Sikkim 25 K - Ministry of Environment and Forests

This publication deals with the updated database andstatus of wetlands, compiled in Atlas format. Increasingconcern about how our wetlands are being influenced hasled to formulation of a project entitled “National WetlandInventory and Assessment (NWIA)” to create an updateddatabase of the wetlands of India. The wetlands arecategorised under 19 classes and mapped using satelliteremote sensing data from Indian Remote SensingSatellite: IRS P6- LISS III sensor. The results areorganised at 1: 50, 000 scales at district, state andtopographic map sheet (Survey of India reference) levelusing Geographic Information System (GIS). Thispublication is a part of this national work and deals withthe wetland status of a particular State/Union Territory ofIndia, through text, statistical tables, satellite images,maps and ground photographs.The atlas comprises wetland information arranged intonine sections. How the NWIA project work has beenexecuted highlighted in the first six sections viz:Introduction, NWIA project, Study area, Data used,Methodology, and Accuracy. This is the first time that highresolution digital remote sensing data has been used tomap and decipher the status of the wetlands at nationalscale. The methodology highlights how the four spectralbands of LISS III data (green, red, near infra red and shortwave infra red) have been used to derive various indicesand decipher information regarding water spread,turbidity and aquatic vegetation. Since, the aim was togenerate a GIS compatible database, details of thestandards of database are also highlighted in themethodology.The results and finding are organised in three sections;viz: Maps and Statistics, Major wetland types, andImportant Wetlands of the area. The Maps and Statisticsare shown for state and district level. It gives details ofwhat type of wetlands exists in the area, how manynumbers in each type, their area estimates in hectare.Since, the hydrology of wetlands are influenced bymonsoon performance, extent of water spread and theirturbidity (qualitative) in wet and dry season (postmonsoonand pre-monsoon period) are also given.Similarly the status of aquatic vegetation (mainly floatingand emergent types) in two seasons is also accounted for.Status of small wetlands are also accounted as numbersand depicted in maps as points. Wetland map also showimportant ancillary information like roads/rail, relevanthabitations. False Colour Composite (FCC) of the satelliteimage used (any one season) is shown along with thederived wetland map to give a feeling of manifestation ofwetlands in remote sensing data and synoptic view of thearea. The status of some of the important wetlands likeRamsar sites, National Parks are shown with recent fieldphotographs.For further details contact:Director,Space Applications Centre, ISRO,Ambawadi Vistar (P.O.)Ahmedabad – 380 015director@sac.isro.gov.in

AtlasSAC/EPSA/AFEG/NWIA/ATLAS/36/2011NATIONAL WETLAND ATLASSIKKIMSponsored byMinistry of Environment and Forests, Government of IndiaAs a part of the project on National Wetland Inventory and Assessment (NWIA)Space Applications Centre (ISRO)AhmedabadFebruary 2011

First Publication: February 2011, Space Applications Centre (ISRO), AhmedabadCopyright:2011, SAC, ISROThis publication may be produced in whole or in part and in any form for education or non-profit uses,without special permission from the copyright holder, provided acknowledgement of source is made.SAC will appreciate a copy of any publication which uses this publication as a source.Citation:Available from:Production:National Wetland Atlas: Sikkim, SAC/EPSA/ABHG/NWIA/ATLAS/36/2011 Space Applications Centre(ISRO), Ahmedabad, India, 84p.Space Applications Centre, ISRO, Ahmedabad – 380 015, IndiaSAC, Ahmedabad carried out the work, Sponsored by Ministry of Environment and Forests, Govt. ofIndia.

MESSAGEIt gives me great pleasure to introduce this Atlas, the latest in a series, prepared by Space ApplicationsCentre, Ahmedabad in connection with the National Wetland Inventory and Assessment Project.This Atlas maps and catalogues information on Wetlands across India using the latest in satellite imaging,one of the first of its kind. Wetlands are areas of land critical ecological significance that support a largevariety of plant and animal species adapted to fluctuating water levels. Their identification and protectionbecomes very important.Utility-wise, wetlands directly and indirectly support millions of people in providing services such as food,fiber and raw materials. They play important roles in storm and flood control, in supply of clean water, alongwith other educational and recreational benefits. Despite these benefits, wetlands are the first target ofhuman interference and are among the most threatened of all natural resources. Around 50% of theearth’s wetlands are estimated to already have disappeared worldwide over the last hundred years throughconversion to industrial, agricultural and residential purposes. Even in current scenario, when theecosystem services provided by wetlands are better understood - degradation and conversion of wetlandscontinues.Aware of their importance, the Government of India has formulated several policies and plans for theconservation and preservation of these crucial ecosystems. Realising the need of an updated geospatialdata base of these natural resources as the pre-requisite for management and conservation planning,National Wetland Inventory and Assessment (NWIA) project was formulated as a joint vision of Ministry ofEnvironment & Forestry, Govt. India, and Space Applications Centre (ISRO). I am told that the latestremote sensing data from Indian Remote Sensing satellite (IRS P6) have been used to map the wetlands.The present atlas is part of this project and highlights the results of the study state in terms of statistics ofvarious types of wetlands, extent of water, aquatic vegetation and turbidity in pre and post monsoon period.I also note that special efforts are made to provide detailed information of important wetlands like Ramsarsites, National Parks etc.I am certain that this Atlas will raise the bar in developing such database and will be of great use forresearchers, planners, policy makers, and also members of the general public.

FOREWORDWetlands defined as areas of land that are either temporarily or permanently covered by water exhibitenormous diversity according to their genesis, geographical location, water regime and chemistry. Wetlandsare one of the most productive ecosystems and play crucial role in hydrological cycle. Utility wise, wetlandsdirectly and indirectly support millions of people in providing services such as storm and flood control, cleanwater supply, food, fiber and raw materials, scenic beauty, educational and recreational benefits. TheMillennium Ecosystem Assessment estimates conservatively that wetlands cover seven percent of the earth’ssurface and deliver 45% of the world’s natural productivity and ecosystem services. However, the veryexistence of these unique resources is under threat due to developmental activities, and population pressure.This calls for a long term planning for preservation and conservation of these resources. An updated andaccurate database that will support research and decision is the first step towards this. Use of advancedtechniques like Satellite remote sensing, Geographic Information System (GIS) is now essential for accurateand timely spatial database of large areas. Space Applications Centre (ISRO) took up this challenging taskunder the project “NWIA” (National Wetland Inventory and Assessment) sponsored by Ministry ofEnvironment & Forests. To account for numerous small yet important wetlands found in the country, mappingat 1:50,000 scales has been taken up. Two date IRS LISS III data acquired during pre and post monsoonseason are used for inventory to account for wet and dry season hydrology of wetlands. The map outputsinclude the status of water spread, aquatic vegetation and turbidity. Ancillary layers like road/rail, habitationsare also created. Very small wetlands below the mappable unit are also identified and shown points. Theresults are complied as Atlases of wetlands for states/Union Territories of India. This Atlas highlights resultsfor a particular state/UT and hopes to improve our understanding of the dynamics and distribution of wetlandsand their status in the area.I congratulate the team for bringing out this informative atlas and sincerely hope that this will serve as auseful source of information to researchers, planners and general public.January 25, 2010

ACKNOWLEDGEMENTSThe project “National Wetland Inventory & Assessment (NWIA)”, is sponsored by Ministry of Environment &Forestry (MoEF), Govt. of India and executed by Space Applications Centre, ISRO, Ahmedabad. We aregrateful to Dr. Ranganath R. Navalgund, Director, Space Applications Centre, for his encouragement to takeup this challenging task and formulation of the project team for timely implementation. Earnest thanks are alsodue to Dr. Jai Singh Parihar, Dy. Director, Earth, Ocean, Atmosphere, Planetary Sciences and ApplicationsArea, Space Applications Centre, for providing overall guidance and support to the project. The present Atlasfor the state of Sikkim is a part of the “National Wetland Atlas”. We thank Shri M. L. Arratiwati, IFS, Secretary,Department of Science & Technology cum Member secretary, Sikkim State Council of Science andTechnology for his support and guidance to the state team in this project.This project has benefited from the wisdom of many people. It is a pleasure to acknowledge the contributionsmade by the wetland experts especially to Prof. C.K. Varshney, Former Dean, School of EnvironmentalSciences, Jawaharlal Nehru University, New Delhi, Prof. A.R. Yousuf, The University of Kashmir, Srinagar,Prof. Pradeeep Shrivastava, Head, Wetland Research Centre, Barakatullah University, Bhopal, Dr. PrikshitGautam, Director, WWF-India, Dr. S. Narendra Prasad, Salim Ali Centre for Ornithology and Nature,Coimbtore and Dr. R.K. Suri, Additional Director, Ministry of Environment and Forests, Govt. of India, NewDelhi, and the database experts from ISRO who participated in the peer Review meeting to finalise the“Wetland Classification System” followed in this projectWe acknowledge the positive role played by 16 th SC-B (Standing Committee on Bioresources andEnvironment) of NNRMS (National Natural Resources Management System) meeting in formulating thisproject. We are extremely thankful to the members of the“Steering Committee” of the project, under thechairmanship of Dr E J James, Director – Water Institute, Karunya University, for their periodical review,critical comments and appreciation of the efforts by the project team. We are thankful to SC-B under thechairmanship of Secretary, MoEF, for periodic review of the progress of the project and guidance towardstimely completion of the work. We acknowledge the valuable contributions made by Dr J K Garg, the thenscientist of SAC for his active role in formulation of this project, co-authoring the procedure manual document.We are grateful to Dr G V Subramanyam, Adviser, MoEF for his very active and positive role forimplementation of the project. We are thankful to Dr Jag Ram, Director, MoEF and Dr Harendra Kharwal,MoEF for their support. We acknowledge the support received from Dr P S Roy, Dy Director, NRSC andDr S Sudhakar, Head, LRD, NRSC in terms of valuable suggestions and providing the geo-referenced imageof NRC-LU&LC project for use as master image in this project. We are thankful to the “Technical Review”team of SAC for critical comments and suggestion to finalise the Atlas. We thank Mr Pragnesh KumarVaishnav and Ms Yatisha P Vaishnav, Geology Department, M G Science Institute, Ahmedabad and Shri N MSuthar, SAC for their support in Quality Check and finalization of GIS database.Project team from State Remote Sensing Applications Centre, Sikkim express specific gratitude toDr. Sandeep Tambee, Mr. Nima Bhutia and Mr. Laku Bhutia for support in field photographs of high-altitudelakes (wetland) and all other officers and staff of Department of Science and Technology and Council for theirco-operation and support during the execution of this project.

