Question

how the system of water harvesting is different in hilly or mountain areas as compared to plains or plateau regions?

Answer 1

In hilly regions in the north east India, some indigenous rainwater harvesting systems is used for cultivation. Settled agriculture is done in the form of irrigated terrace cultivation in parts of Nagaland and Meghalaya. Fields are irrigated through channels which are dug. Another source of irrigation is the bamboo irrigation system found in parts of Meghalaya and Nagaland.
In plateau regions, water is drawn from tanks for irrigation. Different mechanisms are used depending on the size of the tank. For a small tank, a straight tunnel across the base of the bund is constructed using stones. A log is pitched at the mouth of the tunnel and plastered with clay. It is removed when water is required. For a medium or large tank, a straight tunnel is constructed across the base of the bund using stones over which a stair-like structure is built, with a opening on each side. This is stopped with a stone slab or a wooden log carefully plastered with clay.