N. Chandrasekar

Coastal erosion hazard and vulnerability assessment for southern coastal Tamil Nadu of India by using remote sensing and GIS

Coastal hazards in many areas of the world are increasing as a result of rapid changes in various geological and physical variables driven by dynamic coastal processes. Development activities, global warming, climate change and sea-level rise not only introduce any new types of coastal hazards, but they also affect the existing hazards. The southern coastal Tamil Nadu of India faces severe threat due to rapid changes in geology and geomorphology, sea-level change, tropical cyclones and associated storm surges. In this present work, erosion hazard and vulnerability level along the southern coastal Tamil Nadu have been assessed using remote sensing and GIS. The erosion and accretion made in different parts of the study area have been measured and analysed. The coastal vulnerability index (CVI) has been used to map the relative vulnerability along the study area. The CVI ranks both geological and physical variables in terms of their physical contribution to sea-level rise and vulnerability. The data within the coastal vulnerability index show significant variability at different spatial scales. The vulnerability is caused by a complex interaction of various natural and human-induced coastal processes. The natural processes due to geology and geomorphology, the combined action of waves and currents, variations in sea level, tectonics and storms affect the vulnerability. The human activities include manipulation of hydrological cycles through construction of buildings along beaches, coastal structures such as harbours, beach protecting structures and jetties, mining of beach sand, destruction of protective dune systems. Thus, the present study clearly focuses on the vulnerability and risk parameters along the study area. It is also recommended that proper coastal management plans, beach filling and nourishment projects should be made to save the coastal area from severe erosion threat and hazards.

Grain Size Analysis and Depositional Environment Condition along the Beaches between Ovari and Kanyakumari, Southern Tamilnadu Coast, India

Textural analysis is the epicenter of any sedimentological research. Granulometric analyses of unconsolidated sediments are used as an index to decipher the depositional environment. The granulometric analysis display a significant fluctuation in mean size, sorting, skewness, and kurtosis due to the variation in wave energy and the extent of turbulence affecting the beach environment during the crosshore and alongshore movement of sediments. The present study is to document the variation in grain size distribution within foreshore sediments, i.e., between the high water line and the plunge point wherein the sediments are deposited under different wave energy conditions.

Correlation between coastal geomorphology and tsunami inundation along the coast of Kanyakumari, India

An investigation has been carried out in the vicinity of the coastal villages of Kanyakumari District, India to decode the influence of coastal geomorphology on inundation degree and run-up level. Even though the tsunami waves approach the study area in different patterns, the consequences are found to be mainly dependent upon the coastal configuration and local geographic setting, the study area are considered to be of three types based upon the geomorphic arrangement, namely shallow coast, elevated coast and estuarine coast. The inundation and run-up level vary from coast to coast even though there is no remarkable variation in the intensity of the approaching tsunami surge. The inundation extent ranges from to 54 m to 413 m with maximum along estuarine coast and minimum along elevated coast. Estuarine coast recorded the maximum run-up level of about 6 m and the minimum of about 1 m along the elevated coast. The percentage of inundated area in the total coastal area varies between 19% to 10% along estuarine coast and elevated coast respectively. Inundation and run-up level cannot be appreciable in the inland along the elevated coast. The beaches of elevated coast are less affected whereas those of estuarine coast are highly affected. Inundation is limited in the elevated beaches along the study area.

Geospatial Application in the Study of Beach Placer along the Coast of Gulf of Mannar, India

Abstract Geospatial analysis of marine mineral placer deposits along the Gulf of Mannar is attempted. This study develops a method for the spatial anlaysis of data using geographical information system (GIS). Specifically, creating attribute data base structure, data encoding, data interpolation, and view shed analysis are attempted to delineate the opaque and garnet occurrences in the beach sediments. Data integration including the creation of digital files using TNT Mips software is performed. The interpolation of the spaced data is achieved by inverse distance weighed interpolation to define the zone of heavy mineral enrichment. This study has established the digital elevation model (DEM) capability to identify the potential beach placer zones in the study area.

ONWET: A Simple Integrated Tool for Beach Morphology and Wave Dynamics Analysis

The analysis of beach profile combined with wave data provides a clear understanding of beach topography and physical behavior of the coast. Numerous commercial and noncommercial computer programs and add-on tools are available to analyze beach profile and wave data. But, most of them are specifically designed for particular coastal application. Moreover, searching of open source software for diverse coastal application is a tedious process. To make it easily accessible, we have developed an integrated Matlab GUI for beach morphology and wave analysis. The tool “ONWET (OceaN WavE Tool)” mainly includes wave processes, beach morphology, spatiotemporal variation in beach profile, wave refraction, and sediment transport rate. The tool has automated inbuilt functions and is designed to accommodate importing/exporting of data (results both in data and graphical format). It includes user friendly options and can be freely download from our institutional website. The tool is very useful for researchers, scientists, engineers, and environmentalists who are working in the field of coastal studies and beach nourishment.

