Remote Sensing And GIS Application In Wetland Mapping

BySwetha A

Introduction

Land consisting of marshes or swamps that is saturated with moisture .Wetlands are areas of land that are either temporarily or permanently covered by water

Time depending on seasonal variability.

Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors, including human disturbance.

Wetlands are also considered the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal life.

The largest wetlands in the world include the Amazon River basin and the West Siberian Plain. Another large wetland is the Pantanal, which straddles Brazil, Bolivia, and Paraguay in South America

v Hydric S oilS oil that develops certain characteristics from being s aturated for several weeks .

v Hydrophytic VegetationVegetation that thrives in wetland conditions

v HydrologyWater either from ground or s urface s ources

Three Major Criteriaof Wetlands

DATA USED Remote 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 23.5 m spatial resolution,141km-wide swath and 24 day repeat cycle.

The spatial resolution is suitable for 1:50,000 scale mapping. The state of Karnataka is covered in 24 IRS LISS III scene

Two-date data, October/November= post-monsoon April/May =pre-monsoon

National Wetland Inventory and Assessment (NWIA) project was formulated as a joint vision of Ministry of Environment & Forestry, Govt. India, and Space Applications 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 Simulation Program 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

Vegetation unioned with…

…Geology.

Union the two layers…

…to form one layer withboth attributes.

1.

2.

3.

By using SQL we canisolate polygons withattributes that meetwetland requirements…

…to delineate the possible locations of wetlands seen hereisolated in bright blue.

Map showing distribution of various types of wetlands in India derived using LISS III

KARNATAKA

Bangalore Rural

IRS LISS-III FCC - 5 km buffer area of Maddur Lake

25 MARCH 2012

Karnataka (4250 ha) Magadhi Gudavi Bird Sanctuary Bonal Hidkal & Ghataprabha Heggeri Ranganthittu K.G. Koppa

State-wise area of identified Wetlands underNational Wetland Conservation & Management Program (NWCMP)

Importance of Wetlands in Ecological Functions

Wetlands act as the biological "kidneys" of the landscape by filtering out any water

coastal wetlands can actually be regarded as stress-controlled ecosystems.

The presence of wetlands in a hydrological basin can modify the floods by reducing the total volume of 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 radiation through photosynthesis

important functions of upland and aquatic systems, physical and biological processes

Cnt2..

Wetland biodiversity is a remarkable part of Earth's biodiversity.

Wetlands offer rich grazing materials for cattle, sheep and goats during a long period of the year.

An erosion control value since it retains soil and disseminates 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 industrial

wastewater. Non-point Sources -urban and agricultural run-off Major degrading factors - acidification from

atmospheric sources, acid mine drainage; contamination by toxic metals such as mercury and organic compounds such as poly-chlorinated biphenyls.

CONSEQUENCES OF LOSS OF WETLANDS

The tanks were reclaimed for various purposes such as residential layouts, commercial establishments, sport complexes, etc.

For e.g. Darmombuditank has been converted into the current city bus stand, Millers tank into a residential layout, Sampangitank into the Kanteervastadium,etc.

This has changed the climate of the city and affected its ground water level.

Cnt…

The loss of wetlands has led to decrease in water storage capacity, wetland area, number of migratory birds, floral and faunal diversity and ground water table.

Studies reveal the decrease in depth of the ground water table from 35-40 to 250-300 feet in 20 years due to the disappearance of wetlands

Conservation of wetlands An ecosystem approach is needed to address the wetland

problems

The ecosystem approach considers both human water needs within the larger context of the drainage basin and environmental water needs or ecological requirements.

Increasingly, constructed wetlands are used for the treatment of municipal and industrial wastewater before the treated water is let into lakes and wetlands.

They offer the most sustainable means for the treatment of wastewater

NATIONAL WETLAND ATLAS ,KARNATAKA

Sponsored by -Ministry of Environment and Forests, Government of India As a part of the project on National Wetland Inventory and Assessment (NWIA) Space Applications Centre (ISRO), Ahmadabad And Karnataka State Remote Sensing Applications Centre, (KSRSAC), Bangalore

National Wetland Conservation & Management –Minister Environment & Forests Government of India.

Wetlands Mapping Standard-FGDC Wetlands Subcommittee July 2009

Wetlands Indicators: A Guide to Wetland Identification, Delineation, Classification, and Mapping by

Ralph W. Tiner

References:

Thank you

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