rainwaterharvesting

Normally,debris, dirt and dust get deposited on the roof during non-rainy periods.When the first rains arrive, this unwanted material will be washed into the storage tank. This may cause contamination of water collected in the storage tank thereby rendering it unfit for drinking and cooking purposes. Therefore, a first flush system can be incorporated in the Roof top Rainwater Harvesting Systems (RRHS) to dispose of the first flush so that it does not enter the tank. There are two such simple systems. One is based on a simple manually operated arrangement whereby, the down pipe is moved away from the tank inlet and replaced again once the first flush water has been disposed. In another simple and semi automatic system, separate vertical pipe is fixed to the down pipe with a valve provided below the T junction. After the first rain is washed out through the first flush pipe the valve is closed to allow the water to enter the down pipe and reach the storage tank.

(1) Sloping roofs
Roofs made of corrugated iron sheet, asbestos sheet or tiles can be utilised for harvesting the rainwater. Gutters and channels can be fixed on the edges of roof all around to collect and transport the rain water from the roof to the storage tank. Gutters can be prepared in semi-circular and rectangular shapes. Locally available material such as plain Galvanized Iron sheets can be easily folded to required shapes to prepare semi-circular and rectangular gutters. Semi-circular gutters of PVC material can be readily prepared by cutting the PVC pipes into two equal semi-circular channels. Bamboo poles can also be used for making gutters if they are locally available in sufficient quantity. Use of such locally available materials reduce the overall cost of the system.

If the roof is thatched, polythene sheets can be
used for collecting the rainwater

The collected rainwater is filtered through a filter filled with pebbles in the bottom and coarse sand on the top

The filtered water is collected either in storage tank of existing sump and the overflow water may be diverted to percolation pit nearby.

In a slopped/tiled house the rainwater from the roof is collected through the gutter in the roof.

The collected water is filtered through a filter filled with pebbles in the bottom and coarse sand on the top.

The filtered water is collected either in a storage tank or existing sump. Over flow water may be diverted to an existing open well / bore well or percolation pit.