It was considered dÃ©classÃ© to refer to one's own townhouses, estates or villas (or those of friends) as mansions and modern etiquette books still advise that the terms house, big house or great house be used instead.
Waste weir. A waste weir on a navigable canal is a slatted gate on each canal level or pound, to remove excess water and to drain the canal for repairs or for the winter shutdown.
Weirs are used to keep water levels higher on one side and to help slow the flow to a lower level The advantages are they trap debris to make removal easy and prevent blockages at the lower levels They are also used to increase the oxygen content in the water and so help water quality and the oxygen availability for the aquatic creatures ..