QUANTITATIVE ASSESSMENT OF COASTAL CHANGES BETWEEN NARMADA AND KIM RIVER OF SOUTH GUJARAT, INDIA

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1 QUANTITATIVE ASSESSMENT OF COASTAL CHANGES BETWEEN NARMADA AND KIM RIVER OF SOUTH GUJARAT, INDIA Janak P Joshi 1, Sumit Dabral 2 and *Bindu Bhatt 2 1 Department of Geography, the Maharaja Sayajirao University of Baroda 2 NHPC Ltd., Tawang Hydro-Electric Project Stage I, Nehru Market, District: Tawang , Arunachal Pradesh, India *Author for Correspondence ABSTRACT Coastal areas are very important for human beings since the beginning of time. Change detection is the process of identifying differences in the state of an object or phenomenon by observing it at different times. Coastal changes are attracting more focus since they are important environmental indicators that directly impact coastal economic development and land management. Both natural and anthropogenic processes along the coast control the erosion, and accretion activities of the coastal zones The study quantifies the changes along the Coast between Narmada and Kim River of South Gujarat, India by using geospatial techniques. The analysis of the multi-temporal remote sensing data shows that the coast is subject to important changes during years between time interval including erosion and accretion. The study also demonstrates the applicability and efficacy of geospatial technique for quantitative assessment and monitoring of the coastal environment. Key Words: Quantitative, Erosion, Accretion, Coastal Region, Geospatial INTRODUCTION Coastal zone is the transition area between land and ocean Aidy et al., (2007) and is an area of complex, dynamic and delicate environment. External factors influencing the coastal zone are the sediment supply by the rivers and coastal processes. Coastal environment is one of the complex and 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. this environment, now highly disturbed and threatened due to increase of population and developmental activities (Thanikachalam and Ramachandran, 2005). Worldwide coastal zones are experiencing significant transformations due to climate change (e.g. sea level rise, increase of tropical cyclone intensity) and anthropogenic interventions (e.g. urbanization, reduced sediment delivery to the coast) (Roebeling et al., 2011) A careful assessment of changes that occur in the coastal environments and in coastal ecosystems forms a major milestone for effective coastal ecosystem management and leads to sustainable utilization of coastal resources. Accurate demarcation and monitoring of shorelines (seasonal, short-term and longterm) are necessary for understanding various coastal processes (Nayak, 2002). Remote sensing technology in recent years has proved to be of great importance in acquiring data for effective resources management and hence could also be applied to coastal environment monitoring and management. Further, the application of GIS (Geographical Information System) in analyzing the trends and estimating the changes that have occurred. Several studies using Remote sensing data have proven its efficiency and wide applicability in understanding various coastal processes Wagner et al., (1991); Ahmed and Neil (1994); Anbarasu et al., (1999); Makota et al., (2004); Mani et al., (2009); Boutiba and Bouakline (2011). The Remote sensing data in its various capacities has provided a synoptic view which enables the user to visualize the real time information captured and has contributed much in present developmental planning and management of resources. 89

2 Space technologies have the capability to provide information over a large area on a repetitive basis and therefore, very useful in identifying and monitoring various coastal features. Today these technologies are indispensable when developing suitable action plans for development in any coastal area (Chandrasekar, 2000). The advantages of GIS for the integration of thematic information derived from satellite data and other collateral data, such as socioeconomic, cultural data, etc. are significant factors in integrated coastal zone management practices (Desai et al., 2000). Study Area Geologically and geomorphologically, the coastline of Gujarat is quite distinct from the rest of the West Coast. About 1600 km. long and overlooking the Arabian Sea, its various segments provide evidences of the role played by eustatic and coastal processes operating during the Quaternary period. Figure 1: Study Area The Gulf of Cambay, also called as Gulf of Khambhat, is a dynamic coastal region situated on the Western Coast of India. It is an inlet of the Arabian Sea forming a Quaternary coastal segment of the western coast endowed with a fascinating diversity of geological features. The Gulf is tectonically active and delimited by the various Cambay Basin bounding faults. The coastline of the Gulf of Cambay is 90

