Remote Sensing And GIS Application In Wetland Mapping
Remote Sensing AndGIS Application InWetland MappingBySwetha A
Introduction Land consisting of marshes orswamps that is saturated withmoisture .Wetlands are areas ofland that are either temporarily orpermanently covered by water Time depending on seasonalvariability. Wetlands vary widely because ofregional and local differences insoils, topography, climate,hydrology, water chemistry,vegetation, and other factors,including human disturbance.
Wetlands are alsoconsidered the mostbiologically diverse of allecosystems, serving ashome to a wide range ofplant and animal life. The largest wetlands inthe world include theAmazon River basin andthe West Siberian Plain.Another large wetland isthe Pantanal, whichstraddles Brazil, Bolivia,and Paraguay inSouth America
vHydric S oilS oil that develops certain characteristics frombeing saturated for several weeks.vHydrophytic VegetationVegetation that thrives in wetland conditionsvHydrologyWater either from ground or surface sourcesThree Major Criteriaof Wetlands
DATA USEDRemote sensing data IRS P6 LISS III data was used to map the wetlands . IRS P6 LISS III provides data in 4 spectral bands; green, red,Near Infra Red (NIR) and Short wave Infra Red (SWIR), with 23.5m spatial resolution,141km-wide swath and 24 day repeat cycle. The spatial resolution is suitable for 1:50,000 scale mapping. Thestate of Karnataka is covered in 24 IRS LISS III scene Two-date data, October/November= post-monsoon April/May =pre-monsoon
National WetlandInventory andAssessment (NWIA)project was formulatedas a joint vision ofMinistry ofEnvironment &Forestry, Govt. India,and SpaceApplications Centre(ISRO) .
Normalised Difference Water Index (NDWI) = (Green-NIR) / (Green + NIR) 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) Normalised Difference Turbidity Index (NDTI) = (Red – Green) / (Red + Green)
GIS Application Link between Water Analysis SimulationProgram v.4 (WASP4) and Arc/Info Spatial/temporal analysis of data Model input configuration/editing/conversion Model output interpretation/reporting/display Model calibration/confirmation/application
Importance of Wetlands inEcological Functions Wetlands act as the biological "kidneys" of thelandscape by filtering out any water coastal wetlands can actually be regarded as stress-controlled ecosystems. The presence of wetlands in a hydrological basincan modify the floods by reducing the total volumeof floodwater and retarding flood peaks.
Cnt1… Wetlands, having dense vegetation, reduce flow velocity,which facilitates sedimentation. Temperature is regulated by these wetlands. Wetlands constitute about 6% of the hydrosphere Various autotrophic organisms convert solar radiationthrough photosynthesis important functions of upland and aquatic systems, physicaland biological processes
Cnt2.. Wetland biodiversity is a remarkable part of Earthsbiodiversity. Wetlands offer rich grazing materials for cattle, sheep andgoats during a long period of the year. An erosion control value since it retains soil anddisseminates Erosional forces of flowing water and waves Their role in trapping atmospheric carbon dioxide Biodegradation of organic matter, paleoecology,biodiversity,
Human Impact on Wetlands Land development Waste dumping that pollutes the wetlands Hunting and trapping Wetlands for agricultural drainage
SOURCES OF POLLUTION Point Sources -municipal and industrialwastewater. Non-point Sources -urban and agricultural run-off Major degrading factors - acidification fromatmospheric sources, acid mine drainage;contamination by toxic metals such as mercuryand organic compounds such as poly-chlorinatedbiphenyls.
CONSEQUENCES OF LOSS OFWETLANDS The tanks were reclaimed for various purposessuch as residential layouts, commercialestablishments, sport complexes, etc. For e.g. Darmombuditank has been converted intothe current city bus stand, Millers tank into aresidential layout, Sampangitank into theKanteervastadium,etc. This has changed the climate of the city andaffected its ground water level.
Cnt… The loss of wetlands has led to decrease in waterstorage capacity, wetland area, number ofmigratory birds, floral and faunal diversity andground water table. Studies reveal the decrease in depth of the groundwater table from 35-40 to 250-300 feet in 20 yearsdue to the disappearance of wetlands
Conservation of wetlands An ecosystem approach is needed to address the wetlandproblems The ecosystem approach considers both human water needswithin the larger context of the drainage basin andenvironmental water needs or ecological requirements. Increasingly, constructed wetlands are used for the treatmentof municipal and industrial wastewater before the treatedwater is let into lakes and wetlands. They offer the most sustainable means for the treatment ofwastewater
NATIONAL WETLAND ATLAS ,KARNATAKASponsored by -Ministry of Environment and Forests,Government of India As a part of the project on NationalWetland Inventory and Assessment (NWIA) SpaceApplications Centre (ISRO), Ahmadabad And KarnatakaState Remote Sensing Applications Centre, (KSRSAC),Bangalore National Wetland Conservation & Management –MinisterEnvironment & Forests Government of India. Wetlands Mapping Standard-FGDC WetlandsSubcommittee July 2009 Wetlands Indicators: A Guide to Wetland Identification,Delineation, Classification, and Mapping byRalph W. TinerReferences: