Rain Water Harvesting

For centuries, people have relied on rainwater harvesting to supply water for household, landscape, livestock, and agricultural uses. Before the advent of large centralized water supply systems, rainwater was collected from roofs and stored on site in tanks known as cisterns. With the development of large, reliable water treatment and distribution systems and more affordable well drilling equipment, rain harvesting was all but forgotten, even though it offered a source of pure, soft, low-sodium water. A renewed interest in this time-honored approach of collecting water has emerged in India and elsewhere because of escalating environmental and economic costs of providing water by centralized water systems or by well drilling. The health benefits of rainwater harvesting and potential cost savings associated with rainwater collection systems have further spurred this interest. Water is our most precious natural resource and something that most of us take for granted. We are now increasingly becoming aware of the importance of water to our survival and its limited supply, especially in such a dry continent as many states in India.

The harvesting of rainwater simply involves the collection of water from surfaces on which rain falls, and subsequently storing this rain water for later use. Normally water is collected from the roofs of buildings and stored in PVC, RCC or modular rainwater tanks. This is very common in all over the world. Water can also be collected in dams from rain falling on the ground and producing runoff. By capturing water directly, we can significantly reduce our reliance on water storage dams. This places less stress on these dams and can potentially reduce the need to expand these dams or build new ones. Collecting and using your own water can also significantly reduce your water bills. By capturing water, the flow of storm water is also reduced and this minimizes the likelihood of overloading the storm water systems in our neighborhoods. There are a number of devices like first flush device which allow for the first flow of water to the rainwater storage tank to be diverted from the tank. By doing this, any dirt on the roofs of buildings that has built up prior to the rain can be excluded from the tank.

The most appropriately sized rainwater storage can be chosen by quantitatively assessing the performance of various sized storage capacities. By assessing the performance of various sized storage capacities, it is possible to make an informed decision as to what would be the most suitably sized storage capacity for the given application. The input for the assessment is historical daily rainfall data, budget and the performance of a particular storage capacity can be judged by how much water is required to be supplied from other sources to make up for any shortfall in demand. Construction activity in and around the city is resulting in the drying up of water bodies and reclamation of these tanks for conversion into plots for houses. Free flow of storm runoff into these tanks and water bodies must be ensured. The storm runoff may be diverted into the nearest recharge pits and rainwater tanks, which will create additional recharge. As the demand of water is increasing day by day and we became more dependable on ground water use, Over exploitation of ground water, decline in well yields and fall in water levels, Reduction in open soil surface area, Reduction in infiltration and deterioration in water quality., rainwater harvesting become very essential now a days for everyone. Rainwater harvesting can be done in many ways like water spreading, recharge through pits, trenches, wells, shafts, rooftop collection of rainwater, road top collection of rainwater etc.