INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 2, No 1, Copyright 2010 All rights reserved Integrated Publishing Association

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1 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 2, No 1, 2011 Copyright 2010 All rights reserved Integrated Publishing Association Research article ISSN Change detection studies in coastal Zone features of Nagapattinam, Tamilnadu by Remote Sensing and Krishnakumar. P 1, Lakshumanan.C 1, Viveganandan. S 1, Jonathan. M.P 2, Muthukumar. S 1 1- Centre for Remote Sensing, Khajamalai Campus, Bharathidasan University, Trichirapalli , Tamil Nadu, India 2-Centro Interdisciplinario de Investigaciones y Estudios sobre Medio Ambiente y Desarrollo (CIIEMAD), Instituto Politécnico Nacional (IPN), Calle 30 de Junio de 1520, Barrio la Laguna Ticomán, Del. Gustavo A. Madero, C.P.07340, México D.F., México. drlaks@gmail.com doi: /ijes ABSTRACT Landuse/land cover changes have emerged as a global phenomenon and perhaps the most significant regional anthropogenic and natural disturbance to the environment. The study aided with temporal remotely sensed data for landuse/ land cover mapping in Nagapattinam coastal area between 1999 and 2007 with reference to SOI toposheets to assess the changes that has taken place in the coastal landuse. The interpreted data were verified in the field and results were corrected. The major types of land cover area are agriculture land, plantations, settlement, salt affected land, aquaculture, land with shrub and sandy area. The results indicate that agriculture area is dominant landuse class in Nagapattinam coast and its surroundings followed by plantation. Same time, 22.5 km 2 of salt affected area increased due to brackish water aquaculture and tidal inundation. The major geomorphic features identified are deltaic plain, mud/ tidal flat, paleo-beach ridge, beach ridge, sand dune, salt flat and coastal plain. Among these, deltaic plain covers majority of the area (62.4 %). The baseline information generated on land use pattern and geomorphology of the area would be of immense help for protecting the coastal environment to sustainable development. The study recommends the use of satellite imagery for effective environmental monitoring and assessment. Keywords: Landuse / Land Cover, coastal, Remote Sensing and GIS, Nagapattinam 1. Introduction Coastal environment is one of the complex phenomena, owing to its progressive or cyclic changes due to dynamic processes and it supports a variety of economic activities such as industrial, commercial and recreation, etc. In this environment, now highly disturbed and threatened due to increase of population and developmental activities (Thanikachalam and Ramachandran, 2005). It is necessary to protect coastal environment to ensure sustainable development. Landuse/land cover is an important tool for the various planning authorities with responsibilities for the management of territory at a regional level (Marcal et al., 2005). Using Landuse/land cover tool allows for the identification of major processes of change and, by inference, the characterization of land use dynamics (Ademiluyi et al., 2008). Same time, the knowledge of landuse/land cover map is very important to understand the coastal environment, utilization, conservation and management. Globally, land cover nowadays is altered predominantly by direct human use. Therefore land degradation is mainly due to population pressure, which leads to intense landuse without proper management practices (Raju et al., 2006)). These landuse/ land cover changes perturb the existing coastal ecosystem Received on April 2011 Published on September

