Figure 6 - uploaded by Tanya Silveira
Content may be subject to copyright.
The recent high-tide swash line (red dashed line) on the beach face on a cliff coast.  

The recent high-tide swash line (red dashed line) on the beach face on a cliff coast.  

Source publication
Technical Report
Full-text available
Following a review of Vital Signs in the coastal parks of the Northeast Coastal and Barrier Network, knowledge of shoreline change was ranked as the top variable for monitoring. Shoreline change is a basic element in the management of any coastal system because it contributes to the understanding of the functioning of the natural resources and to t...

Citations

... Coastline is here acknowledged as a static boundary. Both distances were measured in a GIS environment using the ArcGIS extensions Digital Shoreline Analysis System (Thieler et al., 2009) and the Coastline Change Mapper (Psuty et al., 2010) using a set of predefined transects perpendicular to the coastline and spaced in between of 50 m. ...
Article
The world's coastlines are dominated by rocky coasts, where embayed and shore platform beaches develop. The intrinsic characteristics of these environments make them extremely vulnerable to changes in oceanographic forcing. Assessing long-term beach evolution can be a challenging task because coastline indicators were developed for wide and low-lying sandy beaches. For example, as most shore platforms beaches are limited by a cliff or structure, they have a static landward boundary (coastline), thus inhibiting the use of any coastline indicator as a proxy of beach volume changes. Also, as shoreline position is highly dependent on short-term sea-level fluctuations, the use of shoreline indicators is frequently subject to high uncertainty. This work presents an unconventional way to evaluate shore platform beach evolution by proposing a new indicator - the beach toe (BT) - to assess changes in sand retention for shore platform/perched beaches. BT position, together with a profile model, provide an effective tool to assess beach volume over time. The proposed beach indicator was tested at 12 shore platform beaches located at Cascais coast (Portugal), which can be considered illustrative of this type of beach. Results show that the new approach provides an objective indicator to assess both the beach configuration and changes in volume, being easily implemented using common vertical imagery. The comparison of Beach Toe and High-Water Line indicators with field data show a better performance of the BT indicator, supporting the use of the proposed indicator on shore platform beaches. The proposed analysis can be easily replicated to other similar rocky coasts, thus representing a much-needed advancement in the study of beaches perched on platform shores.
... The metric of displacement was determined by the application of the DSAS program created and maintained by the USGS [43] that compares position along established transects to generate vectors of change. The resulting displacement was portrayed temporally and spatially by the Shoreline Mapping Program [44]. ...
... Dune crests may be interrupted in areas of overwash. Dune crest position and changes were portrayed with the application of DSAS [43] and the Shoreline Change Mapper Program [44]. ...
Article
Full-text available
Beach nourishment was applied at three fetch-restricted sites along the estuarine margin of Delaware Bay, New Jersey. Evaluation of geomorphological performance of the nourishment project was conducted through seasonal monitoring to track linear features (shoreline, dune crest, peat edge) and to create digital elevation models (DEMs). Comparisons of the DEMs yielded sediment budgets of the updrift, fill area, and downdrift zones as well as the spatial and temporal evolution of the tidal flat, beach, and dune features within the zones. Through four years, Moore’s Beach lost all of the emplaced fill as well as an additional −5446 m3 from the fill area. The shoreline position shifted inland −12.78 m, and the foredune crest shifted inland −9.23 m. The fill area at Pierce’s Point lost all of the fill and an additional −3810 m3. The shoreline and dune crest shifted inland −7.35 m and −1.17 m, respectively. The Reed’s Beach study area benefited from beach fill updrift that more than offset the losses in the fill area, a net gain of 2107 m3. There was a major contrast in volumetric change between the updrift and downdrift portions. Sediment budget calculations established alongshore transport was an important factor in the fetch-restricted estuarine environment driving the variable geomorphological responses in the updrift, fill, and downdrift zones.
