River Flood: a Study of Tufanganj-Ii Block of Koch Bihar District,West Bengal, India
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[ VOLUME 5 I ISSUE 4 I OCT.– DEC. 2018] E ISSN 2348 –1269, PRINT ISSN 2349-5138 RIVER FLOOD: A STUDY OF TUFANGANJ-II BLOCK OF KOCH BIHAR DISTRICT,WEST BENGAL, INDIA Prasanya Sarkar* & Rajib Mitra** *Guest Teacher, Cooch Behar College, Coochbehar, West Bengal, India . **Research Scholar, Department of Geography and Applied Geography, University of North Bengal. Received: July 26, 2018 Accepted: October 05, 2018 ABSTRACT Flood is a natural hazard which has an adverse effect on normal life of the people. The Koch Bihar district in West Bengal is susceptible to river floods due to its topography, rainfall characteristics, nature of rivers, anthropogenic activities, etc. For our present study we have selected the Tufanganj-II block to identify the riverineflood prone areas. The work has been done by analysed and interpreted the secondary data using remote sensing and GIS techniques.The study reflects that out of 55 villages 22 villages are most vulnerable due to river flood. The causes behind the flood havoc and government strategies to remove the flood hazard in this block also mentioned throughout the work. Keywords: Flood, Tufanganj-II block, Vulnerable Villages, flood management. Introduction Flood is a stage of high water level, which inundatesthe low lying area of the adjacent flood plains. In any reach ofthe river system floodshave direct relationship with the catchment characteristics of its upstream area (Smith et al, 1998).Basically flood is a natural feature of the rivers which replenishes the floodplain areas and convertsit into fertile land. But sometimes it becomes disastrous when associated with high discharge, heavy rainfall, etc. In Koch Bihar district, Tufanganj-II block is affected by riverine floodsalmost every year. Raidak-I, Raidak-II and Sankosh Rivers are the major rivers which caused flood havoc in this block. Both structural and non-structural measures have been taken to check the problem of floods. Initial emphasis was given only on structural measures like embankments, reservoirs and improvement of drainage channel. But now focus have been shifted to non-structural measureslike flood forecasting, flood plain zoning, etc. Application of GIS and modern remote sensing technology make it easier to map flood prone areas of Tufanganj Block II, identify the most vulnerable and vulnerable areas on the basis of flood recurrence. It will help the government to plan different strategies to cope with flood problems in the study area and also the people to save their lives and properties from the damages of a flood. The present study aims to give an account of flood prone areas of Tufanganj II block along with assessment of the causes behind the flood havoc and present day picture of different strategies taken by government to fight against the flood situation in this block. Data base and methodology The secondary data is used in the paper which have been collected from the Disaster Management Plan, Koch Bihar for the year 2016. For the present study, the relevant maps have beenpreparedin ArcGIS 10.2software using satellite imagery.In the study, Landsat images have been obtained from the Earth Explorer gateway of United Nations Geological Survey (USGS). To analyse the existing status of the water cover NDWI map has been prepared.The normalized difference water indexes (NDWIs), calculated from various band combinations ((green, near-infrared (NIR), or shortwave-infrared (SWIR)), have been successfully applied to land surface water (LSW) mapping.The formula is used for calculating NDWI is: NDWI= (GREEN -NIR)/ (GREEN+NIR) Characteristics of the study area Koch Bihar district is located at the foothills of the eastern Himalaya and in this region after heavy rainfall the catchment of the rivers attain strong current and flooded in the adjacent areas. The river of Koch Bihar district flow from north-west to south-east direction. Mainly six major rivers flow throughout the district,namely, Tista, Jaldhaka,Torsa,Kaljani, Raidak and Gadadhar.Flood is almost a yearly phenomenon in Koch Bihar district.Here some recorded data of flood occurrences of the district are given (table. 1). Tufanganj II is an administrative division of Tufanganj subdivision of Koch Bihar district in West Bengal. This block has an area of 257.08 sq.km. The turbulent rivers carry pebbles, sand and silts in and around the block. The soil is formed mainly by the alluvial deposits and slightly acidic in nature. It is friable loam to 514헎 IJRAR- International Journal of Research and Analytical Reviews Research Paper [VOLUME 5 I ISSUE 4 I OCT. – DEC. 2018] e ISSN 2348 –1269, Print ISSN 2349-5138 http://ijrar.com/ Cosmos Impact Factor 4.236 sandy loam ranging in depth from 0.15 to 1 metre. The soil has a low level of nitrogen, deficiency of zinc, calcium, magnesium and sulphur are also found here. The block is litho-stratigraphically composed of Holocene deposits.As per 2011census, the block comprises a total population of 1, 86,726 out of which 1, 16,081 people are affected by flood. Gram Panchayats of Tufanganj IIblock areBarokodali I & II, Bhanukumari I & II, Falimari, Mahishkuchi I & II, Rampur I & II and Salbari I& II. Among 141 gram sangsads, 45 villages are most vulnerable and 31 are in vulnerable conditions. Fig. 1 Fig.2: Rainfall characteristics of the Tufanganj-II block (2013-2015); Source: Disaster Management Plan, Koch Bihar, 2016 and complied by the researchers. Research Paper IJRAR- International Journal of Research and Analytical Reviews 515헎 [ VOLUME 5 I ISSUE 4 I OCT.