'Johads' and 'Khadins' are traditional methods of water harvesting used in which state?

Johads and khadins are traditional methods of rainwater harvesting used in Rajasthan, a dry state where rainfall is low and uncertain. They help store rainwater, recharge groundwater and make farming possible.

A johad is a small, crescent-shaped earthen check dam built across the slope of land to collect and store rainwater. The stored water is used for drinking, for animals and for irrigation, and it seeps into the ground, raising the water level in wells. Johads are common in the Alwar district. In the 1980s and 1990s, the social worker Rajendra Singh, known as the "Waterman of India", and his organisation Tarun Bharat Sangh helped villagers build thousands of johads in Alwar. This revived several dried-up rivers, such as the Arvari, and Rajendra Singh received the Ramon Magsaysay Award in 2001 and the Stockholm Water Prize in 2015 for this work.

A khadin, also called a dhora, is a traditional system developed in the 15th century by the Paliwal Brahmins of the Jaisalmer region. A long earthen embankment is built across the lower slope of a field to trap the rainwater flowing down. The water soaks into the field, and crops are later grown on the moist, fertile soil.

Other traditional water harvesting systems in Rajasthan include kunds or tankas (underground tanks for storing rainwater from roofs and courtyards), baoris and bawaris (stepwells), nadis (village ponds) and jhalaras.

Other states have their own traditional systems:

• Kuhls: Himachal Pradesh (diversion channels).
• Zabo: Nagaland (a system combining water conservation with forestry, farming and animal care).
• Bamboo drip irrigation: Meghalaya.
• Eris: Tamil Nadu (tanks).
• Apatanis: Arunachal Pradesh (paddy-cum-fish farming).

Why not the other options?

• ✗Himachal Pradesh is known for kuhls.
• ✗Nagaland is known for the zabo system.
• ✗Tamil Nadu is known for eris (tanks).