Shoreline Change Studies Research Articles

Comparison of Shoreline Change from High Resolution Aerial and Satellite Imagery: A South Carolina Case Study

Coastal shorelines are complex and valuable environments that are ever changing. Remote sensing technologies such as satellites and aerial imaging sensors provide an aerial perspective for mapping and analyzing shoreline change. This study aims to compare two accessible and widely used remote sensing data sources- MAXAR WorldView 2 satellite (WV2) and National Agriculture Imagery Program (NAIP) aerial imagery, while also identifying shoreline change trends adjacent to North Inlet, South Carolina. We found that the NAIP and WV2 imagery were very similar in their ability to provide a reliable backdrop for digitizing shoreline data, albeit with differing costs and temporal considerations. In the case study application of using the imagery to detect shoreline change at North inlet over a 12-year period, we found that the three northern regions of the study area experienced overall average erosional impacts of −2.1 m, −4.5 m, and −11.3 m per year. The southernmost region experienced an overall average accretional rate of + 10.6 m. These changes were like a few nearby inlet-adjacent shoreline change studies and are considered to be caused by storm and tidal events, natural sediment drift, and other the dynamic influences of the inlet.

Study of Shoreline Changes Due to Tidal Flood at the Coastal City of Meulaboh

The coastline is constantly changing over time. The process of change that occurs continuously makes the coastline dynamic. Shorelines are vulnerable to changes caused by natural and human factors. One of the causes of shoreline changes due to natural factors is tidal flooding. Tidal floods cause abrasion of the coastline and create inundation on land. The coast of Meulaboh City has experienced tidal floods in 2020. The tidal floods that occur make the coastline abrasion and residential areas inundated. This study aims to determine the shoreline changes and the shoreline recovery process due to abrasion and accretion after tidal floods from 2020 to 2021. The shoreline in July 2019, 2020 and 2021 were analysed using DSAS tools to see horizontal shoreline changes. Measurement of the transverse profile of the beach was carried out 17 times in 12 transverse profiles. This measurement aims to map the profile condition after the tidal flood in July 2020. Measurement data for each profile was analysed using the EOF method to see vertical shoreline changes one year after the July 2020 tidal flood. Based on DSAS analysis, the shoreline conditions after tidal flooding (2019-2020) regressed with an average regression of 25.48 m and showed an accretion process after a year (2020-2021) with an average accretion of 14.38 m. Shoreline recovery due to tidal flooding can be seen well based on measurements for 1 (one) year and the results of Empirical Orthogonal Function (EOF) analysis. The recovery pattern is visible after 4 months of tidal flooding in July 2020. The beach profile tends to experience an accretion process in the 8th to 13th measurements and tends to experience abrasion in the 16th to 17th measurements. This shows that the accretion process on the transverse coastal profile is influenced by the east wind season, and the abrasion process generally occurs in the west wind season.

Statistical analysis of shoreline change reveals erosion and baseline are increasing off the northern Tamil Nadu Coasts of India

Many tourists have been recently attracted towards the coasts around the world, especially to the large urban centres and economically significant areas. In the last four decades, there is a significant increase in the key coastal developments and tourist's attractions like major ports, minor ports, fishing harbours, desalination plants, shore protection structures, and many more along the southeast coasts of India, in particular, northern Tami Nadu coastal stretches. The shoreline change study of these regions were carried out using the geospatial technologies (satellite remote sensing and geographical information system) to examine potential modifications occurred during the last 32years between March 1990 and May 2022. This study used Landsat satellite images of spatial resolution 30m to track the shoreline changes which was extracted using the Digital Image Processing software and techniques. In addition, the United States Geological Survey (USGS) developed Digital Shoreline Analysis System (DSAS) v5.2 software, an add-on tool to ArcGIS used for the statistical analysis to compute the shoreline rate of change. The linear regression rate (LRR) and end point rate (EPR) statistics were used to identify the eroding, accreting, and stable shoreline between Kattupalli coast and Kalpakkam coast of the northern Tamil Nadu coasts. This shoreline study of 106km was carried out by dividing it into six zones (zone 1 to zone 6), and the DSAS analysis conveys that the shoreline of zone 1 (Kattupalli) and zone 2 (Ennore) shows erosion compared to other four zones. In locations where the coast is vulnerable, national mitigation measures must be implemented.

