RAINWATER AVAILABLE FOR HARVESTING Total rooftop and surface area: 13,910 square metres (sq m)
Average annual rainfall in Noida: 792.4 millimetres (mm)
Total Volume of rainwater harvested: 4,446 cubic metres (m 3 ) or 44,50,000 litres
Therefore, 85 per cent of the total rooftop and surface runoff is being harvested.
WATER SUPPLY SOURCE The water requirement is met by one bore well located near the Plant room and is supplemented by municipal supply. On an average 2,38,000 litres of water is consumed daily for potable and non-potable purposes.
RAINWATER HARVESTING SYSTEM Rooftop rainwater harvesting: The rooftop rainwater from the C1, C2, C3, D1 and D2 blocks is collected in collection chambers and then through a network of interconnecting pipes, diverted into different recharge wells. The recharge wells are located near the parking shed of the C1 block, the lawn near the D1 block and near the Plant room. The recharge wells are of the size of 3 m x 2 m x 2 m and provided with recharge bores of 150 mm diameter and 16 m depth to facilitate the recharge. Layers of filtering material like boulders, pebbles and coarse sand ensures efficient filtration.
Surface runoff harvesting: Surface runoff generated from the paved area and roads is harvested through two recharge trenches constructed along the road near the D1 block. These trenches are 3m x 0.6 m x 0.9 m in size and are provided with two recharge bores of 150 mm diameter and 16 m depth to facilitate the recharge.
Similarly, part of rooftop rainwater of the C3 block is collected into the storm drain and is diverted to a nearby percolation pit. The pit is 0.6 m x 0.6 m x 0.6 m in size and is provided with a recharge bore of 150 mm diameter and 16 m depth. Coir wrapping on slotted pipe and filtering material like pebbles ensures better filtration of water.
Similar percolation pits provided in the storm drains running along the eastern boundary wall, takes care of the surface runoff from the paved areas and roads as well as the overflow from the overhead tank which takes place throughout the year.
The implementation was completed in May 2002 and the groundwater level, as in February 2004, was around 17 m below ground level (bgl).