Adam P. Young

Application of Airborne LIDAR for Seacliff Volumetric Change and Beach-Sediment Budget Contributions

Abstract Coastal seacliff erosion in California threatens property and public safety, whereas coastal beach erosion threatens the coastal tourism economy. While coastal rivers, seacliffs, and gullies supply the majority of littoral material to California beaches, the relative contributions of these sources are coming into question. These beach-sediment sources must be accurately quantified to formulate proper solutions for coastal zone management. This study evaluated the seacliff and coastal gully beach-sediment contributions to the Oceanside Littoral Cell using airborne LIght Detection And Ranging (LIDAR). Seacliff and gully beach-sediment contributions were compared with coastal river beach-sediment contributions estimated in previous studies. This study took place over a relatively dry period from April 1998 to April 2004. The results indicate that seacliffs provided an estimated 67% of the beach-size sediment to the littoral cell, followed by gullies and rivers at 17% and 16%, respectively, over the period of the study. The total volumetric seacliff erosion rates were used to back-calculate average annual seacliff face retreat rates for the study period. These rates ranged from 3.1 to 13.2 cm/yr and averaged 8.0 cm/yr for the Oceanside Littoral Cell. Comparison of these results to previous studies suggests that the relative seacliff sediment contributions may be higher than previously thought. Conversely, beach-sediment contributions from gullies were significantly lower compared with previous studies. This is likely because of the episodic nature of gullying and the relatively dry study period. Nevertheless, the results of this study indicate that seacliff sediment contributions are a significant sediment source of beach sand in the Oceanside Littoral Cell, and the relative annual seacliff beach-sand contribution is likely higher than previous studies indicate.

Comparison of airborne and terrestrial lidar estimates of seacliff erosion in Southern California.

Seacliff changes evaluated using both terrestrial and airborne lidar are compared along a 400 m length of coast in Del Mar, California. The many large slides occurring during the rainy, six-month study period (September 2004 to April 2005) were captured by both systems, and the alongshore variation of cliff face volume changes estimated with the airborne and terrestrial systems are strongly correlated (r 2 = 0.95). How- ever, relatively small changes in the cliff face are reliably detected only with the more accurate terrestrial lidar, and the total eroded volume estimated with the terrestrial system was 30 percent larger than the corresponding airborne estimate. Although relatively small cliff changes are not detected, the airborne system can rapidly survey long cliff lengths and provides coverage on the cliff top and beach at the cliff base.

Coastal cliff ground motions and response to extreme storm waves

Coastal cliff erosion from storm waves is observed worldwide, but the processes are notoriously difficult to measure during extreme storm wave conditions when most erosion normally occurs, limiting our understanding of cliff processes. Over January–February 2014, during the largest Atlantic storms in at least 60 years with deepwater significant wave heights of 6–8 m, cliff-top ground motions showed vertical ground displacements in excess of 50–100 µm; an order of magnitude larger than observations made previously. Repeat terrestrial laser scanner surveys over a 2 week period encompassing the extreme storms gave a cliff face volume loss of 2 orders of magnitude larger than the long-term erosion rate. The results imply that erosion of coastal cliffs exposed to extreme storm waves is highly episodic and that long-term rates of cliff erosion will depend on the frequency and severity of extreme storm wave impacts.

Coarse sediment yields from seacliff erosion in the Oceanside Littoral Cell.

Abstract The coarse sediment fraction of geologic formations exposed in 42 km of southern California seacliffs in the Oceanside Littoral Cell was estimated using more than 400 samples. An impulse laser, oblique photographs, and coastal maps were used to define thickness and alongshore extent of the geologic units exposed in the seacliffs. The coarse sediment (defined as diameter > 0.06 mm) fraction in each geologic unit was estimated by sieving. About 80% of the exposed cliff face is coarse and can contribute to beach building. Finer cliff sediments are transported offshore by waves and currents. Although there are some differences, the observed 80% coarse fraction is generally consistent with previous estimates based on an order of magnitude fewer samples. Coastal development has largely eliminated about 40% of seacliffs in the Oceanside Littoral Cell as potential beach sand sources. For the remaining seacliffs, 1 cm of average cliff retreat yields 10,000 m3 of potential beach-building material.