Study of Shoreline Changes Through Digital Shoreline Analysis System and Wave Modeling: Case of the Sandy Coast of Bou-Ismail Bay, Algeria

Study of Shoreline Changes Through Digital Shoreline Analysis System and Wave Modeling: Case of the Sandy Coast of Bou-Ismail Bay, Algeria

Application of Geospatial Techniques to Determine Coastal Erosion and Accretion along the Ramanathapuram Shore, Tamil Nadu, India

Abstract The coastal region is one of the most sensitive areas on earth. This region has a diversified ecosystem. Erosion and accretion are common natural phenomena that can be seen in this region. In some circumstances, these changes become hazardous to the coastal ecosystem. Natural processes such as rainfall, flood, cyclone, longshore drift, and tectonic shifts can trigger irregular coastal changes. Similarly, anthropogenic factors such as urbanization, unscientific land usage, mining, etc., enhance coastal dynamics and make larger changes. Hence identification of such region has great importance. Geospatial technology has brought various advanced methods for shoreline change studies. It has decreased the huge effort for getting an accurate result for a larger area. Landsat satellite imageries with 30 m spatial resolution have been used for studying the changes in the shoreline of Ramanathapuram for the years 2000, 2005, 2010, 2015 and 2020. In Geographic Information System (GIS) software, the Digital Shoreline Analysis System (DSAS) tool is added for shoreline change analysis. DSAS will build the baseline transects. The rate of shoreline change was calculated using the MATLAB feature runtime function for ArcGIS. Based on the DSAS output, the region of high erosion, low erosion, stable, and low accretion, high accretion zones have been identified on the shore. The results reveal that 5.1% of the shoreline, around 9.3 km is under high erosion, 11.5% of the shoreline, which is around 20.8 km, is under low erosion, 71% of the shoreline, around 128 km, is a stable region, 6.7% of shorelines, around 12 km, have low accretion, and 5.6% of shorelines, around 10.1 km, have high accretion. The coastal villages, namely, Mayakulam, Keelakakrai, Periapattinam, Mandapam, West-Pamban, and East-Rameswaram, have a high erosion with a maximum rate of change between 2.29 to 5.11 m/y. The coastal villages Ervadi, Kalimankund, Sattankonvalsai, South-Pamban and South-Rameswaram have high accretion with a maximum rate of change between 2.34 to 5.24 m/y.

Shoreline changes due to construction of groyne field in north of Chennai Port, India.

Chennai Port (13.099872° N, 80.297407° E), located along the southeast coast of India, has been a hub for maritime trade since the fifteenth century. An artificial harbour was initially constructed in 1881 which underwent numerous expansions in the following years. The breakwaters of the harbour intercepted the heavy sediment-laden littoral drift along the coast, resulting in the formation of the world's second-longest urban beach south of the port, i.e. on its up-drift side. Meanwhile, the coast north of the port, i.e. the down-drift side, experienced intense erosion due to a lack of sediment supply and forces induced on the coast due to waves and currents. The shoreline change study in this paper investigates a shoreline stretch of about 6km (protected by transitional groynes), north of Chennai Port by dividing it into three segments. The rate of shoreline changes over a period of about 12years across three different segments was assessed using statistical parameters by employing remote sensing techniques complemented with geographical information system (GIS) and digital shoreline analysis system (DSAS) tool. It is inferred that the coast has witnessed accretion and sizable growth in beach width has been observed post the construction of groyne field.

Shoreline change study between Vembar and Tharuvaikulam coastal zones along the coast of Thoothukudi district, Tamil Nadu, India, using remote sensing and GIS techniques

