Access to water a will define  development throughout the world in the near future.  We need to explore ways of using water sustaianably.  New technologies and policies will need to be utilised.  However can we learn from the past?

Agarwal and Narain Editors of Dying Wisdom (1999) has documented how India had developed sustaianable water solutions over its vast arays of climates and topography. Tamil Nadu (TN) is a case in point, seen from the air (after a monsoon) TN looks like the land of a thousand lakes (there were 39,000 tanks within TN). However on the ground, one realises that these are all human made structures. 

We know from poems written on palm leafs of the Sangam period (150 BC to 200 AD) that paddy (rice) cultivation from both river (Tambraparni) and eirs (tanks) took place.  Irrigation grew during the Pandya and Chola kings (750-1300 AD) where irrigation from tanks is mentioned.  Recorded history describes fields being irrigated from channels leading from temporary dams constructed across rivers, and how the channels fed huge tanks .  The tanks then fed other channels which irrigated fields as far as 25 Kms away.

There are many areas of TN that have no rivers so the next technological solution was harvesting rainwater into large tanks.  Often these tanks were designed so that as they filled during the rains, the run off drained from one tank to the next, only using gravity.  This design made it possible to harvest most of the rain water.  This captured rainwater was used thourghout the year.   The village had developed a participatory, decentralized, self reliant tank maintenance system.  Sir P Griffiths stated:

“The villagers of that period were to a large extent self governing, the forces of  democracy that operated in them were perhaps more vital than those that have  been so laboriously imposed on India in modern times”  Thomas, H (1937)

However, today this hydrological marvel are mostly in poor shape and under used or unused.  Hopefully we can learn from the past and create more sustainable rainwater harvesting (methodologies and social structures that promote sustainaable water capture and use).