Shoreline Retreat Research Articles

The Application of GIS and Remote Sensing in a Spatiotemporal Analysis of Coastline Retreat in Rufisque, Senegal

This paper is aimed at analyzing the phenomenon of shoreline retreat in the locality of Rufisque from 1978 to 2018 mainly using geospatial data and field visits. A set of Landsat images from different dates at 10 year intervals was then acquired through the United States Geological Survey platform and shoreline change analysis was run using the Digital Shoreline Analysis System. In addition to that desktop work, interactions with local residents allowed the determination of ongoing adaptation strategies actually in place to cope with coastal erosion. The study showed that Rufisque is subject to serious rates of erosion reaching −19.48 m/year from 1978–1988, close to −8 m/year from 1988–1998, −5.88 m/year from 1998–2008 and −6.67 m/year from 2008–2018. Beside that coastal erosion, it has been noticed that the coastline also experienced in some of its parts cases of accretion reaching 4.94 m/year for 1988–1998, 7.29 m/year from 1998–2008 and 7.68 m/year during the period 2008–2018. In terms of surfaces, Rufisque’ shoreline respectively lost 156.81 ha (1978–1988), 80.55 ha (1988–1998), 6.94 ha (1998–2008), 12.93 ha (2008–2018) and in the same note gained 2.86 ha (1988–1998), 32.51 ha (1998–2008) and 19.16 ha (2008–2018) attesting to the fact that the coastline is subject to both spatiotemporal changes. Finally, this study also reveals that while authorities’ reaction is taking place at much lower pace, local communities are actually using their ingenuity to put in place strategies to tackle coastal erosion.

Spatial-Planning-Based Ecosystem Adaptation (SPBEA): A Concept and Modeling of Prone Shoreline Retreat Areas

Ecosystem-based adaptation to climate change impacts, such as shoreline retreat, has been promoted at the international, national, and even local levels. However, among scientists, opinions about how to implement it in spatial-planning practices are varied. Science-based environmental factors, human wellbeing, and sustainable development can be strengthened by developing spatial-planning-based ecosystem adaptations (SPBEAs). Therefore, this article aims to assess how the SPBEA model can be developed within an area prone to shoreline retreat. A coastal area of the Sayung subdistrict in Central Java, Indonesia, was selected as a study area because it has experienced a massive shoreline retreat. A multicriteria analysis (MCA) method was employed for developing the model by using the geographic information system (GIS) technique of analysis, divided into three steps: the fishpond zone determination, which involved the analytical hierarchy process (AHP) method in the process of model development; the fishpond site determination; SPBEA fishpond site development. The results show that the SPBEA model is the best practice solution for combatting shoreline retreat because of tidal waves and/or sea-level rise. The spatial site management should empower the coastal protection zone and the sustainable fishpond zone by implementing a silvofishery approach.

The Effect of Wave-Induced Current and Coastal Structure on Sediment Transport at the Zengwen River Mouth

The mechanisms that control estuarine sediment transport are complicated due to the interaction between riverine flows, tidal currents, waves, and wave-driven currents. In the past decade, severe seabed erosion and shoreline retreat along the sandy coast of western Taiwan have raised concerns regarding the sustainability of coastal structures. In this study, ADCPs (Acoustic Doppler Current Profiler) and turbidity meters were deployed at the mouth of the Zengwen river to obtain the time series and the spatial distribution of flow velocities and turbidity during the base flow and flood conditions. A nearshore circulation model, SHORECIRC, has been adapted into a hybrid finite-difference/finite-volume, TVD (Total Variation Diminishing)-type scheme and coupled with the wave-spectrum model Simulating Waves Nearshore (SWAN). Conventional finite-difference schemes often produce unphysical oscillations when modeling coastal processes with abrupt bathymetric changes at river mouths. In contrast, the TVD-type finite volume scheme allows for robust treatment of discontinuities through the shock-capturing mechanism. The model reproduces water levels, waves, currents observed at the mouth of the Zengwen River reasonably well. The simulated residual sediment transport patterns demonstrate that the transport process at the river mouth is dominated by the interaction of the bathymetry and wave-induced currents when the riverine discharge was kept in reservoirs. The offshore residual transport causes erosion at the northern part of the river mouth, and the onshore residual transport causes accretion in the ebb tidal shoals around the center of the river mouth. The simulated morphological evolution displays significant changes on shallower deltas. The location with significant sea bed changes is consistent with the spot in which severe erosion occurred in recent years. Further analysis of morphological evolution is also discussed to identify the role of coastal structures, for example, the extension of the newly constructed groins near the river mouth.