PROJECT TEAMProject Director: Dr. (Mrs) Sushma PanigrahySpace Applications Centre, ISRO, AhmedabadShri T. V. R. MurthyShri J. G. PatelShri N. M. SutharSikkim State Council of Science & Technology, GangtokShri D.G ShresthaShri N.P. SharmaShri Benoy Kr. Pradhan

CONTENTS1.0 INTRODUCTION1.1 Wetlands1.2 Mapping and Geospatial Technique1.3 Wetland Inventory of India2.0 NATIONAL WETLAND INVENTORY AND ASSESSMENT2.1 Wetland Classification System2.2 Spatial framework and GIS database contents3.0 STUDY AREA3.1 Physiography and Surface Drainage3.2 Geology3.3 Climate3.4 Important Wetlands4.0 DATA USED4.1 Remote sensing data4.2 Ground truth data4.3 Other data5.0 METHODOLOGY5.1 Creation of Spatial Framework5.2 Geo-referencing of Satellite Data5.3 Mapping of Wetlands5.4 Conversion of Raster (indices) into a Vector Layer5.5 Generation of Reference Layers5.6 Coding and Attribute Scheme5.7 Map Composition and Output6.0 ACCURACY ASSESSMENT6.1 Data Verification and Quality Assurance of Output Digital Data Files7.0 WETLANDS OF SIKKIM: MAPS AND STATISTICS7.1 DISTRICT-WISE WETLAND MAPS AND STATISTICS7.1.1 North7.1.2 West7.1.3 South7.1.4 East8.0 MAJOR WETLAND TYPES OF SIKKIM9.0 IMPORTANT WETLANDS OF SIKKIM9.1 Khechodpalri Lake9.2 Gurudongmar Lake9.3 Tsomgo LakeREFERENCESAnnexure–I: Definitions of wetland categories used in the project.Annexure–II: Details of district information followed in the atlas

List of FiguresFigure 1: Spectral Signature of various targetsFigure 2: Various land features as they appear in three spectral bands and in a typical threeband FCCFigure 3: Location mapFigure 4: Spatial framework of SikkimFigure 5: IRS P6 LISS-III coverage of SikkimFigure 6: IRS LISS-IV FCC (Early winter and midwinter), Part of Sikkim stateFigure 7: Flow chart of the methodology usedFigure 8: Steps in the extraction of wetland componentsFigure 9: Various combinations of the indices/spectral bands used to identify wetland componentsFigure 10: Type-wise wetland distribution in SikkimFigure 11: District-wise graphical distribution of wetlandsList of TablesTable 1: Wetland Classification System and codingTable-2: Satellite data usedTable 3: Qualitative turbidity based on Mean and Standard deviation observed in the NDWI imageTable 4: Area estimates of wetlands in SikkimTable-5: District-wise wetland areaTable 6: Area estimates of wetlands in NorthTable 7: Area estimates of wetlands in WestTable 8: Area estimates of wetlands in SouthTable 9: Area estimates of wetlands in EastList of PlatesPlate 1: Major wetland types of SikkimPlate-2a, 2b: Field photographs and ground truth data of pertaining to High altitude lakesPlate 3: Khechodpalri LakePlate 4: Wetland map - 5 km buffer area of Khechodpalri LakePlate 5: Khechodpalri Lake as seen on IRS P6 LISS-IV image with 5 km buffer areaPlate 6: Gurudongmar LakePlate 7: Wetland map - 5 km buffer area of Gurudongmar LakePlate 8: Gurudongmar Lake as seen on IRS P6 LISS-III image with 5 km buffer areaPlate 9: Tsomgo LakePlate 10: Wetland map - 5 km buffer area of Tsomgo LakePlate 11: Tsomgo Lake as seen on IRS P6 LISS-IV image with 5 km buffer area

1.0 INTRODUCTIONIt is increasingly realised that the planet earth is facing grave environmental problems with fast depletingnatural resources and threatening the very existence of most of the ecosystems. Serious concerns are voicedamong scientists, planners, sociologists, politicians, and economists to conserve and preserve the naturalresources of the world. One of the constraints most frequently faced for decision making is lack of scientificdata of our natural resources. Often the data are sparse or unauthentic, rarely in the form of geospatialdatabase (map), thus open to challenges. Hence, the current emphasis of every country is to have anappropriate geospatial database of natural resources based on unambiguous scientific methods. The wetlandatlas of Sikkim, which is part of the National Wetland Atlas of India, is an attempt in this direction.1.1 WetlandsWetlands are one of the crucial natural resources. Wetlands are areas of land that are either temporarily orpermanently covered by water. This means that a wetland is neither truly aquatic nor terrestrial; it is possiblethat wetlands can be both at the same time depending on seasonal variability. Thus, wetlands exhibitenormous diversity according to their genesis, geographical location, water regime and chemistry, dominantplants and soil or sediment characteristics. Because of their transitional nature, the boundaries of wetlandsare often difficult to define. Wetlands do, however, share a few attributes common to all forms. Of these,hydrological structure (the dynamics of water supply, throughput, storage and loss) is most fundamental tothe nature of a wetland system. It is the presence of water for a significant period of time which is principallyresponsible for the development of a wetland. One of the first widely used classifications systems, devised byCowardin et al, 1979, was associated to its hydrological, ecological and geological aspects, such as: marine(coastal wetlands including rock shores and coral reefs, estuarine (including deltas, tidal marshes, andmangrove swamps), lacustarine (lakes), riverine (along rivers and streams), palustarine ('marshy'- marshes,swamps and bogs). Given these characteristics, wetlands support a large variety of plant and animal speciesadapted to fluctuating water levels, making the wetlands of critical ecological significance. Utility wise,wetlands directly and indirectly support millions of people in providing services such as food, fiber and rawmaterials, storm and flood control, clean water supply, scenic beauty and educational and recreationalbenefits. The Millennium Ecosystem Assessment estimates conservatively that wetlands cover seven percentof the earth’s surface and deliver 45% of the world’s natural productivity and ecosystem services of which thebenefits are estimated at $20 trillion a year (Source: www.MAweb.org). The Millennium Assessment (MA)uses the following typology to categorise ecosystem services:Provisioning services:Regulating services:Cultural and Amenity services:Supporting services:The resources or products provided by ecosystems, such as food, rawmaterials (wood), genetic resources, medicinal resources, ornamentalresources (skin, shells, flowers).Ecosystems maintain the essential ecological processes and life supportsystems, like gas and climate regulation, water supply and regulation,waste treatment, pollination, etc.Ecosystems are a source of inspiration to human culture and educationthroughout recreation, cultural, artistic, spiritual and historic information,Science and education.Ecosystems provide habitat for flora and fauna in order to maintainbiological and genetic diversity.Despite these benefits, wetlands are the first target of human interference and are among the mostthreatened of all natural resources. Around 50% of the earth’s wetland area is estimated to already havedisappeared over the last hundred years through conversion to industrial, agricultural and residentialdevelopments. Even in current scenario, when the ecosystem services provided by wetlands are betterunderstood - degradation and conversion of wetlands continues. This is largely due to the fact that the‘full value’ of ecosystem functions is often ignored in policy-making, plans and corporate evaluations ofdevelopment projects.1.2 Mapping and Geospatial TechniqueTo conserve and manage wetland resources, it is important to have inventory of wetlands and theircatchments. The ability to store and analyse the data is essential. Digital maps are very powerful tools toachieve this. Maps relate the feature to any given geographical location has a strong visual impact. Maps arethus essential for monitoring and quantifying change over time scale, assist in decision making.The technique used in the preparation of map started with ground survey. The Survey of India (SOI)topographical maps are the earliest true maps of India showing various land use/cover classes includingwetlands. Recent years have seen advances in mapping technique to prepare maps with much moreinformation. Of particular importance is the remote sensing and geographic information system (GIS)1

techniques. Remote sensing is now recognised as an essential tool for viewing, analyzing, characterising,and making decisions about land, water and atmospheric components.From a general perspective, remote sensing is the science of acquiring and analyzing information aboutobjects or phenomena from a distance (Jensen, 1986; Lillesand and Keifer, 1987). Today, satellite remotesensing can be defined as the use of satellite borne sensors to observe, measure, and record theelectromagnetic radiation (EMR) reflected or emitted by the earth and its environment for subsequent analysisand extraction of information. EMR sensors includes visible light, near-, mid- and far-infrared (thermal),microwave, and long-wave radio energy. The capability of multiple sources of information is unique toremote sensing. Of specific advantage is the spectral, temporal, and spatial resolution. Spectral resolutionrefers to the width or range of each spectral band being recorded. Since each target affects differentwavelengths of incident energy differently, they are absorbed, reflected or transmitted in different proportions.Currently, there are many land resource remote sensing satellites that have sensors operating in the green,red, near infrared and short wave Infra red regions of the electromagnetic spectrum giving a definite spectralsignature of various targets due to difference in radiation absorption and reflectance of targets. Thesesensors are of common use for land cover studies, including wetlands. Figure 1 shows typical spectralsignature of few targets from green to SWIR region. Converted to image, in a typical false colour composite(FCC) created using NIR, red and green bands assigned as red, green and blue colour, the features becomevery distinct as shown in Figure 2. In FCC, the vegetation thus appears invariably red (due to high reflectionin NIR from green leaves).Since the early 1960s, several satellites with suitable sensors have been launched into orbit to observe andmonitor the earth and its environment. Most early satellite sensors acquired data for meteorological purposes.The advent of earth resources satellite sensors (those with a primary objective of mapping and monitoringland cover) occurred, when the first Landsat satellite was launched in July 1972. Currently, more than adozen orbiting satellites of various types provide data crucial to improving our knowledge of the earth’satmosphere, oceans, ice and snow, and land. Of particular interest to India is the indigenous series ofsatellites called Indian Remote Sensing satellites (IRS-Series). Since the launch of the first satellite IRS 1A in1988, India has now a number of satellites providing data in multi-spectral bands with different spatialresolution. IRS P6/RESOURCESAT 1 is the current generation satellite that provides multi-spectral images inspatial resolution of 5.8 m (LISS IV), 23.5 m (LISS III) and 56m (AWiFS). Over the past few decades, Indianremote sensing data has been successfully used in various fields of natural resources (Navalgund et al,2002).Development of technologies like Geographic Information System (GIS) has enhanced the use of RS data toobtain accurate geospatial database. GIS specialises in handling related, spatially referenced data, combiningmapped information with other data and acts as analytical tool for research and decision making. During thepast few decades, technological advances in the field of satellite remote sensing (RS) sensors, computerizedmapping techniques, global positioning system (GPS) and geographic information system (GIS) hasenhanced the ability to capture more detailed and timely information about the natural resources at variousscales catering to local, regional, national and global level study.Figure 1: Spectral Signature of various targets2

BAND-1: GREENBNAD2: REDBAND-3: NIRLISS-IV FCC: Green Red NIRFigure 2: Various land features as they appear in three spectral bands and in a typical three band FCC3