2 (Chauhan and Nayak, 2005). Hence, studying landuse/ land cover dynamics is an essential in order to examine coastal ecology and developmental consequences of landuse change over a space of time. In fact according to Olorunfemi (1983), monitoring changes and time series analysis is quite difficult with traditional method of surveying but in recent years, remote sensing and s (GIS) are powerful tools to derive accurate and timely information on the spatial distribution of landuse/land cover changes over large areas (Goyal et al and Dwivedi et al., 2005). Nobi et al., (2009) had also suggested that the remote sensing coupled with GIS tool is being extensively used for real time and long term monitoring of the environment. A number of satellite images have been used to identify coastal landuse map, including IRS LISS-II & III (Nobi et al., 2009; Mani Murali et al., 2006; Chauhan and Nayak, 2005; Nagamani and Ramachandran, 2003; Ghosh et al., 2001), Landsat TM and ETM (Okude Adeyinka, 2006) and IKONOS (Berberoglu et al, 2003).The aim of the present study is to analyze Landuse/ Land cover changes using satellite imagery in Nagapattinam coast. Landsat Enhanced Thematic Mapper (ETM+) and IRS 1D-LISS III data for the period of 11 th Nov 1999 and 20 th may 2007 were used for the landuse mapping using visual and digital interpretation techniques coupled with detailed ground truth verification. 2. Study Area The study area is located Cauvery delta region at the southern part of Bay of Bengal in South East coast of India. It is extending from10º30 to 10º 55 N latitude and 79º 45 to 79º 55 E longitude and medium tropical transition climate, characterized by monthly average temperature of above 27º C. The relative humidity ranges from 70 77% and it is high during the period of October to November. The major rivers are Arasalar, Tirumalarajanar, Vettar, Kaduvaiyar and Harichcandranadi (tributaries of river Cauvery) pass through the geranitic terrain and agricultural belt in a region (figure.1). Recently, numerous small-scale aquaculture farms have established along the Vedaraniam canal. 3. Materials and Method Multi-temporal satellite data of LISS III 2007 and Landsat ETM 1999 images were used for generate landuse / land cover map. IRS P6 LISS III satellite data was acquired from the National Remote Sensing agency (NRSA) and Landsat ETM satellite image was downloaded from freely through the global land cover facility (GLCF) ( The use of multi-temporal satellite data at a large scale possesses a number of challenges including geometric correction error, noise erasing from atmospheric effect, error arising from changing illumination geometer and instrument errors (Homer et al. 2004). In this study, the geometric and radiometric errors were rectified through image pre-processing techniques. ETM image was geometrically corrected using ground control points (GCP) were taken from the SOI toposheets with an RMS error of less than 30 m by using nearest neighborhood resampling method. The IRS 2007 image was registered to the previously registered ETM 1999 base year image with UTM Zone, Datum WGS84. After the rectification process an area of interest was selected and initial study sites from both full scenes were subsetted and designated the ETM 1999 and the LISS III 2007 image. The FCC was generated and enhance through the histogram equalization method to distinguish the landuse/land cover features (Figure 2). Different landuse features were mapped such as settlement, agricultural land, river, land with and without scrub, plantation, salt affected land, waterlogged area, marshy/ swampy land, mudflat / tidal flat and aquaculture and their changes were analyzed with the help of GIS (Arc GIS 9.1) software environment. 214

3 Figure 1: Study area map Figure 2: FCC of study area 4. Result and Discussion 4.1 Geomorphology Coastal geomorphology is the study of the landforms and physical processes of the coast. In these coastal environments are rimmed with various coastal geomorphic features viz. beach, beach ridge, paleo beach ridge, deltaic plain, mud/tidal flat, salt flat, flood plain and swale complexes etc., which is presented in Figure 3. For the regional assessment, the geomorphology data were used as indices and the detailed geomorphology was interpreted using IRS LISS III 2007 data by zooming it to 1:10,000 scale and all the geomorphic features were identified. In satellite data shows that deltaic plain dominates in Nagapattinam coast (274.8 km 2 ). Mud / Tidal flats covered an area about km 2 and they are always associated with silted environments like estuaries, backwater and other embankments. A coastal plain is an area of flat, low-lying land adjacent to a sea coast and separated from the interior by other features and occupies about 33.7 km 2. Floodplains are active geomorphic environments because of sedimentation caused by flooding, erosion caused by channel migration, and deposition of sand blown off of barren river bars. The active flood plains found adjacent to the water channels were characterized by light grayish tone on the imagery. The flood plain occupied in region about km 2 (2.7%). Beach ridges and paleo beach ridges, frequent components of coastal plains and indicators of the positions of ancient seashores and associated sea levels. The area covered by paleo beach ridges and beach ridges have been estimated about km 2 (9.7%) and km 2 respectively (Table.1). The Nagapattinam coastline consists of long, narrow, low and sandy beaches and occupied about 5.42 km 2. As seen in table.1, river/canal (8.02 km 2 ), salt flat (29.19 km 2 ), and swale (10.68 km 2 ) constitute fare area coverage in the study area. 215