GIS-based approach to estimate sea level rise impacts on Damietta coast, Egypt

Sea level rise (SLR) is considered to be one of the most significant environmental issues globally. Damietta Governorate is likely to face serious impacts due to SLR because of its low-lying sandy coast. This study investigates the actual impacts of SLR and associated shoreline retreat at Damietta coast using the geographic information system (GIS) despite current uncertainties about SLR. In this study, shoreline retreat at Damietta coast was estimated using the Bruun rule. To achieve this, remotely sensed data including cloudless satellite images (Landsat ETM+7) were used. Moreover, this study used elevation data taken from global digital elevation model (GDEM) data derived from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) project. Many thematic layers including maps of administrative boundaries, the rail and road networks, irrigation, and urban areas were used to address the impacts of SLR. The results showed that, if the SLRs 1 m, the inundated area will include approximately 254 km2 of governorate land, which represents 16% of its total area. In a 2-m SLR scenario, the submerged area will expand to 661 km2, which represents 64% of Damietta’s area. Application of the Bruun rule indicated that SLR would have a small effect on coastline erosion. Upon estimation of the annual shoreline retreat, this was predicted to range from 2.7 to 3.8 m/year at Damietta coast under the impact of SLR. SLR thus poses a serious threat to Damietta Governorate as its land is subsiding at a high rate, which is a major factor that amplifies the severity of potential inundation. Thus, there is a serious need to protect Damietta’s coast and its human population from the impacts of SLR.

A quantitative analysis of shoreline changes along the coast of Bangladesh using remote sensing and GIS techniques

The dynamic shoreline of Bangladesh was analyzed for the last thirty years in this study, in order to identify the positional changes due to erosion and accretion. Remotely acquired, multi-temporal Landsat images, of 30 m resolution and comparable tidal conditions, were collected for the period 1989–2019 at a five-year interval. Shorelines were then manually digitized, and a transect-based analysis was carried out using the Digital Shoreline Analysis System (DSAS) extension in ArcGIS. Rates of shoreline change and net movement along transects were determined for the three different coastal zones of the country. Almost 12,000 transects were cast with 50 m interval, for the whole coast, majority of which showed shoreline retreat. The shoreline variability is found to be the highest in the central zone, with rates of erosion being observed up to ~ 120 m/year and accretion up to ~ 230 m/year. The western zone is found to be retreating steadily over the years, at an average rate of 15–20 m/year, while the eastern zone displayed significant changes only at a few localized sites. A supplementary polygon-based analysis was also carried out in ArcGIS, through which the net area of erosion and accretion was determined for the whole study period. The net area loss is observed to be the highest in central zone (~62 km2), whereas opposite scenario is found in the eastern zone which has gained a net area of around 30 km2.

Did the Construction of the Bhumibol Dam Cause a Dramatic Reduction in Sediment Supply to the Chao Phraya River?