1.3 Wetland Inventory of IndiaIndia with its large geographical spread supports large and diverse wetland classes, some of which areunique. Wetlands, variously estimated to be occupying 1-5 per cent of geographical area of the country,support about a fifth of the known biodiversity. Like any other place in the world, there is a looming threat tothe aquatic biodiversity of the Indian wetlands as they are often under a regime of unsustainable humanpressures. Sustainable management of these assets therefore is highly relevant. Realising this, Govt. of Indiahas initiated many appropriate steps in terms of policies, programmes and plans for the preservation andconservation of these ecosystems. India is a signatory to the Ramsar Convention for management ofwetland, for conserving their biodiversity and wise use extending its scope to a wide variety of habitats,including rivers and lakes, coastal lagoons, mangroves, peat-lands, coral reefs, and numerous human-madewetland, such as fish and shrimp ponds, farm ponds, irrigated agricultural land, salt pans reservoirs, gravelpits, sewage farms, and canals. The Ministry of Environment and Forests has identified a number of wetlandsfor conservation and management under the National Wetland Conservation Programme and some financialassistance is being provided to State Governments for various conservation activities through approval of theManagement Action Plans. The need to have an updated map database of wetlands that will support suchactions has long been realized.Mapping requires a standard classification system. Though there are many classification systems forwetlands in the world, the Ramsar classification system is the most preferred one. The 1971 RamsarConvention on Wetlands of International Importance especially as Waterfowl Habitat is the oldestconservation convention. It owes its name to its place of adoption in Iran. It came into being due to seriousdecline in populations of waterfowl (mainly ducks) and conservation of habitats of migratory waterfowl.Convention provides framework for the conservation and ‘wise use’ of wetland biomes. Ramsar convention isthe first modern global intergovernmental treaty on conservation and wise use of natural resources(www.ramsar.org). Ramsar convention entered into force in 1975. Under the text of the Convention (Article1.1) wetlands are defined as:“areas of marsh, fen, peat-land or water, whether natural or artificial, permanent or temporary, with water thatis static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide doesnot exceed six meters”.In addition, the Convention (Article 2.1) provides that wetlands:“may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine waterdeeper than six meters at low tide lying within the wetlands”.The first scientific mapping of wetlands of India was carried out during1992-93 by Space Applications Centre(ISRO), Ahmedabad, at the behest of the Ministry of Environment and Forests (MoEF), Govt. of India usingremote sensing data from Indian Remote Sensing satellites (IRS-Series). The mapping was done at1:250,000 scale using IRS 1A LISS-I/II data of 1992-93 timeframe under the Nation-wide Wetland MappingProject. Since, no suitable wetland classification existed for comprehensive inventory of wetlands in thecountry at that time; the project used a classification system based on Ramsar Convention definition ofwetlands. The classification considers all parts of a water mass including its ecotonal area as wetland. Inaddition, fish and shrimp ponds, saltpans, reservoirs, gravel pits were also included as wetlands. Thisinventory put the wetland extent (inland as well as coastal) at about 8.26 million ha (Garg et al, 1998). Theseestimates (24 categories) do not include rice/paddy fields, rivers, canals and irrigation channels.Further updating of wetland maps of India was carried out by SAC using IRS P6/Resourcesat AWiFS data of2004-05 at 1:250000 scale. In recent years, a conservation atlas has been brought out by Salim Ali Centre forOrnithology and Natural History (SACON, 2004), which provide basic information required by stakeholders inboth wetland habitat and species conservation. Space Applications Centre has carried out many pilot projectsfor development of GIS based wetland information system (Patel et al, 2003) and Lake Information system(Singh et al, 2003).4

2.0 NATIONAL WETLAND INVENTORY AND ASSESSMENT (NWIA) PROJECTRealising the importance of many small wetlands that dot the Indian landscape, it has been unanimously feltthat inventory of the wetlands at 1:50,000 scale is essential. The task seemed challenging in view of the vastgeographic area of our country enriched with diverse wetland classes. Space Applications Centre with itsexperience in use of RS and GIS in the field of wetland studies, took up this challenging task. This is furtherstrengthened by the fact that guidelines to create geospatial framework, codification scheme, data basestructure etc. for natural resources survey has already been well established by the initiative of ISRO undervarious national level mapping projects. With this strength, the National Wetland Inventory and Assessment(NWIA) project was formulated by SAC, which was approved and funded by MoEF.The main objectives of the project are:• To map the wetlands on 1:50000 scale using two date (pre and post monsoon) IRS LISS III digital datafollowing a standard wetland classification system. (Sikkim state was mapped on 1:25,000 scale usingIRS LISS-IV and LISS-III data)• Integration of ancillary theme layers ( road, rail, settlements, drainage, administrative boundaries)• Creation of a seamless database of the states and country in GIS environment.• Preparation of State-wise wetland atlases.The project was initiated during 2007. The first task was to have a classification system that can be used bydifferent types of users while amenable to database. An expert/peer group was formed and the peer reviewwas held at SAC on June 2007 where wetland experts and database experts participated and finalized theclassification system. It was agreed to follow the classification system that has been used for the earlierproject of 1:250,000 scale, with slight modification. Modified National Wetland Classification system forwetland delineation and mapping comprise 19 wetland classes which are organized under a Level IIIhierarchical system. The definition of each wetland class and its interpretation method was finalized.The technical/procedure manual was prepared as the standard guideline for the project execution across thecountry (Garg and Patel, 2007). The present atlas is part of the national level data base and deals with thestate of Sikkim.2.1 Wetland Classification SystemIn the present project, Modified National Wetland Classification system is used for wetland delineation andmapping comprising 19 wetland classes which are organized under a Level III hierarchical system (Table 1).Level one has two classes: inland and coastal, these are further bifurcated into two categories as: natural andman-made under which the 19 wetland classes are suitably placed. Two-date data pertaining to pre-monsoonand post-monsoon was used to confirm the classes. Wetlands put to agriculture use in any of the two datesare not included as wetland class. Definitions of wetland categories used in the project is given in Annexure-I.2.2 Spatial Framework and GIS DatabaseThe National Spatial Framework (NSF) has been used as the spatial framework to create the database(Anon. 2005a). The database design and creation standard suggested by NRDB/NNRMS guidelines isfollowed. Feature codification scheme for every input element has been worked out keeping in view thenationwide administrative as well as natural hierarchy (State-district- within the feature class for each of thetheme. All data elements are given a unique name, which are self explanatory with short forms.Following wetland layers are generated for each inland wetland:• Wetland extent: As wetlands encompass open water, aquatic vegetation (submerged, floating andemergent), the wetland boundary should ideally include all these. Satellite image gives a clear signatureof the wetland extent from the imprint of water spread over the years.• Water spread: There are two layers representing post-monsoon and pre-monsoon water spread duringthe year of data acquisition.5

• Aquatic vegetation spread: The presence of vegetation in wetlands provides information about itstrophic condition. As is known, aquatic vegetation is of four types, viz. benthic, submerged, floatingand emergent. It is possible to delineate last two types of vegetation using optical remote sensing data.A qualitative layer pertaining to presence of vegetation is generated for each season (as manifested onpre-monsoon and post-monsoon imagery).• Turbidity of open water: A layer pertaining to a qualitative turbidity rating is generated.Three qualitative turbidity ratings ( low, medium and high) is followed for pre- and post-monsoonturbidity of lakes, reservoirs, barrages and other large wetlands.• Small wetlands (smaller than minimum mappable unit: < 0.50 ha) are mapped as point features.• Base layers like major road network, railway, settlements, and surface drainage are created (either fromthe current image or taken from other project data base).Table 1: Wetland Classification System and codingWettcode* Level I Level II Level III1000 Inland Wetlands1100 Natural1101 Lakes1102 Ox-Bow Lakes/ Cut-Off Meanders1103 High altitude Wetlands1104 Riverine Wetlands1105 Waterlogged1106 River/stream1200 Man-made1201 Reservoirs/ Barrages1202 Tanks/Ponds1203 Waterlogged1204 Salt pans2000 Coastal Wetlands2100 Natural2101 Lagoons2102 Creeks2103 Sand/Beach2104 Intertidal mud flats2105 Salt Marsh2106 Mangroves2107 Coral Reefs2200 Man-made2201 Salt pans2202 Aquaculture ponds* Wetland type code6

3.0 STUDY AREAThe Himalayan state of Sikkim is surely one of the mystic places on earth. The rugged terrain, pristine rivers,eye-soothing lakes, majestic mountains and rich cultural heritage makes it a paradise, yet to be explored.Physiographically it has a dynamic variety in its altitude ranging from one of the highest places on earth to aslow as 240 m above MSL (mean sea level). On May 16 th , 1975 Sikkim officially became the 22 nd state of theIndian Union. Sikkim is situated in the North Eastern region of India. The state borders Nepal in the west,China to the north and the east and Bhutan in the southeast. The Indian state of West Bengal borders Sikkimto its south. It lies between 27°04’46’’ N to 28°07’48’’N latitude and 88°00’58’’ to 88°55’25’’E longitude(Figure 3). The total geographical area of the state is 7,096 km 2 occupying an area of 0.67% of the totalgeographical area of the country. It is the second smallest state after Goa.3.1 Physiography and Surface DrainageOn the basis of geographical features, the state is divided into four physiographical units; i) Lower hills,ii) Upper hills, iii) Alpine zones, and iv) Snow landAmong the four districts, North district is covered mainly by snow covered mountains, having the leastpopulation. World’s 3 rd highest mountain, Mount Khangchendzonga, (8598 m) gives a standing guard to thistiny though majestic state of Sikkim which has only 7096 sq. km area. Sikkim is a place of both religiousbeliefs and practices on the one hand, and environmental restoration and conservation on the other.Sikkim has a very rugged and formidable topography and flat lands. The towering mountains that define thisparadise of nature also create a barrier to efficient agriculture. These mountains fall directly in the path of themonsoon clouds making the state one of the wettest in the country. Most of the peaks above 6100 m lietowards the western border of Sikkim. The main mountains other than Khangchendzonga are Kabru,Siniolchu, Pandim, Rathong, Kokthang, Talung, Kanglakhang, Simvo and Jonsang. The central Sikkimtraversed by another mountain ridge in the north to south direction. This mountain ridge separates the Tistaand Rangit valley, and ends at the confluence of these two rivers. The gnarled topography tends, tosmoothen out in the upper reaches of the Tista River in the Lachen valley where the Tibetian Plateau juts intoSikkim. The state of Sikkim also shelters many Glaciers (slow moving river of ice), mainly Zemu Glacier,Rathong Glacier and Lhonak Glacier. The status of these Glaciers has become a measuring stick of climatechange. The mountain ranges are interspersed with passes which can be used to cross from one side toanother. The important passes in east district are Nathula, Jelepla, Bhutan la and Chola. The western part ofthe state has Chiwabhanjang and Kangla. In the North district of Sikkim, Chorten Nyimala, Kongra-la,Lungnala and Donkiala are important pass.Along with the mountains, Glaciers and passes, the state of Sikkim also have many lakes though not of verylarge size. These lakes are both spring fed as well as river fed. The premier lakes of the state are Changu(Tsomgo), Khechodpalri, Gurudongmar, Cholamu, Memencho, Lampokhari, Samiti etc. These lakes also formthe source of many rivers. The main river of Sikkim is Tista which originates from Lake Cholamu. Its maintributary is Rangit which originates from Rathong Glacier and meets Tista at the border between Sikkim andWest Bengal. The river Ramam a tributary of Rangit, a part of Rangit itself and Rangpoo chu, a tributary ofTista define the southern border between Sikkim and West Bengal. The other smaller tributaries of the TistaRiver are Zemu chu, Lonak chu, Lachung chu, Talung chu and Bakcha chu. The state of Sikkim has manyhot-springs known for their medicinal and therapeutic value. The most important are the ones located atPhurchachu (Reshi), Yumthang, Borang, Ralang, Taram-chu and Yumey Samdung. All these hot-springshave high sulphur content and are located near the river banks.3.2 GeologyGeologically, Sikkim state belongs to the young folded mountains of the Himalayan system. Half-schistose,gneissose and Precambrian are the three major rock constituents of the geology of Sikkim. Precambrian rockis found in a big part of the state of Sikkim and hence is a significant part of Sikkim geology. The region takenup by this rock has a relatively smaller age than the hilly regions of the state. The Precambrian rock is madeup of schists and phyllites. The presence of schists and phyllites makes the slopes of the region prone toerosion and weathering. The possibility of erosion of soil and the reduction of mineral content is increased byexcessive rainfall. Such geology is susceptible to natural disasters like landslides. The hilly regions of Sikkimmainly constitutes of two kinds of rocks - half-schistose and gneissose. These two kinds of rocks form crucialconstituents of the geology in Sikkim. The kind of soil prevalent in the north-eastern state of Sikkim is suitablefor deciduous and evergreen forests.The soil does not have a high content of organic matter and is not rich in minerals. The texture of this soil iscoarse. The presence of these two kinds of rocks has turned the soil of these regions brown and clayey.7

