Albuquerque, M., Espinoza, J., Teixeira, P., de Oliveira, A., Corrêa, I., Calliari, L., 2013. Erosion or Coastal Variability: an evaluation of the DSAS and the Change Polygon methods for the determination of erosive processes on sandy beaches. There has recently been growing concern about issues related to erosive processes on sandy beaches and climate change in the scientific community. Several methodologies have been proposed in the worldwide literature to quantify coastline retreat on shorelines in an accurate way. It has been questioned whether these methodologies show the erosive process or the shoreline variability in a certain area. From this perspective, this paper aims at characterizing the accuracy of the Digital Shoreline Analysis System (DSAS) and the Change Polygon Method in the studies of regression on shorelines which are prone to erosion. Data collected by a GPS-RTK along Hermenegildo Beach, located in the south of Brazil, and the geo-referencing of satellite images enabled the ou...

This paper presents the validation of the End Point Rate (EPR) tool for QGIS (EPR4Q), a tool built-in QGIS graphical modeler for calculating the shoreline change with the end point rate method. The EPR4Q tries to fill the gaps in user-friendly and free open-source tools for shoreline analysis in a geographic information system environment since the most used software—Digital Shoreline Analysis System (DSAS)—although being a free extension, it is created for commercial software. Additionally, the best free, open-source option to calculate EPR is called Analyzing Moving Boundaries Using R (AMBUR); since it is a robust and powerful tool, the complexity can restrict the accessibility and simple usage. The validation methodology consists of applying the EPR4Q, DSAS, and AMBUR with different types of shorelines found in nature, extracted from the US Geological Survey Open-File. The obtained results of each tool were compared with Pearson’s correlation coefficient. The validation results indicate that the EPR4Q tool acquired high correlation values with DSAS and AMBUR, reaching a coefficient of 0.98 to 1.00 on linear, extensive, and non-extensive shorelines, proving that the EPR4Q tool is ready to be freely used by the academic, scientific, engineering, and coastal managers communities worldwide.

Albuquerque, M.; Alves, D.C.L.; Espinoza, J.M.A.; Oliveira U. R., and Simões R. S., 2018. Determaning shoreline response to meteo-oceanographic events using remote sensing and unmanned aerial vehicle (UAV): case study in southern Brazil. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 766–770. Coconut Creek (Florida), ISSN 0749-0208. Meteo-oceanographic events are characterized by low pressure centers and intense winds. These systems are responsible for transferring a huge amount of energy from the atmosphere to the ocean that could cause serious socioeconomics damages to the coastal zones. Some of the consequences of these events propagation are an occurrence of large amplitude waves and an increase in the coastal water level. This study aims to characterize the effects of the extratropical cyclone in the southern Brazil occurred in October 2016, see...

Gonzaga, B.A.; Alves, D.C.L.; Albuquerque, M.G.; Espinoza, J.M.A.; Almeida, L.P.M., and Weschenfelder, J., 2020. Development of a low-cost ultrasonic sensor for groundwater monitoring in coastal environments: Validation using field and laboratory observations. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1001–1005. Coconut Creek (Florida), ISSN 0749-0208.This study presents the development and validation of a low-cost ultrasonic sensor (HCSR 04), coupled to an open source Arduino microcontroller platform, for groundwater monitoring in coastal environments. Given the fact that low-lying coastal zones are regions naturally prone to flooding (due to oceanic forcing and pluviosity) and densely occupied, monitoring groundwater variations is crucial for the management of flood-related events. A groundwater monitoring well was built, (made of a PVC pipe with 100 mm in diameter and 2 m long) and installed on the ground of a dune field, located in Cassino beach, southern of Brazil. The system was deployed for 84 consecutive days and programmed to perform water level measurements every 10 min. In laboratory, three units with the same hardware setup of the unit installed in the field (ultrasonic sensor coupled to the Arduino microcontroller) were installed on a 20 liter graduated PVC tube. Varying water levels were tested in the laboratory along the time (changing 1 cm every 2 minutes during 4 hours) in order to reproduce the synthetic signal. Eighty measurements were obtained for each sensor, a total of 240 for each validation process. For the laboratory validation, the results for nonparametric statistical tests (Kruskal and Wallis, and Dunn) presented a correlation of 99%, with Root mean square error (RMSE) 0.4113 and bias 0.0418. For the field tests, 3262 data collected by an ultrasonic sensor during 240 hours showed a means registration of 0.543 m. The minimum and maximum cataloged is 0.40 and 0.70 m, respectively, with 0.1076 m of standard deviation. Groundwater classical measurements, using a measuring tape, showed a mean and standard deviation of 0.544 and 0.1069 m, respectively. These preliminary tests showed that the developed monitoring system performs observations with an accuracy and precision within standard methods, therefore can be applied to monitoring changes in the level of groundwater.

A linha de costa é uma feição geomorfológica em que as mudanças topográficas podem acontecer ao longo de horas ou dias devido a ocorrências de eventos de alta energia. Essa feição é de importância estratégica para o planejamento ambiental das cidades costeiras, sendo necessário o seu monitoramento contínuo. Este estudo propõe analisar a variação da linha de costa na praia do Icaraí, litoral de Caucaia – CE, a partir da aplicação dos métodos Digital Shoreline Analysis System (DSAS) e Polígono de Mudança. O recorte temporal de análise está compreendido entre os anos de 2004 e 2018, pois o agravamento da erosão se deu particularmente nos anos 2000. Os resultados demonstram que os deslocamentos médios da linha de costa, tanto para o DSAS (-3,72 m) quanto para o Polígono de Mudança (-3,41 m), se mostraram muito próximos. No entanto, quando observados parâmetros estatísticos mediana, desvio padrão e deslocamento mínimo e máximo foi observada uma superestimação das taxas obtidas pelo DSAS. A partir de uma análise de regressão linear foi observado que o Polígono de Mudança (R² = 0,9471) se mostrou mais adequado, pois considera todo o segmento costeiro nos cálculos de deslocamento. Tendo em vista os adjetivos e limitações dos métodos empregados, o Polígono de Mudança apresentou um melhor desempenho tanto em termos estatísticos quanto aos erros inerentes. Por fim, estudos de abordagem comparativa entre métodos são de grande importância para os gestores, visto que muitos municípios costeiros do Ceará e do Brasil têm apresentado problemas sérios ligados a erosão costeira. Study of the shoreline behavior at Icaraí beach (Caucaia, Ceará), using digital shoreline analysis system and the change polygon methods A B S T R A C TThe shoreline is a geomorphological feature with variable topographic and subject to changes vary very quickly in the time-space scale, and may present major changes in a few hours, as in the occurence of storm surges. This feature is of strategic importance for the coastal cities environmental planning, being necessary its continuous monitoring. This study aims to analyze the shoreline variation at Icaraí beach, Caucaia – CE coast, using two different methods: the Digital Shoreline Analysis System (DSAS) and the Change Polygon method. The analysis time frame is comprised between the years 2004 and 2018, since erosion worsened occurred particularly in the 2000s. The results showed that the average displacements from the shoreline, both for the DSAS (-3.72 m) and to Change Polygon (-3.41 m), were very close. However, when the other statistical parameters were observed (median, standard deviation, minimum and maximum displacement), an overestimation rates obtained by DSAS was observed. A linear regression analysis showed out that the Change Polygon method (R² = 0.9471), proved to be more suitable for the Icaraí beach, as it considers the entire coastal segment in the calculation of shoreline displacement. Although both methods approaches have their adjectives and limitations, the Change Polygon showed a better performance, both statistical terms and in relation to inherent errors. Finally, studies that take into account the comparative approach between methos are of great importance for managers, given that many coastal municipalities in Ceará and Brazil have presented serious problems related to coastal erosion.Keywords: erosion, DSAS, change polygon, remote sensing.