3rd International Rainwater Cistern Systems Conference
Khon Kaen, Thailand - January, 1987

Section B: Planning

Paper B.3

An Experimental Rooftop Rainwater Harvesting System At A Semiarid Tropical Site

H. I. Somashekar, Scientific Assistant
G. Keertinarayan, Project Officer
N. H. Ravindranath, Senior Scientific Officer
ASTRA

Rama Prasad
Professor
Department of Civil Engineering
Indian Institute of Science
Bangalore
India

Two systems fur collecting rainwater from tiled. roofs were built in Ungra, a village situated in South India. on the basis of the measured domestic water consumption and normal rainfall, a mass curve analysis showed that a root area of 63m² and a storage capacity of 12.6 m², with collection efficiency of 90%, would supply the needs of a six-member family for the entire year. Two types of storage pits were built. One was a kind traditionally built in the area for storage of grain, and the other a pit of rectangular section. Two materials for the gutter (G.I channel and tree trunk) were tried. The pits were lined with clay and lime for water proofing. The performance of the two systems were monitored for one monsoon period. The collection efficiency was 62%, with the G I gutter but oecause of losses, it went down to 50% with the tree trunk gutter. The capital costs of the two systems, are not very different, out were found to be much higher than that of handpump-based systems. Both the systems encountered the problem of lizards, rats, frogs etc. getting into the tank.

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