No need to spend any money on a barrier, that won't work, and be an ecological disaster anyway.
I have seen the same situation on USA east coast beaches for decades.
In areas where it is a nusance, like public beaches, you see a tractor pulling a huge "Rake" down the beach at dawn, cleaning up the unwanted seaweed.
That would be an easy, cheap solution here as well.
There are a dozen things that can then nbe done with the "Weed"!
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that's how it always was done with the unwanted parts, specially on the swimming beaches and along hotelareas. here the same as in the USA, just that most in DR did it by manual/Menlabour, but the same effects.
Todays, just look up the reports about the US Gulf Coast as just one example, the machines can not handle it at all, the amounts are much more than could be used for anything or stored to rotten down naturally anywhere.
btw, the raking machines are proofed to hide the danger to significant beach damage, as they also take significant sand amounts away. the sand and a certain portion of seaweed is necessary to strengthen the beaches/sanddunes etc against the Ocean's tides. machinery cleaned beaches came out to be the weakest and show the negative effects.
you are right,
Barriers can not be brought up all around, itwould produce superlarge amounts along the barriers, killing Ocean Wildlife along those lines, stopping reefs to breath etc. and anyways, a certain amount of the grass should always be allowed to reach the beaches and stay there to naturally break down as part of natures Beach-Defense-meachanisms.
Barriers are for portions of beachstretches, they are consipated to let around a 5th of the oncoming grass thru.
what has to be done with the 80% left in the barriers/areas around the barriers, is a point which i still did not read a suitable solution to.
just to keep it away from the beaches without proactive action about "how to handle it there at the barriers", total agreement, it would be a destroyer for the ocean's health within a very short time frame.
hence small areas are prepared by scientists to get experience and new ideas about the handling of the stuff.
one such area is planned to be in Punta Cana, run by Grupo Punta Cana along their Punta Blanca Beachmiles.
the experimental barrier is planned for a quarter beachmile.
Mike