Rainwater harvesting at Millennium Information Technologies Ltd., Malabe, Sri Lanka

Location: Colombo, Srilanka
Scale: zonal level
Implementing organisation: Millennium Information Technologies Ltd.
Average annual rainfall: 2404 mm

Total volume of rainwater harvested:Approx 2,315 kilo liters
Area: 5,525 m2 roof area

Millennium City, Malabe, a software company is situated about 40 Km. from Colombo city. The complex is spread over large area and is developed on a 6.5 ha sloping site. About 200 staff occupies the space. The site has huge potential for collection and optimum use of rain water management. The key objective of the project is to attain sustainable stormwater management along with rainwater storage for maintaining site green areas.

TECHNOLOGY & DESIGN

The RWH system is designed for a 90 days dry period. Rainwater from 5,525 m2 roof area of 3 main buildings is collected (except from roof gardens) and stored in three ponds with a volume of 2,315 m3. The rainwater ponds are part of the landscaping of the complex. The Ponds are constructed using High-density polyethylene (HDPE) foils and are finished with block work. Harvested rainwater from the ponds reaches the pump & filter units by gravity. There are 2 systems (north and south) which provide the service for complex taking advantage of the topography of the site. Through pressurized pump systems water is supplied using a dedicated network. There is also a back-up system provision to supply pump units with water from the city network. The balance water requirement for landscaping purposes is met by collecting surface run-off in a pond of a volume of approximately 1,450 cubic meter located at the lowest point of the complex.

BENEFITS

The rainwater harvesting on this site helps in water conservation and improves the site’s micro-climatic conditions. The system assures that the interventions into the natural water cycle are virtually zero, as harvested water is finally used on-site for landscaping. The rainwater harvesting act as peak storm water reduction measure. Considering the scarcity and value of clean water, the system contributes significantly to protection of natural water resource.

W.M. Ama Vidarshi Rajakarunanayake
Communication & IT Administrator
Lanka Rain Water Harvesting Forum, 28/3 A ,
Subadarama Lane , Nugegoda , Sri Lanka
Email: