A NEW APPROACH TO NEARSHORE BREAKWATERS: A CASE STUDY FOR UNDULATING CRESTS

Abstract

Traditionally, stone nearshore breakwaters are designed and constructed using standard parameters based on a series of existing equations and calculations (frequently those specified in the Coastal Engineering Manual for the U.S.). These include a calculated crest elevation based on design wave heights, along with computationally derived side slopes and crest widths chosen to either eliminate or reduce wave energy transmission by a desired amount. Another design decision is how frequent and how large to make gaps between the breakwaters, which is more standard for sandy scenarios, but less so when dealing with marsh and bluff shorelines. Additionally, the breakwaters are designed to be constructed within a range of design distances from the shoreline, with parameters chosen to define desired post-construction scenarios such as tombolo or spit formation. There are significant data and existing research allowing for these calculations in sandy environments. For marsh or bluff based shorelines, the offshore distance is often developed based on constructability or a desired marsh restoration template.