Shoreline change study is very challenging for any coastal scientists because of its dynamic changes. Erosion and accretion processes directly control the shoreline and coastal landforms. The present study is attempted to assess the shoreline changes between the Vembar and Tharuvaikulam coast of the Thoothukudi district, Tamil Nadu, India. Both the places were regarded as two zones viz. Vembar and Tharuvaikulam zone. These zones are further sub-divided into three grids to understand and mark the erosion and deposition zones. The shorelines were digitized from satellite images of Landsat – 5 (1997) and Landsat – 8 (2018), and also the base details were extracted from a survey of India (SOI, 1968). These shorelines were taken to Geographic Information System for overlay analysis to determine the extent of erosion and accretion in the study area. The result of this study shows that during the period 1968–1997, Vembar and Tharuvaikulam zones have noticed accretion with a rate of 6.9 m2/y and 4.5 m2/y, respectively. Whereas, during the period 1997 – 2018, the Vembar zone was subjected to erosion with a rate of -1 m2/y. While in the Tharuvaikulam zone, the accretion process has reduced with a rate of 0.1 m2/y. The study results have shown that the Vembar zone has undergone erosion, whereas; the Tharuvaikulam zone has undergone both erosion and accretion. The accretion process rate is less compared to the erosion process during 1968 – 1997. The study concludes that the erosion is increasing due to natural and human intervention.

Beach slope distribution mapping using UAV in the Cirebon coastal area

The beach slope is usually estimated using the conventional ground survey, causing the availability of this parameter data to be limited in some areas. Meanwhile, this parameter is considered crucial in the study of shoreline changes and coastal area protection as well as other coastal morphodynamic research. The aim of this study is to demonstrate an efficient technique to calculate the beach slope as well as its distribution in an area. In the daily intertidal period, the beach profile is assumed to be a static planar beach state which does not change due to the insignificant effect of erosion and accretion process. First, the shoreline data set was delineated from the tidal-varied orthomosaic using the UAV. The beach slope is then calculated by comparing the difference in tide level with the difference in the horizontal distance of shoreline points along a cross-shore transect at different times. The utilization of UAV allows mapping the shoreline in an area in several different tidal conditions, allowing the distribution of the beach slope also be mapped. This technique was then applied in the Cirebon Coastal Area and found an average beach slope of 0.105 with 0.100 being the slope class with the highest number of distributions. It was also found that due to the presence of mangroves and coastal structures, no slope conditions dominated this area. The result of beach slope calculation using this technique shows suitability with other studies and reveals UAVs’ potential in mapping the beach slope distribution more efficiently.

An Improved Method to Detect Shoreline Changes in Small-Scale Beaches Using Google Earth Pro

Shoreline change studies in small-scale beaches require high-resolution satellite images. In this regard, high-resolution satellite images from Google Earth (GE) would be an alternative source however novel studies are needed to verify the effectiveness and the efficiency of applying those images for shoreline change detection in small-scale beaches. Addressing this gap, the current study attempts to develop a new method. Accuracies of delineated shorelines under different scenarios were used to develop relationships with digitizing methods and used eye-altitude to estimate the most effective, efficient and productive method. This was done using Digital Shoreline Analysis System (DSAS) in ArcGIS software. It was found that the eye-altitude influences on digitizing accuracy and it could be improved when increasing the zoom level of the image which is under investigation. Maximum zoom level (50 m) used in this study showed the highest accuracy in shoreline digitizing while the most productive eye-altitude for shoreline delineation was found as 300 m. The current study identified that GE coupled with DSAS tool in ArcGIS software can be used as an effective and efficient method for small-scale shoreline change analysis and it is suggested that this methodology could be adopted for other similar studies.

Spatio-temporal modelling of shoreline migration in Sagar Island, West Bengal, India

Sagar Island is a very popular pilgrimage destination located in the western part of Indian Sundarbans. This study employs Digital Shoreline Analysis System (DSAS) extension tool in ArcGIS platform to study and analyse the shoreline dynamics of Sagar Island by utilizing satellite images extending 40 years (1975–2015). 44 transects with 100 m spacing were laid and divided into six littoral cells (LCs). End Point Rate (EPR) and Linear Regression (LR) models were utilized to analyze the shoreline change patterns and also for predicting the future shoreline positions. It was observed that almost the entire southern portion of Sagar Island is susceptible to high rate of shoreline erosion. Most of the erosion occurred in Dhablat (LC 4 (a)) in the south eastern part at a rate of 11.695 ± 2.1 m/year. The mean shoreline change rate was also high in LC5 (±23.525 m/year). However, the overall shoreline change rate for the island was 4.94 m/year and uncertainty of total shoreline change rate was ±4.4 m/year. The study shows the usefulness of DSAS as a scientific tool for shoreline change studies and highlights state of erosion in the study area.

