The abstracts of this issue are below. Note that ASBPA members only now have access to a full digital edition of Shore & Beach. Become a member now to get immediate access to the latest issue!
From the Editor’s Desk:
A virtual tour of the Pacific
Andrea O’Neill and Lesley Ewing
Measuring historical flooding and erosion in Goodnews Bay using datasets commonly available to Alaska communities
Richard M. Buzard, Christopher V. Maio, David Verbyla, Nicole E.M. Kinsman, and Jacquelyn R. Overbeck
Coastal hazards are of increasing concern to many of Alaska’s rural communities, yet quantitative assessments remain absent over much of the coast. To demonstrate how to fill this critical information gap, an erosion and flood analysis was conducted for Goodnews Bay using an assortment of datasets that are commonly available to Alaska coastal communities. Measurements made from orthorectified aerial imagery from 1957 to 2016 show the shoreline eroded 0 to 15.6 m at a rate that posed no immediate risk to current infrastructure. Storm surge flood risk was assessed using a combination of written accounts, photographs of storm impacts, GNSS measurements, hindcast weather models, and a digital surface model. Eight past storms caused minor to major flooding. Wave impact hour calculations showed that the record storm in 2011 doubled the typical annual wave impact hours. Areas at risk of erosion and flooding in Goodnews Bay were identified using publicly available datasets common to Alaska coastal communities; this work demonstrates that the data and tools exist to perform quantitative analyses of coastal hazards across Alaska.
Observations of wave attenuation, scour, and subsurface pore pressures across three marsh restoration sill structures on a sandy bed
Jordan Converse, Meagan Wengrove, and Pedro Lomonaco
With rising sea levels and more frequent exposure to extreme storms, coastlines worldwide are vulnerable to increased erosion and loss of natural marsh lands. In an effort to lessen these impacts, there is a growing practice of adapting hard or “gray” coastline protection techniques to more nature-based features that promote habitat and ecosystem health. Living shoreline marsh restorations utilize natural and naturebased materials to protect marsh shores from erosion while also allowing intertidal flushing to promote the health and diversity of the marsh. Our study investigates three types of living shoreline sill designs exposed to average and storm-energy wave conditions at varying water levels. The sills were designed to mimic constructed sills in practice (rock, oyster shell, tree root wads), but more generally vary in structure porosity and material dissipation potential. Large-scale laboratory experiments were conducted in the large wave flume at the O.H. Hinsdale Wave Research Laboratory. Wave transmission and reflection are used to demonstrate wave attenuation capability of each sill structure. Scour of the sill, bedload sediment transport rates on the seaward and shoreward sides of the sill, and sediment pore-water vertical hydraulic gradients were used to demonstrate the potential for sediment transport and liquefaction. Results will contribute to understanding the effect of sill material porosity and mass on structure stability, and the effectiveness of using green living shoreline sill structures in the continued effort to establish design criteria for living shoreline implementation.
Toward improved coastal sediment management through coordination in California
Kristen A. Goodrich, Douglas A. George, Marc Beyeler, Phyllis Grifman, and Nick Sadrpour
Sediment is an essential component of contemporary coastal and marine management in California. For decades, multiple coastal sediment management organizations have facilitated and coordinated regional sediment management (RSM) as an approach, and more recently, are increasingly focused on the state’s sea level rise adaptation efforts. From the perspective of representatives and members of some of these organizations, this paper describes challenges of RSM in the areas of organizational capacity and coordination. It also characterizes ways in which organizations are taking leadership and action in overcoming these constraints to fulfill their commitment to improved coastal sediment management.
Planning to adaptation: Informing regional nature-based adaptation to improve coastal resiliency in Santa Monica Bay
Phyllis Grifman, Melodie Grubbs, and Karina Johnston
Los Angeles County is known for its wide sandy beaches, coastal boardwalks, and beach commerce and tourism. Planning for sea level rise and associated coastal hazards poses unique challenges in highly populated urban communities; in particular, sandy beaches play an important role in buffering the land from sea level rise, coastal storms, and associated flooding. With increasing pressure to prepare for and adapt to sea level rise, boundary organizations such as USC Sea Grant and The Bay Foundation are helping coastal communities build their capacity to respond to changing shorelines by providing and translating best available science, providing planning and technical support, building partnerships, and implementing adaptation strategies. This paper evaluates the process and provides recommendations for translating science to on-the-ground planning and adaptation efforts in coastal communities. Regionally, USC Sea Grant’s AdaptLA initiative works with coastal communities to communicate sea level rise science and provide managers with information and tools to assess vulnerabilities and begin to plan for adaptation. Informed by detailed, scaled-down climate change models and science-based demonstration projects, some AdaptLA participants initiated demonstration adaptation projects such as the Santa Monica Beach Restoration Pilot Project discussed in this paper. The Santa Monica Bay case study highlights a sea level rise adaptation process, from community capacity building to planning nature-based adaptation, using beach restoration. Lessons learned from demonstration projects in the region can inform similar projects and potential scaling up of nature-based adaptation on sandy beaches. Through the collective effort of boundary organizations, coordination with multiple jurisdictions and agencies, and community support, this case study demonstrates a model for implementing naturebased adaptation in urban coastal communities.
