A (very) brief history of the River Thames

For the last five months, I’ve lived in a flat in a block which is less than one minute’s walk from the River Thames as it snakes its way through central London. So I see the river every day and, throughout the day and night, it changes level and character considerably because of the tides. An article in the “Guardian” newspaper explains the situation:

The name of the longest river flowing entirely in England may derive from “tamasa”, a Sanskrit word meaning “dark water”.

The Thames has always been brown, and will remain so even if one day it is entirely free of pollution. The brown waters are caused by eight-metre tides that scour its muddy estuary. They are the source of much of its biodiversity: allowing plankton to survive which feed off nutrients in the water column and provide food for fish.

Sixty years ago, however, the Thames was toxic. “The tidal reaches of the Thames constitute a badly managed open sewer,” the Guardian reported in 1959. “No oxygen is to be found in it for several miles above and below London Bridge.”

In 1957 the Natural History Museum declared the Thames to be biologically dead. The Victorian engineer Joseph Bazalgette’s brilliant sewer system, which saved London from the “great stink” of 1858, had been damaged during the second world war. Parts had fallen into disrepair. Heavy industry used the Thames as its free waste disposal service.

Not everyone was outraged. The Guardian reported in 1959 that a member of the House of Lords opined that cleaning the river was unnecessary: rivers were “natural channels for the disposal of waste” and allowing them to break up our waste gave them “something to do”.

Repairs to the sewers and tighter regulations, including to reduce fertilisers and pesticides from farmland draining into rivers, gradually cleaned up the Thames, as did broader economic changes. The decline of Thames-side industry removed pollution; toxic metals have reduced since 2000, helped by the switch to digital photography, which has reduced the photographic industry’s silver pollution.

A time-traveller from the 1950s visiting the hides at the London Wetland Centre (created from disused reservoirs in Barnes) would scarcely believe the great white egrets, kingfishers, hobbies and dragonflies that are testimony to a new, enriched urban ecosystem.

The Thames is more wildlife-friendly than it was, but it is not perfect. Salmon were reintroduced to the Thames, but this scheme seems to have failed. The inner Thames is too busy and noisy with boats for dolphins or porpoises to thrive (seals do not hunt using sound and so are more able to survive alongside water traffic).

A species as rare as a tiger still snakes through the capital – the endangered European eel – but it is in drastic decline. Like London’s citizens, the future prospects for this and many Thames species depend on the world beyond it.


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