First national inventory of wetlands prepared

Ahmedabad, Jun 20 (PTI) A detailed national inventory
of Indian wetlands has been prepared on the basis of satellite
imagery provided by Indian Space Research Organisation (ISRO),
highlighting areas of critical ecological significance and
those facing threat due to developmental activities.
This is for the first time in India that the
city-based Space Application Centre (SAC), a part of ISRO, has
prepared such an inventory and atlas of all the wetlands that
are existing in the country.
"Wetlands are the most productive ecosystems which
play crucial role in hydrological cycle like helping in storm
and flood control, water supply, providing food, fibre and raw
materials and in recreational benefits," said SAC Director Dr
Ranganth R Navalgund.
They also support lakhs of migratory birds coming from
colder regions of the world in summers, apart from diverse
local flora and fauna.
"However, the very existence of these unique resources
is under threat due to developmental activities and population
pressure. This calls for long-term planning for preservation
and conservation of these resources," Navalgund said.
"Creating an updated and accurate database that
supports research and decision making is the first step
towards this.
SAC took up this challenging task under the project
National Wetland Inventory and Assessment (NWIA) sponsored by
Ministry of Environment and Forests," he said.
"Two-date, satellite data acquired during pre and
post-monsoon seasons are used for inventory of wet and dry
season hydrology of wetlands. They have been categorised in 19
classes and mapped following standard map projection. The map
outputs include status of water spread, aquatic vegetation and
turbidity," Navalgund said.
As per the finding of SAC study, excluding rivers,
wetlands cover some 10 million hectares, or a little over
three percent of the country's geographical area.
Of this 10 million hectares, reservoirs account for
about 2.5 million hectares, inter-tidal mud flats for 2.4
million hectares, tanks for 1.3 million hectares, lakes/ponds
for 0.70 million hectares, mangroves for some 0.47 million
hectares and corals for about 0.14 million hectares.
The main objective of the project were wetland mapping
and inventory at 1:50,000 scale resolution by analysis of
digital satellite data of post and pre-monsoon seasons,
creation of digital database in GIS environment and
preparation of state-wise wetland atlases.
State wise distribution of wetlands showed that
Lakshadweep has 96.12 per cent of geographic area under
wetlands followed by Andaman and Nicobar Islands (18.52 per
cent), Damand and Diu (18.46 per cent) and Gujarat (17.56 per
cent) have highest extent of wetlands.
Puducherry (12.88 per cent), West Bengal (12.48 per
cent), Assam (9.74 per cent) are wetland rich states. States
like Mizoram, Haryana, Delhi Sikkim, Nagaland and Meghalaya
the extents of wetland is less than 1.5 per cent.
The inventory said, India has long coast line and
large area under coastal wetlands like inter-tidal, mudflat,
lagoon and creek.
The inventory has also mapped high altitude lakes
lying above 3,000 meter elevation. The Indian Himalayas cover
almost 18 per cent of India’s land surface and is spread over
six states, which have 4703 lakes above 3,000 meter elevation.
This includes 1996 small lakes. The total area of these lakes
is 1.26 lakh hectares.