Mother Dairy F & V Unit's Rainwater Harvesting System

RAINWATER AVAILABLE FOR HARVESTING

Total rooftop and surface area: 89,370 square metres (sq m)
Average annual rainfall in Delhi: 611 millimetres (mm)
Total volume of rainwater harvested: 32,250 cubic metres (m 3) or 3,22,49,802 litres.

Therefore, 59 per cent of the total rooftop and surface runoff is being harvested.

WATER SUPPLY SOURCE

Four bore wells located in the premises to meet industrial requirements and drinking water is sourced from the municipal supply. On an average 2,50,000 litres of water is consumed daily for potable and non-potable purposes.

RAINWATER HARVESTING SYSTEM

Rooftop rainwater harvesting: Rooftop rainwater from the administrative block, workers amenities, engineering store and central godown buildings is flown down to the ground and then taken to storm water drains. The storm water

drains are intercepted at strategic locations and rainwater is diverted into recharge wells. The recharge wells are 2.5 m x 2 m x 2 m in size and provided with recharge bores of 300 mm dia and 15 m depth to facilitate the recharge. Layers of filtering material like boulders, pebbles and coarse sand inside the recharge well ensure efficient filtration.

Dry bore well recharging: In order to make rainwater harvesting scheme more economical three existing dry/abandoned bores are used for recharging groundwater in the premises. The rooftop rainwater outlets discharge onto the roads and are channelised into storm water drains. This water is finally diverted into the dry bore well by converting them into recharge wells. Recharge wells are 2m x 2m x 2m and 3m x 3m x 2m in size. Slots are provided in the casing pipe. A layer of boulders, pebbles and coarse sand filled inside the recharge well ensures proper filtration of harvested water.

Implementation of this project was completed in April 2004, and the water level as in January 2005 was around 7.5 m below ground level (bgl).

Cost of the rainwater harvesting system: Rs 4.35 lakhs.