Numerous snow-fed streams in Sikkim have carved out river valleys in the west and south of the state. Thesestreams combine into the Teesta and its tributary, the Rangeet. These are the two main drainage basins. TheTeista, described as the "lifeline of Sikkim", flows through the state from north to south.Sikkim is covered by nineteen 1:50,000 scale SOI topographical maps and sixty 1:25,000 scale maps thatform the spatial frame work for mapping (Figure 4).A detail of district information followed in the atlas is given in Annexure-II.Figure 3: Location mapFigure 4: Spatial framework of Sikkim8

3.3 ClimateThe climate ranges from sub-tropical in the south to tundra in the northern parts. The tundra-type region in thenorth is clad by snow for four months a year though the temperature drops below 0 °C (32 °F) almost everynight. Most of the inhabited regions of Sikkim, however, witness a temperate climate, with the temperaturesseldom exceeding 28 °C (82.4 °F) in summer or dropping below 0 °C (32 °F) in winter. The mean monthlytemperature in summer is 15 °C. The average annual temperature for most of Sikkim is around18 °C(64.4 °F). The record for the longest period of continuous rain is 11 days. In the northern region, because ofhigh altitude, temperatures drop below −40 °C (−40 °F) in winter. The maximum rainfall of the state isrecorded in the month of July and August. During the monsoon, heavy rains that increase the possibility oflandslides.3.4 Important wetlandsAlong with the mountains, Glaciers and passes, the state of Sikkim also have many lakes though not in verylarge size. The lakes are both spring fed as well as river fed. The premier lakes of the state are Changu(Tsomgo), Khechodpalri, Gurudongmar, Cholamu, Memencho, Lampokhari, Samiti etc. The Tsomgo lakecovering and area of 24.47 ha is one of the important tourist sites in the state .The lake is about 15 m deepand is a home for brahiminy ducks. These ecosystems are ideal habitat for Red Panda, Rhododendrons andvarious species of birds. To, preserve such biosphere the Kanchenjunga National Park and reserve has beenestablished in 1977.4.0 DATA USED4.1 Remote sensing dataIRS P6 LISS IV and LISS III data have been used to map the wetlands. The spatial resolution of LISS-IV datais suitable for 1:25,000 scale mapping. The state of Sikkim is covered in 2 IRS LISS III scene (Figure 5). Twodate data, were used to capture the pre-monsoon and post-monsoon hydrological variability of the wetlandsrespectively (Table-2). Figure 6 shows the overview of the part of Sikkim as seen in the LISS IV FCC of postmonsoonpre-monsoon data respectively.Table-2: Satellite data usedSr. No. Path-Raw orbit Date of AcquisitionLISS-IV1 101-052 021924 07-January-20082 101-053 021924 07-January-20083 101-054 021924 07-January-20084 101-055 021924 07-January-20085 101-057 022393 09-February-20086 101-060 022393 09-February-20087 102-006 022663 28-February-20088 102-022 026073 25-October-20089 102-023 026073 25-October-200810 102-033 028801 05-May-200911 102-038 031529 13-November-200912 102-038 031188 20-October-200913 102-039 031529 13-November-200914 102-039 031600 18-November-200915 102-040 026826 17-December-200816 102-040 031600 18-November-200917 102-041 026826 17-December-200818 102-042 026826 17-December-200819 102-043 030918 01-October-200920 102-043 026826 17-December-200821 102-045 031941 12-December-200922 102-046 031941 12-December-200923 102-049 031870 07-December-200924 102-050 031870 07-December-200925 102-051 031259 25-October-200926 102-052 031259 25-October-200927 102-053 031259 25-October-200928 102-055 027167 10-January-2009LISS-III107-51 Nov 15, 2005, Jan 26, 2006, and Apr 13, 2005107-52 Nov 15, 2005, Jan 26, 2006, and Apr 13, 20059

Figure 5: IRS P6 LISS-III coverage of Sikkim4.2 Ground truth dataRemote sensing techniques require certain amount of field observation called “ground truth” in order toconvert into meaningful information. Such work involves visiting a number of test sites, usually taking thesatellite images. The location of the features is recorded using the GPS. The standard proforma as per theNWIA manual was used to record the field data. Field photographs are also taken to record the water quality(subjective), status of aquatic vegetation and water spread. All field verification work has been done duringOctober and November 2008.4.3 Other dataSurvey of India topographical maps (SOI) were used for reference purpose. Lineage data of National WetlandMaps at 1:250,000 scale was used for reference.5.0 METHODOLOGYThe methodology to create the state level atlas of wetlands is adhered to NWIA technical guidelines andprocedure manual (Garg and Patel, 2007). The overview of the steps used is shown in Figure 7. Salientfeatures of methodology adopted are• Generation of spatial framework in GIS environment for database creation and organisation.• Geo-referencing of satellite data• Identification of wetland classes as per the classification system given in NWIA Manual and mapping ofthe classes using a knowledge based digital classification and onscreen interpretation• Generation of base layers (rail, road network, settlements, drainage, administrative boundaries) fromsatellite image and ancillary data.• Mosaicing/edge matching to create district and state level database.• Coding of the wetlands following the standard classification system and codification as per NWIAmanual.• Preparation of map compositions and generation of statistics• Outputs on A3 size prints and charts for atlas.Work was carried out using ERDAS Imagine, Arc/Info and Arcgis softwares.5.1 Creation of Spatial FrameworkThis is the most important task as the state forms a part of the national frame work and covered in multiplemap sheets. To create NWIA database, NNRMS/NRDB standards is followed and four corners of the1:50,000 (15’ x 15’) grid is taken as the tics or registration points to create each map taking master grid as thereference. Spatial framework details are given in NWIA manual (Patel and Garg, 2007). The spatialframework for Sikkim state is shown in Figure 4.10

Early winter (September 2009)Mid winter (December 2009)Figure 6: IRS LISS-IV FCC (Early winter and midwinter), Part of Sikkim state11

5.2 Geo-referencing of Satellite DataIn this step the raw satellite images were converted to specific map projection using geometric correction.This is done using archive geometrically corrected LISS III data (ISRO-NRC-land use / land cover project).Standard image processing software was used for geo-referencing. First one date data was registered withthe archive image. The second date data was then registered with the first date data.5.3 Mapping of WetlandsThe delineation of wetlands through image analysis forms the foundation for deriving all wetland classes andresults. Consequently, a great deal of emphasis has been placed on the quality of the image Interpretation. Inthe present study, the mapping of wetlands was done following digital classification and onscreen visualinterpretation. Wetlands were identified based on vegetation, visible hydrology and geography. There arevarious methods for extraction of water information from remote sensing imagery, which according to thenumber of bands used, are generally divided into two categories, i.e. Single-band and multi-band methods.Single-band method usually involves choosing a band from multi-spectral image to distinguish water fromland by subjective threshold values. It may lead to over- or under-estimation of open water area. Multi-bandmethod takes advantage of reflective differences of each band.In this project, five indices known in literature that enhances various wetland characteristics were used exceptNDPI and MNDWI due to lack of SWIR/MIR band in LISS-IV (McFeetres, 1986; Xu Hanqiu, 2006; Lacaux etal, 2007; Townshend and Justice, 1986; Tucker and Sellers, 1986) as given below:i) Normalised Difference Water Index (NDWI) = (Green-NIR) / (Green + NIR)ii)iii)iv)Modified Normalised Difference Water Index (MNDWI) = (Green-MIR) / (Green + MIR)Normalised Difference Vegetation Index (NDVI) = (NIR - Red) / (NIR + Red)Normalised Difference Pond Index (NDPI) = (MIR – Green / MIR + Green)v) Normalised Difference Turbidity Index (NDTI) = (Red – Green) / (Red + Green)IRS P6 LISS III(pre- and post-monsoon data)Spatial frame workLegacy dataGeo-referenced imagesAdmin. Boundaries(State, District)On-screen interpretation/Digital analysisSOI topographic mapsGround truthMorphometric(Wetland extent)Physical(Wetland type)Biological(Wetland vegetation)Base layers(Road, Settlement, drainage)Quality CheckGIS DATABASE(Wetland layers, Base layers)NWIA Database Organisation(District, State, Country)Accuracy Assessment/Quality CheckAnalysisAtlases/ReportFigure 7: Flow chart of the methodology used12

The indices were generated using standard image processing software, stacked as layers (Figure 8). Variouscombinations of the indices/spectral bands were used to identify the wetland features as shown in Figure 9.The following indices were used for various layer extractions:• Extraction of wetland extent :NDWI, NDVI and NDTI image was used to extract the wetland boundary through suitable hierarchicalthresholds.• Extraction of open water :NDWI was used with in the wetland mask to delineate the water and no-water areas.• Extraction of wetland vegetation :NDVI image was used to generate the vegetation and no-vegetation areas within a wetland using asuitable threshold.• Turbidity information extraction :NDWI image was used to generate qualitative turbidity level (high, moderate and low) based onfollowing steps:a) Conversion of post and pre-monsoon water spread polygons into Area of Interest (AoI).b) Grouping of all AoIs excluding all non-wetland areas into a single entity.c) Generate a signature statistics like minimum, maximum, mean and standard deviations.d) Generate a raster turbidity image through a model for AoI only with conditional categorisation.e) Convert the raster into vector and update the attributes or edit the water spread layer (copied asturbidity layer) in polygon mode so as to retain all the attributes.f) Assign turbidity classes as per the Table 3.Figure 8: Steps in the extraction of wetland componentsTable 3: Qualitative turbidity based on Mean and Standard deviation observed in the NDWI imageSr. No. Conditional criteria Qualitative Turbidity1. -1σ to +1σ Low13

NDWI NDTI NDTIUseful for delineation of wetland boundaryNDWI NDVI NDTIABIRS P6 LISS-IV FCC G R NIRA: Open-waterB: Semi-frozen waterUseful for delineation of open-water and vegetationσ -BASED CLASIFED NDWI IMAGEUseful for qualitative turbidity ratingFigure 9: Various combinations of the spectral bands/ indices used to identify wetland components14