TopCAT-Topographical Compartment Analysis Tool to analyze seacliff and beach change in GIS

This paper discusses the development of a new GIS extension named the Topographic Compartment Analysis Tool (TopCAT), which compares sequential digital elevation models (DEMs) and provides a quantitative and statistical analysis of the alongshore topographical change. TopCAT was specifically designed for the morphological analysis of seacliffs and beaches but may be applied to other elongated features which experience topographical change, such as stream beds, river banks, coastal dunes, etc. To demonstrate the capabilities of TopCAT two case studies are presented herein. The first case examines coastal cliff retreat for a 500m section in Del Mar, California and shows that large failures comprised a large portion of the total eroded volume and the average retreat rate does not provide a good estimate of local maximum cliff retreat. The second case investigates the alongshore volumetric beach sand change caused by hurricane Bonnie (1998) for an 85km section in the Cape Hatteras National Seashore, North Carolina. The results compare well (generally within 6%) with previous investigations. These case studies highlight additional information gained through performing a detailed, discretized analysis using TopCAT.

Adipose-Derived Stem Cells: Methods for Isolation and Applications for Clinical Use

Adipose tissue sciences have rapidly expanded since the identification of regenerative cells contained within the stromal vascular fraction (SVF) of fat. Isolation of the SVF, containing adipose-derived stem cells (ADSC), can be accomplished efficiently in the operating room or in the laboratory through enzymatic digestion of the adipose tissue and concentration of SVF. Cells can be directly re-injected as a mesotherapeutic agent, recombined with a tissue scaffold (e.g., cell-enriched fat grafts) or expanded in culture for tissue-engineered cell therapeutics. The potential for cell therapy is under current investigation by researchers around the world. This chapter reviews laboratory methods for isolating ADSCs and the ongoing clinical trials evaluating cell therapeutic efficacy across many specialties, including cardiology, neurology, immunology, tissue engineering, sports medicine, and plastic and reconstructive surgery.

Rapid Response to Seacliff Erosion in San Diego County, California Using Terrestrial LIDAR

Seacliff erosion plagues the coastline of northern San Diego County, California through both marine and subaerial processes. Heavy development on seacliffs and the economic value of beaches in San Diego County, California place a heavy emphasis on maintaining a healthy and safe beach. This paper illustrates the development of a rapid response program to study and document seacliff erosional processes utilizing a terrestrial LIght Detection And Ranging (LIDAR) system in combination with interactive visualization techniques to publically present this research. One of the cliff failures currently being studied as part of this rapid response program is described in this paper to demonstrate the insights that can be gained by observing the temporal change of a failure mass using frequent site monitoring.

Chapter 9 The rock coast of the USA

Abstract The coastline of the USA is vast and comprises a variety of landform types including barrier islands, mainland beaches, soft bluffed coastlines and hard rocky coasts. The majority of the bluffed and rocky coasts are found in the northeastern part of the country (New England) and along the Pacific coast. Rocky and bluffed landform types are commonly interspersed along the coastline and occur as a result of relative lowering of sea level from tectonic or isostatic forcing, which can occur on timescales ranging from instantaneous to millenia. Recent research on sea cliffs in the contiguous USA has focused on a broad range of topics from documenting erosion rates to identifying processes and controls on morphology to prediction modelling. This chapter provides a detailed synthesis of recent and seminal research on rocky coast geomorphology along open-ocean coasts of the continental United States (USA).

VR-based visual analytics of LIDAR data for cliff erosion assessment

The ability to explore, conceptualize and correlate spatial and temporal changes of topographical records, is needed for the development of new analytical models that capture the mechanisms contributing towards sea cliff erosion. This paper presents a VR-centric approach for cliff erosion assessment from light detection and ranging (LIDAR) data, including visualization techniques for the delineation, segmentation, and classification of features, change detection and annotation. Research findings are described in the context of a sea cliff failure observed in Solana Beach in San Diego county.

A framework for sea level rise vulnerability assessment for southwest U.S. military installations

We describe an analysis framework to determine military installation vulnerabilities under increases in local mean sea level as projected over the next century. The effort is in response to an increasing recognition of potential climate change ramifications for national security and recommendations that DoD conduct assessments of the impact on U.S. military installations of climate change. Results of the effort described here focus on development of a conceptual framework for sea level rise vulnerability assessment at coastal military installations in the southwest U.S. We introduce the vulnerability assessment in the context of a risk assessment paradigm that incorporates sources in the form of future sea level conditions, pathways of impact including inundation, flooding, erosion and intrusion, and a range of military installation specific receptors such as critical infrastructure and training areas. A unique aspect of the methodology is the capability to develop wave climate projections from GCM outputs and transform these to future wave conditions at specific coastal sites. Future sea level scenarios are considered in the context of installation sensitivity curves which reveal response thresholds specific to each installation, pathway and receptor. In the end, our goal is to provide a military-relevant framework for assessment of accelerated SLR vulnerability, and develop the best scientifically-based scenarios of waves, tides and storms and their implications for DoD installations in the southwestern U.S.