Long and Short-Term Coastal Changes Assessment Using Earth Observation Data and GIS Analysis: The Case of Sperchios River Delta

The present study provides information about the evolution of the Sperchios River deltaic area over the last 6500 years. Coastal changes, due to natural phenomena and anthropogenic activities, were analyzed utilizing a variety of geospatial data such as historic records, topographic maps, aerial photos, and satellite images, covering a period from 4500 BC to 2020. A qualitative approach for the period, from 4500 BC to 1852, and a quantitative analysis, from 1852 to the present day, were employed. Considering their scale and overall quality, the data were processed and georeferenced in detail based on the very high-resolution orthophoto datasets of the area. Then, the multitemporal shorelines were delineated in a geographical information system platform. Two different methods were utilized for the estimation of the shoreline changes and trends, namely the coastal change area method and the cross-section analysis, by implementing the digital shoreline analysis system with two statistical approaches, the end point rate and the linear regression rate. Significant river flow and coastline changes were observed with the overall increase in the delta area throughout the study period reaching 135 km2 (mean annual growth of 0.02 km2/yr) and the higher accretion rates to be detected during the periods 1805–1852, 1908–1945 and 1960–1986, especially at the central and north part of the gulf. During the last three decades, the coastline has remained relatively stable with a decreasing tendency, which, along with the expected sea-level rise due to climate change, can infer significant threats for the coastal zone in the near future.

Rapid detection of changes in the riverbanks of Laigiang river of the South Central Coast Vietnam: A methodology based on Digital Shoreline Analysis System and Sentinel-2

The research focuses on using Sentinel-2 that can be integrated with the Digital Shoreline Analysis System (DSAS) as an effective tool for the determination of changes in the riverbanks and using linear regression to predict shoreline changes. The research applied the assessment of shoreline changes in the period of 2015- 2020 and forecast to 2025 in Laigiang river of the South Central Coast region of Vietnam. Based on the DSAS tool, parameters such as Shoreline Change Envelope (SCE), Net Shoreline Movement (NSM), End Point Rate (EPR) and Linear Regression Rate (LRR) were determined. The analysis results show that the accretion process in the Laigiang river in the period of 2015-2020 with the accretion area ranges from 81.47 ha. Meanwhile, the area of shoreline erosion only fluctuates around 54.42 ha. The rhythm of evolution is a determinant element for this transitional system.

Long-Term Shoreline Evolution Using DSAS Technique: A Case Study of Quang Nam Province, Vietnam

A Quang Nam coastline, located in the central of Vietnam, has been strongly affected by severe erosion and accretion due to climate change and human activities. Thus, understanding the causes and mechanisms of coastal morphology changes is essential to offer optimal coastal management and protection solutions. In this research, the Digital Shoreline Analysis System (DSAS) technique developed by the United States Geological Survey was adopted to calculate rate-of-change statistics from multiple historical coastline positions of Quang Nam province extracted from satellite images, i.e., Landsat and Sentinel images from 1990 to 2019. The coastal dynamic was digitized, visualized, and compared by two statistical parameters provided in DSAS, namely End Point Rate (EPR) and Linear Regression Rate (LRR). The final results reveal that the Quang Nam coast experienced remarkable phenomena of erosion and accumulation over the past three decades. The total number of erosional and accretional transects obtained from the EPR results are 401 and 414, with annual change rates of −1.7 and 0.77 m/year, respectively. The LRR parameter was also considered and illustrated a significant correlation with the EPR, as the obtained R2 value of 0.96. The lowest value of EPR over the period 1990–2019 is −42.4 m/year, highlighting the most significant erosion at the north of Cua Dai estuary, whereas coastline advance is recorded in the south segment. As a result, this study’s outcomes provide helpful information for better and sustainable coastal management in Quang Nam province of Vietnam.

Deteksi Perubahan Garis Pantai Menggunakan Teknik Geospasial, Studi Kasus Kecamatan Tejakula

The coastal area in Tejakula Subdistrict has many potential benefits for local people and the development of the region. Regarding its economic perspective, marine biodiversity can be utilized for tourism development. In terms of culture and history, this area has many archaeological findings ranging from prehistory until the colonial period. However, the recent study from Balai Arkeologi Bali stated the objects were sunk into underwater at a depth of 1-2 meters due to the abrasion process. Therefore, this research discussed the changes of shoreline in the Tejakula Subdistrict area as a preliminary study to protect and preserve its potential values. This research, both in terms of economy, culture, and history. The calculation of shoreline changes is using the Digital Shoreline Analysis System (DSAS) application with Net Shoreline Movement (NSM) and End Point Rate (EPR) methods. The results showed that the coastal segment in Tejakula District experienced an abrasion change with an abrasion rate of 0.89 m/year based on the SPOT satellite image analysis and 0.17 m/year from Landsat satellite imagery.