3 featured by a number of estuaries, islands, cliffs, mud flats, salt marshes and mangrove forests. The prominent estuaries are the Narmada, Dhadhar and Kalubhar. There has been an appreciable infilling in the estuarine deltas and rivers bifurcate around the islands. The Gulf presents a complex scenario of sediment input, transport and deposition and redistribution of sediments, comprising an area experiencing high tidal fluctuations and is characterized by domination of strong tidal currents. The tidal current directions during flood and ebb tides follow almost identical paths and reflect bathymetric features of the Gulf. The tidal currents have mainly been responsible for most of the depositional and erosional features of the gulf. The study by Rajawat, et al suggests that the Gulf of Khambhat is getting silted at a rapid rate. A temporal Study by Mahapatra et al., (2013) in the southern part of Gujarat concluded that the coastal erosion is a major problem in the south Gujarat coast. During the study time period from , it was observed that % of the South Gujarat coast is eroding, about 10.15% of coast is stable and about 6.78 % of the coast is accreting in nature the erosion length is more as compare with the accreting and stable coast. The most erosion area was found along the Valsad district as compare to Navsari and Surat district. The study covers the coastal region of Bharuch district and the geographical extents are 21º to 21 º N latitude and 72 º to 72 º E longitude. The study area is characterized by the presence of Estuaries of Narmada River in north and Kim River in the south. The Narmada River is one of the big perennial rivers draining part of Gujarat. Narmada is the fifth largest river in India and largest west flowing river of Indian peninsula originating from Maikala ranges at Amarkantak in Madhya Pradesh at an elevation of 900 m. (Narmada Valley Development Authority). The Narmada also host several Dams in its upper catchment. Objective The present study investigates the temporal change as well as quantifies the changes along the Coastal Region between Narmada and Kim River of South Gujarat, India by using Landsat images and Geospatial tool. MATERIALS AND METHODS In the present study, Landsat Images were used, Landsat MSS of November, 1978, TM November, 1990, Landsat ETM of November 2001, Landsat TM November Figure 2: FCC image of the study area For quantifying changes along the south Gujarat coast for 1990, 2001 and 2011 keeping 1978 as base year are used. The data is processed and analyzed by software like ERDAS image processing, Arc GIS. Quantification of erosion/accretion rate is done using Arc-GIS software package. a) Shoreline Demarcation 91

4 The water line i.e. the shore line are identified by interpreting the satellite images based on the land use land cover characteristic and its association feature like vegetation limits, mudflats, salt pans, marshy area etc. and were digitized for all the 4 time period and this lines were consider as the limit of the coastal land. The visual analysis of the FCC image also clearly gives the picture of the dynamic characteristics of the study area, sculptured by the tidal and fluvial process in situ with the sediment and geological characteristics. The change in the time spans has become permanent as evident from the dense vegetation cover. b) Change Visualization The band differencing was employed to understand the pattern of maximum change evolved during the decades using band 4 (VNIR). The resultant image shows brighter shade for maximum change and vice versa (Figure 2) The maximum changes shown in terms of brighter shade in the figure are the areas which have shown the signs of erosion or deposition, (i.e. a new land cover). The sedimentation in the study area is seen in the southern part which has led to the increase in the land part. c) Quantifying the Change Figure 3: Decadal change ( ) The bank of the Narmada River and the coastal belt are very dynamical and irregular in shape owing to several creeks and water channels of the river Kim and Narmada in their estuarine area. The changes are being measured by drawing the Smoothed Baseline Transects at an interval of 500 meters on the baseline to intersect all the shoreline using DSAS extension for Arc GIS (Thieler et al., 2009). This enables to calculate the distance along the transact in between two shoreline giving the value of Net Shoreline Movement, It reports the distance between the oldest and youngest shorelines for each transect. The End point Rate (EPR) is calculated by dividing the distance of net shoreline movement by the time elapsed in year between the oldest (1978) and the most recent shoreline (2011). The EPR value will be negative for the eroding coastline and positive for the accretion. 92

