Rainfall is a naturally occurring source of water. Every year, some parts of the world experience water shortage or drought conditions. So rainwater harvesting is done to overcome the diﬃculties during the situations like water crisis and droughts.
What Is Rainwater Harvesting?Rainwater harvesting is the process of accumulating and storage of rainwater in a systematic manner, rather than allowing the rainwater to runoﬀ.
The rainwater can be accumulated in a water tank or it is also used to recharge the groundwater by using specific methods and techniques.
The stored water can be used for domestic, commercial, and agricultural purposes like cleaning, washing clothes, irrigation of land, in toilets and bathrooms, and even for drinking purposes after some purification treatment and making it suitable for drinking.
Methods Of Rainwater HarvestingThere are two methods for rainwater harvesting. They are as follows:
- Surface runoﬀ method
- Roof top method.
1. Surface Runoﬀ Method
In this method, the rainwater which runs oﬀ along the surface of the land is collected in a tank which is kept below the surface of the ground. This water is utilized for irrigation and other such purposes.The major drawback of the surface runoﬀ method is that the rate of loss of water is high and the water is lost due to evaporation.
2. Rooftop Method
In this method, rainwater is collected from the rooftops of various buildings and structures. The water collected by this method is collected either in a tank or it is diverted to artificial recharge systems. It is a very eﬃcient and cost-effective method for harvesting rainwater.
- Residential buildings, bungalows, houses, villas.
- Educational institutes such as schools and colleges.
- Commercial buildings such as oﬃces and commercial apartments.
- Government buildings.
- Industrial buildings.
- Hotels, restaurants, resorts.
- Swimming pools, stadiums, etc.
- Storage of direct use.
- Recharging groundwater aquifers.
- Recharging of bore wells.
- Recharge pits.
- Soakway or recharge shafts.
- Recharging of dug wells.
- Recharge trenches.
- Percolation tank.
Components Of Rainwater SystemThe basic components of rainwater harvesting systems are as given below:
1. Collection AreaThe collection area is provided to collect the rainwater obtained from the rainfall. Water is collected on the roof surface itself and hence it is known as a collection area. Sometimes a tank is provided for the accumulation of rainwater.
2. Conveyance System
The conveyance system is provided for the conveyance of water from the water collection area to the water storage area. The conveyance system comprises gutters or flat roofs, drainage holes, pipe systems, and downspouts.
3. Water StorageIt is a chamber or a tank in which the rainwater coming from the collection area is stored. The stored water is utilized when the need for water arises. The storage is located above or below the ground and it comprises either a single tank or multiple tanks.
4. Filtration SystemA filtration system is provided to filter the water and keep the debris out of the system. Rainwater cannot be used directly as it may contain harmful substances in it, which may harm the people using it. The water stored as groundwater contains harmful elements like arsenic and salts. So the water is filtered before it is distributed and taken for use.
4. Distribution System
The water distribution system consists of the pipe system or the plumbing system through which the water is disturbed to the dedicated area for use such as houses, oﬃce, schools, etc.
Benefits And Advantages Of Rainwater HarvestingRainwater harvesting is equally important for all. Below listed are some benefits:
- It is relatively easy to install, operate and maintain.
- It ensures the fulfillment of the need for water in the future.
- It is a cost-effective process.
- It acts as an excellent source of water for irrigation.
- The harvested rainwater is used during times of water crisis.
- It reduces flooding on road.
- It reduces water bills and water consumption by as much as 40%.
Disadvantages Of Rainwater Harvesting
• Due to unpredictable rainfall, the system’s efficiency may be affected.
• The initial cost of a rainwater harvesting system is relatively higher.
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