Coalition to Restore Coastal Louisiana

Hosted by: Coalition to Restore Coastal Louisiana
Ione E. Burden Conference Center, LSU AgCenter

Panel Members: Bill Good, Cindy Steyer, Lawrence Rozas, Russ Joffrion

These issues were raised with a discussion between panel members and attendees.

Needs:

• Models on waves at various pool depths (How close should terraces be constructed?)
• Design criteria should be modeled. There is apparently different goals for constructed terraces, based upon what is ultimately desired. Still, our design criteria to date are essentially the same regardless of where built and regardless of ultimate goals for the projects.
• There was a large consensus to fund studies on elements not yet examined and to build funding for experiments and monitoring into construction projects. For CWPPRA projects, a request for performance evaluations could be made.
• It is clear that the various projects presented had different goals, however it is not clear if the success criteria were presented in the planning stages of these projects. Clear goals and success criteria should be required.
• There was a sense of the group that earthen terraces can be used to help reduce storm surge, however this would need to be tested and modeled.
• Though some in the group felt that permitting should be slowed until we learn more, others felt that we should continue to permit terrace construction since we know that there are some known payoffs.

Other issues:

• There are many terraces in various locations, therefore an existing set for potential study
• The question of mitigation was raised and whether or not we are creating land, since we borrow from the pond bottoms to construct terraces. Is there a net gain of sediments? (No)
• The group discussed why some many have been built if we know relatively little. The answers were that they are inexpensive (relatively), quick and easy to build, there is a lot of habitat edge, which increases WVA assessments and that terraces can be scaled to need from very small to very large

Some of the Negative Issues:

• These could be lost to storms. This was felt to be trivial since they are easy and inexpensive to build.
• Borrow ditches (trenches) were an issue that was raised periodically.
• Are they sediment sinks?
• Fish and gators will use in the summer, believed to be cooler in the deeper waters, and predators could congregate impacting food webs. This was raised as a possibility. No one had any evidence one way or another.
• The group sense is that the jury is still out and more research is needed on the borrow ditches