Tideway

The Tideway is a name given to the part of the River Thames in England that is subject to tides. This stretch of water is downstream from Teddington Lock and is in its widest definition just under 160 kilometres (99 mi) long. The Tideway includes the Thames Estuary, the Thames Gateway and the Pool of London.

Depending on the time of year, the river tide rises and falls twice a day by up to 7 m (24 ft) and due to the need to overcome the outflow of fresh water from a significant part of England takes longer to subside (ebb) (6–9 hours) than it does to flow in (4–5 hours).

London Bridge is used as the basis for published tide tables giving the times of high tide. High tide reaches Putney about 30 minutes later, similarly Teddington/Ham.

Low-lying banks of London have been defended against natural vulnerability to flooding by storm surges. The threat has increased due to a slow but continuous rise in high water level, caused by the extremely slow 'tilting' of Britain (up in the north and down in the south) due to post-glacial rebound and the gradual rise in sea levels due to climate change. The Thames Barrier was constructed across the Thames at Woolwich to deal with this threat.

The Tideway is managed by the Port of London Authority (PLA) and is often referred to as the Port of London. The upstream limit of its authority is marked by an obelisk just short of Teddington Lock. The PLA is responsible for one lock on the Thames: Richmond Lock.

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