... Coastline in these cases is a static boundary represented by the LMPMAVE (Maximum line of equinoctial spring high tides). Both measures were calculated in a GIS environment using the ArcGIS extensions Digital Shoreline Analysis System (Thieler et al., 2009) and the Coastline Change Mapper (Psuty et al., 2010). ...
Conference Paper
Full-text available
Platform beaches are small sand accumulations resting on a rocky platform, bounded landward by a cliff or artificial structure and extending seaward not far into the sea. Measuring long-term evolution of platform beaches is essential for an effective and sustainable coastal zone management, but can be challenging because coastline indicators (e.g. foredune/cliff toe) cannot be used and shoreline indicators are highly dependent on local water-levels. This work aims to explore unconventional ways to evaluate platform beach evolution, using Cascais beaches as a study-case. The study proposes an original methodology assess beach evolution, identifying the beach seaward limit, together with standard shoreline indicators. This approach provides objective indicators of beach configuration and volume, and is easily implemented using orthophotomaps.
... There have been wide applications of DSAS in the study of cliff behavior and shoreline dynamics by many authors throughout the world (Morton and Miller, 2005;Houser et al., 2008;Hapke et al., 2009;Abuodha and Woodroffe, 2010;Psuty et al., 2010;Armah, 2011;Carrasco et al., 2012;Perez-Alberti et al., 2012;Yang et al., 2012;Hapke et al., 2013;Albuquerque et al., 2013;Th ebaudeau et al., 2013;Rangel-Buitrago et al., 2015). This is the first application of the system to the coastline of Bulgaria. ...
... System (Thieler et al., 2009), and Shoreline Change Mapper (Psuty et al., 2010). ...
Thesis
Full-text available
Beaches occur when sediment is available and where accommodation space exists for the sediments to settle and accumulate. Beaches that occur within one coastal cell share the same oceanographic forcing climate, essentially related to waves and tides, and the same distribution and intensity of sources and sinks of sediment. However, contrasting beach forms and dynamics are frequent along the same coastal cell, leading to the questioning of what other factors are controlling beach morphodynamics. Conceptual models have been developed and are very useful in describing and classifying beaches according to the characteristics of the incoming waves and beach sediments or morphology. Still, several studies suggest that site-specific characteristics, such as the geology, geomorphology or even the human-induced framework of beaches, can play a determinant role in beach systems’ behavior and evolution. However, the majority of studies focusing on the role of geomorphological framework on beach dynamics, address cases sharing the same general characteristics. This thesis focused on how the geomorphological framework interacts with the available coastal sediments and controls the subaerial beach configuration and responses. It investigates a myriad of beach geomorphological conditions along a high-energy coastal stretch that is under the influence of the same general deepwater wave regime. By comparing the morphodynamic response of adjacent constrained and unconstrained, platform and no-platform beaches, exposed to the same offshore forcing conditions, the present work provides new insights on the role of the geomorphological settings on beach dynamics. The central hypothesis of this study was formulated as follows: the geomorphological constraints and the local settings of beaches are the primary drivers for the varying temporal and spatial groupings of morphological responses. In order to verify this, work was carried out at the seasonal scale, under modal process-response conditions, and over a two and a half year period, along 14 selected beach sites representative of a 200 km coastal stretch. The study was divided in three major components: 1) geomorphological framework; 2) beach response; and 3) hydrodynamic forcing. Geomorphological framework was analyzed in terms of planform geometry and description of physical boundaries, and type of nearshore and backshore features present at each study site. Beach response investigation relied upon regular field sampling planned to ensure accurate and representative data collection on subaerial beach morphology and