The Bhumibol Dam on Ping River, Thailand, was constructed in 1964 to provide water for irrigation, hydroelectric power generation, flood mitigation, fisheries, and saltwater intrusion control to the Great Chao Phraya River basin. Many studies, carried out near the basin outlet, have suggested that the dam impounds significant sediment, resulting in shoreline retreat of the Chao Phraya Delta. In this study, the impact of damming on the sediment regime is analyzed through the sediment variation along the Ping River. The results show that the Ping River drains a mountainous region, with sediment mainly transported in suspension in the upper and middle reaches. By contrast, sediment is mostly transported as bedload in the lower basin. Variation of long-term total sediment flux data suggests that, while the Bhumibol Dam does effectively trap sediment, there was only a 5% reduction in sediment supply to the Chao Phraya River system because of sediment additions downstream.

Coastal Stability using Remote Sensing and Radioactive Materials in the Northwest Nile Delta Coast, Egypt

This paper points to changes of the coastline using two ways, calculating the annual rate of erosion using 1) radioactive materials and 2) GIS and DSAS extension. Finally, both results were verified. Radioactivity results indicate both erosion and accretion zones, the annual scavenging rate in Promontory area shows that it is presented main accretion area, unlike the results of the DSAS extension, which showed that the Promontory is erosion area. The Burullus area annual scavenging rate results showing erosion, despite results of DSAS, it shows that it is an accretion area, but this was clarified by calculating the average distance between the shoreline of 2017 and 2018, and the 2018 shoreline retreat with an average distance 41.4 cm, which makes the Burullus region suffer from erosion. Two methods showed similarity in results in the Edco area, which shows that the Edco area suffers from erosion.

Evaluation of decadal shoreline changes along the Parnaíba Delta (NE Brazil) using satellite images and statistical methods

This study investigated changes of the shoreline position in the Parnaíba River Delta (PRD), which is in an underdeveloped and sparsely populated area. The general behavior of the shoreline between 1984 and 2017 was analyzed using 12 Landsat satellite images and the Digital Shoreline Analysis System (DSAS) software. DSAS applied statistical methods, such as Weighted Linear Regression (WLR) and End Point Rate (EPR), to define whether the shoreline was retreating or accreting.Data analysis revealed that, on a decadal time scale (33 years), 52% of the PRD shoreline retreated under erosional conditions, while 48% accreted. Accretion mainly occurred at the vicinities of the river mouth, especially eastward where the highest progradation rate was observed (maximum of 29 m/year). Shoreline retreat, up to 9 m/year, occurred predominantly in the western part of the PRD and away from the river mouth.However, changes of the general behavior of the shoreline (retreat/accretion) were observed at an interdecadal time scale, which were positively related to variations in river discharge. Variations of river discharge are directly dependent on the rainfall amount along the drainage basin that, in this region, is controlled by climatic conditions such as El Niño and La Niña. Therefore, the reduced river discharge observed between 1995-1999 and 2009–2012 (El Niño periods), was the major cause the triggered the observed coastal retreat (>6 m/year) on PRD shoreline during these periods.Consequently, the variability of natural factors, such as river discharge and rainfall, are the main drivers of shoreline changes on PRD, since anthropogenic impacts have hitherto only marginal effects on the delta region and on the drainage basin of the Parnaíba river.

