Revisiting rainwater harvesting as a disaster risk reduction tool

Implementing the National Rainwater Harvesting Policy and relevant legislation is now urgent fo promote rain water harvesting practices across the island as a key disaster risk reduction (DRR) tool, especially in the wake of unprecedented climate change, triggering natural disasters of colossal losses such as the recent Ditwah cyclone. Success stories in rainwater harvesting from sev- eral other Asian counterparts offer cues for us to follow.

- By RANDIMA ATTYGALLE

Lahore's underground water storage tanks help mitigate flooding Rainwater harvesting tank installed by LRWHF at Weragala Rahula Kanishta Vidyalaya provided clean water to several flood-affected people Ready to install RWH tanks is a potential business opportunity as well

(Dr. Tanuja Ariyananda)

SRI Lanka adopted the National Rainwater Harvesting Policy n 2005 making t mandatory for new buildingsin urban areas.

The objective ofthismove was two-pronged: toaddress both scarcity of water and floods. The policy was followed by relevant legislation in 2009 which amended the UDA bylaw on drainage, making provisions for rainwater harvesting (RWH) in buildings within a municipal area. However, this isnotimplemented, resultingin considerable ‘waterloss. The policies and laws related to RWH envisage assuring water security by reducing the reliance on main supplies, disaster risk reduction (asin the case of loads and droughts) and also as atool of mitigating groundwater depletion.

Thebasicconcept of RWHisto collectand retain or store rainwater. RWH can play acitical role especialy in stormwater management and flood contolin an urban setting The recent experience of Ditwah cyclone best manifests this. During peak flows caused by intenserainfall storm water can be managed by individual detention and retention systems through rainwater harvesting systems.