Sand-Filled Geotextile Tubes as Coastal Armoring in Florida

1. Sand-Filled Geotextile Tubes as Coastal Armoring in Florida Panacea for coastal armoring or a danger to our coastal habitat?

2. A History…. Geotextile tube have been used for dewatering dredge sediments and coastal stabilization. This history information comes from a recently completed FL DEP report to the legislature. Sand filled containers have been used in some form since 1970. First one was on Alligator Point. They were not durable and were damaged by UV radiation and projectiles. They gained popularity in the mid-80’s and most were built on the east (Volusia County to Palm Beach) and southwest coast (Sarasota to Collier). Only in the last four years were they used in the Panhandle.Geotextile tube have been used for dewatering dredge sediments and coastal stabilization. This history information comes from a recently completed FL DEP report to the legislature. Sand filled containers have been used in some form since 1970. First one was on Alligator Point. They were not durable and were damaged by UV radiation and projectiles. They gained popularity in the mid-80’s and most were built on the east (Volusia County to Palm Beach) and southwest coast (Sarasota to Collier). Only in the last four years were they used in the Panhandle.

3. The most recently promoted technology is the ProTech tube, a dune scour protection structure. The horizontal width is approximately 27 feet with a vertical height of 6.5 ft. Surface fabric is ‘puncture-resistant’ and has ‘permeable’ or impermeable options.The most recently promoted technology is the ProTech tube, a dune scour protection structure. The horizontal width is approximately 27 feet with a vertical height of 6.5 ft. Surface fabric is ‘puncture-resistant’ and has ‘permeable’ or impermeable options.

4. Concerns with Geotextile Tubes Completely different type of armoring Toe extends onto footprint of beach—significantly different than vertical seawall Absolutely NO quantitative data on the impacts these tubes will have on Florida’s coastal processes, habitat, and fauna

5. Available quantitative data Texas study (Geotubes) (http://www.beg.utexas.edu/coastal/presentations_reports/Geotubes2003finalreport_web.pdf) There are many differences between the Geotubes presented here and the new ProTech technology: Mono vs. multiple celled, vertical vs. more gently sloped, the geotube is more easily broken. However, we still feel that the results of these same types of armoring can be compared, especially with the lack of data. Left picture is after TS Allison. This section was completely destroyed 4 months later. On right, notice erosion behind structure. Bottom picture: Tubes survived TS Allison. Note sand fence.There are many differences between the Geotubes presented here and the new ProTech technology: Mono vs. multiple celled, vertical vs. more gently sloped, the geotube is more easily broken. However, we still feel that the results of these same types of armoring can be compared, especially with the lack of data. Left picture is after TS Allison. This section was completely destroyed 4 months later. On right, notice erosion behind structure. Bottom picture: Tubes survived TS Allison. Note sand fence.

6. Texas Study Conclusions Storm-surge protection function has not been fully tested as of March 2003 Geotextile tubes will fail when exposed to direct wave attack making them useful only for short-term erosion control It is critical to keep them covered with sand, to maintain a beach in front of them and to repair holes as soon as possible. Beaches in front of geotextile tubes need to be at least 50-ft wide to keep tubes from being exposed and damaged by mild storms like TS Allison

7. Keeping tubes repaired, sand covered, and vegetated requires a significant effort Beaches in front of the geotextile tubes are narrower than adjacent beaches Geotextile tubes alter the natural geomorphology of the beach/dune system and have hindered the formation of coppice mounds and natural dunes They have not enhanced the erosion rates on adjacent beaches, with one exception.

8. New ProTech technology evaluation PBS&J performed an evaluation of the ProTech tubes at Cape San Blas/White Sands for the FL DEP. The research found a lack of quantitative data regarding ProTech tubes and their performance.PBS&J performed an evaluation of the ProTech tubes at Cape San Blas/White Sands for the FL DEP. The research found a lack of quantitative data regarding ProTech tubes and their performance.

