scholarly journals Analysis of shoreline changes along the coast of Tiruvallur district, Tamil Nadu, India

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
K. Jayakumar

Shoreline change is considered as one of the most dynamic process, which was mapped along the coast of Tiruvallur district by using topographic maps of 1976 and multi-temporal satellite images. The satellite images were pertaining to 1988, 1991, 2006, 2010, 2013 and 2016 which were used to extract the shorelines. It is important to map and monitor the HTL (High Tide line) at frequent time interval as it considered as shoreline, which was demarcated by using visual interpretation technique from satellite images and topographic maps. Followed by this, an overlay analysis was performed to calculate areas of erosion and accretion in the study area. The results revealed that the coast of Tiruvallur district lost 603 ha and gained 630 ha due to erosion and accretion respectively. It was confirmed after the ground truth survey carried out in the study area. The high accretion of 178 ha was found nearby Pulicat Lake and low accretion of 19 ha seen between Pulicat lake to Kattupali port. The high erosion area was found along the Pulicat lake, Kattupali and Ennore ports, and Ennore creek mouth and south of Ennore such as Periya Kuppam, Chinna Kuppam, Kasi Koil Kuppam, and Thyagarajapuram. It may be concluded that the main causes of coastal erosion and accretion in the study area are anthropogenic and natural factors, which alter the coastal environment. 

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
K. Jayakumar

Shore line change is considered as one of the most dynamic processes, which were mapped along the coast of Tiruvallur district by using topographic maps of 1976 and multi-temporal satellite images. The satellite images pertaining to 1988, 1991, 2006, 2010, 2013 and 2016 were used to extract the shorelines. It is important to map and monitor the HTL (High Tide Line) at frequent time intervals as the shoreline was demarcated by using visual interpretation technique from satellite images and topographic maps. Followed by this, an overlay analysis was performed to calculate areas of erosion and accretion in the study area. The results revealed that the coast of Tiruvallur district lost 603 ha and gained 630 ha due to erosion and accretion respectively. It was confirmed after the ground truth survey carried out in the study area. The high accretion of 178 ha was found nearby Pulicat Lake and low accretion of 19 ha was seen between Pulicat Lake and Kattupali Port. The high erosion area was found along the Pulicat Lake, Kattupali and Ennore ports, and Ennore creek mouth and southern Ennore such as Periya Kuppam, Chinna Kuppam, Kasi Koil Kuppam, and Thyagarajapuram. It may be concluded that the coastal erosion and accretion in the study area were mainly caused by anthropogenic and natural factors, which altered the coastal environment.


Author(s):  
B. Santhosh Kumar ◽  
A. Balukkarasu ◽  
K. Tamilarasan

The southern part of the Indian peninsula of Tamil Nadu coast is potentially more vulnerable to hazards. This research aims to classify the coastal vulnerable zones of the Tuticorin, Tamil Nadu using Coastal Vulnerability Index (CVI). The multi-spectral satellite data of Landsat series was used for shoreline change analysis from 1978 to 2017. The Digital Shoreline Analysis System (DSAS) software extension was used to calculate the shoreline rate-of-change statistics from multiple historic shoreline positions developed by the United States Geological Survey. The study reveals significant erosion and accretion demarcated based on DSAS computed values along the coastal stretch. The six physical variables characterizing the vulnerability of the coast, including the geomorphology, shoreline change rate (m/yr), coastal slope (deg), relative sea-level change (mm/yr), mean wave height (m) and mean tide range (m). The geomorphology map was created using Landsat OLI satellite data in 1: 50,000 scale. The Shoreline change rate was calculated using temporal satellite data. Based on the CVI value, low vulnerable to very high vulnerable areas were identified. Besides, Vembar, Periyasamypuram, Vaippar, Kallurni, Pattanamarudur areas were identified in erosion. The Muttayyapuram coast has accretion by the consequence of sediment transport from the Thamiraparani estuary. The coastal zones are highly fragile for dynamic nature and resource. The sources of anthropogenic and natural processes are accelerating the erosion and accretion along the coast. Hence the vulnerability map prepared for the southeast coast of India and it can be most helpful for stakeholders and future coastal disaster mitigation and management.


Earth ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 544-555
Author(s):  
Ibra Lebbe Mohamed Zahir ◽  
Buddhika Madurapperuma ◽  
Atham Lebbe Iyoob ◽  
Kafoor Nijamir

Detecting coastal morphodynamics is a crucial task for monitoring shoreline changes and coastal zone management. However, modern technology viz., Geoinformatics paves the way for long-term monitoring and observation with precise output. Therefore, this study aimed to produce explicit shoreline change maps and analyze the historical changes of the coastline at the east coast of the Ampara District in Sri Lanka. The histogram threshold method is used to extract data from satellite images. The time-series satellite images, acquired from 1987 to 2017, toposheet, and Google Earth historical images were compared having adjusted with the ground-truth to find the seashore changes in the study area. The histogram threshold method is used on band 5 (mid-infrared) for separating land from water pixels which means that the water pixel values were classified to one (1) and land pixel values to zero (0). The extracted shoreline vectors were associated with each other to determine the dynamics of changing shoreline of the study area. The Digital Shoreline Analysis System (DSAS) was used to find shoreline movements for each period of time. As a result, it was observed by the cross-section analysis within 100 m shoreline—seaward range along the study area—in which severe erosion has occurred northward of the Oluvil Harbor and anomalous accretion southward of the harbor because of the breakwaters constructed in the port entrance which hinder the long shore sediment transport along the study area. This situation has resulted in many ramifications to the coastal zone of the study area in socio-economic and environmental aspects in which the coastal protection mechanisms have not been well implemented to curb such issues.


2021 ◽  
Vol 13 (8) ◽  
pp. 1505
Author(s):  
Klaudia Kryniecka ◽  
Artur Magnuszewski

The lower Vistula River was regulated in the years 1856–1878, at a distance of 718–939 km. The regulation plan did not take into consideration the large transport of the bed load. The channel was shaped using simplified geometry—too wide for the low flow and overly straight for the stabilization of the sandbar movement. The hydraulic parameters of the lower Vistula River show high velocities of flow and high shear stress. The movement of the alternate sandbars can be traced on the optical satellite images of Sentinel-2. In this study, a method of sandbar detection through the remote sensing indices, Sentinel Water Mask (SWM) and Automated Water Extraction Index no shadow (AWEInsh), and the manual delineation with visual interpretation (MD) was used on satellite images of the lower Vistula River, recorded at the time of low flows (20 August 2015, 4 September 2016, 30 July 2017, 20 September 2018, and 29 August 2019). The comparison of 32 alternate sandbar areas obtained by SWM, AWEInsh, and MD manual delineation methods on the Sentinel-2 images, recorded on 20 August 2015, was performed by the statistical analysis of the interclass correlation coefficient (ICC). The distance of the shift in the analyzed time intervals between the image registration dates depends on the value of the mean discharge (MQ). The period from 30 July 2017 to 20 September 2018 was wet (MQ = 1140 m3 × s−1) and created conditions for the largest average distance of the alternate sandbar shift, from 509 to 548 m. The velocity of movement, calculated as an average shift for one day, was between 1.2 and 1.3 m × day−1. The smallest shift of alternate sandbars was characteristic of the low flow period from 20 August 2015 to 4 September 2016 (MQ = 306 m3 × s−1), from 279 to 310 m, with an average velocity from 0.7 to 0.8 m × day−1.


2021 ◽  
Author(s):  
Lisa Baron

In 2018 and 2019 the Southeast Coast Network (SECN), with assistance from park staff, collected long-term shoreline monitoring data at Cape Hatteras National Seashore as part of the National Park Service (NPS) Vital Signs Monitoring Program. Monitoring was conducted following methods developed by the NPS Northeast Coastal and Barrier Network and consisted of mapping the high-tide swash line using a Global Positioning System unit in the spring of each year (Psuty et al. 2010). Shoreline change was calculated using the Digital Shoreline Analysis System (DSAS) developed by the United States Geological Survey (USGS; Himmelstoss et al. 2018). Following the same field methods used for monitoring long-term shoreline change, geospatial data were collected as part of the Hurricane Dorian (or Dorian) Incident Response from September 12–16, 2019. This report summarizes the post-Dorian data and the previous two shoreline data collection efforts (spring 2019 and fall 2018).


2018 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Shimona Kealy ◽  
Lucas Wattimena ◽  
Sue O'Connor