A Shoreline Change Detection (2012-2021) and forecasting Using Digital Shoreline Analysis System (DSAS) Tool: A Case Study of Dahej Coast, Gulf of Khambhat, Gujarat, India

Shoreline is one of the coastal landforms which continuously changing in nature. Hence, monitoring of shoreline change is very obligate to understand and manage the coastal process. The objectives of the present study were i) to identify the shoreline change detection (2012 to 2021) based on various statistical methods along Dahej coast, Gujrat. ii) to forecast the shoreline position after 10 years. DSAS tool and Multi-dated satellite images (Sentinel-2 and LISS-IV) were used in present study. The result shows that, the pattern of rate of change was more or less similar with little variation in the values for the 3 different methods. Highest erosion rate was for End Point Rate, Linear Regression Rate and Weighted Linear Regression rate found -33m, -31m, -31m respectively at transect no 54. Highest accretion rate was 38m (EPR), 50m (LRR), 51m (WLR) along a particular transect. The forecast of shoreline position for the year 2032 observed through Kalman Filter Model. Seasonal analysis for 3 years (2016, 2017, 2018) shows the region not having any seasonal pattern.

DETEKSI PERUBAHAN GARIS PANTAI MENGGUNAKAN CITRA SATELIT SENTINEL-1 (Studi Kasus: Pesisir Kabupaten Lampung Selatan)

Garis pantai merupakan salah satu fitur linear yang penting di permukaan bumi. Perubahan garis pantai ini dapat terjadi di sepanjang pantai akibat abrasi dan akresi secara kontinu. Provinsi Lampung memiliki Panjang garis pantai Provinsi Lampung lebih kurang 1.105 km, yang membentuk 4 (empat) wilayah pesisir, yaitu Pantai Barat (210 km), Teluk Semangka (200 km), Teluk Lampung dan Selat Sunda (160 km), dan Pantai Timur (270 km). Pada Analisa perubahan garis pantai dengan menggunakan Citra Sentinel-1 dengan rentan pengamatan 4 tahun dari 2016-2019 dengan menggunakan Digital Shoreline Analysis System (DSAS), Nilai perubahan garis pantai diprediksi dari perubahan Net Shoreline Movement (NSM) dan End Point Rate (EPR). Berdasarkan pengolahan data sepanjang garis pantai Lampung Selatan mengalami dominansi abrasi dengan akresi hanya 3 dari 20 titik pengamatan. Nilai NSM maksimum sebesar 18,07 meter dan minimum - 82,65 meter. Nilai EPR maksimum sebesar 5,24 meter dan minimum sebesar -23,96 meter. Perubahan garis pantai yang ditinjau dari 20 titik pengamatan dari bulan Januari 2016 sampai Juli 2019, memiliki rata-rata abrasi 50,905 m/thn, sedangkan akresi memiliki rata-rata 16,699 m/thn.

