STUDY ON TYPE AND DISTRIBUTION OF WETLANDS OF SIKKIM HIMALAYAS USING SATELLITE IMAGERY WITH REMOTE SENSING & GIS TECHNIQUE Narpati Sharma, Safal Pradhan, M. L. Arrawatia and D.G. Shrestha Department of Science and Technology and Climate Change, Government of Sikkim, Development Area, Gangtok, Sikkim
Wetlands temporarily or permanently covered by water. neither truly aquatic nor terrestrial: or can be both (seasonal variability). Wetlands enormous diversity according to their genesis, geographical location, water regime and chemistry, dominant plants and soil or sediment characteristics boundaries difficult to define. (transitional nature) Wetlands share a few attributes common to all forms. (esp. hydrological structure) presence of water for a significant period of time principally responsible for its development
SIKKIM 22nd state of the Indian Union North Eastern region of India. Shares border with Nepal, China, Bhutan and West Bengal. 27 0 04 46 N to 28 0 07 48 N latitudes and 88 0 00 58 to 88 0 55 25 E longitudes. The total geographic area of the state is 7,096 km 2 0.22% of the total geographical area of the country. Numerous snow-fed streams has carved out river valleys These streams combine into the Teesta and its tributaries. Main drainage basins: Teesta and Rangeet. The Teesta, described as the "lifeline of Sikkim", flows north to south There are 84 glaciers mapped in Sikkim. Numerous high altitude lakes in entire state. The premier lakes are Changu (Tsomgo), Khechodpalri, Gurudongmar, Cholamu, Memencho, Lampokhari, Samiti etc.
OBJECTIVES Mapping the wetlands of Sikkim using IRS LISS III digital data following a standard wetland classification system. Integration of ancillary theme layers (road, settlements, drainage, administrative boundaries). Creation of a seamless database in GIS environment. Comparative study of wetland with Wetlands of India - An Atlas of Sikkim (1998).
METHODOLOGY Generation of spatial framework in GIS environment for database creation and organization Geo-referencing of satellite data Identification of wetland classes as per the knowledge based digital classification and onscreen interpretation Generation of base layers (road network, settlements, drainage, administrative boundaries) from satellite image and ancillary data. Attribute coding of the wetlands following the standard classification system and codification. Preparation of map compositions and generation of statistics
Work was carried out using ERDAS Imagine, Arc/Info and ArcGIS software. The widely used classification system, devised by Cowardin et al., (1979), was used during the study. The methodology was adhered to National Wetland Inventory and Assessment, technical guidelines and procedure manual (Garg and Patel, 2007). Data used: IRS P6 LISS III Pre-Monsoon (April 13, 2005); IRS P6 LISS III Post-Monsoon (January 26, 2006) and Topographic map of Sikkim (1:50,000 scale) The satellite data were registered by image-image registration process with acceptable RMS (Root Mean Square) error of 0.76 using ERDAS Imagine 9.1 software.
Flow chart of the methodology
RED GREEN NIR RED GREEN NIR SWIR Various land features as they appear in four spectral bands & in a typical 3 band FCC
ACCURACY ASSESSMENT Determination of thematic classification as well as location accuracy Database evaluated for accuracy and to ensure reliability of data Quality assurance and quality control measures were taken for data collection, analysis, verification and reporting The study has used well established, time-tested, fully documented data collection conventions All interpreted imagery was reviewed by technical expert for accuracy and code. Quality check includes: 1. Image to image Geo-referencing/Data generation. 2. Wetland mapping using visual/digital interpretation techniques. 3. Geo-data base creation and organization. 4. Output products.
Gurudogmar lake Cholamu lake Aqua-veg Khechodpalri lake IRS P6 LISS III imagery of Sikkim
ACKNOWLEDGEMENTS The authors greatly acknowledge all officers and staffs of Department of Science and Technology and Climate Change, Government of Sikkim and all the Scientists and staff of Space Application Centre (ISRO), Ahmedabad The encouragement received from Shri G. Madhavan Nair, Chairman, Indian Space Research Organization (ISRO), Bangalore is thankfully acknowledged. We thank Dr. (Smt.) Susma Panigrahy, Group Director, Agriculture, Forestry and Environment group for her support, guidance, interest and critical inputs. Our special thanks goes to Dr. Sandeep Tambee (Special Secretary, RMDD, Govt. of Sikkim), Mr. Nima Bhutia (TMI) and Mr. Laku Bhutia (Himal Raksak) for providing us photographs of high-altitude lake (wetland).
REFERENCES: Cowardin, L.M., Carter, V., Golet, E.C. and La Roe (1979). Classification of wetlands and deep water habitats. USFWS/085-79/31, Office of the Biological Services, U.S. Fish and Wildlife Service, Washington, D.C. Garg J.K. and Patel J. G., 2007. National Wetland Inventory and Assessment, Technical Guidelines and Procedure Manual, Technical Report, SAC/EOAM/AFEG/NWIA/TR/01/2007, June 2007, Space Applications Centre, Ahmedabad, Garg, J.K., Singh, T.S. and Murthy, T.V.R. (1998). Wetlands of India. Project Report: RSAM/sac/resa/pr/01/98, June 1998, 240 p. Space Applications Centre, Ahmedabad, Lillesand, T.M. and Keifer, R.W. 1987. Remote Sensing and Image Interpretation. John Wliey and Sons, New York. Manorama Yearbook 2007 Millennium Ecosystem Assessment. 2005, Ecosystems and Human Well-being: A Framework for Assessment, http://www.maweb.org Navalgund, R.R., Nayak, S.R., Sudarshana, R., Nagaraja, R. and Ravindran, S. 2002. Proceedings of the ISPRS Commission VII. Symposium on Resource and Environmental Monitoring, IAPRS & SIS, Vol.35, Part-7, NRSA, Hyderabad. Risley, H. H. 2001, The Gazetteer of Sikkim Verma, Rajesh, 2009. Sikkim Guide
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