Dynamics of coastal landform features along the southern Tamil Nadu of India by using remote sensing and Geographic Information System

This article reveals an application of multi-spectral satellite data for analysing the dynamics of different coastal landform features along the southern coastal Tamil Nadu of India. An integrated approach comprising visual image interpretation and maximum-likelihood supervised classification has been employed to classify the coastal landforms by using IRS data (during the period 1999–2006). The quality of image classification has been assessed by performing the accuracy assessments with the existing thematic maps and finally the coastal landforms have been mapped. The study reveals that the dynamics of coastal landforms such as sandy beaches, mud-flats, sand dunes and salt marshes along the study area are mostly influenced by the coastal processes, sediment transport, geomorphology and anthropogenic activities. Major anthropogenic sources for the perturbation of beach sediment budgets and a cause of beach erosion along the study area are excessive sand mining, removal of sand dunes, coastal urbanization, tourism and developmental activities.

Features Sustaining the Formation of Beach Placers along the Southern East Coast of India

Beaches between the Kallar and Vembar River mouths on the southeast coast of India are rich in placer mineral deposits. Beach sediments were sampled along this 25-km shoreline and were analyzed to determine the density sorting patterns in order to understand the process of beach placer formation. Determinations of individual placer minerals reveal that the density variations reflect the sorting process and were most effective in concentrating ilmenite, garnet and zircon, while the concentrations of quartz were reduced. This pattern of sorting reflects the density and grain size variations of the minerals present in the beach. Density sorting plays a very crucial role in the concentration of placer minerals in this region. The economically viable heavy mineral deposits are governed by the presence of the source rock being in close proximity, the existing drainage pattern, topography, climate, and coastal processes. These factors permit the identification of regions where the formation of placer deposits is favored.

Management of Coastal Erosion Using Remote Sensing and GIS Techniques (SE India)

World wide, coastal erosion is recognized as a great threat for beach environment. Total control of coastal erosion is not feasible but it should not be ignored and needs timely management. Erosional activities have been significantly noticed along the coastal tract of Vembar and Kallar (Kallurani), South India. An attempt has been made here to delineate different zones based on their sand budget and erosion rate. Linear Imaging Self Scanning Sensor (LISS) III 2001 and Linear Imaging Self Scanning Sensor III and PAN merged data of the year 2001 have been utilized to identify the coastal geomorphological features, shoreline changes and river course changes. A Geographic Information System (GIS) software namely ArcGIS (9.1) has been used as a tool to delineate the coastal erosion hazard for proper planning and management of coastal developments. Beach profile studies have shown significant variation in the beach morphology. The study area has been categorized into five different zones in the GIS analysis based on the degree of coastal erosion and sediment dynamics namely (i) very high - Kalaignanapuram, (ii) high - Sippikulam (iii) medium - Periyasamypuram (iv) low - Vembar and Kallar (Kallurani) (v) very low - Pachayapuram.

Management and development of coastal and marine areas along the Indian coast

The marine environment of India, which includes the adjacent coastal areas, supports productive and prospective habitats such as mangroves, coral reefs, and sand dunes. The main challenge facing the sustainable use of coastal and marine areas is the loss of natural habitat and biodiversity, and consequently the loss of opportunity of exploiting renewable living resources. The marine environment is facing extreme pressure due to the growing needs of people and the multi-use that coastal and marine areas are put to. These pressures contribute to the depletion of marine resources and degradation of the marine environment. This paper briefly discusses the sustainable development of coastal zone including islands and the unsustainable anthropogenic activities that enhance the vulnerability of the coastline. In the absence of integrated coastal and marine management, our coasts may witness severe stress in the near future.

Marine mineral policy considerations for India’s exclusive economic zone

In general, for any country, the national marine mineral resource policy deals with all aspects of marine resource research, exploration, development, or exploitation. Because of the pioneering nature of marine mineral resource activities, it is imperative that nations put in place the basic structure of a national marine mineral resource policy that will ensure that all activities are conducted in such a way so as to maintain national sovereignty, self-sufficiency, and self-determination while promoting the development of the valuable resources of their EEZ (exclusive economic zone). The keystone of any national policy will be to optimize the economic returns from a marine mineral mining enterprise, both for the nation and the investor, within the constraints of such a pioneering activity. A critical consideration for many countries would be to balance national and international deep ocean research in EEZ with the interests of economic development by the private sector.