User:Rahul569

WEIR A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water & usually results in a change in the height of the river level. There are many designs of weir ,but commonly water flows freely over the top of the weir crest before cascading down to a lower level.

Weirs are used to prevent flooding, measures water discharge & help render rivers more navigable by boat. In some locations, the terms dam & weir are synonymous,but normally there is a clear distinction mar e between the structure. A dam is usually specially designed to impound water behind the wall, whilst a weir is designed to alter the river flow characteristics.Weir

A common distinction between dams & weirs is that water flows over the top ( crest) of a weir or underneath it for at least some of its length according, the crest of an overflow spillway on a large dam many therefore be referred to as a weir.

WATERMILLS

Mill ponds are created by a weir that impours water than then flows over the structure.The energy created by the change in height of the water can than be used to power waterwheels &  sawmills grinding wheels & other equipment.