From the editor’s desk: Understand the past, anticipate the future
Lesley C. Ewing
We’ll take Manhattan: Preserving an urban (Southern California) beach in the 21st century
Lindsey Sheehan, Kristina Kunkel, Philip King, Dana Murray, and Nicholas Garrity
https://doi.org/10.34237/1009031 Shore & Beach 90(3), p. 3-16
The City of Manhattan Beach is updating its Local Coastal Program-Land Use Plan (LCP-LUP), a planning document that regulates development in the city’s coastal zone and establishes a long-range vision for the community. Before embarking on updating the LCP, the city and the community need to better understand coastal vulnerabilities with sea level rise, to analyze the physical and economic risks, and to implement actions to prepare and adapt to the impacts of sea level rise. The authors conducted a Sea Level Rise Risk, Hazards, and Vulnerability Assessment (ESA 2021b) and Adaptation Plan (ESA 2021a). As part of the Adaptation Plan, we compared a “no action scenario” with a potential adaptation scenario designed to mitigate future coastal hazard risks. The economic and fiscal impacts of the no action scenario were compared to the relative costs and benefits of the adaptation scenario. The analysis indicates that sea level rise and the resulting beach erosion may negatively impact the city of Manhattan Beach’s ability to provide visitors with adequate recreational capacity by mid-century. The analysis also indicates that Manhattan Beach and Los Angeles County will lose significant tax revenues without adaptation, approximately $107 million in transient occupancy taxes (TOTs) and $39 million in county (sales) taxes. Adding to beach capacity through dune restoration and nourishment would preserve $65 million in non-market value through 2100. Given these values, it is likely that nourishment or dune restoration would yield the most net benefits as adaptation strategy in the future.
An ASBPA White Paper: U.S. community perspectives on coastal flooding
Nicole Elko, Tiffany R. Briggs, Reza Marsooli, Patrick Barrineau, Cheryl Hapke, Kimberly McKenna, Jonathan Simm, Marc Beyeler, Matt Smith, and Cary Troy
https://doi.org/10.34237/1009032 Shore & Beach 90(3), p. 17-29.
Coastal flooding, from both extreme events and sea level rise, is one of the top management challenges facing U.S. coastal stakeholders today. The intensity of coastal flooding is expected to increase with global sea level rise. This paper focuses on flooding challenges from the perspective of coastal communities. The myriad of flood mitigation strategies that have been implemented across the U.S. vary based on a multitude of factors including spatio-temporal scale of the coastal flooding hazard. ASBPA administered a survey of 106 coastal stakeholders from around the U.S. to assess specific community challenges and needs related to coastal flooding in late 2021. A majority of respondents indicated that their community includes an underserved population or neighborhood (54%) or nearby communities do (25%). While the vast majority of survey respondents indicated that flooding was a major challenge, only 24% of respondents’ communities have a coastal flooding adaptation plan. Improvements to drainage systems are the most commonly implemented gray infrastructure strategy in the Southeast and Gulf coast regions. Respondents from all regions noted that beach and dune restoration has been the most widely implemented nature-based flood mitigation strategy. Interest is now high in other nature-based solutions with application in low-lying, vulnerable coastal areas such as thin-layer placement on marshes, living shorelines, and hybrid projects on estuarine shorelines. This paper does not provide an exhaustive review of the science, forcings, or policies on coastal flooding in the U.S.; rather, it captures the perspectives of coastal communities and aims to inform and prioritize future research investments related to coastal flooding.
Research Letter: Perceptions and factors impacting visitor decisions: The Blue Flag pilot at Galveston, TX
Kristin Butler and Annie Mercer
https://doi.org/10.34237/1009033 Shore & Beach 90(3), p. 30-35.
