In Germany (on the island Sylt) they recently removed all of these structures again after decades of them being a staple on Sylt's beaches. They were found to have no positive effect on protecting their shores.
I'm having a hard time to find a good source to quote but look for: "sylt tetrapoden" if you want to dive deeper.
Well, confusingly, the last picture on the blogpost look (to my untrained eye) to be tetrapods. Those are 'tetrahedral' (ish) shapes.
In contrast, the https://en.wikipedia.org/wiki/Dolos (plural 'Dolosse') are two tapering cylinders at right angles to each other. They have the same symmetry, but a different structure. Does that make any difference to how effective they are? No idea!
edit: When I said the "same symmetry" of course I should have said the dolos has some of the symmetries of the tetrapod (subgroup?).
Interesting. Been to South Africa a bunch but never clocked that they were different from the more common antecedent, the tetrapod[1].
1: https://en.wikipedia.org/wiki/Tetrapod_(structure)
In Germany (on the island Sylt) they recently removed all of these structures again after decades of them being a staple on Sylt's beaches. They were found to have no positive effect on protecting their shores.
I'm having a hard time to find a good source to quote but look for: "sylt tetrapoden" if you want to dive deeper.
Ok I stand corrected these are NOT tetrapods. Sorry for the confusion
Well, confusingly, the last picture on the blogpost look (to my untrained eye) to be tetrapods. Those are 'tetrahedral' (ish) shapes.
In contrast, the https://en.wikipedia.org/wiki/Dolos (plural 'Dolosse') are two tapering cylinders at right angles to each other. They have the same symmetry, but a different structure. Does that make any difference to how effective they are? No idea!
edit: When I said the "same symmetry" of course I should have said the dolos has some of the symmetries of the tetrapod (subgroup?).