9. Rated for a 5-10 year storm eventRated for a 5-10 year storm event

10. After being in place for 17 months, the area was hit by Hurricane Ivan. The ProTech tubes are not rated for a hurricane storm event. The following conclusions were drawn from post-hurricane evaluation: After being in place for 17 months, the area was hit by Hurricane Ivan. The ProTech tubes are not rated for a hurricane storm event. The following conclusions were drawn from post-hurricane evaluation:

11. The revegetated dunes were washed away and the Protech tubes were exposed. The tubes caused a ridge and runnel system that likely caused increased erosion damage in the lee of the tube. The beach behind the tubes had similar erosion damage as beaches nearby

12. At the ends of the tubes, erosion was exacerbated. Beach and dunes did not fare any better than adjacent, non-protected beaches The ProTech tubes did not sustain any damages from the hurricane.

13. San Souci Condominium Exposed for approximately a year before buried by Pensacola Beach Restoration Project A 200-foot segment of the Protech tube failed when overtopped by Hurricane Isadore (2002)

14. Homeowner’s biggest concern These tubes are not designed to protect property during hurricane storm events Beach will still need to be renourished after hurricane storm events Why spend time and money to both install tubes and renourish? Homeowners should be educated on the limits of this technologyThese tubes are not designed to protect property during hurricane storm events Beach will still need to be renourished after hurricane storm events Why spend time and money to both install tubes and renourish? Homeowners should be educated on the limits of this technology

15. Geotextile Tubes vs. Marine Turtles? Again, we note that there is no data concerning the effect of these tubes on the coastal habitat and its fauna. Because these tubes extend onto the beach, they are of more immediate concern for beach wildlife, such as sea turtles, than vertical sea walls. There is evidence (see photo) that theses tubes, if not properly covered, will cause false crawls and abandonment of nesting activities.Again, we note that there is no data concerning the effect of these tubes on the coastal habitat and its fauna. Because these tubes extend onto the beach, they are of more immediate concern for beach wildlife, such as sea turtles, than vertical sea walls. There is evidence (see photo) that theses tubes, if not properly covered, will cause false crawls and abandonment of nesting activities.

16. Loggerhead Nesting Decline Loggerhead turtle nesting in Florida is in a serious decline. The reasons for this are unknown, but it is alarmingly lower than any normal cycle in recorded nesting history. Florida’s coastal policies need to be in tune to the needs of the five endangered and threatened species of sea turtles that nest on its beaches. There needs to be research to assess the impacts of geotextile tubes on turtle habitat, nesting, and nesting success.Loggerhead turtle nesting in Florida is in a serious decline. The reasons for this are unknown, but it is alarmingly lower than any normal cycle in recorded nesting history. Florida’s coastal policies need to be in tune to the needs of the five endangered and threatened species of sea turtles that nest on its beaches. There needs to be research to assess the impacts of geotextile tubes on turtle habitat, nesting, and nesting success.

17. Ways that turtles could be impacted by geotextile tubes Sand cover Quality of nesting habitat Plastics and phthalates Cumulative impacts To explain point two: will change sand moisture, affecting adult nesting and nesting success. The constant renourishing of these tubes will cause habitat degredation for these reasons: compaction of sand, differing grainsize, altered slope, color of sand which affects temperature, and light issues.To explain point two: will change sand moisture, affecting adult nesting and nesting success. The constant renourishing of these tubes will cause habitat degredation for these reasons: compaction of sand, differing grainsize, altered slope, color of sand which affects temperature, and light issues.