4 Figure 3: Geomorphology of the Nagapattinam coast Table 1: Geomorphology and Landuse / Land cover changes S.No Geomorphology class Landuse class (Sq.km) (Sq.km) (Sq.km) 1 River/Stream/Canal 8.02 Agriculture land Beach ridge Aquaculture Beach 5.45 Land with scrub Coastal plain Land without scrub Waterlogged area 2.93 Marshy vegetation Mudflat/Tidal flat Mud flat/ Tidal flat Swale Plantation Deltaic plain River / Canal Flood plain Salt affected Land Paleo beach ridge Sandy area Salt flat Settlement Sand dune 0.37 Waterlogged Land Landuse / Land cover The Landuse/land cover assessment based on visual interpretation for the period 1999 and 2007 as derived from Landsat ETM and LISS III satellite image respectively (Figures 4 & 5). The result indicate that dominant landuse/land cover categories in 1999 was Agricultural land, which was occupied about 59.2% of the study area, plantation covering 19.2%, settlement occupying 4.1%, water logged area and aquaculture covered 4 %, 1.5% respectively (Figure 6). While River/Canal (9.1 km 2 ), salt affected land (6.78 km 2 ), sandy area (12.92 km 2 ) and 216

5 land without scrub (14.02 sq.km) constitute fare area coverage in the region. In 2007, the three categories continued to dominate the area (Agricultural land sq.km, settlement km 2 and plantation 48 km 2 ), here plantation decreased (8.3%) while settlement (housing, industries, towns) increased (8.9%) due to the change in population density, labor force in agriculture and population growth. As evident from the figures 4 and 5, rapid land use changes and massive agricultural land loss in the region according to the conversion matrix from the classification (Table.1). The proportion of land that underwent changes was as high as 9.4% among the total land. There were two major types of land use changes conversion from agricultural land to built-up areas and development sites, conversion from agriculture land to aquaculture farm. In recent years, aquaculture has become largest growing food industry in India. Interest in aquaculture farming developed in the late 1980s and was inspired by the huge success of shrimp production in 1990s in the region. Vedaraniam canal and Cauvery tributaries such as Vettar, Uppanar and Vellar River surroundings are potentially suitable land for brackish water aquaculture and also number of small scale aquaculture farm established around this area. As seen in table 1, while the areas well changed for aquaculture was 6.61 km 2 in 1999; this number increased 2.0% and became km 2 in On the other hand 22.5 km 2 of salt affected land area were increased because of the pressure of aquaculture practice and tidal inundation during (Figure.7). Figure 4: Landuse / Land Cover Figure 5: Landuse/Land Cover

6 Figure 6: Landuse / Land cover 1999 and 2007 Figure 7: Status of Aquaculture and Salt affected land during

7 4.3 Shoreline change Shoreline is the boundary between land and sea keeps changing its shape and position continuously due to dynamic environmental conditions. The changes in shoreline was mainly associated with waves, tides, winds, periodic storms, sea level change, the geomorphic processes of erosion and accretion and human activities. The survey of India toposheets 1971 and satellite data of 1999 and 2007 were used to assess the changes in the shoreline of the Nagapattinam coast. As seen in the figure 8 erosion has been observed Pattanachcheri to Velanganni and deposition has been served pattanavarnattam of the study area. These changes are attributed to construction of tsunami, sediment dynamic, artificial barriers like breakwater, jetties, etc. Also the shoreline protection measures were adopted in mouth of the Vedaraniam canal as a result of shoreline erosion. 5. Conclusion Figure 8: Shoreline change map a) , b) The present study has revealed that satellite data has the unique capability to detect the changes in landuse/land cover quickly and accurately. From the analysis, it has been found that the satellite data is very useful and effective for getting the results of temporal changes, with this effective data it has been found that the landuse changes are mostly caused by salt affected area imposed by aquaculture farm, backwater and rapid population growth. Also, the satellite imagery confirms that Nagapattinam coast still retain more agricultural land when compared to all other landuse/land cover features. This will help in maintaining the ecological balance and improving microenvironment of the region. At same time, plantation of salt tolerance species like prosopis, casuarinas should be taken up to stabilize the salt affected land and shoreline. It may conclude that the use of Landsat and LISS III scene for mapping landuse/land cover changes in the Nagapattinam coast area provided a satisfactory 219