5.4 Conversion of the Raster (indices) into a Vector LayerThe information on wetland extent, open water extent, vegetation extent and turbidity information wasconverted into vector layers using regional growing properties or on-screen digitization.5.5 Generation of Reference LayersBase layers like major road network, settlements, drainage are interpreted from the current image or takenfrom other project data base. The administrative boundaries (district, state) are taken from the knownreference data.5.6 Coding and Attribute SchemeFeature codification scheme for every input element has been worked out keeping in view the nationwideadministrative as well as natural hierarchy (State-district-taluka) within the feature class for each of the theme.All data elements are given a unique name/code, which are self explanatory with short forms.5.7 Map composition and outputMap composition for atlas has been done at district and state level. A standard color scheme has been usedfor the wetland classes and other layers. The digital files are made at 1:50,000 scale. The hard copy outputsare taken in A3 size.6.0 ACCURACY ASSESSMENTA comprehensive accuracy assessment protocol has been followed for determining the quality of informationderived from remotely sensed data. Accuracy assessment involves determination of thematic (classification)as well as location accuracy. In addition, GIS database(s) contents have been also evaluated for accuracy.To ensure the reliability of wetland status data, the project adhered to established quality assurance andquality control measures for data collection, analysis, verification and reporting.This study used well established, time-tested, fully documented data collection conventions. It employedskilled and trained personnel for image interpretation, processing and digital database creation. All interpretedimagery was reviewed by technical expert team for accuracy and code. The reviewing analyst adhered to allstandards, quality requirements and technical specifications and reviewed 100 percent of the work. Thevarious stages of quality check include:1. Image-Image Geo-referencing/Data generation2. Reference layer preparation using NWIA post monsoon and pre-monsoon LISS-IV and LISS-III data.3. Wetland mapping using visual/digital interpretation techniques.4. Geo-data base creation and organization5. Output products.6.1 Data verification and quality assurance of output digital data filesAll digital data files were subjected to rigorous quality control inspections. Digital data verification includedquality control checks that addressed the geospatial correctness, digital integrity and some cartographicaspects of the data. Implementation of quality checks ensured that the data conformed to the specified15

criteria, thus achieving the project objectives. There were tremendous advantages in using newertechnologies to store and analyze the geographic data. The geospatial analysis capability built into this studyprovided a complete digital database to better assist analysis of wetland change information. All digital datafiles were subjected to rigorous quality control inspections. Automated checking modules incorporated in thegeographic information system (Arc/GIS) were used to correct digital artifacts including polygon topology.Additional customized data inspections were made to ensure that the changes indicated at the imageinterpretation stage were properly executed.16

MAPS AND STATISTICS17

7.0 WETLANDS OF SIKKIM: MAPS AND STATISTICSArea estimates of various wetland categories for Sikkim have been carried out using GIS layers of wetlandboundary, water-spread, aquatic vegetation and turbidity. Total 451 wetlands have been mapped at 1:25,000scale in the state. In addition, 245 wetlands (smaller than 0.50 ha) have also been identified. Total wetlandarea estimated is 8463 ha accounting for about 1.19 per cent of the geographic area of stateThe major wetland types are High altitude lakes accounting for 35.48 per cent of the wetlands (3003 ha),river/stream (5097 ha) and Lake/ponds (118 ha). Graphical distribution of wetland type is shown in Figure 10.For assessment of qualitative turbidity based on signature statistics of NDWI image for open water featureshas been considered as explained in the methodology. Accordingly, wetlands where open water featureshave not been manifested on satellite data were excluded in spite of the fact that these wetlands areassociated with water. Overall three wetland types are assessed for turbidity namely Lake/Pond, Highaltitude lake and River/Stream. Aquatic vegetation seen in lake/pond category having 7 ha in post- andpre-monsoon seasonsThe extent of open water in post-monsoon of the year 2006 is 7092 ha which comprised 2380 ha of low and4712 ha of moderate turbidity. The extent under turbidity classes changed considerably in the pre-monsoon of2005 which is estimated as 885 ha of low and 4136 ha of moderate turbidity out of 5021 ha of open waterfeatures based on LISS-III data. Details of the wetland statistics of the district is given in Table 4.Table 4: Area estimates of wetlands in SikkimArea in haSr.No.WettcodeWetland CategoryNumberofwetlandsTotalwetlandarea% ofwetlandareaOpen WaterPostmonsoonareaPremonsoonarea1100 Inland Wetlands - Natural1 1101 Lakes/Ponds 45 118 1.40 8 82 1103 High altitude wetlands 405 3003 35.48 2953 8823 1106 River/Stream 1 5097 60.22 4131 4131Sub-Total 451 8218 97.11 7092 5021Wetlands (

High Altitude Wetlands occupy an important place in terms of their ecological character and conservationvalue. Analysis of these wetlands falling three altitudinal zones has been carried out with the aid of a DigitalElevation Model (SRTM-DEM). Accordingly, three altitudinal zones were identified and distribution along withextent has been estimated. There are 10 wetlands of this category with an extent of 108 ha in 3000-4000 maltitude zone. While the zone between 4000-5000 m, there are 130 wetlands with an extent of 920 ha and inthe zone > 5000 m, there are 119 wetlands with an extent of 2022 ha.7.1 DISTRICT-WISE WETLAND MAPS AND STATISTICSThe state has four districts. District-wise distribution of wetlands showed that three districts can be called aswetland rich. North has highest concentration with around 60.40 percent of total wetland area in state and itshare 1.21% of geographic area of district. This is mainly due to the location of the famous GurudongmarLake. The other two districts are: East and West comprise 14.43 and 14.23 per cent of area under wetlandrespectively. South district has the lowest area under wetland (10.94 %) out of the total wetland extract.Wetland category of High altitude was observed only in three districts. District-wise wetland area estimates isgiven in Table-5. District-wise graphical distribution of wetlands is depicted in Figure 11. The districts withvery high concentration of small wetlands (< 0.50 ha) is North with 171 followed by West and East Districtwith 41 and 30 respectively, while south district has lowest with 3 such wetlands.Wetland statistics followed by wetland map and corresponding satellite data for each district is given to havea fairly good idea about the distribution pattern and density of wetlands in the district.Table-5: District-wise wetland areaGeographic Wetland% ofSr.% of totalDistrict Area AreageographicNo.wetland area(sq. km) (ha)area1 North 4226 5112 60.40 1.212 West 1166 1204 14.23 1.033 South 750 926 10.94 1.234 East 954 1221 14.43 1.28Total 7096 8463 100.00 1.19Figure 11: District-wise graphical distribution of wetlands20

7.1.1 NorthThe North district with its headquarter at Mangan (72 Km from Gangtok) lies between 88°07’00” E to88°31’48” E Longitudes and 27°04’12” N and 27°33’00” N Latitudes and the total geographical area of theDistrict is 4226 Sq. Km. It is bounded on the North by China, on the South by South West and East District,on the East by China. The total population of the district is 41030 (census 2001). The District is divided intotwo Sub-Divisions, viz (1) Mangan Sub-Division with its HQ at Mangan, and (2) Chungthang Sub-Division withits HQ at Chungthang. This district can be termed as the wetland district of the state as the wetland areaestimated is 5112 ha, accounting for 1.21 per cent of geographic area. The wetland types found are Highaltitude lakes (wetland) and River/Stream. Small wetlands, which are less than minimum mapable units(MMU), are 171 in the district. The dominant type of wetland found in the North district is high altitude lakes(wetland) which account for around 52.70 per cent of the total wetland area of the district. Major part of thefamous Gurudogmar Lake lies in this district. All the wetlands of this district come under open water andthere is no aquatic vegetation found in this district. The turbidity rating of the open water is observed to bemainly moderate following low. Details of the wetland statistics of the district is given in Table 6.For assessment of qualitative turbidity based on signature statistics of NDWI image for open water featureshas been considered as explained in the methodology. Accordingly, wetlands where open water featureshave not been manifested on satellite data were excluded in spite of the fact that these wetlands areassociated with water. Overall two wetland types are assessed for turbidity namely High altitude wetlandsand River/Stream. The extent of open water in post-monsoon of 2006 is 4543 ha which comprised 2171 ha oflow and 2372 ha of moderate. The extent under turbidity classes changed considerably in the pre-monsoon of2005 which is estimated as 598 ha of low and 1987 ha of moderate turbidity out of 2585 ha of open waterfeatures.Table 6: Area estimates of wetlands in NorthArea in haSr.No.WettcodeWetland CategoryNumberofwetlandsTotalwetlandarea% ofwetlandareaOpen WaterPostmonsoonareaPremonsoonarea1100 Inland Wetlands - Natural1 1101 Lakes/Ponds 15 19 0.37 - -2 1103 High altitude wetlands 321 2694 52.70 2674 7163 1106 River/Stream 1 2228 43.59 1869 1869Sub-Total 337 4941 96.65 4543 2585Wetlands (

7.1.2 WestThe West district and its district headquarter Gayzing lies in the western part of Sikkim at and 88°01’00” E to88°21’00” E Longitude and 27°06’00” N to 27°36'00” N Latitude. It is the border district of the state. Itsneighbors are Nepal in west, south district in the east, West Bengal on the south and North district of Sikkimon the north. The district headquarter is about 95 km away from Gangtok. The famous lake Khechodpalri liesin this district and Yaksum the first capital of the state and Rabdesi the second capital of state also lies in thisdistrict. The total geographical area of the district is 1166 sq. km. The district is divided into two subdivisionviz. Gayzing and Soreng. As per Census 2001, the population of the district is 1, 23,256 with the density ofpopulation per sq. km. being 84. The wetland area estimated is 1204 ha. Small wetlands, which are less thanminimum mapable units (MMU), are 41 in the district. The major wetland type is river/stream andLakes/Ponds, which account for 81.83 % and 8.08 % (Table 7). There is only one lake/pond with 97 ha ofextent. Till the date of data acquisition (November 15, 2005) freezing has taken place and on the other handin pre-monsoon (April 13, 2005) melting has not occurred which resulted in lower pre-monsoon open waterextent compared to post-monsoon open water extent. Details of the wetland statistics of the district is given inTable 7.For assessment of qualitative turbidity based on signature statistics of NDWI image for open water featureshas been considered as explained in the methodology. Accordingly, wetlands where open water featureshave not been manifested on satellite data were excluded in spite of the fact that these wetlands areassociated with water. Overall three wetland types are assessed for turbidity namely lakes, High altitudewetlands and River/Stream. The extent of open water in post-monsoon of 2005 is 949 ha which comprised158 ha of low and 791 ha of moderate. The extent under turbidity classes has shown a change in the premonsoonof 2005 which is estimated as 235 ha of low and 714 ha of moderate turbidity out of 949 ha of openwater features.Table 7: Area estimates of wetlands in WestArea in haSr.No.WettcodeWetland CategoryNumberofWetlandsTotalWetlandArea% ofwetlandareaOpen WaterPostmonsoonAreaPremonsoonArea1100 Inland Wetlands - Natural1 1101 Lakes/Ponds 1 97 8.08 8 82 1103 High altitude wetlands 17 81 6.69 81 813 1106 River/Stream 1 985 81.83 860 860Sub-Total 19 1163 96.59 949 949Wetlands (

