Conference program and abstracts - Coastal-Change.Org

Vulnerable Deltas of Indian Coast
Prof . Ramesh Ramachandran and
Dr. Purvaja Ramachandran
National Centre for Sustainable Coastal Management. Chennai
ABSTRACT
Deltas are highly productive, ecologically rich and are dependent on the
interaction between the river’s sediment, water and nutrient flux and the
wave and tidal currents. A recent study indicates that most of the world’s
low-lying river deltas are sinking and making them increasingly vulnerable
to flooding from rivers and ocean storms exposing tens of millions of
people at risk. At present nearly 500 million people live in deltas. In South
Asia the population densities exceed 1000 people km-2 when compared
to a global average of 45 people km-2.
Problems associated with this include depleted fresh water supplies, land
subsidence and erosion, sea level rise, infrastructure development, salt
water intrusion, habitat loss and the threat of natural disasters. Sinking of
deltas in Indian coast is enhanced by the upstream trapping of sediments
by reservoirs and dams that retain these sediments. In this paper, an
attempt is made to highlight some of the vulnerabilities, as a result of the
changes in some of the major delta regions of India:
a) Reduction of sediment load and freshwater flow
b) Subsidence
c) Coastal erosion
d) Habitat loss
Additionally, GIS mapping has been used as a management tool that
allows the identification of such vulnerable zones, i.e. zones which are
both sensitive and subject to risks. In this way, it is possible to build models
for geomorphological evolution, prediction of changes and
management of deltas and coastal areas.
The Fourth IGCP 588: PREPARING FOR COASTAL CHANGE 27