Spatio-temporal Coastal Morphological Changes of Godavari Delta Region in the East Coast of India

Murali, R.M.; Reshma, K.N.; Kumar, S.S.; Balaji, S.A.; Raju, D.M.K., and Ramakrishnan, R., 2020. Spatio-temporal coastal morphological changes of Godavari delta region in the east coast of India. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 626–631. Coconut Creek (Florida), ISSN 0749-0208.Understanding the characteristics of coastal morphology is necessary to analyse the causes of its changes and its consequences. The present study focuses on the satellite-derived and in-situ measurement based changes along the Godavari delta region to estimate the changes of the geomorphologic units. Three years (2017 – 2019) of seasonal observations along the coast of Godavari delta with fifteen beach profiling stations were carried out to estimate the volumetric changes along this coast. Out of these 15 transects, three stations, S2(i), S6(i), and S6(iv), experienced dynamic changes. The station at Odalarevu [S6(ii)], near Vainateyam river mouth, has undergone severe erosion, indicating an overall shoreline change of 670 m. The changes near this river mouth eventually eroded the nearby two stations by 25m3/m and 11m3/m in volume, respectively. Similarly, Chirra Yanam [S2(i)] showed a gradual accretion of 46m3/m in the same period. Shoreline change study from 1973-2019 using satellite images show erosion of 300 m near Vainateyam river mouth, 140m in the intermediate station, and 50 m in Odalarevu beach. An erosion of 70m is also noted in Chirra Yanam. These results are attributed to the combination of anthropogenic and the response of this delta region for the regional and global processes. The combination of in-situ and satellite observation gives a better insight into the quantitative estimate of morphological changes and their response behavior.

Documenting a Century of Coastline Change along Central California and Associated Challenges: From the Qualitative to the Quantitative

Wave erosion has moved coastal cliffs and bluffs landward over the centuries. Now climate change-induced sea-level rise (SLR) and the changes in wave action are accelerating coastline retreat around the world. Documenting the erosion of cliffed coasts and projecting the rate of coastline retreat under future SLR scenarios are more challenging than historical and future shoreline change studies along low-lying sandy beaches. The objective of this research was to study coastal erosion of the West Cliff Drive area in Santa Cruz along the Central California Coast and identify the challenges in coastline change analysis. We investigated the geological history, geomorphic differences, and documented cliff retreat to assess coastal erosion qualitatively. We also conducted a quantitative assessment of cliff retreat through extracting and analyzing the coastline position at three different times (1953, 1975, and 2018). The results showed that the total retreat of the West Cliff Drive coastline over 65 years ranges from 0.3 to 32 m, and the maximum cliff retreat rate was 0.5 m/year. Geometric errors, the complex profiles of coastal cliffs, and irregularities in the processes of coastal erosion, including the undercutting of the base of the cliff and formation of caves, were some of the identified challenges in documenting historical coastline retreat. These can each increase the uncertainty of calculated retreat rates. Reducing the uncertainties in retreat rates is an essential initial step in projecting cliff and bluff retreat under future SLR more accurately and in developing a practical adaptive management plan to cope with the impacts of coastline change along this highly populated edge.

PHÂN TÍCH VÀ ĐÁNH GIÁ QUÁ TRÌNH XÓI LỞ VÀ BỒI TỤ Ở KHU VỰC CỬA SÔNG ĐỒNG TRANH - CẦN GIỜ (TP.HCM)

Study site is a part of Can Gio mangrove biosphere reserve in Can Gio district, Ho Chi Minh City. At present, this area is eroded strongly due to the effects of hydrodynamic impact. Based on the field measurements of coastal profile and shoreline changes from 2013 to 2017 and combination of remote sensing method and GENESIS model, the erosion and deposition processes in 5 years are evaluated and analyzed. The results show that the study site keeps eroding over time and trend to continue in the future. Moreover the study also shows that the erosion rate in the northeast monsoon is higher than that in the southwest monsoon. These results are very important in contribution to shoreline change studies.

