Resilience Concepts Behind Living Breakwaters

I was asked by an intern at City Atlas, Travis Gonzales, to answer his well-posed questions on our winning Rebuild By Design entry, Living Breakwaters, and here is that Q&A, which I think gets addresses some important aspects of the concept.

1. The proposal for Living Breakwaters states that the breakwater system developed to protect Staten Island’s coastline could be used in other vulnerable communities. Yet, the Island’s location at the mouth of the harbor makes for a special case of erosion. Do you think that a proposal like this, and Rebuild’s competition by extension, supports experimenting with coastal protection locally in a way that can be used throughout the coastal US?

Staten Island is a somewhat unusual semi-protected coastal location, where waves are typically small, but can be large during coastal storms.  However, the irregular US Northeast coast has many locations with similarities, such as beach areas near Boston, as well as all of coastal Masschusetts and New Hampshire.

A distinguishing feature of a coastal area like that of Staten Island is that waves are not a normal feature utilized for recreation, such as surfing.  So, it’s an ideal location where modification of the wave climate will not cause opposition of surfers and others who enjoy the waves.  However, the approach could also be used selectively at open coastal locations where there is surfing, as long as surfers are brought into the process of planning reefs that they might enjoy using for surfing.

2. Because the breakwaters aren’t a type of levee or berm but instead a buffer, how long do you think they will remain effective, given issues like continual sea level rise or the potential for stronger storms?

One of the main innovations with the breakwaters is that they are designed to GROW with sea level rise, as oyster beds can easily grow at a similar or faster rate.

In terms of extreme storms, which can happen today and aren’t only a thing of the future, the breakwaters gradually become less effective at reducing wave heights as a flood deepens above them.  But this is part of the plan; the purpose of our approach is actually to NOT have a flood elevation where the adaptation abruptly becomes useless (or worsens the dangers).

This is in contrast to levees, which always have a “design height” and this is typically the height of a 100-year storm, plus one or more extra feet allowing for sea level rise.  Once the flood goes above a levee design height you have abrupt rushing water filling in the “protected” area, which can make the hazard MORE deadly than a gradually rising water level.   In New Orleans, this occurred many times over and over through history, not just in 2006 (see this reference).  The paired problems of sea level rise and urban coastal flooding is a very complex and dynamic problem involving not just physical flooding, but also sociology, psychology (do I evacuate?), economics and politics.  Levees are a static solution to this very dynamic problem.

3. Staten Island coastal areas, while good for recreation, do not have the same vital infrastructure points as Lower Manhattan. Why is protecting Staten Island a concern for New York City?

Actually, the project isn’t really about “protecting” Staten Island.  It aims to improve the area’s resilience in a much broader way, including economics and coastal storms.  We do this by restoring Staten Island’s historical water culture, reducing flood and wave risks, reducing erosion, improving educational and recreational opportunities at the shore, and thus making the ocean tides and waves (and their risks) more visible and tangible.  It’s much broader.

New York City has a very large coastal population in flood zones, and they expect something to be done in response to Sandy, and the options often boil down to vertical protections (e.g. levees) and other options, and we feel we have created a very appealing alternative.  That being said, our living breakwaters are an offshore option, and communities can still work with the city and Corps of Engineers to build vertical protections such as dunes or levees.

4. If you have any other thoughts or insights on Rebuild by Design that you’d like to share, please do.

When there is a disaster, the political response by government is to try to help people and to stop the same disaster from happening again.  But when it comes to coastal flooding, it’s also important to have some sort of long-term thinking.  We know we have many feet of future sea level rise coming, possibly within just this century, and simply stopping today’s flooding problem isn’t necessarily the best solution.

This was the brilliant justification behind Rebuild By Design — bringing the world’s designers, scientists and engineers together to come up with new ideas for more forward-thinking solutions to the increasing problem of sea level rise and coastal flooding.

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1 Response to Resilience Concepts Behind Living Breakwaters

  1. Pingback: Rebuild by Design and Seaport City: NYC’s coastal future takes shape | New York

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