Kathmandu, March 27 -- The Kathmandu Valley civilisation can also be called a hydrological culture where sophisticated water management allowed densely-packed settlements to co-exist with intense agriculture on the fertile soil of the former lake-bed.

Both needed plenty of water, but the Valley's rivers are not snowfed. So, the rulers of the kingdoms sourced them from the surrounding hills in an elaborate network of canals that did not just provide water for irrigation and fill ponds that recharged ground water, but also ensured urban supply through sunken spouts called hiti.

Read also: Saving Nepal's hiti heritage

The fact that the hiti system is still a vital source of water for the residents of inner city Kathmandu, Patan or Bhaktap...