Everybody knows what rainwater harvesting is, its the process through which one would store rain water falling in your property, be it a house or a plot, into some kind of a storage from which you either replenish underground or surface reservoirs or simply use it for your household or agricultural requirements directly. If you want a proper definition visit Wikipedia.
In this post I will talk about how it is helpful for the environment as well as you personally. Also I will talk about the techniques and cost of setting up a system for harvesting free water falling on your roof top and plot.
How it helps nature?
Reduce erosion and mixing of pollutants in water.
Ideally the flow of water should be slow and spread across a large area to help it to be absorbed into the ground and recharge underground water reservoirs. Even when this rainwater forms small streams and end up in big rivers, the velocity and volume of water, that this stream would have in nature would be much less that scour velocity.
Due to this reduced velocity and volumes, the contaminant present in the water would be naturally filtered by soil and thus these pollutants did not enter the underground reservoirs or the streams and rivers.
Also, erosion of soil and scouring of stream lines did not happen.
But cities being mainly roofs, roads and other hard pavements, water is not allowed to percolate and so flows over them with great velocity and volume, thus collecting all the pollutants on these surfaces, before entering into a natural stream or percolating into the soil.
Helps in hydrological cycle
As said earlier, cities are covered with hard non permeable surfaces, thus not allowing water to filter and percolate into the ground. This runoff water is a major cause for flooding, pollution of natural water bodies and erosion.
But, actually it should have been percolating into the ground and replenishing underground reservoirs and a major chunk of it held by the soil itself.
When we harvest this rain water, we would eventually use it for different household and gardening purposes. And through these process we gradually keep adding water into the soil and thus restoring the hydrological cycle.
Reduce your carbon footprint
Water needs pumping, purification and transportation before it reaches your showers and taps. And all of these procedures require energy which increases your carbon footprint.
Rainwater is pure and needs no to little purification and transportation. Thus harvesting rainwater will reduce your carbon footprint.
Rain water is better for your garden
Rain water has the perfect nitrate and other contents naturally.
Also, it does not have any dissolved salts or toxins which most other sources of water would have now a days.
Thus, in short, you cannot provide your garden with better water.
Most importantly rainwater harvesting conserves water and reduces the load in other sources of water
Most water for household work is either drawn from a well or a surface reservoir like a lake or a river.
Almost all such reservoirs are over drawn and strained in the developed world.
But when we harvest and use rain water instead, the strain on these above said sources is reduced greatly, and in fact help them to replenish.
Why rainwater harvesting will help you personally as well as the community you live in?
Does not require any complicated water pipelines and storage tanks, which a community would need.
Water can be used onsite, and only would require pumping to a overhead tank.
Reduces further demand on the community water supply system, thus not requiring up-gradation.
Reduces the need for treatment of water, will reduce pollution, energy use and public funding.
If you live in a municipality, the water you use is usually bought. Rainwater harvesting will reduce your water bills.
Your garden would be moist most time of the year and you would get to use the best quality of water available.
Preparations needed for rainwater harvesting.
There are primarily two methods for rainwater harvesting.
Surface runoff harvesting
Rooftop rain water harvesting
In both the concepts the catchment area or the surface from which rainwater is intended to be collected are different, but the principle remains the same. To channel the water, filter and store.
Rooftop rainwater harvesting is most commonly adopted method in which the catchment area is the roof of ones house and the water is channeled into the storage tank placed at ground level or built underground.
It is important to filter the water before it enters the tank, and that the surface runoff from the first rain be channeled away from the tank, as it may contain contaminants and impurities, collected from the atmosphere and the roof surface.
Also, if stored properly without letting sunlight into the tank, the water stored can be used for a long period of time.
Well or Bore well recharge benefits
In heavy rainfall receiving areas, your storage tanks would be filled in no time. Or sometimes people would not actually need a storage tank, as they might have a well which provides good quality water throughout the year. In that case, if you let the filtered rainwater into the well or bore-well, it will replenish the ground water reservoir from which the well is drawing water. Also, the quality of the water will be much better as rainwater does not contain any salts, thus reducing the concentration of salts in the ground water.
Does it cost much?
No. Rainwater harvesting does not really cost much. All it requires is some pipes, valves, a filtering unit which can be made at home using gravel, sand, stones and charcoal and a storage tank. Also in places where you get a lot of rain, you don't have to channel all the water from the roof top to your tank. A section of your roof would do the necessary work.
Overall benefits that you personally would experience.
Practise of rainwater harvesting is extremely beneficial for the environment as well as for the person doing it. The expenses compared to the benefits is minimal, and can be afforded by most people.
To list some:
Reduced water bills
Best quality water, without any contaminants.
Satisfaction of doing your bit for the nature.
Reduced carbon footprint.
Reduced soil erosion from your plot.