offshore reefs

[Bobby J]

Does anyone think these would have more merit then beach re nourishment? According to the site the reefs dissipate wave energy before it hits the beach.

"Naturally occurring submerged offshore reefs typically promote the development of wide sandy beaches in their lee. These beaches are less prone to severe erosion problems due to the protection provided by the reef.
The beaches inside the barrier reefs of Tahiti are a classic example.
The concept behind artificial submerged reefs is to mimic the results found in nature."

Here is the link. http://www.spacecoastreef.com/index_files/Page934.htm

It would also greatly help the surf around here, continuing to enhance tourism... ;-)

 

[seacrestkristi]

The wildlife seems to it. Wonder where the best place to put it would be

 

[Kurt]

Silly surfboy! Once you build on your primary dune line, your barrier island simply needs a barrier island of its own. ;-)

 

[BeachSiO2]

In areas where a community is willing to invest in beach restoration or nourishment, it is typically because there is a sand shortage. One of the biggest problems with using structures instead of sand is that structures do not "create" more sand. Offshore structures work to slow or completely stop the movement of sand along the beach. This is the same whether a structure is perpindicular to the beach like a groin, or parallel to a beach like a breakwater.

Assuming the offshore structure is working well, let's take three houses as an example, A, B, C. In this case, sand is moving down the beach from A to B to C. House B places an offshore breakwater. Now, the same amount of sand moves from house A to house B, but due to the effectiveness of the structure behind house B less sand is moving to house C. Typically, if you have an eroding shoreline before you install a structure like behind house C and that area begins receiving less sand after the structure is installed, that stretch of beach would be at an even greater sand deficit and thus more erosion. All this being said, structures are sometimes used in conjunction with beach restoration to assist in holding the sand in place. Once again, it's a case of site specific needs and one alternative definitely doesn't fit all locations.

As for the project you linked to, I believe it is being funded as an innovative technology and will have a rigorous experimental test plan to evaluate it's effectiveness. I hope it works also as it would be a very innovative approach. One cautionary note. In the late 80's or early 90's (I think), a submerged reef, called the PEP reef, was constructed along the east coast of Florida and in its lee there was more erosion due to the pumping action caused by the interaction of the waves and structures. Waves came over the reef, and then rushed around the edges like a rip current looking for a location to get back out since it couldn't go over the constructed reef.

One final note, the website mentioned naturally occurring reefs as an example. A big difference between our area and naturally occurring reefs is that reefs produce carbonate sands that move onto a beach. Thus, new sand being created and arriving fairly constantly. Our sand is silicate sand and we have a limited sand supply that was delivered thousands of years ago from the Appalachian Mountains.

 

[Beachlover2]

I have been to Tahiti and the beaches are beautiful and the barrier reefs are something to see - they ring the islands and if you are sailing there are very few openings to get into the island - local knowledge is key when sailing there. It is very impressive to see the huge waves come along the reefs and just disappear. The area by the beaches is very calm and peaceful. Just thinking about it makes me want to go back. Ahhhhhhhhhhh............

 

[John R]

if any good can come from geotubes, this may be it. they're just being put in the wrong place presently.

 

[BeachSiO2]

if any good can come from geotubes, this may be it. they're just being put in the wrong place presently.

Did you notice that Lee Harris who is working on some of the ProTecTube installations on Walton County beaches is the same Lee Harris working on the project Bobby J cited :scratch:

 

[Chickpea]

I have been to Tahiti and the beaches are beautiful and the barrier reefs are something to see - they ring the islands and if you are sailing there are very few openings to get into the island - local knowledge is key when sailing there. It is very impressive to see the huge waves come along the reefs and just disappear. The area by the beaches is very calm and peaceful. Just thinking about it makes me want to go back. Ahhhhhhhhhhh............

Always have wanted to go there - the beaches are seemingly incredible!! Diving there must be spectacular.

Just got back from Mexico and was blown away by beauty of beaches in Tulum - wide, expansive, white sands, turquoise waters, palm trees and secluded (although this is changing fast!)

 

[Beachlover2]

Chickpea - diving was incredible - but be prepared to see sharks - can't really dive there without seeing them. After the initial shock it really was more fascinating than frightening. I'd do it again in a heartbeat.

 

[Chickpea]

Chickpea - diving was incredible - but be prepared to see sharks - can't really dive there without seeing them. After the initial shock it really was more fascinating than frightening. I'd do it again in a heartbeat.

Do the sharks just avoid you???? Swim alongside? One of these days I do really hope to get there - it just does not seem to get any prettier....