– DEC. 2018] E ISSN 2348 –1269, PRINT ISSN 2349-5138 Table 1: Occurrence of flood in Koch Bihar district(2004-2014) Date of Affected areas No. of affected villages Affected River occurrence and blocks people 12th July, Mathabhanga , Santoshpur, 341 villages and 2 69,968 Raidak I, Mansai, 2004 Tufanganj I, Arampur spur I , municipalities Kaljani and Balarampur Gadhadhar 28 th July, Mathabhanga, Kedarhat and 113 villages 25000 Torsa, Mansai and 2007 Jorshimuli Sankosh 22nd July, Tufanganj, Mathabhanga Ghaonapara, - Raidak II, Mujnai 2008 Mahiskuchi and Torsa 27th August, Koch Bihar Sadar and Wards 1,2,3,6,7,10 and Torsa and Teesta 2008 Mekhliganj 11 2000 17th August, 25-Teesta Payosthi, 40- Mekhliganj 337 Teesta , Torsa 2009 Payosthi, 72-Nijtaraf, families Kuchlibari and Paniyachar at Mekhliganj 17th June, Tufanganj, Dinhata and Koch Tufanganj I & II, Sankosh, Raidak, 2012 Bihar Dinhata I & II, Koch Kaljani, Torsa and Bihar I & II 40000 Mansai 17th July, Mekhliganj, Mathabhanga and Koch Bihar I & II, 50000 Teesta, Torsa, 2012 Koch Bihar Town Mathabhanga I& II and Jaldhaka, Kaljani Mekhliganj and Sankosh 28th August, Villages of Natabari, Tufanganj I& II, Koch 25000 Kaljani 2014 Chilakhana, Bhuchumari Bihar I & II Source: Disaster Management Plan, Koch Bihar, 2016 and complied by the researchers. Results and Discussion The water bodies have a unique spectral response in the visible range when compared tothe surrounding land cover. Each of the visible bands, displays a unimodel histogram withno indication of a separate group of data for water pixel. The infrared band classificationgives a much better representation in the water related features than do the other visiblebands. This property makes the water pixel well identifiable, appearing blue to dark blue infalse colour composite. Water extraction image, NDWI (satellite imagery 6th April 2014) processed for delineating the area. Remote sensing has more advantages than the traditional methods of land surface water (LSW) mapping because it is a low-cost, reliable information source that is capable of making high-frequency and repeatable observations. Here the NDWI map of the study area showed to glean out the wetness condition of the area demarcated from grey to black tone combination whereas the blue tone is the signature of land surface (Fig. 3). Fig. 3: NDWI maps of the study area 516헎 IJRAR- International Journal of Research and Analytical Reviews Research Paper [VOLUME 5 I ISSUE 4 I OCT. – DEC. 2018] e ISSN 2348 –1269, Print ISSN 2349-5138 http://ijrar.com/ Cosmos Impact Factor 4.236 Raidak-I, Raidak-II and Sankosh Rivers are the main rivers throughout the block and they inundate the riparian villages in every year. The villagers have been affected by floods in 2016 is 85793 (Table. 2). It has been observed that out of 55 villages 22 were most vulnerable due to river floods (Fig. 4). The most vulnerable villages are Bhandijilas, Langolgram, Begarkhata, Debgram, Dhanmatia, Saoerkuti, Manshai, Vanukumari, Chht Bara Laoukuti, Phalimari, Fersabari, Mahishkuchi, Paglirkuthi, Takua Mari, Chadbhalka, Rampur, Garbhanga, Jaldhao, Khagribari, Madhurbasa, Rampur-II, Singhimari and Shalbari. The villages are situated along the banks both left and right of the rivers. Table 2: Flood prone areas of Tufanganj II block Name of Name of the Flood prone No of persons to the river GP Mouza be affected 1. Falimari 2. Takulya Colony 3. Barnikata Raidak-II & 4. Khunipara Sankosh Falimari 5. Madhyachar 9376 6. Pora Colony 7. Chikantala 8. Bhubonerchar 9. Pachani Para 10. ChhatFalimara 11. PurbaFalimari 1. Ghonapara 500 2. Gedarchar 2212 3. Fersabari 546 Raidak-II & Mahishkuchi-I 4. Ghokso Part 645 Sankosh 5. Jaldhowa part 2020 6. Kathalguri 2500 7. Mahiskuchi part 4453 1. Takomari 2130 2. Paglirkuthi 765 3. Jaldhowa pat 657 Raidak-II & Mahishkuchi- 4. Rasikbeel 2145 Sankosh II 5. Bakla 1654 6. Atiamochar 546 7. Taterkuthi 654 1. Harirpur Part 1654 2. Bhandijelash part 1876 3. Langalgram 1235 Raidak-I Barokodali-I 4. Boalimohan 2 part 376 5. Jhingapuni 1134 6. Barokodali part Mechkoka 2236 1. Debagram 1654 2. Mansai 2534 Raidak-II Barokodali-II 3. Dhanmatia 1252 4. Sourkhata 3123 5. Begarkhata 1654 6. Boalimohan 150 1. Chhotolowkuthi 2745 2. ChhitBorolowkuthi 3354 Raidak-I Bhanukumari- 3. Bhanukumari Char 3425 Research Paper IJRAR- International Journal of Research and Analytical Reviews 517헎 [ VOLUME 5 I ISSUE 4 I OCT.– DEC.