Innovations in Coastline Management With Natural and Nature-Based Features (NNBF): Lessons Learned From Three Case Studies

Abstract

Coastal communities around the world are facing increased coastal flooding and shoreline erosion from factors such as sea-level rise and unsustainable development practices. Coastal engineers and managers often rely on gray infrastructure such as seawalls, levees and breakwaters, but are increasingly seeking to incorporate more sustainable natural and nature-based features (NNBF). While coastal restoration projects have been happening for decades, NNBF projects go above and beyond coastal restoration. They seek to provide communities with coastal protection from storms, erosion, and/or flooding while also providing some of the other natural benefits that restored habitats provide. Yet there remain many unknowns about how to design and implement these projects. This study examines three innovative coastal resilience projects that use NNBF approaches to improve coastal community resilience to flooding while providing a host of other benefits: 1) Living Breakwaters in New York Harbor; 2) the Coastal Texas Protection and Restoration Study; and 3) the South Bay Salt Pond Restoration Project in San Francisco Bay. We synthesize findings from these case studies to report areas of progress and illustrate remaining challenges. All three case studies began with innovative project funding and framing that enabled expansion beyond a sole focus on flood risk reduction to include multiple functions and benefits. Each project involved stakeholder engagement and incorporated feedback into the design process. In the Texas case study this dramatically shifted one part of the project design from a more traditional, gray approach to a more natural hybrid solution. We also identified common challenges related to permitting and funding, which often arise as a consequence of uncertainties in performance and long-term sustainability for diverse NNBF approaches. The Living Breakwaters project is helping to address these uncertainties by using detailed computational and physical modeling and a variety of experimental morphologies to help facilitate learning while monitoring future performance. This paper informs and improves future sustainable coastal resilience projects by learning from these past innovations, highlighting the need for integrated and robust monitoring plans for projects after implementation, and emphasizing the critical role of stakeholder engagement.

An integrated approach for physical, economic, and demographic evaluation of coastal flood hazard adaptation in Santa Monica Bay, California

“…While it does not completely eliminate flooding within the study area, the targeted dune scenario still provides a minimum 71% reduction in flood area in the Venice Canals. Although not quantified here, NNBF systems like dunes can also provide a range of secondary benefits, including habitat and recreational/aesthetic value (Sutton-Grier et al, 2015), and may be more palatable to local residents than an extensive sea wall (Palinkas et al, 2022).…”

“…The evaluation of coastal adaptation strategies often relies on economic cost-benefit analysis that accounts for construction costs and avoided damages to structures (Reguero et al, 2018;Palinkas et al, 2022). However, the vulnerability of different demographic groups and the ability of communities to adapt in response to disasters are also important considerations when deciding how to respond to SLR and coastal flooding (Nastev and Todorov, 2013).…”

Impact of Climate Change on Global Health: A Comprehensive Review

“…Case studies highlighting successful adaptation initiatives and lessons learned from past experiences in building health resilience to climate change have also shown the significant contribution of women to three major areas of community resilience: social, economic, and ecological resilience [61]. Successful projects on the mitigation of the effects of climate change often adopt innovative strategies and emphasize integrated and robust monitoring systems [61,62].…”

Is the coastal future green, grey or hybrid? Diverse perspectives on coastal flood risk management and adaptation in the UK

“…Furthermore, hybrid solutions that use features to enhance biodiversity still very much rely on the built part for flood protection (Rubinato et al, 2020). Hybrid solutions that are a mix of grey and green approaches in one location are reported to be more impactful (Palinkas et al, 2022) but still can have a negative impact due to the hard engineering (Sutton-Grier et al, 2015). Overall if the existing infrastructure does not allow for NbS, a mix of options or integrated greening of grey infrastructure even applied retrospectively can be an important strategy.…”