COVID-19 changed the way people interacted with outdoor spaces and heavily impacted summer tourism trends. With the federal government’s encouragement, many people chose beach outings where they could enjoy a vacation while minimizing the risk of contracting COVID-19. It was during this time in 2020-2021 that East Beach (managed by the Galveston Island Park Board of Trustees) in Galveston, Texas, was the site of a survey study concerning beachgoer interest in the Blue Flag award program. The Blue Flag program operates in 48 countries focusing on environmental education, safety and security, environmental management, social responsibility, and responsible tourism among beaches, marinas, and tourism boat operators. Before the study began, training on the Blue Flag program was given to the student researcher to provide an informational basis for explaining the program and award criteria to participants. Participants for this study were sampled from the beach-going population at East Beach in Galveston. A total of 53 participants completed the entire survey for a completion rate of 82.81%. The positive responses in support of the Blue Flag program found in this survey shows interest in East Beach would likely increase if the Blue Flag award were attained and a larger sample of responses were collected for analysis.
Improving coastal resilience planning with respect to long-term water level fluctuations by examining decadal coastal profile behavior at sandy, harbor filet beaches along Lake Michigan in the Great Lakes of North America
Ethan J. Theuerkauf, Guy A. Meadows, and Lorelle A. Meadows
https://doi.org/10.34237/1009034 Shore & Beach 90(3), p. 36-43.
Resilient planning for coastal hazards requires an understanding of both short-term and long-term coastal change dynamics. Numerous studies have been conducted throughout the Great Lakes of North America on processes and responses associated with short-term coastal changes, such as storms and seasonal fluctuations in lake level; however, few datasets exist that can capture long-term coastal morphodynamics in this region. Lack of data and knowledge creates a barrier for accurately modeling future coastal change, which underpins proactive coastal management. This is particularly problematic at sites adjacent to coastal infrastructure, such as those near harbors. To address this, we utilize a 32-year record of coastal profile change from several sites along the Lake Michigan shoreline of Michigan to examine profile evolution in response to changing lake levels and human disturbance. These data reveal that coastal sites without shoreline armoring can recover from erosive high lake level phases if lake level remains low for an extended period. However, if sites are armored, or if future climate conditions result in more frequent or more extreme lake level fluctuations, full recovery of the coastal profile is unlikely. Managers and decisionmakers can utilize this information to evaluate their site conditions and proactively plan for future coastal changes.
Coastal Forum: Haulover sandbar dredging controversy
Stephen P. Leatherman, Stephen B. Leatherman, and Mystic Duke
https://doi.org/10.34237/1009035 Shore & Beach 90(3), p. 44-49.
Bakers Haulover Inlet in Miami-Dade County, Florida, is an important waterway for recreational boaters connecting Biscayne Bay to the Atlantic Ocean. The dredging of the Haulover sandbar (properly termed the flood tidal delta) by the U.S. Army Corps of Engineers is very controversial because it has become a major attraction for boaters. This narrow inlet was artificially created for non-commercial watercraft in 1925 to provide access to the Atlantic Ocean, but it also helps promote flushing of Biscayne Bay, which is presently having pollutant problems. Maintenance dredging has occurred every three to five years since the 1960s, with the last project completed in 2017. The Corps of Engineers is providing 100% funding of the forthcoming dredging project in order to provide maintenance of the Atlantic Intracoastal Waterway and beach nourishment for the downdrift beach of Bal Harbour. Haulover sandbar parties are advertised by Trip Advisor among others as a Miami hot spot for outdoor recreation, drawing hundreds of boats and thousands of people during low tide, especially during the weekend.
Coastal Forum: Who owns the beach?
James R. Houston and Angus D. Gordon
https://doi.org/10.34237/1009036 Shore & Beach 90(3), p. 50-58.