Alarming coastal vulnerability of the deltaic and sandy beaches of North Africa

The arid coasts of North Africa, extending over 4633 km from the Gulf of Tunis to the Nile Delta, are undergoing pronounced shoreline retreats and coastal floodings that are reported as a consequence of the ongoing sea level rise resulting from global warming. Of particular interest are the abnormal shoreline dynamics for deltaic and sandy beaches, which are severely impacted by abrupt decadal variabilities in both climatic and anthropogenic drivers resulting in their increased vulnerability to disturbances from coastal hazards. Unfortunately, the evolution, distribution and impacts of these drivers remain largely unquantified, let alone understood, for these extensive arid coasts that harbor the major portion of North Africa’s population as well as unique and fragile marine ecosystems. To address this deficiency, we use GIS-based multi-criteria approaches combined with analytic hierarchy process to map the Coastal Vulnerability Index and the Socioeconomic Vulnerability Index along these coasts to investigate the amplitude and extent of shoreline deterioration resulting from sudden fluctuations in sediment transport to the coastline. We use the western bay of the Gulf of Tunis, the coasts of Tripoli and the Nile Delta as three validation sites for our vulnerability assessment. The statistical Integrated Coastal Vulnerability Index map reveals that 47% of arid North African coasts are characterized by high to very high vulnerability. In particular, we observe that the densely populated deltaic coasts in both Tunisia and Egypt are 70% more vulnerable than any others coast in the eastern Mediterranean Basin. These abnormally high-vulnerability extensive areas are also correlated with significant deterioration of coastal aquifers and hence in crop production, compromising local food security and resulting in increasing outflow migration trends. Both Tunisia and Egypt observed dramatic increases in the net population outflow migration by respectively 62% and 248% between 2000 and 2016, mostly from coastal areas. Our source analysis of the amplitude and extent of these high coastal vulnerabilities suggests that they result from the anthropogenic drivers of damming and rapid urban growth over the last few decades rather than the effects of global warming.

A review of Gulf of Mexico coastal marsh erosion studies following the 2010 Deepwater Horizon oil spill and comparison to over 4 years of shoreline loss data from Fall 2010 to Summer 2015

The 2010 Deepwater Horizon (DWH) oil spill affected nearly 1105 km of coastal marsh. Long-term shoreline loss in the northern Gulf of Mexico is an important question with far-reaching ecological and human-use implications. Numerous studies have examined potential exacerbated marsh shoreline retreat after the DWH using ground-level sampling and/or aerial/satellite imagery interpretation. This paper reviews previous DWH erosion studies, discusses their limitations and sometimes conflicting results, and provides a comprehensive analysis of a larger data set. Shoreline retreat measurements from multiple studies following the DWH incident were combined for 131 herbaceous marsh sample sites for the period from Fall 2010 to Summer 2015. Significant increases in shoreline loss were found only in the period from Fall 2010 to Fall 2011 for heavily oiled shorelines relative to other periods. The evidence does not suggest widespread long-term coastal marsh erosion from the DWH.

Probabilistic characterisation of coastal storm-induced risks using Bayesian networks

Abstract. A probabilistic estimation of hazards based on the response approach requires assessing large amounts of source characteristics, representing an entire storm climate. In addition, the coast is a dynamic environment, and factors such as existing background erosion trends require performing risk analyses under different scenarios. This work applies Bayesian networks (BNs) following the source–pathway–receptor–consequence scheme aiming to perform a probabilistic risk characterisation at the Tordera delta (NE Spain). One of the main differences of the developed BN framework is that it includes the entire storm climate (all recorded storm events, 179 in the study case) to retrieve the integrated and conditioned risk-oriented results at individually identified receptors (about 4000 in the study case). Obtained results highlight the storm characteristics with higher probabilities to induce given risk levels for inundation and erosion, as well as how these are expected to change under given scenarios of shoreline retreat due to background erosion. As an example, storms with smaller waves and from secondary incoming direction will increase erosion and inundation risks at the study area. The BNs also output probabilistic distributions of the different risk levels conditioned to given distances to the beach inner limit, allowing for the definition of probabilistic setbacks. Under current conditions, high and moderate inundation risks, as well as direct exposure to erosion can be reduced with a small coastal setback (∼10 m), which needs to be increased up to 20–55 m to be efficient under future scenarios (+20 years).

