Date of Award

1-10-2024

Publication Type

Thesis

Degree Name

M.Sc.

Department

Earth and Environmental Sciences

Keywords

Physics, Plant Science, Water Resource Management

Supervisor

Chris Houser

Rights

info:eu-repo/semantics/openAccess

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

The use of nature-based solutions and engineering ideas has sparked interest in the value of vegetated shorelines for protecting against erosion. However, there is a lack of field data, and more research is needed to understand how effective vegetation is in reducing the impact of wind waves and boat wakes. The difference in period between wind waves and boat wakes suggests that they may be attenuated differently, requiring further study to determine the optimal management design. The purpose of this study is to quantify the ability of artificial vegetation to attenuate boat wakes and calculate the drag coefficient for model vegetation. The field study was completed on Peche Island in the Detroit River that is estimated to have decreased in area due to the passage of cargo and recreational vessels capable of generating large wakes. Pressure transducers were constructed to track the amount of wave decay occurring between vegetated and non – vegetated transects from boat wakes occurring at the shoreline, these values were calculated for drag coefficients and plotted alongside previous study results. Results suggest that the artificial vegetation was capable of attenuating wakes, but only after the cross-shore variation in wave height was deshoaled to account for the increase in wave height. Using the deshoaled wave heights, the calculated drag coefficient is greater than all previous studied vegetation and did not exhibit the decay observed in other studies of both artificial and natural vegetation. It is believed that the limited variation in drag and a lack of energy decay is due to the vegetation remaining equally rigid over the wake train and not swaying independently in response to the individual waves. In this respect, the artificial vegetation is an effective attenuator of wakes and a total of 3 stalks per m2 would be required to provide sufficient attenuation. If installed along the length of Peche Island (1.124km) it is estimated that ~33,720 stems would be required at a cost of ~$505,800 not including the cost of installation and annual maintenance.

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