ABSTRACT:
Rainwater harvesting is the accumulation and storage of rainwater for reuse, before it reaches the aquifer. It has been used to furnish drinking water, water for livestock, water for irrigation, as well as other typical uses given to water. Rainwater collected from the roofs of houses, tents and local institutions can make an important contribution to the availability of drinking water. It can supplement the sub soil water level and increase urban greenery. Water collected from the ground, sometimes from areas which are especially prepared for this purpose, is called Storm water harvesting. In some cases, rainwater may be the only available or economical water source. Rainwater harvesting systems can be simple to construct from inexpensive local materials, which are potentially successful in most habitable locations. Roof rainwater can't be of good quality and may require treatment before consumption. As rainwater rushes from roof(s), it may carry pollutants in it, such as the tiniest bit of mercury from coal burning buildings to bird feces. Although some rooftop materials may produce rainwater that is harmful to human health, it can be useful in flushing toilets, washing clothes, watering the garden and washing cars. These uses invariably halve the amount of water used by a typical home. Overflow from rainwater harvesting tank systems can be used to refill aquifers in a process called groundwater recharge, though this is a related process, it must not be confused with Rainwater harvesting. The proposed RS Model establishes the merits of rain water harvesting and conjures up all the nuances that lead up in furnishing an optimum solution and justifying the motto of the proposed model; “Go Green and Earn Green.” There are a number of types of systems to harvest rainwater ranging from very simple to complex industrial systems. The rate at which water can be collected from either system is dependent on the plan area of the system, its efficiency, and the intensity of rainfall (that is, annual precipitation (mm per annum) x square meter of catchment area = litres per annum yield). Rainwater harvesting can assure an independent water supply during water restrictions, that is, somewhat dependent on end use and maintenance. Usually, it is of acceptable quality for household needs and renewable at acceptable volumes despite forecast of climate changes (CSIRO, 2003). It produces beneficial externalities by reducing peak storm water runoff and processing costs. In municipalities with combined sewer systems, reducing storm runoff is especially important, because excess runoff during heavy storms leads to the discharge of raw sewage from outfalls, when treatment plant capacity cannot handle the combined flow. Running costs are negligible, and they provide water at the point of consumption.