An analysis of the factors responsible for the shoreline retreat of the Chao Phraya Delta (Thailand)

Deltas are inherently low-lying structures and thus subject to large threats due to sea level rise, erosion and other coastal processes. The shorelines in many deltas around the world are now retreating and most cases appear to result from a decreasing sediment supply as a consequence of upstream dam construction. We present here results of an investigation of riverine sediment fluxes, coastal retreat, and coastal sediment accumulation in the Chao Phraya River and Delta (Thailand). This deltaic shoreline has one of the highest rates of shoreline retreat in the world. Surprisingly, our results show that in spite of the construction of two large storage dams, one on the Ping River (Bhumibol Dam, 1964) and the other on the Nan River (Sirikit Dam, 1972) that merge to form the Chao Phraya, sediment accumulation in the delta was actually higher over the last several decades than prior to dam construction. The recent higher rates of sediment accumulation, based on 210Pb dating, appear to be the result of increased sediment supply in the lower reaches of the river relating to expansion of aquaculture and other activities in the delta beginning in the 1970s. We also show that mangrove removal, in order to further develop shrimp farming, charcoal production, and other pursuits, was not responsible for most of the shoreline erosion. Rather, subsidence, mainly induced by groundwater withdrawal, together with worldwide sea level rise appears to be the main factor affecting the very rapid shoreline retreat of the Chao Phraya Delta.

The Role of Thermal Denudation in Erosion of Ice-Rich Permafrost Coasts in an Enclosed Bay (Gulf of Kruzenstern, Western Yamal, Russia)

Coastal erosion in the Arctic has numerous internal and external environmental drivers. Internal drivers include sediment composition, permafrost properties and exposure which contribute to its spatial variability, while changing hydrometeorological conditions act as external drivers and determine the temporal evolution of shoreline retreat. To reveal the relative role of these factors, we investigated patterns of coastal dynamics in an enclosed bay in the southwestern Kara Sea, Russia, namely the Gulf of Kruzenstern, which is protected from open-sea waves by the Sharapovy Koshki Islands. Using multitemporal satellite imagery, we calculated decadal-scale retreat rates for erosional segments of the coastal plain from 1964 to 2019. In the field, we studied and described Quaternary sediments and massive ground-ice beds outcropping in the coastal bluffs. Using data from regional hydrometeorological stations and climate reanalysis (ERA), we estimated changes in the air thawing index, sea ice-free period duration, wind-wave energy and total hydrometeorological stress for the Gulf of Kruzenstern, and compared it to Kharasavey and Marre-Sale open-sea segments north and south of the gulf to understand how the hydrometeorological forcing changes in an enclosed bay. The calculated average shoreline retreat rates along the Gulf in 1964–2010 were 0.5 ± 0.2 m yr−1; the highest erosion of up to 1.7 ± 0.2 m yr−1 was typical for segments containing outcrops of massive ground-ice beds and facing to the northwest. These retreat rates, driven by intensive thermal denudation, are comparable to long-term rates measured along open-sea sites known from literature. As a result of recent air temperature and sea ice-free period increases, average erosion rates rose to 0.9 ± 0.7 m yr−1 in 2010–2019, with extremes of up to 2.4 ± 0.7 m yr−1. The increased mean decadal-scale erosion rates were also associated with higher spatial variability in erosion patterns. Analysis of the air thawing index, wave energy potential and their total effect showed that inside the Gulf of Kruzenstern, 85% of coastal erosion is attributable to thermal denudation associated with the air thawing index, if we suppose that at open-sea locations, the input of wave energy and air thawing index is equal. Our findings highlight the importance of permafrost degradation and thermal denudation on increases in ice-rich permafrost bluff erosion in the Arctic.

VARIAÇÃO DA LINHA DE COSTA NO LITORAL LESTE DO ESTADO DO CEARÁ: O CASO DA RESEX DA PRAINHA DO CANTO VERDE

A zona costeira, área de extrema dinamicidade devido à interação entre os sistemas marinhos e continentais e aos também fenômenos climáticos, tem passado por consequentes alterações em decorrência das mudanças climáticas cada vez mais recorrentes e severas, implicando diretamente na linha de costa, seja na forma de erosão, seja na progradação. Dessa forma, utilizando-se das metodologias associadas às técnicas de geoprocessamento, foi possível verificar que nos últimos 13 anos o trecho de praia que compreende a Resex da Prainha do Canto Verde, localizada no litoral leste do Ceará, apresentou taxas de erosão que variamentre -4,14 m/ano e -2,33 m/ano (EPR) e de -3,66 m/ano a -1,77 m/ano (LRR). Em termos totais, isso representa um recuo da linha de costa que variou entre pouco mais de 50 m, no máximo, e mínimo de 23 m de acordo com as estatísticas utilizadas pela extensão DSAS.
 Palavras-chave: erosão costeira, linha de costa, gerenciamento costeiro.

