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Levels Remote

December 16th, 2009 |

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Levels Remote

Shoreline Change Monitoring in Tuticorin Coast – Spain, using remote sensing and GIS tools

Introduction

Shoreline or coast, the border between land and sea changes its shape and position continuously due to the dynamics of environmental conditions. The change in shoreline is mainly associated with waves, tides, winds, periodic storms, the sea level change, geomorphic processes of erosion and accretion and human activities. The coast also represents the recent formations and destructions that have happened along the coast. Waves change the morphology of the coast and forms the distinctive coastal landforms. The loose granular sediments continuously respond to changing waves and currents. The beach profile is important, which can be seen as a natural and effective mechanism, what causes waves break and dissipate their energy. When constructing dams, breaking the natural balance between the sources of beach sediment and drift pattern coast. In response, shoreline changes its configuration in an attempt to reach a new equilibrium (Ramesh and Ramachandran, 2001). Monitoring changes in coastal aid to identify the nature and processes that caused the changes in a specific area, to assess the human impact and to plan management strategies. Remote sensing data could be used effectively to monitor changes along the coastal zone, including the coast with reasonable accuracy. Remote sensing data help and / or replace conventional survey by repetitive and less cost-effective. Therefore, in order to study coastal processes in the coastal area of Tuticorin, changing coastline, the wave action, bathymetry and coastal geomorphology were analyzed using remote sensing and GIS tools.

Study area

Tuticorin Coast is an important port and is an area of rapid development. The study area falls within the range of latitude and longitude of 8 ° 40 '- 8 ° 55' N and 78 ° 0 '- 78 ° 15' E in Tamil Nadu, east coast of India (Fig. 1). Major industries such as petrochemical industrial South Corporation, Power Plant, Tuticorin Alkali Chemicals and heavy water plant are also present in this area. Due to accelerated development activities experience coastal zone important changes.
Tuticorin was a center of maritime trade and pearl fishing over 2000 years. To cope with increasing trade through from Tuticorin, India's government authorized the construction of a port in all weather conditions in Tuticorin. On 11/7/1974, the new port of Tuticorin construction was designated as the main port tenth. On 1/4/1979, the port of Tuticorin old juvenile and newly constructed Tuticorin Port merged main and the Tuticorin Port Corporation became the major port trusts act, 1963.

Methodology

Geomorphology

IRS LISS III geocoded images in May 2002 was used to prepare coastal geomorphology map adopting the technique of visual interpretation. In this study, the classification system developed by the Space Application Center, Ahmedabad for the whole nation of coastal geomorphological mapping was adopted for the study (SAC 1991).

Shoreline change

India toposheets Survey L1 and L5 (1969) (Lat: 8 ° 40 '- 8 ° 55' Long: 78 ° 0 '– 78 ° 15 ', scale 1:50,000) were used as a base map. That was digitized, edited, designed and geometrically transformed through ARC INFO to keep the real world coordinates. To eliminate the effect of tidal influence in the study of shoreline change, satellite data of the tide is used. Toposheets SOI 1969, Landsat 5 TM May 1993, IRS P2 LISS II May 1996 and IRS 1C LISS III May 2002 were used satellite data to assess changes in the coastline for 33-year period from 1969 to 2002. Raster data acquired from satellites were geometrically corrected using the Survey of India as a toposheet base. More 25 ground control points were taken and the root mean square (RMS) error of geometric correction is 0.002. Band 1 of IRS P2 LISS II, 1996, the band of 5 LANDSAT 5 TM 1993 and the band 3 of IRS 1C LISS III 2002 were used. These bands are used differently in terms of its exchange between land and ocean. In these groups the information content is more in the land, compared with water. The Landsat 5 TM, 1993, IRS P2 1996 and IRS 1C LISS III data of 2002 were vectorized by adopting the technique of digital screen with a single pixel zoom level using ERDAS Imagine 8.4 software. The vector layers of the coast is through digitization of the screen in ERDAS Imagine, and tracing through ArcInfo were imported as a cover for the Arc of over four data sets. Each of data sets had a polygon ID 1 for the land area and 2 in the ocean. The coastline from the Survey of India toposheet the 1969 and enclosed littoral by satellite data from Landsat 5 TM, 1993, IRS P2 1996, and IRS 1C 2002, they remained in coverage for many in the same projection and map coordinates. These four overlapped coverages through the Arc GIS information. Map of shoreline change from 1969 to 1993, 1993 and 1996 and 1996 to 2002 were generated. The resolution is different satellite products for different data. For Landsat 5 TM, IRS 1C and IRS P2 resolutions were 30m, 73.5m, and 23.5 million respectively. Although there is a difference in resolution, the edge detection technique gives a clear demarcation of land borders and water. The characteristics of the coast were taken to ArcView GIS for querying and analysis.

