“Jetty†covers a lot of possible structures. If theyâ€re planning on a pier built on wood pilings, something modest to tie a dive boat to (for example), that would probably have a different impact from the construction of a stone or concrete groyne thatâ€s intended to control the movement of sand.
This is what UNESCO has to say about the latter (these are excerpts from a large document you can read here http://www.unesco.org/csi/pub/source/ero18.htm)
“While groynes trap sediment on one side, they cause a sand deficit and therefore erosion on the other side. In effect, one property owner may gain at the expense of a neighbour.....
Groynes function most effectively along coastlines where the direction of longshore transport [of sand] is constant. In the Caribbean islands with their prevailing Northeasterly Trade Wind regimes, the predominant longshore transport direction is from east to west. Experience has shown that groynes work best along north- or south-facing coastlines and are least effective on east- or west-facing coastlines. For example, groynes have worked reasonably effectively on the north coast of Nevis. Similarly, much of the south coast of Barbados has been stabilized with groynes.â€
So looking at the results in Duncans Bay or Treasure Beach would not seem to apply in this case.
Also, the idea that one landowner could singehandedly alter the structure of the coastline seems just wrong! Certainly any decisions to stabilize a coastal stretch should be a community decision, with due consideration for longterm environmental impacts.. But I still would like to know -- what are they planning to build???