5 Figure 4: Erosion Point Rate (Meter/Year) Figure 5: Net shoreline movement and end point change rate ( ) 93

6 RESULTS AND DISCUSSION The shoreline in the estuarine area shows that the erosion was greater at the southern bank of River Narmada. The deposition of the sediment has been in the south of the Aliabet Island which has elevated the sediments from shallow water land to land part. This also suggests that the tidal force have dominated the fluvial process in the estuarine area and eroded materials are deposited under the tidal force in this part of the Gulf of Khambhat. This can be as a result of the decrease in the Narmada River discharge and other anthropogenic activities also which may be further investigated, to understand its interrelationship. Conclusion The remote sensing data are detrimental to the temporal change studies as in the present study also; it is observed that in the span of 33 years there is large amount of change identified in terms of the accretion and erosion. These changes are so evident that Aliabet a river island in 1978 is a part of land adjoining the coast. The field visits to the area reveals that this change has affected the local communities directly. the earlier population residing on the south bank of Narmada river and costal belt have came into the interior land and Dhanturia, Taria villages were relocated away from the south bank of the river in 1968 due to the rapid erosion and flooding of the southern bank (De et al., 2008). The villages near the costal belt of Hansot Taluka, Bharuch District have witnessed the maximum accretion resulting into filling of southern channel of the Narmada river and eventually becoming the land part. Village like Ambheta were in fishing was the source of livelihood to the villagers, but now fishing community are opting for either migration or changing the economic activity. The villages are also facing a problem of increasing salinity of the soil eroded from the emergent area leading to decreasing quality of the land and decrease in the yield (De et al., 2009). The topographical change has affected the socio- economic characteristics of the population in large and has presented a new set of challenges for conservation and environmental management of the region. Approx Ha area basically saline in nature has evolved which has to be planned and used so that saline ingression is contained. REFERENCES Ahmed W and Neil DT (1994). An evaluation of Landsat thematic mapper digital data for discriminating coral reef zonation, heron reef (GPR). International Journal of Remote Sensing Aidy MM, Giles MF and Atkinson PM (2007). Shoreline Mapping from Coarse Spatial Resolution Remote Sensing Imagery of Seberang Takir, Malaysia. Journal of Coastal Research 23(6) Anbarasu K, Baskaran R and Rajamanickam GV (1999). Influence of sea level changes in the development of landforms around Chidambaram, Tamilnadu. Indian Journal of Geomorphology 4(1&2) Boutiba M and Bouakline S (2011). Monitoring shoreline changes using digital aerial photographs, quick-bird image and DGPS topographic survey: Case of the east coast of Algiers, Algeria. European Journal of Scientific Research 48(3) Chandrasekar N, Anil Cherian, Rajamanickam M and Rajamanickam GV (2000). Coastal landform mapping between Tuticorin and Vaippar using IRS-IC data. Indian Journal of Geomorphology 5(1&2): De J, Bhatt B, Lakhia N and Joshi J (2008). Application of Remote Sensing and GIS Technologies in Detecting Micro-level Morphological Changes in the Estuarine and Coastal Areas of Narmada and Kim Rivers. The Geographical Society of India 70(4) De J and Bhatt B (2009). Environmental Impact of Land Use Changes in the Narmada Window of South Gujarat: A Study of Narmada-Kim Interfluve Belt. Unpublished Report No. DST/ SR/S4/ES- 21/NARMADA WINDOW/PI. Desai PS, Honne Gowda H and Kasturirangan K (2000). Ocean research in India; Perspective for space. Current Science 87(3)

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