18. Sand Cover Sand needs to be deep enough to allow the largest turtles (Leatherbacks) to nest in Florida. This is over 5 feet of sand. Keeping tubes covered with sand is problematic Maintenance costs are prohibitive and it is unclear on who they fall At another ProTech installation at Longboat Key, the Corps of Engineers (Technical letter No.1110-2-353) stated that, during summer months, part of the geotextile tube was exposed and especially during energetic winter conditions, the whole length of tube was exposed. At another ProTech installation at Longboat Key, the Corps of Engineers (Technical letter No.1110-2-353) stated that, during summer months, part of the geotextile tube was exposed and especially during energetic winter conditions, the whole length of tube was exposed.

19. Nesting habitat Permeable/Impermeable tubes may change sand moisture, affecting adult nesting and nesting success Constant renourishing Compaction of sand Differing grain size Altered slope Color of sand/temperature Light issues/elevation

20. Phthalates and developing turtles—Endocrine disruptors Worldwide concern Can affect in two ways Organizational Activation Under best case scenariio, with three feet of sand rule, eggs could be in direct contact with plastic. The geotextile tubes are made with a vinyl coated polyester. Vinyls contain a set of chemical plasticizers called phthalates. Phthalates are known endocrine disruptors. Phthalates are anti-androgens, which affect a developing male and female reproductive system as well as other organs. This affects not only the developing turtle embryos, but their future reproductive ability and that of their offspring. These chemicals are even being tracked in humans by the CDC and are of concern. Putting developing turtles in such close proximity to these chemicals could cause mutations for generations. Dr. Louis Guillette from the University of Florida, among others, has been doing research on endocrine disruptors and their effects on reptiles and mammals for many years and has spoken in several countries on this topic. He has stated that phthalates are one of the chemicals that have not been properly researched yet and should be of interest.Under best case scenariio, with three feet of sand rule, eggs could be in direct contact with plastic. The geotextile tubes are made with a vinyl coated polyester. Vinyls contain a set of chemical plasticizers called phthalates. Phthalates are known endocrine disruptors. Phthalates are anti-androgens, which affect a developing male and female reproductive system as well as other organs. This affects not only the developing turtle embryos, but their future reproductive ability and that of their offspring. These chemicals are even being tracked in humans by the CDC and are of concern. Putting developing turtles in such close proximity to these chemicals could cause mutations for generations. Dr. Louis Guillette from the University of Florida, among others, has been doing research on endocrine disruptors and their effects on reptiles and mammals for many years and has spoken in several countries on this topic. He has stated that phthalates are one of the chemicals that have not been properly researched yet and should be of interest.

21. Cumulative Impacts 15-20% of Florida’s shoreline is armored 59% of Florida’s beaches are eroding Affect the existing shoreline rate of change permanently locking the dune sites in place interfering with the dunes’ ability to recover by artificially supplementing the replenishment cycle of sand dunes altering sea turtle habitat in a way that would significantly impair essential behavioral patterns

23. DEP Proposed Armoring Rule Change A billed was filed in the 2005 Florida legislative session to exempt geotextile tubes from emergency permitting DEP negotiated to substitute this for rulemaking and drafted proposed language The proposed language would remove a regulatory bias in favor of seawalls Apparently drafted in the interest of sea turtles

24. DEP Proposed Armoring Rule Change The UFLaw Conservation Clinic and CCC reviewed the proposed rule and expressed concern that DEP failed to address a fundamental distinction Geotextile tubes have a signficantly larger footprint on the the beach, extending on to the nesting beach Geotextile tubes replace turtle habitat with inferior surrogate habitat that must be maintained in perpetuity Neither the proposed rule nor current permit conditions consider this distinction

25. DEP Rule Development Workshop CCC and The Clinic put their concerns on the record at a rule development workshop on May 6 in Tallahassee Notwithstanding the substantive question of whether geotextile tubes should be treated the same as other armoring, the CCC and Clinic suggested DEP consider the following in the rule:

26. DEP Rule Development Workshop Require continuing operation and maintenance (keeping sand over the structure) Analogous to a stormwater system O & M permit (ERP) Require financial assurances Performance bond, letter of credit, etc. Require that the permit bind subsequent property owners “Run with the land”