Water Harvesting - Traditional and Modern Methods

Water harvesting is the practice of collecting and storing rainwater or surface runoff for later use, or directing it into the ground to recharge aquifers.

The water table is the level below which the ground is saturated with water. In deserts, due to extremely low rainfall and high evaporation, the water table is typically very deep.

When rainwater seeps into the ground (infiltration), it reduces surface runoff. By slowing down the flow of water across the surface, it helps prevent flash floods.

Rainwater harvesting is primarily a technique used to collect and store rainwater for future use, which is a fundamental practice for water conservation. It helps recharge groundwater and provides a water source during dry periods.

The people of rural India use different methods to collect water. Water-harvesting techniques used depend on the location where it is to be used.

Water harvesting is an age-old concept in India. Khadins, tanks and nadis in Rajasthan; bandharas and tals in Maharashtra; bundhis in Madhya Pradesh and Uttar Pradesh; ahars and pynes in Bihar; kulhs in Himachal Pradesh; pond in the Kandi belt of Jammu region and eris (tanks) in Tamil Nadu; surangams in Kerala; and kattas in Karnataka are some of the ancient water harvesting, including water conveyance structures.

Modern rainwater harvesting systems often utilize both rooftop collection (from buildings) and surface runoff collection (from land areas) to maximize water capture.

When rainwater seeps through the soil, it percolates into the ground and replenishes aquifers. This process is essential for maintaining the level of the water table.

A rooftop rainwater harvesting system typically includes a catchment area (the roof), a first flush diverter to remove initial contaminants, and a filter to clean the water before it enters the storage tank.