Dinamika perubahan garis pantai Kabupaten Kendal tahun 2000-2020

Abstrak Pemantauan garis pantai akibat adanya proses akresi dan abrasi merupakan salah satu upaya untuk menjaga batas wilayah wilayah di Kabupaten Kendal. Lima multitemporal citra Landsat 7 ETM+ dalam periode tahun 20 tahun (2000-2020) digunakan untuk menganalisis perubahan garis pantai di Kabupaten Kendal.Tujuan dari penelitian ini adalah untuk menganalisis perubahan garis pantai dan menganalisis dampak serta upaya mitigasi dalam menangani perubahan garis pantai di Kabupaten Kendal. Digital Shoreline Analysis System (DSAS) digunakan untuk menganalisis perubahan garis pantai dengan metode Net Shoreline Movement (NSM), End Point Rate (EPR), dan Linear Regression Rate-of-Change (LRR). Hasil penelitian menunjukkan bahwa nilai tertinggi dari Linear Regression Rate-of-Change (LRR) selama periode 20 tahun adalah sebesar 50,9 m/tahun sedangkan nilai terendah sebesar -35,81 meter/tahun. Nilai rata-rata EPR dan NSM selama periode 20 tahun adalah sebesar -0,07 m/tahun dan -1,14 meter. Berdasarkan studi ini, dampak dari perubahan garis pantai yang disebabkan abrasi dan akresi adalah adanya peningkatan dan penurunan luas wilayah. Bentuk mitigasi perubahan garis pantai di Kabupaten Kendal yakni dengan pembangunan breakwater dan penanaman hutan mangrove. Abstract Monitoring shoreline change due to accretion and abrasion processes is one of the efforts to protect the maritime boundary of Kendal Regency. Five multi-temporal Landsat 7 ETM + images spanning 20 years (2000-2020) is used in the tudy for the analysis of shoreline change in Kendal Regency. This study aims to investigate the shoreline change, analyze the impact, and propose mitigation of shoreline change in Kendal Regency as well. Digital Shoreline Analysis System (DSAS) is utilized for the analysis of the shoreline change through Net Shoreline Movement (NSM), End Point Rate (EPR), and Linear Regression Rate-of-Change (LRR). The result shows that the highest value of the Linear Regression Rate (LRR) for 20 years is 50.09 m/year and the lowest value of LRR is -35.81 m/year. The average EPR and NSM are -0.07 m/years and -1.14 m. From this study, it can be observed that the impact of shoreline change induced by accretion and abrasion are the addition and subtraction of the predetermined area. The impacts can be mitigated by building breakwaters and planting mangroves.

End Point Rate Tool for QGIS (EPR4Q): Validation Using DSAS and AMBUR

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.

Remote Sensing of Narrowing Barrier Islands along the Coast of Pakistan over Past 30 Years

Barrier islands (BIs) are the first line of defense against the sea/wave actions in coastal areas, and assessing their stability is crucial in the context of effective coastal planning. Therefore, this study evaluates the spatial–temporal shoreline changes of the BIs in Pakistan over the past three decades (1989–2018). Satellite data from Landsat missions are used to delineate the shorelines of 19 BIs in Pakistan. After delineating the shorelines from satellite observations, two well-known statistical methods (i.e., end point rate (EPR) and linear regression rate (LRR)) are used to capture the localized changes in the BIs. The results ascertain that nearly all of the BIs have experienced noteworthy erosion during the past three decades. While the mean erosion over all the BIs during the study period is estimated to be >6 m/y, significant spatial heterogeneities among the individual BIs exist. The interdecadal comparison indicates that the highest mean erosion of the BIs occurred during the period 1989–1999 (13.03 ± 0.62 m/y), which gradually reduced over the preceding decades (i.e., 7.76 ± 0.62 m/y during the period 1999–2009 and 3.8 ± 0.7 m/y during the period 2009–2018). Nevertheless, ~65% of the total BIs experienced high erosion (>2 m/y), ~15% experienced moderate (<2 m/y), and ~20% experienced low erosion (<1 m/y) during the period 1989-2018. This situation implies that while ~65% of these BIs need immediate interventions from the concerned authorities, the 15% BIs with moderate erosion might experience high erosion in the wake of rising sea levels and decreasing sediment influx in the near future without proper measures. This depletion of the BIs might not only affect Pakistan but also have regional consequences due to their various services.

End Point Rate Tool for QGIS (EPR4Q): Validation Using DSAS and AMBUR

This paper presents the validation of the End Point Rate (EPR) tool for QGIS (EPR4Q), a tool built-in QGIS Graphical Modeler to calculate the shoreline change by End Point Rate method. The EPR4Q tries to fill the gap of user-friendly and free open-source tool for shoreline analysis in Geographic Information System environment, since the most used software - Digital Shoreline Analysis System (DSAS) - although is a free extension, is suited for commercial software. Besides, the best free open-source option to calculate EPR called Analyzing Moving Boundaries Using R (AMBUR), since it is a robust and powerful tool, the complexity and heavy processes can restrict the accessibility and simple usage. The validation methodology consists of applying the EPR4Q, DSAS, and AMBUR on different examples of shorelines found in nature, extracted from the U.S. Geological Survey Open-File. The obtained results of each tool were compared with Pearson correlation coefficient. The validation results indicate that the EPR4Q tool created acquired high correlation values with DSAS and AMBUR, reaching a coefficient of 0.98 to 1.00 on linear, extensive, and non-extensive shorelines, guarantying that the EPR4Q tool is ready to be freely used by the academic, scientific, engineering, and coastal managers communities worldwide.