Applicability of management guidelines for surfing resources in California
Edward A. Atkin, Dan R. Reineman, Jesse Reiblich, and David L. Revell
Surf breaks are finite, valuable, and vulnerable natural resources, that not only influence community and cultural identities, but are a source of revenue and provide a range of health benefits. Despite these values, surf breaks largely lack recognition as coastal resources and therefore the associated management measures required to maintain them. Some countries, especially those endowed with high-quality surf breaks and where the sport of surfing is accepted as mainstream, have recognized the value of surfing resources and have specific policies for their conservation. In Aotearoa New Zealand surf breaks are included within national environmental policy. Aotearoa New Zealand has recently produced Management Guidelines for Surfing Resources (MGSR), which were developed in conjunction with universities, regional authorities, not-for-profit entities, and government agencies. The MGSR provide recommendations for both consenting authorities and those wishing to undertake activities in the coastal marine area, as well as tools and techniques to aid in the management of surfing resources. While the MGSR are firmly aligned with Aotearoa New Zealand’s cultural and legal frameworks, much of their content is applicable to surf breaks worldwide. In the United States, there are several national-level and state-level statutes that are generally relevant to various aspects of surfing resources, but there is no law or policy that directly addresses them. This paper describes the MGSR, considers California’s existing governance frameworks, and examines the potential benefits of adapting and expanding the MGSR in this state.
A summary of beach nourishment in China: The past decade of practices
Gen Liu, Feng Cai, Hongshuai Qi, Jianhui Liu, Gang Lei, Jun Zhu, Huimei Cao, Jixiang Zheng, Shaohua Zhao, and Fan Yu
Beach nourishment has been widely used for beach protection around the world. However, there is limited information about beach nourishment in China. This study offers an overview of beach nourishment practices, status and technological advances in China, based on the literature, reports, and personal communications. The results demonstrate that beach nourishment has been recognized as an effective and environmentally friendly measure to combat coastal erosion and has been increasingly adopted in China, especially in the past decade. The unique characteristics of coastal China resulted in a difference in beach nourishment between China and Western developed countries in terms of the types, objectives, and shapes of beach nourishment. For the types of nourishments in China, there were approximately the same number of restored beaches and newly constructed beaches. For fill sediment, homogeneous fill and heterogeneous fill comprised 51.1% and 48.9% of projects, respectively. The objective of beach nourishment was mainly to promote coastal tourism, and the shape of nourished beaches was dominated by headland bays. This study also indicated that China has achieved a number of technological advances in beach nourishment, including methods of beach nourishment on severely eroded coasts and muddy coasts, an optimized design of drain pipes involved in urban beaches, and ecological design considerations. From the past decade of practices, four aspects were proposed as considerations for future nourishment: sand sources, technique advances, ecological effects, and management of beach nourishments.
In Memoriam: A tribute to Choule Sonu
ASBPA White Paper: Best management practices for coastal inlets
Nicole Elko, Kimberley McKenna, Tiffany Roberts Briggs, Nicholas Brown, Michael Walther, and Dawn York
Coastal inlets separate individual barrier islands or barrier spits and adjacent headlands (Hayes and Fitzgerald 2013). Inlets modify longshore transport and store sediment in flood and ebb shoals leading to dynamic adjacent shorelines. For example, 80% to 85% of the beach erosion in Florida can be attributed to inlets (Dean 1991). In some cases, structured inlets are designed to trap sand in a preferred location to minimize interference with navigation and facilitate its removal through dredging. Sound coastal engineering practice requires that this sand be placed on adjacent eroding beaches (NRC 1995) to protect coastal resources. This paper provides a brief overview of coastal inlet management and identifies Best Management Practices (BMPs) intended to balance human needs for inlet navigation with the natural systems adjacent to tidal inlets. Today’s conservation measures, which are a result of considerable monitoring, numerical modeling, and other science-based methods, demonstrate that BMPs improve management of sand resources and reduce impacts associated with tidal inlet dredging. For some inlet conditions, BMPs include use of inlet sediment sinks as cost-effective and eco-friendly sand sources for beach nourishment projects located close to the inlet. For optimal coastal inlet management, the ASBPA Science and Technology Committee recommends the following BMPs and conservation measures: