A johad is a small earthen check dam that captures and conserves rainwater, improving percolation and groundwater recharge. It is a community-owned traditional harvested rainwater storage wetland principally used for effectively harnessing water resources in the states of Rajasthan and Haryana. Johads are often surrounded by embankments, with water wells and trees around them. They are spread across more than 650 villages in Alwar district, Rajasthan. Johads retain the rain that falls in July and August and use it throughout the year. They are also used for raising fishes on a contract basis for commercial fishing. Johads cater to resident and seasonal migrant birds as well as wildlife animals from the nearby forest.

Johads are similar to khadins, which are low and long earthen bunds built in the Jaisalmer district to collect surface runoff water for use in agriculture. Khadins are also a traditional method of rainwater harvesting in India. Both johads and khadins are age-old systems of rainwater harvesting primarily employed in India. They are community-owned structures that promote groundwater recharge and percolation.