|
Wave Robbers™: Erosion Control and Land Reclamation
research
Preliminary Function Evaluation and Design Refinement Study - Innovative Coastal Restoration Tools
Land and wetland loss occurs along the edges of wetlands, water courses, and
shorelines across Coastal Louisiana. Conventional shoreline protective structures are
expensive to construct in these environments and impede environmental exchanges
essential for connectivity and functionality. Webster Pierce of Pierce Industries, LLC of
Cut Off, Louisiana recently invented modular shoreline protection/sediment retention
systems that could become a preferred alternative. Pre-fab, modular construction
allows easy delivery and installation even in remote shallow-water environments and
potential removal and re-use. Water exchange across the units provides hydrologic
and ecological connectivity. These features make this system unique and, if proven
effective, would also make it a commercial success resulting in numerous Louisiana
jobs.
Pierce Industries, LLC conducted some crude testing of the Wave Suppression/
Sediment Collection (WSSC) System during its development that showed extraordinary
potential. Extensive additional testing and design refinement is necessary to move
the system to engineering implementation. The University of Louisiana has teamed
up with Pierce Industries, LLC to conduct the testing required to move the WSSC
System to viable engineering product. This includes constructing laboratory-scale
models and conducting extensive testing of their performance in the hydraulic flume,
fitted to function as a wave tank, at the University of Louisiana at Lafayette. Laboratory
Research is being conducted for the purposes of design and optimization. With this
research, design guidelines will be written for typical applications and further study will
explore atypical situations for additional guidelines. Face-slope optimization, sediment
transfer and retention efficiencies, and anchoring system design have been theoretically
modeled and calculated as well as experimentally tested. Initial experiments have
confirmed the original hypothesis of Webster Pierce. The Wave Robbers™ do their job
by absorbing or reflecting most of the energy of the wave back to open water. Sixty to
seventy percent of the wave height has been eliminated by the Wave Robbers™.
Upwards of 80 percent of the suspended sediment added to the tank was
transported through the units and deposited in the relatively calm water behind the
units. Horizontal forces due to waves hitting the units can be quite substantial, ranging
about 10-30 pounds per square foot, requiring an anchoring system to be designed
for significant shear forces. Unit stability has also been an area of concern, requiring
adjustments to the anchoring system. Field research will be conducted to show the “real
world” feasibility of this project. Based upon these results, the research team will work
with Pierce Industries, LLC to generate a refined design and evaluate the commercial
viability of the product
The WSSC System is one tool that could impact the future of Coastal Restoration,
not only by reducing the impact of erosion, but by reversing the process. Wave energy
is responsible for washing away the delicate land areas that make up the Coastal
Region of South Louisiana. Wave Robbers™ utilize that wave energy to transport the
sediments to more quiescent water, allowing land reclamation without any external
energy required. This reduced erosion and land rebuilding does not require large,
unsightly structures or dredging for soil reclamation which, although faster, is much
more expensive. This solution also allows hydraulic and ecological connectivity unlike
rock or earthen dikes which cut off the steady flow of water and life.
|
|
|