sediments. A total of 52 beach profiles were monitored quarterly along the study area. The hydrodynamic forcing description included characterization of the deepwater and nearshore wave regimes at each study site and made use of numerical modelling of wave propagation. In addition, total water levels were computed for each site. The overall results were further explored to derive metrics and investigate and detect spatial organizations related to the geomorphological settings. The geomorphological framework analysis attests to the high variability of settings in which the studied beaches occur. These include several combinations between nearshore and backshore type of features, physical boundaries and subsequent wave obliquities and degrees of indentation. Beach response was analyzed in terms of geoindicators, which were used to evaluate and describe the study sites’ seasonal behavior. Results show that the magnitude of seasonal change between study sites varied considerably, in relative as well as absolute terms, especially regarding the morphological geoindicators. The hydrodynamic forcing included the analysis of a 36-year time series, used to describe the typical modal and storm regimes, and of a two and a half years subset, synoptic of the sediment and morphological field surveys. Results show that the study period was appropriate to characterize the modal process-response conditions, descriptive of a period with no extreme events. They also highlight the differences between sites exposed to higher and lower waves and total water level regimes. The exploratory analyses of the data showed no linear relationship between forcing, controlling and response variables. However, it put in evidence the existence of clusters of beaches sharing similarities in types of boundaries. Beaches with rocky platforms experienced low volumetric variation, consistently lower than beaches with no rocky platform. In addition, within the no-platform beaches, those with the higher degree of embaymentization, varied the most. A conceptual model of the subaerial beach dynamics as a function of the geomorphological framework is put forth, in which the magnitude of beach variation is controlled by: 1) the presence of a rocky platform; and 2) in no-platform beaches, by the degree of embayment and its impact on beach circulation. It is suggested that the presence of a permanent and rigid obstacle in the surf zone, such as a rocky platform, limits the range of broken wave characteristics reaching the subaerial beach, and thus the amount of volumetric variation. On the other hand, beaches characterized by a mobile substrate (no-platform beaches) can present a variety of morphological features in the surf zone, and are expected to allow for a wider range of broken wave conditions and subsequent effects on the subaerial beach, including higher volumetric changes. Within the no-platform beaches, subaerial volume variations increase with the degree of embaymentization. Unconstrained beaches have open lateral boundaries, and therefore see their cross-shore morphology and volume vary mostly with the cross-shore sediment exchanges, that are expected to be small under modal conditions. The constrained beaches (with higher degree of embaymentization) on the other hand, are bounded laterally and therefore are prone to beach rotation processes (and subsequent higher volume variation) promoted by longshore sediment transport that occurs under modal conditions. The conceptual model herein proposed departs from existing morphodynamic models that apply only to unconstrained beaches. It incorporates both unconstrained and constrained beaches and relates the constraining boundaries (both lateral and vertical) to the beach subaerial dynamics. It provides a first description on how the geomorphological framework controls subaerial beach dynamics, and hopefully can be developed and evaluated further.
... There have been wide applications of DSAS in the study of cliff behavior and shoreline dynamics by many authors throughout the world (Morton and Miller, 2005;Houser et al., 2008;Hapke et al., 2009;Abuodha and Woodroffe, 2010;Psuty et al., 2010;Armah, 2011;Carrasco et al., 2012;Perez-Alberti et al., 2012;Yang et al., 2012;Hapke et al., 2013;Albuquerque et al., 2013;Th ebaudeau et al., 2013;Rangel-Buitrago et al., 2015). This is the first application of the system to the coastline of Bulgaria. ...