Survei arkeologi sangat penting untuk penemuan dan interpretasi sisa-sisa yang ditinggalkan oleh aktivitas manusia prasejarah. Saat ini penginderaan jarak jauh dan model prediktif telah meningkatkan jangkauan dan keberhasilan survei arkeologi, namun survei pejalan kaki untuk mengembangkan parameter model dan prediksi kebenaran dasar masih penting untuk keberhasilan suatu penemuan. Penelitian ini merupakan hasil survei arkeologi tahun 2017 di Pulau Babar Besar dan Pulau Wetang yang termasuk dalam bagian dari kelompok Kepulauan Babar, Maluku Barat Daya, Indonesia. Tercatat sebanyak 62 situs arkeologi ditemukan di kedua pulau tersebut, tujuh diantaranya merupakan situs lukisan cadas baru yang ditemukan di Pulau Wetang. Hasil survei ini menunjukkan keberhasilan penggunaan peta geologi dan topografi di samping citra satelit dalam mendeteksi daerah prospektif untuk survei. Hasil penelitian ini juga menunjukkan bahwa pemahaman karakteristik geologi daerah yang lebih rinci dan komparatif diperlukan sebelum dilakukan survei jarak jauh yang lebih lanjut di wilayah Maluku Barat Daya, Indonesia.Archaeological surveys are essential to the discovery and interpretation of remains left by past human activities. While remote sensing and predictive models have greatly improved the reach and success of archaeological survey, pedestrian surveys to develop model parameters and ground-truth predictions is still imperative for successful discoveries. Here we present the results of the 2017 archaeological survey of islands Babar Besar and Wetang in the Babar Island Group, Maluku Barat Daya, Indonesia. A total of 62 archaeological sites were recorded between the two islands; seven of which represent new rock art sites on Wetang island. Our survey results indicate the successful use of geological and topographic maps alongside satellite images in detecting prospective regions for survey. Results also indicate however that a more detailed and comparative understanding of the regions geology is required before more advanced forms of remote survey are conducted in the Maluku Barat Daya region.


2021 ◽  
pp. 151-170
Author(s):  
Keval Jodhani ◽  
Pulkit Bansal ◽  
Priyadarshna Jain

2019 ◽  
Vol 9 (20) ◽  
pp. 4466 ◽  
Author(s):  
Min Zhou ◽  
Mengquan Wu ◽  
Guangzong Zhang ◽  
Lianjie Zhao ◽  
Xiaoyun Hou ◽  
...  

Using remote sensing images of different time phases from 1990 to 2018, the surface coverage information of northern Yantai (coastline, 2 km from coastline to land) was extracted by means of average high tide line and visual interpretation. The end point change rate (EPR) and linear regression rate were used to study the coastline change rate, the fractal dimension of the coastline in the study area was analyzed, and the change of the type of coastal surface cover was analyzed by the transition matrix. The results show that: (1) Form 1990 to 2018, a significant trend of a continuous increase in the total length of coastline was observed with an increase of 181.08 km (43.18%). In the study area, the coastline of Laizhou had the greatest change rate with an EPR value of 33.67 m/a, whereas the coastline of Laishan had the smallest change rate with an EPR value of 0.30 m/a. (2) Over the past 30 years, with the rapid economic development of Yantai and the ensuant urbanization, the total surface area of the coastal zone in the study area has increased by 144.94 km2, mainly in the areas covered by structures and forests/grasses, by 112.96 km2 and 96.08 km2, respectively, while the areas of desert/bare land and water have decreased by 92.26 km2 and 12.32 km2, respectively. (3) The changes among different types in the study area were clear, mainly from desert/bare land, cultivated land, and building areas to forests/grasses cover and structures. The change areas were mainly concentrated in Laizhou, Longkou, Zhifu, and Penglai. Frequent human activities are an important factor affecting the continuous expansion of the coastal areas of Jiaodong Peninsula to the sea. Aquaculture, coastal construction, construction of artificial islands, and expansion of port terminals have seriously affected the sustainability of ecological resources in the coastal areas. At the same time, the changes in the ecological environment in the coastal zone will have a greater impact on the health of the coastal zone.


2019 ◽  
Vol 7 (6) ◽  
pp. 172 ◽  
Author(s):  
Evelien Brand ◽  
Lars De Sloover ◽  
Alain De Wulf ◽  
Anne-Lise Montreuil ◽  
Sander Vos ◽  
...  

Sediment transport is a key element in intertidal beach morphodynamics, but measurements of sediment transport are often unreliable. The aim of this study is to quantify and investigate cross-shore sediment transport and the resulting topographic changes for a tide-dominated, sandy beach. Two fortnight-long field experiments were carried out during which hydrodynamics and sediment dynamics were measured with optical and acoustic sensors, while the beach topography was surveyed with a permanent terrestrial laser scanner. Suspended sediment was generally well-mixed and currents were largest at approximately 1.5 m above the bed, which resulted in a peak in sediment transport at 1/3 of the high tide level. The mean transport direction was onshore during calm conditions (wave height <0.6 m) thanks to tidal currents and offshore during energetic conditions due to undertow. Oscillatory transport was always onshore because of wave asymmetry but it was subordinate to mean transport. The intertidal zone showed an alternation of erosion and accretion with formation of morphological features during energetic (no storm) conditionsand smoothening of the morphology during calm conditions. A good qualitative and quantitative agreement was found between the daily cross-shore suspended load and beach volume changes, especially during calm conditions.


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