Spatio-Temporal Analysis of Shoreline Movements along the Coastal Stretch from Bortianor to Winneba, Ghana

Shoreline movement is largely dependent on the extent of erosion and accretion, thus making it one of the most dynamic geomorphic phenomena along the coast. The study sought to assess the spatio-temporal dynamics of shoreline movements along the coastal stretch between Bortianor in the Greater Accra Region and Winneba in the Central Region of Ghana from 2000 to 2020. The study used shoreline data mapped from field-based high resolution aerial imagery and Landsat 7 and 8 images. Digital Shoreline Analysis System (DSAS) software 5 was used for the data processing and analysis, with reference to Shoreline Change Envelope, Net Shoreline Movement, End Point Rate, Linear Regression Rate and Weighted Linear Regression. It was observed that the entire shoreline under study generally experienced a continuous retreat than advancement due to the moderate to very high accretion. This notwithstanding, very high erosion was observed on the eastern side of the coast in Fete, leading to an advancement of the shoreline. The study recommends constant monitoring of the coastline by researchers and relevant stakeholders and also the need to put in place protective mechanisms such as sea defenses by the Ministry of Water Resources, Works and Housing to avoid the worse scenarios being experienced in other parts of the Ghanaian coastline. Keywords: shoreline movements, accretion, erosion, shoreline retreat, shoreline advancement DOI: 10.7176/JEES/11-1-04 Publication date: January 31 st 2021

ДИНАМИКА БЕРЕГОВ ОСТРОВОВ СЕВЕРНОЙ ЧАСТИ КАРСКОГО МОРЯ (ст. 1. Остров Ушакова)

The analysis of a large complex of materials – satellite images, UAV surveys, meteorological observations of polar stations, and archival data made it possible to establish the shoreline retreat rates of Ushakov Island. The island is entirely coved by the glacial dome formed above the late Cretaceous and Quaternary rock formations. The ice/rock interface is partially located below sea level. lying on the Ushakov island is located in the northern part of the Central Kara Upland and was discovered in 1935 by Soviet sea expedition visited by scientific expeditions extremely rare. For a long time, Ushakov Island was maintained by slightly negative (up to 1% volume annually) ice balance, a short ice-free period, and protected from storm waves by fast ice. At the beginning of the XXI century, the situation changed – the air temperature began to increase noticeably, the area of sea ice decreased, and the wave activity increased during the warm season. The edges of Ushakov ice dome began to break off and float into the sea as icebergs evenly around the perimeter with an increasing rate: from 10.9 m/year in 1954–2011, up to 27.3 m/year in 2011–2019. The area of the island decreased in 2002–2019 by 230.8 ha/year, in 2015–2019 – up to 294 ha/year. The glacier surface around the polar station has decreased by 15 m in 65 years. A monument of science and technology - the polar station (built in 1954, 800 m from the edge of the glacier) was washed away to the sea in 2018. The subtype of ice shores has changed from ice barriers up to 3 m high (low cliffs of floating ice) to ice walls up to 45 m and more.

