The Nature Conservancy yesterday released to the public a groundbreaking case study that provides a preliminary, comprehensive evaluation of how nature-based defenses, in conjunction with gray solutions, can effectively be used to protect communities in New York City and around the globe from the impacts of climate change.
The highlights of the Urban Coastal Resilience Report, the first-ever analysis of its kind, are that:
- Nature-based features (such as mussel beds and restored marsh) can be successfully used in a dense, urban setting in combination with “gray” defenses (like sea walls and flood gates) to provide efficient and cost-effective protection from sea level rise, storm surge and coastal flooding;
- There are rigorous and valid ways to value the contributions of nature.
For the report, experts analyzed several infrastructure alternatives, ranging from purely nature-based solutions to one consisting of only gray defenses.
The study found that combining natural and gray defenses holds the most benefits. Analysis shows that a hybrid alternative could result in avoided losses in this one neighborhood of up to $244 million from the current 1-in-100 year storm event.
Demonstrating the benefits of a hybrid approach in terms of future cost-avoidance provides a strong basis for making investments that use both nature-based and gray systems in community resiliency that are critically needed today.
The best conceptual alternative and most cost-effective, according to the study, utilizes restored marsh habitat on the coast, hard toe mussel beds along the shoreline, floodgates and sea walls to protect against storm surge and rising sea levels and rock groins on the shoreline to help prevent erosion.
The general concept of this alternative is illustrated in an infographic that shows the approximate location of each type of infrastructure as analyzed in the study.