7.1.3 SouthSouth district with its district headquarter at Namchi (85km from Gangtok), has the total geographic area of750 sq km. Its location is 88°15’00” E to 88°32’00” E longitude and 27°04’00” N to 27°32’00” N latitude. Thedistrict is bounded by Tista River in the East, Rangit River in the south and west, Dzongu area of North districtin the North. There are two subdivision viz. Namchi and Ravongla. Namchi is the fast growing town of Sikkimwith the development of various tourist spots and other small scale industries. Agriculture is the mainoccupation of the people in the district. The total population of the district is 1, 31,525 (census 2001).The district receives least rainfall in comparison with the other district hence regarded as the driest district ofSikkim. The district has least presence of wetlands excepting river/stream. The wetland area estimated is926 ha, which is only due to the presence of river/stream. Small wetlands, which are less than minimummapable units (MMU), are 3 in the district. Due to perennial nature, the open water extents (737 ha) ofriver/stream have remained unchanged irrespective of seasons. Details of the wetland statistics of the districtis given in Table 8.As mentioned earlier, wetlands where open water features have not been manifested on satellite data wereexcluded in spite of the fact that these wetlands are associated with water. Only wetland type is assessed forturbidity namely River/Stream. The extent of open water in post-monsoon of 2005 is 737 ha which comprisedof moderate turbidity. The turbidity of open water remained moderately turbid in both seasons.Table 8: Area estimates of wetlands in SouthArea in haSr.No.WettcodeWetland CategoryNumberofwetlandsTotalwetlandarea% ofwetlandareaOpen WaterPostmonsoonareaPremonsoonarea1100 Inland Wetlands - Natural1 1101 Lakes/Ponds - - - - -2 1103 High altitude wetlands - - - - -3 1106 River/Stream 1 923 99.68 737 737Sub-Total 1 923 99.68 737 737Wetlands (

7.1.4 EastEast district, with headquarter at Gangtok, located in the south eastern corner of Sikkim. Its location is88°26 ' 00 ” E to 88°55 ' 00” E and 27°08 ’ 00” N to 27°25 ' 00”N and has an area of 954 sq. km. According to 2001census, the total population of the district is 2, 45,040. The district is divided into 3 revenue Sub-divisions,namely Gangtok subdivision, Pakyong subdivision and Rongli subdivision. The district is mainly drained bytributaries of Tista River, Rangpo chu, Ronghichu. Tshangu Lake is the important lake of the East Districtwhich attracts many tourists to the state. The wetland area estimated is 1221 ha. Small wetlands, which areless than minimum mapable units (MMU), are 30 in the district. This is mainly due to presence ofriver/streams and high altitude lakes. River/stream dominates the wetland area comprising 78.64 % of areawith perennial nature. High altitude lakes show reduction in extent of open water from post-monsoon to premonsoonowing to non-melting. Details of the wetland statistics of the district is given in Table 9.For assessment of qualitative turbidity based on signature statistics of NDWI image for open water featureshas been considered as explained in the methodology. Accordingly, wetlands where open water featureshave not been manifested on satellite data were excluded in spite of the fact that these wetlands areassociated with water. Overall two wetland types are assessed for turbidity namely lakes, High altitudewetlands and River/Stream. The extent of open water in post-monsoon of 2005 is 863 ha which comprised 51ha of low and 812 ha of moderate turbidity. The extent under turbidity classes changed marginally in the premonsoonof 2005 which is estimated as 52 ha of low and 698 ha of moderate turbidity out of 750 ha of openwater features.Table 9: Area estimates of wetlands in EastArea in haSr.No.WettcodeWetland CategoryNumberofwetlandsTotalwetlandarea% ofwetlandareaOpen WaterPostmonsoonareaPremonsoonarea1100 Inland Wetlands - Natural1 1101 Lakes/Ponds 2 2 0.18 - -2 1103 High altitude wetlands 67 229 18.73 198 853 1106 River/Stream 1 960 78.64 665 665Sub-Total 70 1191 97.54 863 750Wetlands (

MAJOR WETLAND TYPES41

8.0 MAJOR WETLAND TYPES OF SIKKIMMajor wetland types observed in the state are Lakes, High-altitude lakes, Rivers and lake with aquavegetation(Plate 1). Ground truth data was collected for selected wetland sites. A standard proforma wasused to record the field data. Field photographs are also taken to record the water quality (subjective), statusof aquatic vegetation and water spread. The location of the features was recorded using GPS.Field photographs of different wetland types are shown in Plate 2a, and 2b.IRS P6 LISS-IV FCC (G R NIR)FCC of Indices (NDWI NDVI NDTI)Glaciated LakeHigh Altitude wetlandHigh Altitude wetlandRiver/StreamPlate 1: Major wetland types of Sikkim43

Plate-2a: Field photographs and ground truth data of pertaining to High altitude lakes44

Plate-2b: Field photographs and ground truth data of pertaining to High altitude lakes in Sikkim45

IMPORTANT WETLANDS OF SIKKIM47

9.0 IMPORTANT WETLANDS OF SIKKIMSikkim has many lakes even though they are not very big in volume. The Lakes are spring fed as well as riverfed and most of the lakes in sikkim are considered sacred and are revered by the people.The North Sikkim plateau adjoining Tibet has a number of mountain lakes of which Gurudongmar and Chholamo are the most famous. Chho lamo is the source of the Teesta river. The Tsomgo Lake in east Sikkim isthe most popular with tourists while Khecheopalri in West Sikkim is one of the most beautiful and sacred.On the Gangtok and Nathu la highway, 34 kms from Gangtok lies the serene Tsomgo (Changu) lake at analtitude of about 11,000 feet. Khecheopalri lake is another well known lake that lies on a bifurcation of theroute between Gyalshing and yuksom. Menmecho lake, green lake and Samiti lake are some other beautifullakes. Lakshmi Pokhari and Bidan Chu Lake are the graceful lakes of Sikkim.Extensive field work was carried out for these wetland areas. Wetland maps have been prepared for 5kmbuffer area of wetland site. Details of each wetland and wetland map of 5 km buffer area are shown in plates.9.1 KHECHEOPALRI LAKEKhecheopalri Lake (also called Khachoedpaldri Lake and Chhejo pokhari) in Sikkim is also known as thewishing lake and it can be easily reached from Geyzing via Pemayangtse at about 30 km and locatedbetween 27 0 21’ 10.13” N and 88 0 11’ 25.23” E at about 1820 m altitude. At an altitude of 1820 m amsl(above mean sea level), this unusually tranquil lake is surrounded by blooming forest and is considered asone of the sacred lakes of Sikkim. It is in the fact worshipped both by the Buddhists as well as the Hindus.The real name of the lake is Sho Dzo Sho, meaning “Oh Lady, Sit Here”, but is commonly known asKhachoedpaldri Lake because it sits on the lap of Khachoedpaldri, a very sacred hill.The origin of the lake as narrated in the sacred scriptures of Sikkimese Buddhism starts after the Nepaliinvasion of the medieval kingdom in the 1780s. The Nepali army destroyed the original (third) palace of theNamgyal Dynasty situated at Rabdentse. They also desecrated a holy lake at Yosum, West Sikkim.The lake is enveloped in a dense forest cover of temperate vegetation and bamboo. The placid waters of thelake are visited by many pilgrims and tourists. The closest town is Pelling. From the main gate, where aresmall shops and the road ends, to the lake is about a ten to fifteen minutes walk through a lovely tropicalforest.It is gaining popularity within the tourism sector due to its landscape and rich biodiversity, in addition to thevarious ethnic religio-cultural aspects and sacred beliefs associated with it. Studies show that the lake isfacing immense pressure from the surrounding catchments and its longevity is under threat mainly because ofanthropogenic pressure. By promoting traditional sacred beliefs and its folklores and linking ecotourism withsocial and economic development of the local populace, it may be possible to conserve the natural andcultural heritage of the lake and the Himalayan region as a whole.The significance of Khecheopalri Lake the serene waters of this lake appear to comprise a celestial charisma.Hence, no water sport or other activities besides prayers are allowed around the lake. It is believed that birdsdo not permit even a single leaf to float on the Lake’s surface. This is explained by the duck population whichare known to remove the leaves as soon as they fall on the surface, giving it a clear and smooth surface.It is believed that the deity of the lake one day appeared to a monk and beseeched to be taken out of thedesecrated lake, and she would guide him to the right place. The monk took a vessel of water from the lake49

and through divine guidance, reached Khachoedpaldri hill. Finally, the deity, Goddess Tara, directed him to aplace below the hill, where he prayed and in a shallow depression of the lake, poured the water. Graduallyand miraculously, the lake filled up.Today there is pier that leads to the front of the lake and one can pray and offer incense. An annual Buddhistritual from the readings of the Naysul prayer book describes the origin of Sikkim and has several tantric secretprayers, is offered at the Lake.Long time back this place used to be a grazing ground, troubled by nettle. Then on a certain day, conchshellswere seen falling on the ground. This was followed by severe shaking of the ground and water emerged frombelow. This lake was then termed as the footprints of Goddess Tara. From a high enough vantage point thecontours of the lake look like a footprint - believers hold that it is situated in Shiva's footmarks. Thesurrounding of the lake is an ideal place to find the Lepcha Houses and their communities. Pilgrims andtourists from all parts of the world come to visit this placid lake.The lake represents the original névé (that is, compact granular snow that eventually forms a glacier) regionof an ancient hanging glacier and the depression is formed by the scooping action of the glacier. A moraineridge forms the southern bank of the Lethang valley. The lake has been estimated to be more than 3500years old. Khecheopalri Lake is surrounded by the forested Ramam watershed (named after RamamMountain) and covers an area of 12 square kilometers. It falls on the southern boundary of theKhangchendzonga Biosphere Reserve (Buffer Zone IV), limiting on the reserved forest boundaries ofKhecheopalri Village. It has an open water surface area of 3.79 hectares with a mean water depth of 7.2meters. The lake is well drained from the watershed with internal seepage flows from 2 perennial and 5seasonal inlets and is drained out through a major perennial outlet. The lake drainage area constitutes of 91hectares from the total area of the Ramam watershed. The lake is a halting place for Trans-Himalayanmigratory birds. In addition to being a pilgrimage site, the lake provides recreational tourism opportunities. Alarge number of religious festivals are performed every year and these attract pilgrims (7,800 in 1998) fromwithin the state as well as the nearby countries of Nepal and Bhutan. About 8,000 national and 2,000international tourists visit the lake annually. Khecheopalri Lake as seen on satellite image as well as in thefield is depicted in the plate 3 along with specific information on the lake. Wetland map for 5 km buffer area ofKhechodpalri Lake and corresponding satellite image are shown in plate 4 and 5 respectively.9.2 GURUDONGMAR LAKEGurudongmar Lake (also known as Gurudogmar Lake) is the largest, perhaps the highest lake in Sikkim,India lies between 28 0 02’ 07.88” and 88 0 42’ 44.36” E at altitude of 5148 m. The very appearance of serenewaters of the lake brings a sense of relief to the beholder. Situated at an elevation of 17,100 feet (5,148 m),Gurudogmar Lake rests on the northern side of the Khangchengyao Range, close to the Indo-China Border inthe province of North Sikkim, Sikkim, India in a high plateau area next to the Tibetan Plateau. GurudongmarLake is a watercourse of high reverence for the Sikkimese and Buddhists the stream emerging from the lakeis one of the source-streams of the Tista River and is revered by both Buddhists and Hindus as a sacred lake.The lake is named after Padmasambhava, the Indian tantric Buddhist who conducted rituals here. It is saidthat this is why even at the height of winter one portion of the lake never freezes. Guru Nanak, also known asNanak Lama, who was a devotee of Padmasambhava, visited many of the places where Padmasambhavaprayed at, including this lake in North Sikkim.The lake is highly revered by the Sikkimese and Buddhists and the waters are supposed to have curativeproperties. The Indian Army got into a conflict with the Sikkim Government when they erected a Gurdwara (aSikh temple) near the lake in the 1990s: the Gurudwara has now become a 'Sarva Dharma Sthal' (House ofworship for All Religions), and ruffled feathers have been smoothened.50