Wave pattern recognition

Remote sensing is becoming an important tool in the identification of processes coastal spatially. Infrared band the maximum of information on ocean parameters, so the band 3 of IRS P2 1996, the band 2 of IRS 1C 2001 and the band 2 of IRS 1C 2002 were used for the identification of wave patterns. Noise reduction technique is applied to the IRS P2 May 1996, IRS 1C May 2001 IRS 1C May 2002 data to improve the image. Filtering technique with 3 * 3 convolution edge detection kernel is applied to IRS P2 May 1996, IRS 1C May 2001 to IRS 1C May 2002 to improve the wave characteristics for interpretation.

Coastal Bathymetry

For studies of coastal bathymetry Naval Hydrographic Organization (NHO) Charter 1999 is interpolated, interpreted and analyzed using ArcInfo and ArcView GIS. The number of successes is NHO 2075, scale 1:50000 and density of sampling points is 4 per km This picture was taken in 1975-1976, the Transverse Mercator projection, updated in 1999 and levels of the tides that refers to the reference of the polls is Lat 8 ° 48 'and Long 78 ° 10' and heights in meters above datum is TSM 1.0, MHWN 0.7, MLWN 05, MLWS 03 and MSL 0.6, respectively. TIN interpolation technique is adopted for spatial interpolation and DEM generation. Zero is defined as data or reference to the measured depth. Representation of the seabed of this model is in a matrix of elevation formed by superimposing a mesh grid over the surface and record the elevation value for each grid cell. The cell values are arranged in a matrix in row and column of numbers, involves the xy co-ordinate of the cells, respectively. The elevation matrix is produced by the interpolation of points irregularly spaced bathymetric data over a contour map. The three-dimensional view and the slope of the bathymetry is derived through the application of TIN model of spatial analysis using ArcView 3.2a software.

Results and Discussion

Coastal Geomorphology

Beach

Sandy beaches are the product of interaction with waves on a sandy beach on the coast. The sandy beaches are fully developed along the entire coast of the study area, except in some places. Tuticorin is covered by long sandy beaches and extensive. That trends north-south. Well developed sandy beach below the south jetty of the port. This beach is dominated by a mixture of quartz, feldspar and mica minerals. The beach is like a thick white patch in the south of the dike south of the port on the satellite images (Fig. 2).

Spit

A Grill is a small point or low tongue bankment narrow, usually consisting of sand or gravel deposited by a long beach drift and with one end attached to the mainland and the other terminating in the open Tues Is identified in the white patch in satellite imagery (Fig. 2). Two formations have been seen spitting in the south of the urban coast. Normally, saliva formation has been attributed to the movement and deposition of materials along the coast current (Thornbury 1969). Spit progradation to indicate Sea (Loveson and Rajamanickam 1987). Saliva, near Tuticorin is 0.75 to 2 km in length and tongue shape. Spitting Tuticorin has led to shore by the currents of time during monsoon and Sediment Discharges Tamiraparani River.

Beach Ridges

Beach ridges are moderately hilly terrain characteristics of the type marine sediment, formed during the last pliestocene age, on the plains of the study area. They are low, essentially continuous beach or on the beach dune material (sand, gravel and gravel) piled up by wave action and currents on the backshore of a beach beyond the present limit of storm waves or the reach of tides normal, and occurs as one or as part of a series of deposits of approximately parallel (Chockalingam 1993). The beach ridges have been recognized as representing of successive still standing sea coast progress of satellite images. Tuticorin beach ridges are reworked.

