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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
exploration of marine fisheries, mitigation of coastal disasters and
understanding of sediment dynamics. GIS has been used for the
integrating satellite based information for identifying aquaculture
sites, coastal regulation and environmentally sensitive zones.
2. ISSUES FOR COASTAL ZONE MANAGEMENT
The following issues are critical in context of coastal zone
management (Nayak, 2000).
Coastal ecosystems and marine living resources
i) Generation of reference or baseline data,
conservation and restoration of vital and critical
habitats such as mangroves, coral reefs, sea-grass
beds, etc.
ii) Reclamation of wetland for agricultural and
industrial purposes a
ii) Exploration and sustainable use of living resources
Shoreline protection
i) Identification of vulnerable areas including eroded
areas and developmental activities
ii) Planning and implementation of coastal protection
work (erosion, flood protection, salt water
intrusion, etc.)
iv) Impact of engineering structures and dams on
coastal processes of erosion, deposition and
sediment transport
v) Suspended sediment dynamics
vi) Changes in bottom topography
Coastal water quality
i) Non-point and point pollution
ii) Phytoplankton blooms
Coastal Hazards and Climate Change
1) Cyclones, storm surges, sea-level rise and possible
effects
11) Emergency response plans for natural disasters
such as cyclones, sea level rise, or anthropogenic
activities such as oil spills.
Coastal development
i) Appropriate site selection for industries, landfall
points, aquaculture, recreational activities, etc.
ii) Assessment of conditions in regulation zones,
areas under construction. setback-lines, mega-
cities, etc.
3. COASTAL ECOSYSTEMS AND MARINE RESOURCES
3.1Coastal Ecosystems
Coastal habitats, especially wetlands, coral reefs, mangroves, salt
marshes, and sea grasses, are highly productive, serve important
ecological functions, provide coastal protection and are critical
resources for food, energy, tourism and economic development.
Such coastal systems are under stress or threatened from various
sources, both natural and human. The information on loss of tidal
wetlands is important as they provide a vital link in the marine
energy flow through transfer of solar energy into forms, which are
readily usable by a wide variety of estuarine organisms.
Satellite imagery has immensely helped mapping of coastal
ecosystems and provided estimates of extent and alteration in land
cover in coastal ecosystem. A baseline information on coastal
habitat (critical/vital) and associated shore land features along the
entire Indian coast on 1:250,000/1:50,000 scale has been carried
out through visual interpretation of multi-spectral IRS LISS II and
LISS III and LANDSAT TM data for macro-level planning for
the first time (Nayak et al. 1991, Jagtap et al. 2001, Nayak, 2002).
Low-tide image of period December-February was used. Image-
interpretation key was developed to identify various components
of the ecosystem. The degradation of mangroves (about 25 per
cent) and coral reefs, reclamation of lagoons and mudflats was
observed (Desai et al. 1991, Nayak et al. 1992 a, Nayak, 1996,).
Classification accuracy of 85 per cent at 90 per cent confidence
level was achieved. Synergistic use of SAR and optical data
improve distinction of wetlands (Kushwaha, 2000). Attempts are
being made to use interferometric SAR to study small elevation
changes in the inter-tidal zone (Cracknell, 1999).
3.2 Mangroves
Mangroves help in the production of detritus, organic matter,
recycling of nutrients and thus enrich the coastal waters and
support benthos population of sea. Mangroves cover about
200,000 sq km areas on the globe, mainly around tropics. It has
been estimated that half of the world mangroves may have been
lost. The Forest Survey of India has been providing estimates of
mangroves based on satellite data since 1987. However, in some
regions, mangroves have increased due to plantation as well as
regeneration. In India, mangroves have reduced from 6740 to
4460 sq. km (Nayak, 1992). Mangroves are degraded and
destroyed due to conversion of these areas for agriculture,
aquaculture on the East Coast and industrial purposes on the West
Coast (Fig.1).
Areal extent of the Indian mangroves
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[1986 area (sq km) 1199083 area (sq km)
Fig. 1. Change in mangrove area during 1986-1993.
Dense, degraded, mangrove plantation areas and reclaimed areas
can be distinguished using IRS LISS III data (Nayak et al. 1996,
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