The coastal areas of the Region affected by the tsunami present highly diversified human activities, from inland fresh

Machilipatnam area, Andhra Pradesh. 18 Dec (above) and 27 Dec (below) Click to view larger image

water rice-based systems and wetlands to mangrove and coastal strips used primarily for fishing.

Much irrigation (mainly rice) is practised in the coastal low-lying areas where drainage is often difficult due to lack of slope.

Assessment of the impacts of the tsunami will address the damage by flooding (duration), erosion, scouring, deposition and salinity in these fragile tropical agro-ecosystems.

This will require mapping the aquatic and agro-ecosystems and diagnosing the physical impact of the tsunami (extent, severity and type). High resolution global irrigation maps show no irrigation in coastal areas in Aceh and North Sumatra, none or almost none in Thailand's affected areas.

This suggests a concentration of likely effects to irrigated rice production in South-Eastern India, West Coast and the middle of Southern Coast of Sri Lanka. Very roughly, the coastline of the affected areas would be 700 to 800 km in Sri Lanka, 2000 km in Aceh, and 2000 km in South-east India.