Barreiro

Mudflat is a flat area that contains a liquid plastic mixture of finely-derived particles of solid material, mainly silt and clay in water. They are always associated with sediment-filled environments such as lagoons, estuaries and reservoirs others. Wetlands are formed by the deposition of inorganic materials and wastes organic fine particulate form. Mud flats are broad deposit fees of clay, silt, mud, etc. (Davies, 1972). Marshes are well developed in the river mouth of Koramballam Oodai an estuarine environment. They appear as dark black tone on satellite imagery.

Dune complex

Complex Dune is an important geomorphological unit consisting of active sediment landfills and loose with a negligible amount of vegetation. In this area, wind activity is reported as a result of high migration, a major change in its forms. It indicates the age Pliestocene to Recent (Loveson 1993). Tuticorin is located in the dune complex.
Teri dune complex

Teri dune complex is an undulating terrain with lots of loose red sand and silt dust from wind. They represent Pliestocene at the age of recent training (Loveson 1993; Loveson et. Al. 1990). They appeared as round or oval shaped assemblies with dense vegetation. It is assumed that strong Continuous winds and southwest monsoons sweep vast clouds of dust from the dry surface of the red clay exposed at the base of the hills that have brought and deposited its cargo of sediments near the coast of the plains to form a complex of dunes Teri (Ahmad 1972). All complexes of dunes in this area are trends in the northeast to the southeast. In recent years, these Teri dune complex is also used for cultivation. It is found in yellow-green in satellite images.

Shoreline change

Coastline is one of the important dynamic characteristics of the coast where land, sea and air. In any open coast where man-made structures such as breakwaters interfere with port or change the currents of coastal shoreline dramatically. Chauhan and Nayak (1995) have studied the changes of the coast using satellite data for the period between low tide. During low tide condition, maximum land sets and line water, even under / boundary of ground water and high water line are clearly visible. This allows for better allocation of the coast. The demarcation and the areal extent of the sites of erosion and accumulation are consulted and are estimated using Arc View GIS package (Fig. 3). Of the total area of erosion during periods from 1969 to 1993, 1993 to 1996 and 1996 to 2002 are shown in Table 1. It was noted that during 1969 and 1993, erosion in the coastal area of Tuticorin was 9 hectares. During the period 1993 to 1996 was 14 ha and in the period 1996 to 2002 was 18 hectares. Most of the erosion was noted in the sandbank Hare Island and the urban coast (Fig. 3). Of the total area of accretion during the periods 1969 to 1993, 1993 to 1996 and 1996 to 2002 are shown in Table 2. The accumulation during different periods were 138 hectares (1969 to 1993),
18 ha (1993 to 1996) and 23 hectares (1996 to 2002) (Fig. 3). Since the accretion was more that erosion, the entire coast could be considered coastal progradation. Rajamanickam (1991) observed the characteristics of emergence and immersion, respectively, along the southern parts of Tamil Nadu. He also suggested upwarping along the Tuticorin area.

For the analysis of shoreline change in the study area, specific sites such as south of the harbor breakwater, Hare Island, sand spit and the urban coast were studied by erosion and accretion. Urban coast line is coastal urban area. It is delineated and shown in Figure 3. The areal extent of erosion and accumulation observed in the abovesaid areas are presented in Table 3 and 4. Both the erosion and accumulation of factors that were avoided in the estuarine environment from the demarcation of shoreline is not exactly possible in the environment estuaries, because this area is very dynamic.

In the sandbank (Fig. 4 and 5), during 1969 to 1993 was 4 ha, erosion and accumulation was 7 hectares during 1993 to 1996 was 4 ha, erosion and accumulation was 3 ha and during 1996 to 2002 erosion was 5 ha. and the accumulation was 2 ha (Table 3 and 4). In the language of sand erosion is noted in the wave exposed side and accretion is noted in the leeward side of saliva. This may be due to sediment eroded wave exposed side to the leeward side of saliva.

Tombal the structure formation is observed in between the mainland and Isle of Tuticorin ago
(Fig. 2). This is due to longshore sediment from south to north, resulting in the Hare Island and the mainland link. It took years to link geological mainland and Hare Island. Yesterday, on the island (Fig. 4 and 5) for the period from 1969 to 1993 erosion was 4 hectares during 1993 to 1996 erosion was 6 acres and during 1996 to 2002 erosion was 6 ha (Table 3). There is no activity observed accretion in the island of Hare.

