What is rain water harvesting (RWH)?

Water is essential to all life forms on earth – human, animal and vegetation. It is therefore important that adequate supplies of water be developed to sustain such life. Development of water supplies should, however, be undertaken in such a way as to preserve the hydrological balance and the biological functions of our ecosystems. Consequently, the human endeavour in the development of water sources must be within the capacity of nature to replenish and to sustain. If this is not done, costly mistakes can occur with serious consequences. The application of innovative technologies and the improvement of indigenous ones should therefore include management of the water sources to ensure sustainability and to safeguard the sources against pollution.

As land pressure rises, cities are growing vertical,Horizontal and in countryside more forest areas are encroached and being used for agriculture. In Hyderabad the small farmers depend on Monsoon where rainfall is from June to November and much of the precious water is soon lost as surface runoff. While irrigation may be the most obvious response to drought, it has proved costly and can only benefit a fortunate few. There is now increasing interest in the low-cost alternative-generally referred to as ‘Rain Water Harvesting’ (RWH).

Water harvesting is the activity of direct collection of rainwater, which can be stored for direct use or can be recharged into the groundwater. Water harvesting is the collection of runoff for productive purposes.

Rain is the first form of water that we know in the hydrological cycle, hence is a primary source of water for us. Rivers, lakes and groundwater are all secondary sources of water. In present times, we depend entirely on such secondary sources of water. In the process, it is forgotten that rain is the ultimate source that feeds all these secondary sources and remain ignorant of its value. Water harvesting is to understand the value of rain, and to make optimum use of rainwater at the place where it falls.

Methods of Rainwater Harvesting:

Rainwater stored for direct use in above ground or underground sumps / overhead tanks and used directly for flushing, gardening, washing etc. (Rainwater Harvesting). Recharged to ground through recharge pits, dug wells, bore wells, recharge trenches, etc. (Ground water recharge)

Rain water Harvesting Potential in Hyderabad upto ORR

In an area of 1076 Sq.ft. or 100 Sq.mt. (32 ft. X 32 ft. site) around 80,000 liters of rainwater can be harvested (Annual rainfall in Hyderabad is around 800 mm / 31.5 inches). The amount of rainwater that can be harvested depends on the catchment area, rainfall in that area and collection efficiency etc.

Rain Water Harvesting potential for individual houses in Cu m (1 Cum=1000 lt)