51°34′12″N 2°49′30″W / 51.57°N 2.825°W
The Caldicot and Wentloog Levels are two areas of low-lying estuarine alluvial wetland and intertidal mudflats adjoining the north bank of the Severn Estuary, either side of the River Usk estuary near Newport in south east Wales. They are also known collectively as the Monmouthshire Levels or Gwent Levels, and the name Wentloog is sometimes spelled Wentlooge in official publications.
A weir /wɪər/ or low-head dam is a barrier across the width of a body of water that alters the flow characteristics of water and usually results in a change in the height of the water level. Weirs are used to control the flow of water for rivers, outlets of lakes, ponds, and reservoirs, industrial discharge, and drainage control structures. There are many weir designs, but commonly water flows freely over the top of the weir crest before cascading down to a lower level. There is no single definition as to what constitutes a weir.
Weir can also refer to the skimmer found in most in-ground swimming pools, which controls the flow of water pulled into the filtering system.