The overall goal of our proposed research project is to evaluate recovery trajectories and the potential resilience benefits of nature-based adaptation approaches, specifically beach and dune restoration projects, in southern California. These projects can be considered Natural and Nature-Based Features (NNBF). The recovery trajectories of NNBF projects focused on beach and dune restoration along urban coasts are relatively understudied and synthesis is lacking, especially in the context of enhancing coastal resiliency. There is a major need to consolidate and analyze existing information, collect new standardized data across a variety of project sites, and synthesize these results into a useable framework with outcomes that can be disseminated to the public and coastal resource managers. The majority of these existing dune restoration projects are small demonstration (<5 acres) making scaling of this approach as an adaptation strategy for enhancing coastal resilience a key question of our study. The existing projects represent a gradient of shapes (long and narrow or short and wide) and implementation approaches ranging from passive restoration of groomed beaches to active construction of artificial dunes with resistant cores. To address these needs and inform policy, our proposed research objectives are to monitor, compile, catalog, analyze, and synthesize the ecological and physical trajectories of dune restoration projects on sandy beaches in southern California. We will evaluate the efficacy of the different NNBF projects and their design components, including size, in enhancing coastal resilience using the output of coastal vulnerability models, such as CoSMoS 3.0, which projects coastal flooding and shoreline change due to both sea-level rise and storms for southern California.

This study seeks to build on existing research and data using a practical and feasible scientific framework to address key data gaps and questions for coastal NNBF beach and dune restoration projects and develop a synthesis and outputs that can inform coastal adaptation to enhance resilience. We hypothesize that that data from the gradient of proposed study sites, when compared with control and reference locations, will be translated into expected trajectories for these projects that can be used to project responses to climate forcing and allow us to assess the potential contribution of these projects to coastal resilience. Where possible we will take advantage of the datasets generated to assess impacts and recovery of these NNBF projects from storms and from ENSO events which can be used as proxies for future sea level rise. Results from our study will inform design and expectations for future beach and dune restoration projects as well as coastal management and policy.