Due to the extremely inhospitable terrain and the difficulties associated with reaching the place, the lake seesonly a handful of visitors each year. Access is strictly controlled at the Army check post at Giagong. Due tothe altitude, there is a scarcity of oxygen. Visitors are advised to acclimatise overnight at Lachen, carrymedicines like Coca 10, Deryphyllin etc., and to descend quickly in case of acute or persistent discomfort.Over-excitement and loud, stressful talking should be avoided.Encircled all around by snow-covered mountains the lake freezes during the winter, except at one spot said tobe blessed by Guru Rimpoche. The water of the lake is believed to have the miraculous power of grantingchildren to issueless couples. Gurudongmar Lake as seen on satellite image as well as in the field is depictedin the plate 6 along with specific information on the lake. Wetland map for 5 km buffer area of GurudongmarLake and corresponding satellite image are shown in plate 7 and 8 respectively.9.3 TSOMGO LAKE:Tsomgo Lake (also called Changu Lake or Tsongmo Lake) is located between 27 0 21’ 28.36” N and 88 0 46’00.40” E at an altutude of 3780 m in the north eastern part of Sikkim. Etymologically "Tso" means lake and"Mgo" means head, thus literally meaning "source of the lake" in the Bhutia language. The cerulean lake isabout 40 kilometres away from the capital Gangtok at an altitude of 3,780 m (12,400 feet). It is oval-shaped,with a length of nearly a kilometre and has an average depth of fifteen metres. The tarn with its refulgentwaters is situated on the Gangtok-Nathula highway, which makes a role of the erstwhile trade route from Indiato China. This lake has been worshipped as a holy lake by Sikkimese. During the winter season, the lakewould be in frozen condition up to mid-May. A moderate-sized temple of lord Shiva is present on thelakeshore.It falls in the restricted area and hence an inner line permit is required by Indians to visit this place. Foreignnationals are not permitted to visit this lake without special permission. It is also a home of brahminy ducks.It's cool, placid water harmonizes with the scenic beauty around.Between May and August it is possible to see a variety of flowers in blooms, including the Rhododendrons,various species of Primulas, blue and yellow Poppies, and Irises etc. It is also an ideal habitat for the RedPanda and various species of birds. Due to the heavy promotion of tourism in the state, many locals have setup shop here offering yak rides, yak cheese, trinkets, and local curios. Indian Postal Service released acommemorative stamp on the lake on 6 November 2006.Many tributary glaciers feed the trunk glacier. The side valleys, in which these glaciers lie, open into the mainZemu Valley from different directions. Icefalls and waterfalls have formed at the junction of the tributaryglaciers with the Zemu glacier. Tsomgo Lake as seen on satellite image as well as in the field is depicted inthe plate 9 along with specific information on the lake. Wetland map for 5 km buffer area of Tsomgo Lake andcorresponding satellite image are shown in plate 10 and 11 respectively.51

NameLocationAreaKhechodpalri LakeUpper left: 27 0 21’ 11.04” N, 88 0 11’ 09.13” ELower right: 27 0 20’ 53.12” N, 88 0 11’ 22.61” E15.08 haThe lake has 7.11 ha of clear water area and 7.97 ha ofaqua- vegetation area, which is marshy land.Aquatic vegetationAltitudeClimate1820 mAverage annual rainfall: 1183 mmTemperature: 15 o to 28 o C.MorphometricfeaturesTurbidityVegetationMaximum length: 547mMaximum breadth: 352mMaximum depth: 9 mAverage depth: 7.2 mModerateThe Important vegetation of the around the lake arearecorded are Symplocos thaefolia, Eurya acuminataClear waterIRS P6 LISSIV, October 2009FaunaA great diversity of invertebrate and vertebrate fauna areassociated with khechodpalri lake.The lake is enveloped in a dense forest cover oftemperate vegetation and bamboo. Various ethnic religioculturalaspects and sacred beliefs associated with it.Studies show that the lake is facing immense pressurefrom the surrounding catchments and its longevity is underthreat mainly because of anthropogenic pressure.FIELD PHOTOGRAPHNDWI NDVI NDTI from LISS-IV dataPlate 3: Khechodpalri Lake52

Plate 4: Wetland map - 5 km buffer area of Khechodpalri Lake53

Plate 5: Khechodpalri Lake as seen on IRS P6 LISS-IV image with 5 km buffer area55

NameLocationAreaAltitudeClimateMorphometricfeaturesTurbidityVegetationGurudongmar LakeUpper left: 28 0 02’ 07.05” N, 88 0 42’ 18.15” ELower right: 28 0 01’ 04.61” N, 88 0 42’ 52.62” E118 ha5,148 MThe lake is encircled all around by snow-coveredmountains and freezes during the winter except one spotbelieved of having curative properties.Average annual rainfall : 1183 mmTemeperature : 0 o to 35 o C.Maximum lengh : 1954mMaximum breadth : 963mMaximum depth : 4.58 mAverage depth : 2.07 mLowSparse alpine vegetation aroud the lake.GurudongmarIRS P6 LISSIII, 15 November 2005FaunaFew or no fauna is associated with the lake.The lake is situated at very high elevation and rests on thenorthern side of the Khangchengyao Range, close to theIndo-China Border in the province of North Sikkim, in ahigh plateau area next to the Tibetan Plateau. The lake ishighly revered by both Buddhists and Hindus as a sacredlake.MNDWI NDPI NDVI from LISS-III dataPlate 6: Gurudogmar Lake56

Plate 7: Wetland map - 5 km buffer area of Gurudogmar Lake57

Plate 8: Gurudogmar Lake as seen on IRS P6 LISS-III image with 5 km buffer area59

NameLocationAreaAltitudeTsomgo LakeUpper left: 27 0 22’ 36.68” N, 88 0 45’ 28.24” ELower right: 27 0 22’ 22.47” N, 88 0 45’ 58.85” E24.47 ha3,759 MThe lake is nearly oval-shaped and freezes during thewinter season up to mid-May.ClimateMorphometricfeaturesTurbidityVegetationAverage annual rainfall : 1183 mmTemeperature : 0 o to 35 o C.Maximum length : 836mMaximum breadth: 427mMaximum depth: 4.58 mAverage depth : 15 mModerateMainly Alpine vegetation includig Rhododendrons,Primula species, blue and yellow Poppies, IrisesTsomgo LakeIRS P6 LISS IV, January 07, 2008FaunaA great diversity of invertebrate and vertebrate fauna isassociated with Tsomgo Lake. Red Panda, Brahminyducks and various species of birds are found.Indian Postal Service released a commemorative stampon the lake on 6 November 2006.The lake falls in restricted area and hence permit isrequired to visit the place. It is a major hotspot for tourismin Sikkim hence anthropogenic pressure is mounting onthe lake.NDWI NDVI NDTI from LISS-IV dataPlate 9: Tsomgo Lake60

Plate 10: Wetland map - 5 km buffer area of Tsomgo Lake61

Plate 11: Tsomgo Lake as seen on IRS P6 LISS-IV image with 5 km buffer area63

SOI MAP SHEET-WISE WETLAND MAPS(SELECTED)65

REFERENCES1. Anon. 2005, NNRMS Standards. A National Standards for EO images, thematic & cartographicmaps, GIS databases and spatial outputs. ISRO: NNRMS: TR: 112:2005. A Committee Report:National Natural Resources Management System, Bangalore2. Anon. 1993. Directory of Indian Wetlands, 1993. WWF India, New Delhi and AWB Kuala Limpur,xvi+264pp., 32 maps.3. Clark, John R. (1977). Coastal Ecosystem Management, A Wiley Interscience Publication, JohnWiley & Sons, New York.4. Cowardin, L.M., Carter, V., Golet, E.C. and La Roe (1979). Classification of wetlands and deep waterhabitats. USFWS/085-79/31, Office of the Biological Services, U.S. Fish and Wildlife Service,Washington, D.C.5. Encyclopaedic Directory of Environment (1988). (Ed. By G.R. Chatwal, D.K. Pandey, and K.K.Nanda). Vol. I-IV, Anmol Publications, New Delhi.6. 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,7. Garg J.K. and Patel J. G., 2007. National Wetland Inventory and Assessment, Technical Guidelinesand Procedure Manual, Technical Report, SAC/EOAM/AFEG/NWIA/TR/01/2007, June 2007, SpaceApplications Centre, Ahmedabad,8. Glossary of Geology (1974). (Ed. By Margarate G., Robbert, M. Jr. and Wolf, C.L), AmericanGeological Institute, Washington, D.C.9. Jensen, J.R. (1986). Introductory Digital Image Processing: A Remote Sensing Perspective, PrenticeHall, Englewoods Cliff, NJ.10. Lacaux, J.P., Tourre, Y.M., Vignolles, C., Ndione, J.A. and Lafaye, M. 2007. Classification of pondsfrom high-spatial resolution remote sensing: Application to Rift valley fever epidemics in Senegal.Remote Sensing of Environment, 106, pp. 66-7411. Lillesand, T.M. and Keifer, R.W. 1987. Remote Sensing and Image Interpretation. John Wliey andSons, New York.12. Manorama Yearbook 200713. McGraw - Hill Encyclopaedia of Environmental Science (1974). (Ed. Sybil P. Parkar), McGraw-HillBook Company, New York.14. McFeeters, S.K. 1996. The use of Normalised Difference Water Index (NDWI) in the delineation ofopen water features. International Journal of remote Sensing, 7, pp. 1425-1432.15. Millennium Ecosystem Assessment. 2005, Ecosystems and Human Well-being: A Framework forAssessment, http://www.MAweb.org16. Mitsch, William J. and Gosselink, James G. (1986). Wetlands, Van Nostrand Reinhold Company,New York.17. Navalgund, R.R., Nayak, S.R., Sudarshana, R., Nagaraja, R. and Ravindran, S. 2002. Proceedingsof the ISPRS Commission VII. Symposium on Resource and Environmental Monitoring, IAPRS &SIS, Vol.35, Part-7, NRSA, Hyderabad.18. Patel J.G., Singh T.S., Garg J.K. et al, 2003. Wetland Information System, West Bengal,SAC/RSAM/RESA/FLPG/WIS/01/2003, A Technical report: Space Applications Centre, Ahmedabad19. Ramsar Convention (2007). www.ramsar.org20. Reid, George K and Wood, Richard D. (1976). Ecology of Inland Waters and Estuaries. D. VanNostrand Company, New York.21. SACON, 2004, Inland Wetlands of India: Conservation Atlas. Coimbatore, Salim Ali Centre forOrnithology and Natural History, 2004, ISBN 81-902136-1-X. ,Vedams eBooks (P) Ltd. VardhamanCharve Plaza IV, Building # 9, K.P Block, Pitampura,22. Singh T.S., Patel J.G., Garg J.K. et al, 2003. Loktak Lake Resources Information System (LRIS),SAC/RSAM/RESIPA/FLPG/WIS/02/2003, A Technical report: Space Applications Centre,Ahmedabad23. Townshend, J.R., and Justice, C.O. 1986. Analysis of dynamics of African vegetation using theNormalised difference Vegetation Index. International Journal of Remote Sensing, 7, pp. 1435-1445.24. Tucker, C.J. and Sellers, P.J. 1986. Satellite remote sensing of primary productivity. InternationalJournal of Remote Sensing, 7, pp. 1395-1416.25. Xu Hanqiu, 2006. Modification of normalised difference water index (NDWI) to enhance open waterfeatures in remotely sensed imagery. International Journal of Remote Sensing, 7, pp. 3025-3033.79

