“Surfers Point managed shoreline retreat project: Lessons from a cobble beach pilot on a dynamic delta”
Bob Battalio, Marc Beyeler, David M. Hubbard, A. Paul Jenkin, Kiki Patsch, and Louis A. White
Abstract
The Surfers Point Managed Shoreline Retreat Project in Ventura, California, USA, demonstrates an alternative to conventional shoreline armoring by using natural materials and geomorphic design to avoid the negative consequences associated with riprap and seawalls. This paper evaluates the physical performance of Phase 1 of the project, which constructed a dynamic cobble berm/sandy beach and dune system within the active delta of the Ventura River. The design replicated shore form and function while relocating infrastructure inland to restore space for coastal processes. The project met multiple objectives including erosion and flood mitigation, access and recreation benefits, and restoration of natural morphology and ecology. Implementation required extensive coordination among public landowners, managers, regulators, funders, stakeholders, and the public. The engineering design consists of a base layer of cobble, topped with sand and vegetated dunes, intended to respond dynamically to elevated waves and river flows, and variable sediment input from upcoast and the Ventura River. Monitoring from 2011 through 2024 shows a dynamically stable and resilient system. The project provides a valuable case study for cobble-based living shorelines in high-energy coastal environments. An applied geomorphology approach informed by reference sites is a valid basis for establishing the geometry and materials for cobble-boulder berms and vegetated dunes. Landward realignment of built infrastructure was required to provide sufficient space for natural processes. Setback distances were informed by wave run-up calculations. Parametric equations for wave run-up combined with engineering judgement can inform development setbacks. Native dune vegetation and low-relief foredune geometry have proven resilient within this coastal flood plain, with the cobble berm providing protection. The natural infrastructure has accommodated erosion events, dissipated wave run-up and recovered repeatedly with sand deposition since construction in 2012.
"Shore & Beach" is the quarterly peer-reviewed journal of the American Shore and Beach Preservation Association (ASBPA). ASBPA is an association of coastal engineering professionals with state chapters such as the California CSBPA. The journal publishes papers that contribute to the knowledge base necessary for sound coastal decision-making and the important contemporary debates concerning shores and beaches everywhere. Content includes coastal scientific, economic, social, and political findings, coastal observations, and editorials.
References:
“Surfers Point managed shoreline retreat project: Lessons from a cobble beach pilot on a dynamic delta" Bob Battalio, Marc Beyeler, David M. Hubbard, A. Paul Jenkin, Kiki Patsch, and Louis A. White
A pdf of the article may be downloaded here
Shore & Beach ASBPA: https://asbpa.org/publications/shore-and-beach/
Climate.gov (another case study)
