Almost two-thirds of the world (4 billion people) live in regions with severe water shortages.
Water is as essential to us as life itself. Not only do we utilize it for drinking, but it is also used extensively in agriculture.
Currently, agriculture counts for approximately 70% of freshwater usage globally. In a situation where the amount of water available for use is decreasing every day, this is very alarming. So we can use different techniques of water conservation to establish a sustainable future for humankind.
Rainwater harvesting is a system that collects and stores rainwater for human use. It is difficult to trace back the history of rainwater harvesting and the exact person who invented it, but historical evidence suggests that different techniques of rainwater harvesting were used in 2000 BC in India, Mesopotamia, China, and modern-day Israel.
Today, most of the world utilizes rainwater harvesting. Colorado, US, is the only state where rainwater harvesting or barrels is illegal.
Read on to enjoy more important facts on rainwater harvesting below.
Technology of Rainwater Harvesting
The main idea or purpose behind rainwater harvesting is collecting rainwater. Different types of rainwater harvesting technologies are available for use today. These range from a simple rain collection barrel to more complex structures which involve the roof, tank, pumps, and purification systems. The only thing common to each is that all of them require a storage system.
Surface run-off harvesting is a technique mainly utilized if a catchment area is present. Here the rainwater is collected in tanks or natural reservoirs before it is lost as surface run-off.
A roof-top rainwater harvesting system involves diverging the rainwater collected on roof-tops with the help of pipes into storage devices such as rainwater tanks. Apart from being stored in rainwater tanks, water is also sometimes used to replenish the groundwater of an area. Groundwater can be utilized by using a tube well and pump.
Dams are built in such a way that they trap water. Water from the rain is collected directly in the dams and is transferred to treatment plants through a series of pipelines.
The water collected can be used for domestic purposes after it is treated properly by permeating the water through hard surfaces and UV disinfection which clears out any other debris present.
A rain barrel is a simple storage device that can be bought from any retail store. These are used for harvesting rainwater that falls from roof-tops.
This is also the easiest device to install on the roof of your house. All you would need to do is put a barrel near the pipes that drain rainfall into the gutters or your garden.
Then the water will simply get collected in the barrel. This will not only save water and cut costs, but you will also have a self-supply of water for your house.
Limitations of Rainwater Harvesting
Rainwater harvesting, even though ecologically sustainable, has a number of limitations.
It is heavily dependent on rainfall. Rainwater harvesting is heavily dependent on the amount of rainfall that a place encounters.
The greater the amount of rain, the more water is available. But, in regions of unpredictable rainfall, where the monsoon season exists only for a short period of time, the supply of water becomes limited.
So, rainwater harvesting is only suitable for areas that receive a high amount of rain. Those areas wouldn't really need to store rainwater as the frequency of the rains replenishes groundwater as well as other water bodies.
There is a high initial cost. Putting up a rainwater harvesting system in any area is expensive. The cost of the system depends on the complexity and sophistication of the machinery used, and it does not become financially viable until 10 to 15 years of usage.
The device and tank will need regular maintenance. This adds to the cost of owning a rainwater harvesting system.
It cannot be readily used. The water that gets stored in tanks may contain chemical runoffs from your roof or animal excretory products.
It is not family safe and cannot be directly used as drinking water. As such, the water needs to be treated by a system of filters to be safe for drinking. This not only increases the cost of the whole system but also degrades the quality of water.
A tank offers limited storage. The amount of water that can be utilized is directly dependent on the size of the tank. A large tank will store a large amount of water, but still, the amount will be limited.
Cost-Benefit Analysis of Rainwater Harvesting
For a system to stay in use, it must be financially viable to the owner. The cost of installing a rainwater harvesting system, however, depends on the type installed and the amount of rain in your town.
A complex and sophisticated one would cost much more than a simple one. In the long term, rainwater harvesting becomes financially viable, but it takes almost 10 to 15 years for it to reach that point.
In fact, a cost-benefit analysis of rainwater harvesting is perfect for a school project. A model of rainwater harvesting setup is also a cool idea for a school project and can help you understand its usage more.
Ecological Importance
Rainwater harvesting has many benefits because it helps reduce the carbon footprint of mankind. It utilizes water from rain, which is a naturally occurring phenomenon.
The rain from rainwater acts as a substitute source of water. This helps to save large amounts of water because, as we know, water is a scarce natural resource.
Rainwater harvesting helps prevent floods and keeps up the quality of local watersheds by slowing the run-off speeds of rainwater.
It helps to recharge groundwater and balances the hydrological cycle.
Rainwater is soft water, free of chemicals, and has a perfect pH. So it helps rejuvenate plants and keeps gardens fresh, and also reduces the need to use a water softener for doing laundry.
By harvesting rainwater, a reservoir is created, which is useful in times of drought.