Resolution and scale controls on the accuracy of atoll island shorelines interpreted from satellite imagery

Understanding the positional uncertainty of vector objects within a GIS has been widely discussed and a range of approaches have been applied to quantify the uncertainty of such objects. Recently, a number of studies have adopted remote sensing approaches to examine the erosion of low-lying atoll islands. These studies are underpinned by a comparison of shoreline positions interpreted from remote imagery and represented as line features, and/or island areas represented as polygons. However, the effects of image resolution and scale of interpretation have rarely been considered when examining the results of such studies. In order to examine the control of image resolution and scale of interpretation on the accuracy of shoreline positions, repeated digitisation of islands was undertaken under a range of conditions similar to those applied in an operational setting. High-resolution (40 cm) satellite imagery was resampled to coarser resolutions and islands repeatedly digitised at a range of scales. Results quantify seemingly intuitive relationships, whereby shorelines digitised from coarse imagery and at small scales are less accurate than those digitised from high-resolution imagery at large scales. Results of this study provide a useful guide for selecting imagery for shoreline change studies and understanding the positional uncertainty of vector objects within a GIS.

Geospatial Technology Based Shoreline Change Studies In Parts of Cuddalore District, Tamilnadu, India

Geospatial Technology Based Shoreline Change Studies In Parts of Cuddalore District, Tamilnadu, India

Appraisal of long-term shoreline oscillations from a part of coastal zones of Sundarban delta, Eastern India: a study based on geospatial technology

This study aims to analyze the long-term shoreline oscillations and its impact on coastal environment from a part of coastal zone of Sundarban delta over the last four decades. The present study was executed using four multi-temporal Landsat images during different dates. Automatic shoreline extraction model was developed in ERDAS Imagine software to identify the shorelines from satellite images. Digital shoreline analysis system was employed for estimation of shoreline change rate. Shoreline change analysis (erosion and accretion) study has been carried out by developing a model in ArcGIS model development tool. Transect wise shoreline change study revealed that about two third of the total transects exhibits erosion and about one third of the total transects exhibits accretion. The results of average shoreline change rate during different periods show the negative change. This study provides substantial information on the nature of shoreline changes which would assist in proper planning and management.

Extraction of shoreline changes in Selangor coastal area using GIS and remote sensing techniques

Nowadays, coastal zones are facing shoreline changes that stemming from natural and anthropogenic effect. The process of erosion and accretion will affect the physical environment of the shoreline. Therefore, the study of shoreline changes is important to identify the patterns of changes over time. The rapid growth of technology nowadays has facilitated the study of shoreline changes. Geographical Information System (GIS) alongside Remote Sensing (RS) technology is a useful tool to study these changes due to its ability to generate information, monitoring, analysis and prediction of the shoreline changes. Hence, the future projection of the trend for a specific coastal area can be done effectively. This study investigates the impact of shoreline changes to the community in Selangor area which mainly focus on the physical aspects. This study presents preliminary result using satellite image from SPOT 5 to identify the shoreline changes from the year 1984 to 2013 at Selangor coastal area. Extraction of shoreline from satellite image is vital to analyze the erosion and accretion along the shoreline area. This study shows that a shoreline change for the whole area is a categorized as a medium case. The total eroded and accretion of Selangor area from 1984 to 2013 is 2558 hectares and 2583 hectares respectively. As a result, Kapar, Jugra, Telok Panglima Garang and Kelanang are categorized as high risk erosion area. Shoreline changes analysis provides essential information to determine on the shoreline changes trends. Therefore, the results of this study can be used as essential information for conservation and preservation of coastal zone management.

Shoreline Change Studies Due to Construction of Breakwaters at Ariyankuppam River Mouth in Puducherry – a Union Territory of India, South India

Objectives: In the present investigation, the shoreline change studies were carried out along the Pudhuchery coast using an online model such as DHI-LITPACK modules suite. Methods/Statistical Analysis: The study area covers 5 km on the southern side and 10 km on the northern side of the Ariyankuppam river port breakwaters. One year measured data off Puducherry coast at 15 m water depth was used for the estimation of littoral drift and to predict the shoreline changes along the Puducherry coast. The predicted shoreline changes using one-line model show good agreement with historical shoreline changes along the Puducherry coast. Findings: The shoreline change studies with existing coastal structures shows that, on the seawall northern end, the shoreline experiences erosion up to 10m, 20m, 35m, 45m, 55m and 60m after a period of 1, 2, 5, 10, 15 and 20 years respectively and the erosion is noticed for a distance of 1400m along the coast. The shoreline changes study with sand bypassing the net annual littoral sediment of 0.13 x106 m3 from the southern side of the south port breakwater to the northern side of the north breakwater show that shoreline erosion is limited to 20 m and extends 500 m along the coast on the northern end of the seawall. In order to avoid shoreline erosion along the Puducherry coast, the initially implemented sand bypassing operation with beach nourishment has to be carried out with the sand bypassing volume of 0.13 x106 m3 per year at the rate of 0.0188 x 106 m3 per month from March to September. Application/Improvements: After monitoring shoreline behavior with sand bypassing operation for few years, a long term arrangement can be worked out. Moreover, the study indicates that the DHI-LITPACK modules are suitable tools for the estimation of littoral drift and shoreline change studies.