In the south jetty of the port (Fig. 4 and 5), during the period 1969 to 1993 accumulation was 81 hectares, during 1993 to 1996 accumulation was 8 hectares during 1996-2002 accumulation was 18 hectares. There is no erosion observed (Table 4). The accumulation of this takes place in a curvilinear manner. Accretion on curvilinearity of the results along the coast in a formation similar paleo beach and cords were observed besides the beach. The formation of curvilinear cords called geomorphological and paleo strandlines.

In the urban coast (Fig. 4 and 5), erosion was 1 ha and the accumulation was 15 hectares during 1969 to 1993, erosion was 3 acres and accumulation was 6 hectares from 1993 to 1996, and erosion was 3 acres and the accumulation was 3 hectares for the period 1996 to 2002. Observation shows that is lower erosion and accumulation is greater in this site (Table 3 and 4). It is also noted that no shoreline change both in the urban environment. Loveson and Rajamanickam (1987 and 1988a) and Loveson et al (1990) have also reported changes in the coastline of the southern coast of India on the basis of the deposition of the landforms as cords, the appearance of the pool area, etc, through remote sensing based geomorphological interpretation. Loveson and Rajamanickam (1988b) have also pointed to the possible fall of sea level along the coast due to the neotectonic Tuticorin emerging from the seabed. The current account of the winds in the area maximum Tuticorin in northwest, northeast and north, respectively. Prevailing winds were also observed in the South West, South and South East but addresses most months experience NW, NE and N winds only. The wind speed ranges of 9-16 km / hr.

Table 1: The erosion observed in Tuticorin coast during 1969, 1993, 1996 and 2002

The erosion of the Year
1969-1993 9 hectares.
1993-1996 of 14 ha.
1996-2002 18 ha.

Table 2: accretion observed in Tuticorin coast during 1969, 1993, 1996 and 2002,
Year of accretion
1969-1993 138 hectares.
1993-1996 18 ha.
1996-2002 24 hectares.

Table 3: The erosion observed at specific sites in the Tuticorin coast during 1969, 1993, 1996 and 2002,

Spit year ago urban island Costa
1969-1993 4 ha. 4 ha. 1 ha.
1993-1996 4 ha. 6 ha. 3 ha.
1996-2002 5 ha. 6 ha. 3 ha.
1969-2002 13 ha. 16 ha. 7 ha.

Table 4: accretion observed at specific sites in the Tuticorin coast during 1969, 1993, 1996 and 2002,

Year Spit then South Harbor breakwater Costa Urbana
1969-1993 7 ha. 81 is. 15 ha.
1993-1996 3 ha. 8 ha. 6 ha.
1996-2002 2 ha. 18 ha. 3 ha.
1969-2002 of 12 hectares. 107 ha. 24 ha.

Wave pattern

Depending on the type of wave, which was present in the images, the various features like the waves of refraction, diffraction waves and shade the area were identified. These characteristics play an important role in shaping the coast, which also depends on the geographic features that exist along the coast.

Wave refraction

In the study of refraction of the wave zone is observed at the tip of the northern breakwater of the port. Propagation and wave refraction pattern is clearly identified in IRS P2 May 1996 and IRS 1C LISS III May 2001 and IRS 1C LISS III May 2002 satellite image (Fig. 6, 7 and 8). The linear progressive wave of the sea area is about progressing at an angle of 115 degrees from the mainland. The angularity of the wave propagation is measured through Arc View GIS 3.2 software. Propagating in the SW to NE, toward the mainland. The north breakwater is exactly perpendicular (90 °) to the direction of the wave (Figure 6, 7 and 8). When the wave touches the northern breakwater, the wave breaks along the breakwater. The refracted wave passes along the harbor with a breakwater, nearly two miles away and dissipates energy (Fig. 6, 7 and 8). In the south breakwater, a bank is present and the bank makes waves reflected and dissipates its energy. This refracted wave does not cause any coastal geomorphological change to tip because they do not touch it.