A 3-D MODEL USING REPRESENTATIVE WAVES METHOD FOR SHORELINE MORPHODYNAMICS AROUND COASTAL STRUCTURES

The Fort Pierce Shore Protection Project nourishes a 2.1-km Atlantic Ocean shoreline south of Fort Pierce Inlet in St. Lucie County, Florida. The beach fill erodes nonuniformly with a hotspot along the northernmost 0.7 km requiring nourishment after about two years of normal wave regime. This study validated and applied to beach stabilization a shoreline morphology model to evaluate designs and combinations of coastal structures to increase the nourishment interval. Simulations of long-term normal tides, waves, and storm conditions show (a) shoreline movement pattern similar to the general historical pattern observed in the project area, including accurately indicating the largest erosion rate and shoreline retreat along the first 0.7 km south of the jetty; (b) the coastal structures retain beach fill longer, resulting in lower erosion rates from 0.8 to 6.4 km south of the jetty; and (c) the coastal structures alternative extends the normal beach nourishment interval from the current two years to four years. Application of representative waves allows accurate and efficient modeling of long-term 3-D beach and shoreline deformation.

Sandy beaches can survive sea-level rise

It has been asserted by Vousdoukas et al., that climate change, in particular global sea-level rise (SLR), poses a threat to the existence of sandy beaches. The authors used global data bases of sandy beaches, bathymetry, wave conditions and SLR to drive a simple model based on the ‘Bruun Rule’ to quantitatively evaluate shoreline retreat. To this modelled retreat, they add a background ambient trend in shoreline dynamics and the modelled response of an extreme storm, that together contribute c. 20% of the shoreline retreat. When retreat was more than 100 m by 2100, they declared those beaches extinct. This is an incorrect and potentially damaging finding that must be repudiated along with the associated implications.

Potential impact of sea level rise on the geomorphology of Kuwait state coastline

Sea level rise (SLR) is one of the most severe risks threatening coastal zones all over the world. In Kuwait, coastal areas accommodate about 90% of the total population and most of the urban area. Thus, SLR is expected to have significant impacts on Kuwaiti coastal areas, which may lead to changes in their ecosystems and the geomorphological units in the coastal area. This paper aims to assess the impacts of SLR on the geomorphology of the Kuwaiti coastline under two different scenarios of SLR: an integrated analysis model involving a variety of methods and a composite vulnerability index integrating five criteria. The results revealed that about 58% of the total coastal area is susceptible to inundation under 1- and 2-m SLR scenario, whereas 8.3% of Kuwaiti coastal areas have moderate to high vulnerability levels. Moreover, it was found that SLR may have significant implications for some Kuwaiti coastal areas including expanding sabkhas areas, shoreline retreat, changing coastal hydrodynamics, and erosion patterns and accelerated weathering process. To avoid such potential impacts, it is essential to develop a national strategy for adaptation to SLR impact and mainstreaming adaptation into development plans.

ANALYSIS OF CHANGES IN COASTLINES IN DISTRICT OF BANGKALAN MADURA WITH GEOGRAPHIC INFORMATION SYSTEM APPROACH AND LANDSAT 8 SATELLITE IMAGERY


 
 
 
 The coastline is the meeting area between land and sea. In this area, many are influenced by various natural factors and also human activities, where changes that occur such as climatological effects will have an impact on the existing coastline, as well as human activities in the coastal areas will have an impact on the morphological form of the coast including in it the coastline. This study intends to see which mathematical model is most suitable for describing the changes that have occurred and also to measure how much change occurs each year. The method used in this research is spatial analysis using a geographic information system which is used to analyse the Landsat 8 OLI satellite image of the coastline in Bangkalan Madura district, and to measure satellite imagery for a period of 5 years from 2016 to 2020. The results obtained from this study, the polynomial mathematical model is the most suitable model to describe the process of change, where this model provides maximum results with a significant correlation value of 0.8107 for degree 2 and 0.9323 for degree polynomial 3. From this study It can be concluded that Landsat 8 satellite imagery is suitable for data collection on shoreline changes because this satellite image has sufficient resolution to describe in detail the length of the coastline under study. Changes in the coastline that occur are not linear, but throughout the year there are fairly dynamic changes to the shoreline, both in terms of a shoreline retreat or an addition to the coastline.