Rising damp is caused by capillary action drawing moisture up through the porous elements of a building's fabric. Rising damp, and some penetrating damp, can be caused by faults to, or the absence of a damp-proof course (DPC) or damp-proof membrane (DPM). It is continuous layer of impervious material applied to prevent moisture transmission. A common example is

Any hydraulic structure which supplies water to the off taking canal. Diversion head-work provides an obstruction across a river, so that the water level is raised and water is diverted to the channel at required level. The increase water level helps the flow of water

A solid obstruction put across river to raise its water level and divert water into canal (low head structure) Vertical drop wall or crest wall Upstream, downstream cut off wall at the ends of impervious floor

The only difference between a weir and a barrage is of gates, that is the flow in barrage is regulated by gates and that in weirs, by its crest height. Barrages are costlier than weirs. Weirs and barrages are constructed mostly in plain areas. The heading up of water is affected by gates put across the river. The crest level in the barrage (top of solid obstruction) is kept at

Common causes of failure of weirs include: Excessive and progressive downstream erosion, both from within the stream and through lateral erosion of the banks Erosion of inadequately protected abutments