Article
Measuring historical shoreline change and cliff retreat is an essential aspect of understanding the long-term geomorphic evolution of any coastal system. These data are also critical for predicting future changes and incorporating that data into proper coastal management. In recent years, Marine Spatial Planning (MSP) has increasingly been recognized as an important tool in the sustainable management of marine space across Europe and worldwide, including also issues of coastal zone management and land-sea interactions (Directive 2014/89/EU for MSP). This paper deals with investigation of the shoreline changes and cliff retreat along the 34 km section of the Black Sea coast at Shabla Municipality (Northeast Bulgaria). The study area has a low density of development and comprises large sand beaches, dunes and rapidly retreating loess cliffs. The present research was formulated under the European Union (EU) Directive for MSP in the Black Sea Basin (MARSPLAN-BS) Project. The goal was to provide reliable data and useful information in support of the development of a pilot marine spatial plan for Shabla Municipality. The study was focused on the analysis of shoreline movement (at sand beaches – erosion/accretion) and cliff retreat (at rocky coasts) utilizing a Geographic Information System (GIS). Primary data sources include topographic maps in scale 1:5,000, tachometry survey and modern Very High Resolution (VHR) orthophoto images. Change rates were determined using the Digital Shoreline Analysis System (DSAS), an ArcGIS extension for calculating shoreline change (Version 4.3), and rate-of-change statistical method. Management of coastal erosion, hard engineering methods and lack of required setbacks were discussed. Results for rates of shoreline change and cliff retreat were verified with preliminary field measurement studies and cross-checked with existing hydrodynamics, geology and geomorphology of the coast of Shabla Municipality.
... Coastline evolution rates of change (R) were calculated in a GIS environment using the Digital Shoreline Analysis System (Thieler et al., 2009) and the Coastline Change Mapper (Psuty et al., 2010), both ArcGIS extensions. Transects were placed every 250 m, roughly perpendicular to the coastline trend. ...
Article
Full-text available
Regional/national-scale information on coastline rates of change and trends is extremely valuable, but these studies are scarce. A widely accepted standardized methodology for analysing long-term coastline change has been difficult to achieve, but it is essential to conduct an integrated and holistic approach to coastline evolution and hence support coastal management actions. Additionally, databases providing knowledge on coastline evolution are of key importance to support both coastal management experts and users. The main objective of this work is to present the first systematic, national-scale and consistent long-term coastline evolution data of Portuguese mainland low-lying sandy coasts. The methodology used quantifies coastline evolution using a unique and robust coastline indicator (the foredune toe), which is independent of short-term changes. The dataset presented comprises (1) two polyline sets, mapping the 1958 and 2010 sandy beach–dune system coastline, both optimized for working at 1 : 50 000 scale or smaller; (2) one polyline set representing long-term change rates between 1958 and 2010, each estimated at 250 m; and (3) a table with minimum, maximum and mean of evolution rates for sandy beach–dune system coastline. All science data produced here are openly accessible at https://doi.pangaea.de/10.1594/PANGAEA.859136 and can be used in other studies. Results show beach erosion as the dominant trend, with a mean change rate of −0.24 ± 0.01 m year−1 for all mainland Portuguese beach–dune systems. Although erosion is dominant, this evolution is variable in signal and magnitude in different coastal sediment cells and also within each cell. The most relevant beach erosion issues were found in the coastal stretches of Espinho–Torreira and Costa Nova–Praia de Mira, Cova da Gala–Leirosa, and Cova do Vapor–Costa da Caparica. The coastal segments Minho River–Nazaré and Costa da Caparica adjacent to the coast exhibit a history of major human interventions interfering with the coastal system, many of which originated and maintained a sediment deficit. In contrast, the coastal segments Troia–Sines and Sines–Cape S. Vicente have experienced less intervention and show stable or moderate accretion behaviour.
... The United States launched the National Assessment of Coastline Change Project, which delivered a number of reports organized by coastal regions (e.g Fletcher et al., 2012). The European counterpart is the EUROSION project framework (European Commission, 2004), which conducted a country by country evaluation of coastal erosion at European scale and delivered 3 main final products: 1) online reports, including major findings and recommendations, 2) a GIS database, 15 which includes Europe's coastline vectors at 1:100 000 scale, and 3) a Coastline Management Guide. ...
... This stretch is dominated by cliffs, generally high, carved in resistant Paleozoic and Mesozoic rocks. These cliffs are disturbed by Mira, Odeceixe and Aljezur estuaries and lowlands which, together with cliff 15 indentations, accommodate sandy and gravelly beaches, usually with reduced width. The beaches developed on larger stream mouths are often backed by dune systems. ...