Wave diffraction

Diffraction of water waves is a process which the energy flow laterally along the wave crest. The most obvious example is when the waves are intercepted by an impenetrable structure as a breakwater. The presence obstruction of scattered unrest and lead to stoke the train of waves on the lee or shadow of the obstruction. Diffraction is a common phenomenon around the islands and can create substantial distortions to the coastal region that adds even more to the dynamic nature of the coast. IRS P2 May 1996, the IRS LISS III 2001 and IRS LISS III data of 2002 gives a clear representation of the wave diffraction in the study area. Diffraction wave is observed on the island and Vann, and as Hare Island. Since these islands were the main source of obstruction of ocean waves, leading to stoke of wave trains (Fig. 6, 7 and 8). Wave bends around with Hare Island side and dissipates energy. Change in shoreline is clearly seen in Fig. 3. The erosion has been identified in the sand spit island ago and should only be to the diffraction of waves. This is interpreted by IRS P2 1996, IRS 1C 2001 and IRS 1C 2002 study coastal processes and the study of change from 1969 to 2002 the coast. Erosion / Accretion problem in the study area is not due to the location of the port and its activity. Accretion observed in the lee side of sand spit is due to diffraction (Fig. 5). The deposition of sediments is also due to the convergence of the diffracted wave on the windward side of the sand spit.

Shadow Zone

When two waves converge with others, the energy in the place of convergence becomes negligible and the waves become calm. The point at which the two waves is known receives convergent as a rallying point and the area in which this phenomenon occurs is known as the shadow area. Shaded area is well identified from the IRS P2 1996, IRS 1C LISS III 2001 and IRS 1C LISS III 2002 imaginary. In the study area of the shadow zone is observed between Hare Island and the island Vann and also below the south jetty port. When the diffracted wave as Hare Island and the island converges Vann is a shadow zone. The point of convergence and the shaded area is clearly shown in Figure 6. The same phenomenon was observed beneath the south jetty. Here, when it touches the traveling-wave linear southern breakwater at the port of the wave breaks. From inside the country is curvilinear waves converge mainland south jetty with the waves in a gradual and linear in a shaded area (Fig. 6, 7 and 8). No problem, not much, because This formation of a shadow zone in the study area.

Bathymetry

Control of coastal bathymetry is of vital importance for the design of ports and coastal structures. It is also important for the exploration and exploitation of living resources and life, to understand the dynamics of ocean processes on continental shelves, for mooring of vessels and the evaluation of living marine habitats. In a GIS, modeling the Z axis has become an important element. When the 3-D model is specifically applied to represent the field, then this digital representation of elevation is known as a model digital elevation (DEM). The Tuticorin 3D Bathymetry Elevation Model from Naval Hydrographic chart shown in Figure 9. The slope analysis of the port of Tuticorin and its surroundings inferred the 3-dimensional bathymetry reveals that the slope is decreasing gradually in the direction from northwest to southeast. Gentle slope (1 – 4 °) is observed along the urban coast and above and below the port area (Fig. 9). The attenuation of the waves is more when it comes to the area and close the coast where the depth is minimal and the wave patterns observed by this attenuation is clearly seen by satellite remote sensing (Fig. 8).

Waves observed satellite images and shoreline change have been integrated and the wave effect on erosion / accretion site gives the reason for the site to be eroding or accreting. In addition, also supports this bathymetry. The analysis of wave action 1996 – 2002 provides the information that the wave action is similar from the geological past. In addition, the study area also has a specific pattern of accumulation as seen through strandlines present in the southern port of Tuticorin. So this waveform gives a clear idea of shoreline change in the present study. From near the port, NW to SE direction, steep slopes were found further offshore (Fig. 9). The net sediment transport is from south to north. Delta sedimentation also Odai Koramballam observed near the mouth of the river and is protected with the depth value of less than 2m. This is well identified through images satellite. Sediment transport and slope variations inferred from coastal urban areas and port environment clearly show that the chances are less for sediment to enter the dock of the port (Fig. 9). So not much activity dredging required in the area of Tuticorin port.

Conclusion

The coastal processes in the coastal area of Tuticorin, changing shorelines, wave action, bathymetry and coastal geomorphology were analyzed using remote sensing and GIS tools. The erosion and accumulation observed in Tuticorin using satellite images show that the temporal dynamics of the coast and this is natural not due to human interference. Coastal processes play an important role in shaping the configuration of the coast of this area. The integrated approach by remote sensing and GIS tools clearly illustrates the causes and reasons of shoreline change. The results of this survey will be useful for coastal management.

About the Author

The Author is a Project Manager in Stesalit Inc.

http://www.stesalit-inc.com/userexperience.html