Rainwater Harvesting: Water is why life exists on planet Earth; without it, life is unimaginable. How will you plan your survival if one day there is no water on earth? It is hard to even conceive that there is no water on earth. Freshwater sources are becoming scarce over time. Unless the current water situation changes and preventive measures are taken, the world will run out of freshwater by 2050. Here comes Rainwater Harvesting, a sustainable process that helps conserve rainwater for different purposes. Rainwater Harvesting is best defined as the technique by which rainwater is accumulated and stored for later use when there is a scarcity or a drought.

Rain is the natural and purest source of water. How can we store it? What are the methods followed to harvest rainwater? We will answer these questions in this article and learn more about how to conserve rainwater by Rainwater Harvesting.

Rainwater Harvesting: Definition

Rainwater harvesting may be defined as the simple technique of collection and storage of rainwater at the surface or in the subsurface aquifer before it is lost as surface runoff from rooftops, parks, roads, open grounds, etc., for later use.

Potable water is becoming scarce in many countries due to rapid climatic changes, global warming, and population growth. Water levels gradually falling is a cause of serious concern because it results in a shortage of usable water and an imbalance in salinity in coastal areas. Rainwater harvesting is gaining popularity as a source of eco-conservation and constructive use of natural resources since there is no alternative to increasing freshwater supplies. Rainwater harvesting is an easy and economical way to deal with this crisis. Let’s study more to understand the advantages and disadvantages and types of rainwater harvesting.

Types of Rainwater Harvesting

There are two ways of Rainwater harvesting:
1. Rooftop Rainwater Harvesting
2. Surface Runoff Rainwater Harvesting

Rooftop Rainwater Harvesting

a. Rooftop rainwater harvesting or domestic rainwater harvesting is the technique through which rainwater is captured from roof components and stored in tanks/reservoirs/groundwater aquifers.
b. It consists of the conservation of rooftop rainwater in urban areas and utilizing it to augment groundwater storage by artificial recharge.
c. This technique is particularly useful in dryland, hilly, urban and coastal areas. If the system is properly installed and maintained, clean water fit for drinking can be collected and stored.

Components of Rooftop Rainwater Harvesting System

The various components of rooftop rainwater harvesting system are:
1. Roof/catchment area
2. Gutters and downpipes
3. Filter unit or leaf screen
4. Storage tank
5. Delivery system
6. Water treatment unit

Fig: Rooftop Rainwater Harvesting

Surface Runoff Rainwater Harvesting

Harvesting of surface runoff water and storage of the same into reservoirs makes it available for use when required. In this method of collecting rainwater for irrigation, water flowing along the ground during the rains will be collected to a tank below the surface of the ground.

Methods/Process of Rainwater Harvesting

There are three methods of harvesting Rainwater as given below :

(a) Storing rainwater for direct use: Collecting rainwater for direct use is a simple process in places where rains occur throughout the year. Rainwater can be stored in tanks. However, at places where it rains for \(2\) to \(3\) months, a huge volume of storage tanks would have to be provided.

In such places, it will be more appropriate to use rainwater to recharge groundwater aquifers rather than to go for storage. If the strata are impermeable, then storing rainwater in storage tanks for direct use is a better method. Similarly, if the groundwater is saline/unfit for human consumption or the groundwater table is very deep, this method of rainwater harvesting is preferable.

Fig: Storing rainwater for direct use.

(b) Recharging groundwater aquifers from rooftop runoff: Rainwater that is collected on the rooftop of the building may be diverted by drain pipes to a filtration tank from which it flows into the recharge well. The recharge well should preferably be shallower than the water table. This method of rainwater harvesting is preferable in the areas where the rainfall occurs only for a short period in a year, and the water table is at a shallow depth.

Fig: Recharging Groundwater Aquifers from Rooftop Runoff

(c) Recharging groundwater aquifers with runoff from the ground area: The rainwater collected from the open areas may be diverted by drain pipes to a recharge dug well through filter tanks. The abandoned borewell can be used cost-effectively for this purpose.

Fig: Recharging Groundwater Aquifers with Runoff from the Ground Area

Advantages of Rainwater Harvesting

1. Promotes adequacy of underground water.
2. Mitigates the effect of drought.
3. Reduces soil erosion as surface runoff is reduced.
4. Decreases load on stormwater disposal systems and reduce flood hazards.
5. Improves groundwater quality/decreases salinity (by dilution).
6. Prevents ingress of seawater in subsurface aquifers in coastal areas.
7. Improves groundwater table, thus saving energy (to lift water).
8. The cost of recharging subsurface aquifers is lower than surface reservoirs.
9. The subsurface aquifer also serves as a storage and distribution system.
10. No land is wasted for storage purposes, and no population displacement is involved.
11. Storing water underground is environmentally friendly.

Disadvantages of Rainwater Harvesting

1. The cleaning and regular maintenance of tanks are required.
2. No rainfall or limited rainfall affects the storage system.
3. Stagnant water in tanks leads to the breeding of mosquitoes and other waterborne diseases.
4. The setup of a system should be accurate.

Summary

Rainwater is the purest form of water. Rainwater harvesting is the process of saving rainwater. It is predicted that the next world war will be fought for water. Rainwater harvesting will help in preventing floods. This method will reduce the stress on our rivers and lakes. Rainwater harvesting will help aquatic life from getting polluted and depleted. The rainwater harvesting process will maintain a healthy water cycle in our ecosystem. Proper awareness campaigns should be conducted to ensure the awareness of the general public about rainwater harvesting and its uses.

Frequently Asked Questions (FAQs) on Rainwater Harvesting

Q.1. What is Rainwater Harvesting?
Ans: Rainwater harvesting may be defined as the simple technique of collection and storage of rainwater at the surface or in subsurface aquifers before it is lost as surface runoff from rooftops, parks, roads, open grounds, etc., for later use.

Q.2. What are the different methods of rainwater harvesting?
Ans: The different methods of rainwater harvesting are as follows:
1. Storing rainwater for direct use.
2. Recharging groundwater aquifers from rooftop runoff.
3. Recharging groundwater aquifers with runoff from the ground area.

Q.3. What is the importance of rainwater harvesting?
Ans: The importance of rainwater harvesting is that we can store the rainwater for later use when there is a scarcity of water for irrigation, drinking, washing, cleaning, etc.

Q.4. What are the advantages of rainwater harvesting?
Ans: The advantages of rainwater harvesting are listed below:
1. Promotes adequacy of underground water.
2. Mitigates the effect of drought.
3. Reduces soil erosion as surface runoff is reduced.
4. Decreases load on stormwater disposal systems and reduce flood hazards.
5. Improves groundwater quality / decreases salinity (by dilution).

Q.5. What are the factors affecting the amount of rainwater harvested?
Ans: Small storage tanks, less rainfall, types of roofs, etc., are the few factors that affect the amount of rainwater harvested.

Rainwater Harvesting Process and Collection are adequate strategies that can be used to address the problem of the water crisis globally. This water conservation system is a simple and effective procedure with numerous advantages that can be easily practiced in individual homes, gardens, apartments, yawns, and worldwide.

We hope this article served your need. If you face any further issues regarding the Rainwater Harvesting Process do let us know about it below in the comment section and we will get back to you soon.