend to be expensive, short-term options.
      They may also have a high impact on the landscape or environment and be unsustainable.
1.  Build a sea wall.  "Curved sea walls reflect the energy of the waves back to the sea".
      Advantages.  Protects the base of cliffs, land and buildings against erosion. Can prevent coastal flooding
      in some areas.
      Disadvantages.  Expensive to build.  Curved sea walls reflect the energy of the waves back to the sea.
      This means that the waves remain powerful.  Over time the wall may begin to erode.  The cost of
       maintenance is high.   
2.   Build groynes.  Right angle wooden barrier  to the beach.
      Advantages.  Prevents the movement of beach material along the coast by longshore drift.  Allows the
      build up of a beach. Beaches are a natural defence against erosion and an attraction for tourists.
     Disadvantages.  Can be seen as unattractive. Costly to build and maintain.
3.  Rock armour or boulder barriers.  Large boulders piled up on the beach. 
     Advantages.  Absorb the energy of waves.  Costly to build and maintain.
     Disadvantages. Can be expensive to obtain and transport the boulders.
B.  Soft engineering - Soft engineering options are often less expensive than hard engineering
      options. They are usually more long-term and sustainable, with less impact on the environment.  There
      are two main types of soft engineering.
1)  Beach management.  Replace beach or cliff erosion or longshore drift.
      a)  This replaces beach or cliff material that has been removed by erosion or longshore drift.
      b)  The main advantage is that beaches are a natural defence against erosion and coastal flooding.
            Beaches also attract tourists.
      c)  It is a relatively inexpensive option but requires constant maintenance to replace the beach material
           as it is washed away.
2)  Managed retreat.  Areas of the coast are allowed to erode and flood naturally.
      a)  Areas of the coast are allowed to erode and flood naturally. Usually this will be areas considered to
           be of low value - eg. places not being used for housing or farmland.
      b) The advantages are that it encourages the development of beaches (a natural defence) and salt 
          marshes (important for the environment) and cost is low.
      c)  Managed retreat is a cheap option, but people will need to be compensated for loss of buildings and
           farmland. "

 Posted by Kathy Meeh

1 comment:

do nothing city council said...

once again the city council will do nothing until Highway 1 is under water, then they will say hey we don't have to fix it.