Estimating Wave Reduction by Floating-Wetland Breakwaters Using Small-Scale Physical Models

Abstract

Wind-induced waves can cause significant erosion on lake shorelines. One solution to this problem is to absorb the waves before they reach the shoreline. Floating breakwaters have been used to reduce waves, but provide limited ecological benefit. On the other hand, floating wetlands have been used to improve water quality and habitat. The goal of this study is to use scale models estimate the wave height and energy reduction of floating wetlands used as breakwaters. The floating-wetland breakwaters used in this study consist of a base frame filled with Poly-flo filter material, and a cross section made of pipes of uniform diameter. The hypothesis of this study is that wave reduction results from small-scale floating-wetland breakwaters can predict the wave reduction performance of full-scale floating-wetland breakwater designs. Floating-wetland breakwater models were constructed using Froude number similitude. Wave height and energy reduction experiments were conducted on floating-wetland breakwaters at two different scales. Results indicate that, in most instances, floating-wetland breakwaters at different scales exhibit a similar wave reduction performance. Overall, this study provides a framework for individuals and agencies to design and evaluate floating-wetland breakwaters, and helps to address shoreline erosion problems in a cost-effective manner.