Rainwater harvesting is the simple process or technology used to conserve Rainwater by collecting, storing, conveying and purifying Rainwater that runs off from rooftops, parks, roads, open grounds, etc. for later use. The process of rainwater harvesting involves the collection and storage of rainwater with the help of artificially designed systems that run off naturally or man-made catchment areas like- the rooftop, compounds, rock surface, hill slopes, artificially repaired impervious or semi-pervious land surface.
Comparision of rain water harvesting in hilly and plain regions
In plains, the water harvesting structures are crescent-shaped earthen embankments. These are low, straight, and concrete.
In hilly regions, the system of canal irrigation called Kulhsis used for water harvesting. This involves collecting rainwater in a stream, which is then diverted into human-made channels down the hillsides.
- Water harvesting systems used in hilly/mountainous regions are Naula and Kuhl. Naula is a small well, or a pond wherein water is collected by making a stone wall across a stream. This water is used for drinking purposes.
- Kuhl is surface channels that divert water from the natural stream and run at high elevation than the streams to irrigate upstream lands.
- Darns are also built over the hilly mountainous area to store water and later use it for generating electricity.