Many Americans believe that beaches are “owned” by the public from the vegetation line/dunes to the ocean. However, this is not true on the 70% of land abutting the shoreline that is privately owned. This private land extends down to mean high or low water lines. In contrast to relatively uniform ownership boundaries, beach access varies greatly among states and is based on the Public Trust Doctrine (PTD), that in turn is based on English common law. Under English common law shorelines have two titles. One is the public’s right of use, and the other is private rights of possession and exclusive use. States can convey rights of possession, but they cannot convey the public’s trust rights and are obliged to govern, manage, and protect the public’s trust rights. Therefore, even though a property owner may “own” the beach, that ownership is still subject to paramount rights of the public to use trust lands for public purposes. Some states such as Texas, Oregon, Hawaii, North Carolina, and New Jersey have opened up their beaches by giving the public lateral access from the vegetation line down to the ocean despite part of this land being privately owned. Their actions have been backed by state courts that cite the PTD. It is within the power of all states to do the same. The Corps of Engineers has opened up public access on the 350 miles of shoreline where it has placed beach nourishment, because for a project to be funded the Corps requires a perpetual easement for public use, usually from the vegetation line to the ocean. The Corps also requires states or local governments to provide perpendicular access to beaches by providing parking and other amenities. Conflicts between beach owners and the public have increased with private-beach signs and even fences springing up. Sea level rise will intensify these conflicts. If property owners resort to building structures such as seawalls and revetments, publicly accessible beach widths will decrease. If governments buy coastal properties through managed retreat or if owners support beach nourishment, public access will increase. There also will be increasing pressures for states to follow the lead of those that used the PTD to open up lateral access to beaches.
Distribution and dynamics of U.S. continental shelf ridge sediment and morphology: A brief review
Nicholas Brown and Tiffany Roberts Briggs
https://doi.org/10.34237/1009037 Shore & Beach 90(3), p. 59-67.
The U.S. continental shelf is an important sediment source for beach nourishment and restoration efforts that mitigate erosion, increase resilience to storm impacts, provide habitat, and support the economy. The continental shelf is the preferred source for borrow sediment to closely match the native grain size distribution and composition of the site being restored. However, spatiotemporal variability of continental shelf sediment ranges in size and composition, resulting from previous sea levels and contemporary variability such as normal shelf processes, storm waves, and anthropogenic activities. Understanding the nature and distribution of continental shelf ridge sediment changes over time should reduce costs of efforts required to explore offshore sediments for coastal restoration projects. This review examines the present state of knowledge on the availability, distribution, and characteristics of continental shelf sediment under normal conditions and potential variability after storms and dredging. Under normal conditions sediment on the shelf is easily located and characterized as potential borrow areas. However, storms can induce enough sediment transport to change the boundaries of sediment borrow areas and the location of known sand ridges. Dredging can also influence sediment infilling of the dredged borrow areas, which impact benthic infauna and introduce potential onshore impacts depending on the geometry and nearshore proximity of the excavation. The results of this summary have identified gaps in the present knowledge such as a need for additional sand searches in under-investigated regions, a better understanding of storm impacts on hydrodynamic-driven ridge migration and continuing to review best management practices when new research of dredging practices and impacts are presented. A brief review of the present state of knowledge on the distribution and dynamics of continental shelf sedimentology and morphology are presented here to aid in advancing the scientific and coastal management community’s knowledge of shelf sediments and dynamics as well as highlight potential future research needs.
Field measurements of boat wake attenuation in salt marshes of coastal Alabama
Katherine M. Dawson and Bret M. Webb
https://doi.org/10.34237/1009038 Shore & Beach 90(3), p. 68-79.
Four pressure gauges were deployed along natural marsh transects in Mobile, Alabama, to assess the ability of marsh vegetation to reduce the height and energy of oncoming boat wakes. The present study explores the influence of vegetation species, marsh density, wave height, wave frequency, and seabed terrain on the degree of attenuation. The pressure data were translated into instantaneous free surface position and wave height measurements, and the influence of shoaling and wave breaking was accounted for. It was found that attenuation is nonlinear, with an increased concentration of wave height and energy loss occurring in the first few meters, and that the seabed plays a significant role in wave transformation. The highest 1% of wave heights was most effectively reduced due to the combined influence of terrain and vegetation while the mean wave heights were the least reduced wave height statistic. Determination of accurate decay coefficients was complicated by the high degree of variability observed within the study. The results showed a correlation between wave frequency and energy dissipation, with the most substantial loss occurring at the peak frequency. Collectively, the findings highlight the variability between marsh sites and reinforce the recommendation that there be further exploration of wave energy attenuation by marsh grasses.
Book Review: “The Ominous Ocean” by Gary Griggs
Reviewed by Nick Sadrpour