... Measurement uncertainties include errors related to coastline digitization (E d ) (Fletcher et al., 2003), image resolution (E ir ) (Coyne et al., 1999;Catalão et al., 2002) and image rectification (E r ) (Shoshany et al., 1996;Fletcher et al., 2003). 15 According to Fletcher et al. (2003) these errors are random and uncorrelated and can be represented by a single measure (U p ) calculated as the square root of the sum of the squares (Coyne et al., 1999;Fletcher et al., 2003): Fletcher et al. (2003) states another physical components of error, representing short-term variability in coastline position. ...
Article
Full-text available
Regional/global-scale information on coastline rates of change and trends is extremely valuable, but national-scale studies are scarce. A widely accepted standardized methodology for analysing long-term coastline change has been difficult to achieve, but is essential to conduct an integrated and holistic approach to coastline evolution and hence support coastal management actions. Additionally, databases providing knowledge on coastline evolution are of key importance to support both coastal management experts and users. The main objective of this work is to present the first systematic, global and consistent long-term coastline evolution data of Portuguese mainland low-lying sandy. The methodology used quantifies coastline evolution using an unique and robust coastline indicator (the foredune toe), which is independent of short-term changes. The dataset presented comprises: 1) two polyline sets, mapping the 1958 and 2010 sandy beach-dune systems coastline, both optimized for working at 1:50 000 scale or smaller, and 2) one polyline set representing long-term change rates between 1958 and 2010, estimated at each 250 m. The science data produced here are in Open Access at doi:10.1594/PANGAEA.853654 and can be used in other studies. Results show beach erosion as the dominant trend, with a mean change rate of −0.24 ± 0.01 m/year for all mainland Portuguese beach-dune systems. Although erosion is dominant, this evolution is variable in signal and magnitude in different coastal sediment cell and also within each cell. The most relevant beach erosion issues were found in the coastal stretches of Espinho – Torreira and Costa Nova – Praia da Mira, both at sub-cell 1b; Cova Gala – Leirosa, at sub-cell 1c and Cova do Vapor – Costa da Caparica, at cell 4. Cells 1 and 4 exhibit a history of major human interventions interfering with the coastal system, many of which originated and maintained a sediment deficit. In contrast, cells 5 and 6 have been less intervened and show stable or moderate accretion behaviour.
... Additionally, in the definition of an indicator concerning the shoreline position, it should also be considered that data may derive from very different sources (e.g., ground surveys, LiDAR, historical maps, air photos, satellite and video imagery), and can be either feature-based (e.g. Psuty et al., 2010) or datum-based (e.g. Hess, 2003). ...
... Additionally, in the definition of an indicator concerning the shoreline position, it should also be considered that data may derive from very different sources (e.g., ground surveys, LiDAR, historical maps, air photos, satellite and video imagery), and can be either feature-based (e.g. Psuty et al., 2010) or datum-based (e.g. Hess, 2003). ...
Article
Geoindicators are used to describe reference situations and measure changes and trends in physical environment over time. They provide a simplified form to communicate complex data and information, and constitute a facilitator mechanism in the dialog among stakeholders. In this work, a review on the use of geoindicators in sandy coastal environments is performed. It was found that, despite the obvious advantages in reporting the state of the coast using geoindicators, their generalized adoption seems to be stalled and is limited to a few management settings and particular projects. The existence of a myriad of coastal geoindicators, that frequently are poorly defined, is identified as the major difficulty in their widespread use. The present work aims to contribute towards the establishment of a common framework for coastal geoindicators, focusing on sandy coastal environments. The main objective of the compilation and definition of the indicators herein presented is to simplify and clarify their designations, and objectively present the measurement and reporting criteria aiming at a consensus-based approach. Sixteen coastal geoindicators are identified as relevant for the description of the state of beach, coastal dunes, and coastal barrier environments. This effort contributes to the adoption of coastal geoindicators as an effective communication tool leading to a more standardized report on the state of the coastal zone.