Shoreline change rate and erosion risk assessment along the Trou Aux Biches–Mont Choisy beach on the northwest coast of Mauritius using GIS-DSAS technique

The present study investigates the rate of shoreline change and erosion risk along the Trou aux Biches–Mont Choisy beach in the northwest coast of Mauritius using digital shoreline analysis system (DSAS). In this analysis, the long-term shoreline change rate and coastal erosion and accretion pattern are estimated along the coastal stretch using multi-temporal aerial photographs and high resolution satellite images for the past 45 years (1967–2012). The shoreline change rate and erosion/accretion pattern at each transects are estimated by five statistical parameters functionalized in DSAS 4.5 software such as end point rate (EPR), shoreline change envelop (SCE), net shoreline movement (NSM), linear regression rate (LRR), and least median of squares (LMS). The measurement of shoreline change rate and coastal erosion and accretion pattern has been described for three segments namely (1) North–North–West (NNW) to South–South–East (SSE); (2) North–East (NE) to South–West (SW); (3) North–North–East (NNE) to South–South–West (SSW) based on the coastal configuration. The analysis reveals that the severe erosion risk (−1.75 to −0.03 m/year) was noticed between transects 41 and 61 in NE–SW segments and moderate erosion risk (−1.09 to −0.18 m/year) between transects 62 and 95 of the NNE–SSW segments. The NNW–SSE segment shows low erosion risk with an EPR value of −0.55 to −0.05 m/year. The values of shoreline change rate of these transects indicate the occurrence of severe erosion along the coastal area over the periods of 1967–2012. However, the coastal segment in NNW–SSE configuration faces least erosion rate and the protective coral reefs reduce the wave energy action which leads to the formation of sustainable coast in the area. Moreover, poor set back and management activities with reference to high energetic waves, storm surge and cyclonic conditions produce direct impacts on the coastal morphology and degradation of coral reef ecosystem. The shoreline change studies through integrated remote sensing and GIS technology is considered of paramount importance for accurately focusing on planning, management and coastal intervention in long-term purpose.

Shoreline Change Monitoring in Nellore Coast at East Coast Andhra Pradesh District Using Remote Sensing and GIS

The shoreline is one of the most important features on earth’s surface. They are highly dynamic and ever changing. Changes are over time scales including minutes, hours, decades and Centuries. Spatial scales vary from local to regional to worldwide. Although change is continuously occurring, it doesn’t occur in a constant manner. Many factors influence these changes including the type of shoreline (rocky, sandy), wave activity, tidal variations, storms and human impacts. The shoreline change study is necessary for updating the shoreline change maps and management of natural resources. Shorelines are the key element in coastal GIS and provide the most information on coastal landform dynamics. The frequently monitoring coast only to accesses variation of shoreline changes. In this paper investigate the shoreline changes of Nellore district in Andhra Pradesh coast, as well as find the quantity of the erosion and accretion rate. Using multi-temporal resolution satellite data (TM & LISS III, IV) and Geographic information system (GIS) for past 25 years period i.e., from 1989 to 2015. Nellore having length of coast line is 167 km for this study used. The resultant coastal maps were used to estimate the geomorphologic changes and shifting of the shoreline position. This integrated study is found useful for exploring accretion and erosion processes in the region. About 87.6 km of coastline was found to be accreting nature with average of +1.40 m/yr followed by 38.4 km of coastal line eroding with average of -1.36 m/yr and stable coastline of 41.4 km was found. This study demonstrates that combined use of satellite imagery and statistical method such as linear regression for shoreline change analysis are helpful for erosion monitoring and preventive measure.