Question

What is rainwater harvesting? Describe the method of rainwater harvesting.

Answer 1

Hint: The essence of the process of rainwater harvesting lies in the word ‘harvesting’. Many people confuse rainwater harvesting with reuse of used grey water, but that is an incorrect assumption. Harvesting means to gather something that already exists in its natural form but will get wasted or polluted if it is not stored and used.

Complete step-by-step answer:
Rainwater harvesting essentially means to gather the rainwater off impervious surfaces and store it in underground tanks or aquifers for later use. These impervious surfaces usually include roofs, surfaces of rocks, hill slopes that are impervious and many other surfaces. The aim is to collect the run-off from these surfaces and use it wisely for any activities that do not strictly require the potable water that is provided by the government. Hence we can save the water that will run off and ultimately get polluted in the drainage system and also reduce our usage of the water that the corporation provides so that it can be distributed in places where potable water is not available.
The two main types of rainwater harvesting are:

- Surface water harvesting
This type is usually seen in urban regions as there are plenty of flat, impervious surfaces like cement, concrete, glass off which water can run off. This water is then collected by the means of strategically placed channels that interrupt the flow of the water on the surface and direct it to the catchment regions or the groundwater aquifers where it can be further filtered through gravel, sand, and charcoal before use.

- Rooftop rainwater harvesting
This type can be seen in both urban and rural areas as most of the residences will have flat or impervious roofs. Here, a deliberate slope can be created, and all the water that will usually run off will be directed into a pipe that will be constructed. This water will then be filtered for use in basic household activities.

Note:
Rainwater harvesting can also be used to replenish all the groundwater sources that are depleting due to heavy use these days. There are many other ways with which we can harvest rainwater specific to the conditions in a certain place but only 2 are commonly found.