8 result. However, it is recommended to derive landuse / land cover on regular interval so, that the information can be updated through time. 6. Reference 1. Ademiluyi IA, Okude AS, Akanni CO, (2008), An appraisal of landuse and land cover mapping in Nigeria. African Journal of Agricultural Research 3(9), pp Berberoulu S, Alphan H, Yilmaz.KT, (2003), A Remote Sensing Approach for Detecting Agricultural Encroachment on the Eastern Mediterranean Coastal Dunes of Turkey. Journal of Agric Forestry, pp Chauhan HB, Nayak S, (2005), Landuse/ cover changes near Hazira region,gujarat using Remote Sensing Satellite data. Journal of the Indian society of Remote Sensing 33(3), pp Dwivedi RS, Sreenivas K, Ramana KV, (2005), Land-use/land-cover change analysis in part of Ethiopia using Landsat Thematic Mapper data. International Journal of Remote Sensing, 26(7), pp Ghosh T, Bhandari G, Hazra S. Assessment of Landuse/Landcover Dynamics and shoreline changes of Sagar Island through Remote Sensing. 22 nd Asian Conference on Remote Sensing 5-9 November Homer C, Huang C, Yang L, Wylie B, Coan M., (2004), Development of a 2001 National Land cover Database for the United States. Photogrammetric Engineering and Remote Sensing, 70,pp Mani Murali R, Vethamony P, Saran AK, Jayakumar S, (2006), Change detection studies in coastal zone features of Goa, India by remote Sensing, Current science, 91 (6), pp Nagamani K, Ramachandran S, (2003), Evaluation of use/land Cover in Pondicherry using Remote Sensing and GIS. In the Proceedings of the Third International Conference on Environment and Health Journal-AG, 88: held Chennai, India, pp Nobi EP, Umamaheswar R, Stella C, Thangaradjou T, (2009), Land Use and Land Cover Assessment along Pondicherry and its Surroundings Using Indian Remote Sensing Satellite and GIS, American-Eurasian Journal of Scientific Research 4, pp Olorunfemi JF, (1983), Monitoring Urban Land Use in Developed Countries An aerial photographic approach, Environmental International 9, pp Okude AS, Ademiluyi IA, (2006), Implications of the Changing Pattern of Land cover of the Lagos Coastal Area of Nigeria. American-Eurasian Journal of Scientific Research pp Raju K, Anil kumar R, (2006), Land use changes in udumdbanchola taluk, Idukki district Kerala: An analysis with the application of remote sensing data. Journal of the Indian society of Remote Sensing, 34(2), pp

9 13. Thanikachalam M, Ramachandran S, 2005, Remote Sensing and GIS Techniques for monitoring the Coastal Environmenal Changes: A Case Study in Tuticorin Coast, India, Map Asia GIS Development, pp Goyal VC, Sanjay K, Jain, Navneet pareek, 2005, Water logging and drainage assessment in Ravi Tawi irrigation command (J&K) using remote sensing approach. Journal of the Indian society of remote sensing, 33(1), pp Marcal ARS, Borges JS, Gomes JA, Pinto Da Costa JF,2005, Land Cover update by supervised classification of segmented ASTER images. International Journal of Remote Sensing, 26(7), pp