Annexure IDefinitions of wetland categories used in the projectFor ease of understanding, definitions of wetland categories and their typical appearance on satellite imagery is givenbelow:WetlandDefinition and descriptiontype code1000 Inland Wetlands1100 Natural1101 Lakes: Larger bodies of standing water occupying distinct basins (Reid et al, 1976). These wetlandsoccur in natural depressions and normally fed by streams/rivers. On satellite images lakes appear indifferent hues of blue interspersed with pink (aquatic vegetation), islands (white if unvegetated, red incase of terrestrial vegetation). Vegetation if scattered make texture rough.1102 Ox-bow lakes/ Cut off meanders: A meandering stream may erode the outside shores of its broadbends, and in time the loops may become cut-off, leaving basins. The resulting shallow crescentshapedlakes are called oxbow lakes (Reid et al, 1976). On the satellite image Ox-bow lakes occurnear the rivers in plain areas. Some part of the lake normally has aquatic vegetation (red/pink incolour) during pre-monsoon season.1103 High Altitude lakes: These lakes occur in the Himalayan region. Landscapes around high lakes arecharacterized by hilly topography. Otherwise they resemble lakes in the plain areas. For keepinguniformity in the delineation of these lakes contour line of 3000 m above msl will be taken as referenceand all lakes above this contour line will be classified as high altitude lakes.1104 Riverine Wetlands: Along the major rivers, especially in plains water accumulates leading toformation of marshes and swamp. Swamps are ‘Wetland dominated by trees or shrubs’ (U.S.Definition). In Europe, a forested fen (a peat accumulating wetland that has no significant inflows oroutflows and supports acidophilic mosses, particularly Sphagnum) could be called a swamp. In someareas reed grass - dominated wetlands are also called swamps). (Mitsch and Gosselink, 1986).Marsh: A frequently or continually inundated wetland characterised by emergent herbaceousvegetation adapted to saturated soil conditions. In European terminology a marsh has a mineral soilsubstrate and does not accumulate peat (Mitsch and Gosselink, 1986). Tone is grey blue and textureis smooth.Comment: Using satellite data it is difficult to differentiate between swamp and marsh. Hence, bothhave been clubbed together.1105 Waterlogged: Said of an area in which water stands near, at, or above the land surface, so that theroots of all plants except hydrophytes are drowned and the plants die (Margarate et al, 1974). Floodsor unlined canal seepage and other irrigation network may cause water-logging. Spectrally, during theperiod when surface water exists, waterlogged areas appear more or less similar to lakes/ponds.However, during dry season large or all parts of such areas dry up and give the appearance ofmud/salt flats (grey bluish).1106 River/stream: Rivers are linear water features of the landscape. Rivers that are wider than themapping unit will be mapped as polygons. Its importance arises from the fact that many stretches ofthe rivers in Indo-Gangetic Plains and peninsular India are declared important national andinternational wetlands (Ex. The river Ganga between Brajghat and Garh Mukteshwar, is a Ramsar site,Ranganthattu on the Cavery river is a bird sanctuary etc.). Wherever, rivers are wide and features likesand bars etc. are visible, they will be mapped.1200 Man-made1201Reservoir: A pond or lake built for the storage of water, usually by the construction of a dam across ariver (Margarate et al, 1974). On RS images, reservoirs have irregular boundary behind a prominentdyke. Wetland boundary in case of reservoir incorporates water, aquatic vegetation and footprint ofwater as well. In the accompanying images aquatic vegetation in the reservoir is seen in bright pinktone. Tone is dark blue in deep reservoirs while it is ink blue in case of shallow reservoirs or reservoirswith high silt load. These will be annotated as Reservoirs/Dam.Barrage: Dykes are constructed in the plain areas over rivers for creating Irrigation/water facilities.Such water storage areas develop into wetlands (Harike Barrage on Satluj – a Ramsar site, Okhlabarrage on the Yamuna etc. – a bird sanctuary). Water appears in dark blue tone with a smoothtexture. Aquatic vegetation appears in pink colour, which is scattered, or contiguous depending on thedensity. Reservoirs formed by barrages will be annotated as reservoir/barrage.81

1202 Tanks/Ponds: A term used in Ceylon and the drier parts of Peninsular India for an artificial pond, poolor lake formed by building a mud wall across the valley of a small stream to retain the monsoon(Margarate et al, 1974). Ponds Generally, suggest a small, quiet body of standing water, usuallyshallow enough to permit the growth of rooted plants from one shore to another (Reid et al, 1976).Tanks appear in light blue colour showing bottom reflectance.In this category Industrial ponds/mining pools mainly comprising Abandoned Quarries are alsoincluded (Quarry is defined as “An open or surface working or excavation for the extraction of stone,ore, coal, gravel or minerals." In such pits water accumulate (McGraw Hill Encyclopaedia ofEnvironmental Sciences, 1974), Ash pond/Cooling pond (The water body created for dischargingeffluents in industry, especially in thermal power plants (Encyclopaedic Directory of Environment,1988) and Cooling pond: An artificial lake used for the natural cooling of condenser-cooling waterserving a conventional power station (Encyclopaedic Directory of Environment, 1988). These pondscan be of any shape and size. Texture is rough and tonal appearance light (quarry) to blue shade(cooling pond).1203 Waterlogged: Man-made activities like canals cause waterlogging in adjacent areas due to seepageespecially when canals are unlined. Such areas can be identified on the images along canal network.Tonal appearance is in various hues of blue. Sometimes, such waterlogged areas dry up and leavewhite scars on the land. Texture is smooth.1204 Salt pans: Inland salt pans in India occur in Rajasthan (Sambhar lake). These are shallow rectangularman-made depressions in which saline water is accumulated for drying in the sun for making salt.2000 Coastal Wetlands2100 Natural2101 Lagoons/Backwaters: Such coastal bodies of water, partly separated from the sea by barrierbeaches or bass of marine origin, are more properly termed lagoons. As a rule, lagoons are elongateand lie parallel to the shoreline. They are usually characteristic of, but not restricted to, shores ofemergence. Lagoons are generally shallower and more saline than typical estuaries (Reid et al, 1976).Backwater: A creek, arm of the sea or series of connected lagoons, usually parallel to the coast,separated from the sea by a narrow strip of land but communicating with it through barred outlets(Margarate et al, 1974).2102 Creek: A notable physiographic feature of salt marshes, especially low marshes. These creeksdevelop as do rivers “with minor irregularities sooner or later causing the water to be deflected intodefinite channels” (Mitsch and Gosselink, 1986). Creeks will be delineated, however, their area will notbe estimated.2103 Sand/Beach: Beach is an unvegetated part of the shoreline formed of loose material, usually sandthat extends from the upper berm (a ridge or ridges on the backshore of the beach, formed by thedeposit of material by wave action, that marks the upper limit of ordinary high tides and wave wash tolow water mark(Clark,1977).Beach comprising rocky material is called rocky beach.2104 Intertidal mudflats: Most unvegetated areas that are alternately exposed and inundated by thefalling and rising of the tide. They may be mudflats or sand flats depending on the coarseness of thematerial of which they are made (Clark, 1977).2105 Salt Marsh: Natural or semi-natural halophytic grassland and dwarf brushwood on the alluvialsediments bordering saline water bodies whose water level fluctuates either tidally or non- tidally(Mitsch and Gosselink, 1986). Salt marshes look in grey blue shade when wet.2106 Mangroves: The mangrove swamp is an association of halophytic trees, shrubs, and other plantsgrowing in brackish to saline tidal waters of tropical and sub-tropical coastlines (Mitsch and Gosselink,1986). On the satellite images mangroves occur in red colour if in contiguous patch. When mangroveassociations are scattered or are degraded then instead of red colour, brick red colour may be seen.2107 Coral reefs: Consolidated living colonies of microscopic organisms found in warm tropical waters. Theterm coral reef, or organic reef is applied to the rock- like reefs built-up of living things, principallycorals. They consist of accumulations of calcareous deposits of corals and corraline algae with theintervening space connected with sand, which consists largely of shells of foraminefera. Present reefsare living associations growing on this accumulation of past (Clark, 1977). Reefs appear in light blueshade.2200 Man-made2201 Salt pans: An undrained usually small and shallow rectangular, man-made depression or hollow inwhich saline water accumulates and evaporates leaving a salt deposit (Margarate et al, 1974). Saltpans are square or rectangular in shape. When water is there appearance is blue while salt is formedtone is white.2202 Aquaculture ponds: Aquaculture is defined as "The breeding and rearing of fresh-water or marinefish in captivity. Fish farming or ranching". The water bodies used for the above are called aquacultureponds (Encyclopaedic Directory of Environment, 1988). Aquaculture ponds are geometrical in shapeusually square or rectangular. Tone is blue.82

Annexure – IIDetails of District information followed in the atlasSource : Survey of India (Surveyed in 2004 and published in 2005)83

Space Applications Centre (SAC) is one of the majorcentres of the Indian Space Research Organisation(ISRO). It is a unique centre dealing with a wide variety ofdisciplines comprising design and development ofpayloads, societal applications, capacity building andspace sciences, thereby creating a synergy oftechnology, science and applications. The Centre isresponsible for the development, realisation andqualification of communication, navigation, earth &planetary observation, meteorological payloads andrelated data processing and ground systems. Severalnational level application programmes in the area ofnatural resources, weather and environmental studies,disaster monitoring/mitigation, etc are also carried out. Itis playing an important role in harnessing spacetechnology for a wide variety of applications for societalbenefits.SAC is a host institution for the training programmesrelated to Satellite Communication, Satellite Meteorologyand global change under the Centre for Space Science &Technology Education in Asia and the Pacific (CSSTEAP)affiliated to the United Nations (UN).http://www.isro.org

Space Applications centreIndian Space Research OrganisationAhmedabad – 380 015