The Physical Nature of Coastal Zone

The coastline of our state may be viewed as a series of inter-linked physical systems, consisting of both offshore and onshore elements. Sediments (clay, silt, sand, gravel etc.) move around the coast by waves and currents in a series of linked systems. The sediments move from sediment source areas such as eroding cliffs to sea bed by coastal processes to sediment sinks such as beaches, estuaries or offshore sinks. Along a particular stretch these processes bring linked changes i.e., change in one part may lead to adjustment in other parts. Apart from the long shore sediment transportation, estuaries provide important link between sediment transport cells and rivers with their form, their character being determined by the tidal range, river flows and the degree of mixing between the fresh and saline waters. Extensive mudflats and salt marshes have developed where fine grained sediment (clay and silt) is laid down in sheltered areas with high tidal waves, coastal sand dunes developed as a result of the wind blown (aeolian) sand transport method. Major coastal landslide systems are formed on soft rockcoasts prone to marine erosion.

The region of the coastal plain and the eastern coast spreads over an area of about 45000 sq.km. covering parts of Nellore, Prakasam, Guntur, Krishna, West Godavari, East Godavari, Visakhapatnam, Vizianagaram and Srikakulam districts.