What are geotubes and why are they bad for sea turtles?

In November, 2019, thirteen beachfront homeowners in St. Johns County, Florida set a precedent that could obstruct sea turtle nesting in the entire state of Florida where 90% of all endangered sea turtles in the U.S. lay their eggs.

 

These thirteen homeowners hired a $10,000/month lobbyist to help them obtain permits from the Florida Department of Environmental Protection (DEP) so that Geotubes could be installed between their homes and the ocean. Since all of their homes are safely positioned landward of the CCCL (Coastal Construction Control Line), the homes should not have qualified for geotubes. But their hired lobbyist was the former Secretary of DEP, Herschel Vinyard whose political connections enabled the thirteen homeowners to obtain permits.

 

What are Geotubes?
They’re massive geotextile tubes of sand that were stacked over 12 feet high between homes and ocean for an indefinite period of time. They were initially covered with sand, but they’re not expected to stay covered. (Other geotube projects need annual sand replenishment.) Experts say geotubes interfere with sea turtle nesting. Geotubes have the potential to harm nesting sea turtles and cause further erosion to our coastline.

 

Why did the thirteen homeowners want Geotubes?

They believed their homes were in danger even though every one of the homes is far enough back from the high water line to be safe, according to DEP. By issuing Geotube permits for these homes, the DEP has set a precedent for homes statewide that are not at risk. This precedent-setting act potentially endangers sea turtle nesting habitat statewide. Local county officials cannot override DEP’s permits. However, local officials can maintain county beaches with renourishment programs so that local homeowners are less likely to resort to geotubes, sandbags and other stopgap measures.

 

Beaches in Ponte Vedra where the thirteen homes are located were long neglected by local officials, and only recently have steps been initiated to renourish that beach.

 

How do Geotubes erode the beach and hurt sea turtle nesting habitat?

After sand placed on the tubes washes away, the waves hit the tubes directly and take out the sand in front of them which lowers the floor of the beach. When the sandy coastline narrows, there’s less nesting habitat. (Less sand for people, too.) When the tube is uncovered, the turtles cannot nest on the tube. Furthermore, the tubes will initially have 3 feet of sand on them, but endangered leatherbacks need five feet of sand to nest in. Currently, there’s little to no enforcement of frequent violations in sea turtle habitat in Ponte Vedra, so there’s little expectation that DEP will require compliance with maintaining three feet of sand on the geotubes.

 

Our hope is that DEP will call for the geotubes to be removed after beach renourishment takes place. Please see press coverage on NEST’s advocacy against geotubes here:

img_geotubes.jpg

Recent geotube installation in Ponte Vedra Beach, Florida.

Research on geotube projects in the U.S.: 

Florida: Gulf County Cape Sans Blas/White Sands Project http://ajstechnology.com/bluemountainvillas/GeotubeReport.pdf The only comprehensive research in Florida under severe storm conditions showed that geotubes can fail during a major storm event like a hurricane.

Massachusettes: Nantucket http://www.savenantucketbeaches.org/siasconset A large geotube installation in Nantucket Island needs tens of thousands of dollars in new sand added almost annually. Only homes in danger received permits. Some homes were turned down.

Texas: near Galveston https://serc.carleton.edu/vignettes/collection/58381.html

“Geotextile tubes placed along the Bolivar Peninsula gave residents a false sense of security and greatly enhanced the destructive power of Hurricane Ike's storm surge waves. In the area of Caplen, west of the tubes, many more beach houses and slabs survived because there were no tubes to alter the natural geomorphic shape of the beach profile and enhance destructive effects of Hurricane Ike's storm surge.”