Herb,
It's interesting that you should mention beach renourishment as a response
to erosion. "The Corps and the Shore" book argues that groins and
renourishment are destructive, or futile at best.
The authors contend that people need to choose whether they want beaches or
buildings because they can't expect to have both, given that the sea levels
are inexorably rising. This has stirred plenty of controversy here in North
Carolina among owners of beach homes. But the authors have produced a video
(I think it's called "The Beaches are Moving") that helps homeowners build a
more secure beach home or reinforce current beach houses.
I guess beach renourishment is a boon to collectors of fossil shells but I'm
not sure it's good for living marine species of any type.
David Kirsh