Pyne and Ahar
Pyne is a channel constructed to utilise water flowing through hilly rivers. In South Bihar, where it is found, the rivers are generally dry through the major part of the year but swell in the monsoon months. Given the slope and sandy soil, the water is either carried away rapidly or it percolates down through the sand. Hence, a pyne is developed to lead off water from these rivers to agricultural fields.
An ahar is a rectangular catchment basin with three-sides embankments built at the end of a small pyne. This is a commonly used irrigation technique practiced in Bihar. Unlike a tank, the bed of ahar is not dug out. It is, sometimes, built at the end of small riverlet or a pyne to ensure water supply.