Identifier

etd-11052004-152838

Degree

Master of Science in Biological and Agricultural Engineering (MSBAE)

Department

Biological and Agricultural Engineering

Document Type

Thesis

Abstract

Louisiana's coastline has received national attention due to rapid erosion rates estimated from approximately 60 to 100 square kilometers per year. The disappearance of coastal areas jeopardizes public and private infrastructure, property values, aquatic ecosystems, and standards of living. In order to resolve the erosion problem, innovative solutions have been explored that may improve effectiveness and cost efficiency. This research involves a technology, termed an "oysterbreak," which is a bioengineered submerged breakwater. This structure promotes oysters to form a dense structure that dissipates wave energy. Since the structure is biologically dominated, initial material use is modest. The oysterbreak was evaluated through a series of experiments. Settlement patterns were analyzed by quantifying the biological fouling on the structure during its deployment in Grand Isle, Louisiana for one year. Secondly, settlement preference on materials was analyzed in a tank under various flows. To investigate further, the wave interactions with various scaled designs were also analyzed in a wave tank. The transmission, reflection, and dissipation characteristics were determined as growth occurred. Lastly, a predictive model was developed from the results. Experiments suggest that a uniform distribution pattern could be expected in the absence of predation. Also, it was shown that mortar coating was superior for oyster settlement to PVC pipe and commercially available oyster tubes. The wave tank experiments concluded that wave transmission through the structure decreased as growth occurred. It was also shown that a structure with 2 vertical slats/meter, could be used to effectively dissipate waves. The predictive model developed suggests that the oysterbreak can be used in field conditions. The model showed that after one year of growth, an oysterbreak 20 meters wide has the capacity to reduce wave energy by 70%. This prediction is consistent with other submerged breakwater designs. The results of these experiments will be used to design, deploy and monitor full scale oysterbreaks.

Date

2004

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Steven G. Hall

Included in

Engineering Commons

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