A clean bill of health

THE River Thames has breezed through its first full health check, more than 60 years after it was declared ‘biologically dead’. The research and subsequent report, which was undertaken by the Zoological Society of London (ZSL), found that seahorses, oysters, seals and 115 species of fish live in the river, the latter providing food for three species of sharks.

The report findings are in keeping with the river’s increasing numbers of grey and harbour seals: there were 797 harbour seals in 2013 and 932 in 2020; 2,866 grey seals (above, in the Thames Estuary) in 2013, compared with 3,243 in 2020.

ZSL has been working hard to restore the Thames’s delicate ecosystem since 2003 and it’s not only the water that has benefited. Multiple protected areas along its banks means that numbers of wading birds has doubled between 1993 and 2017.

In the same week, it was revealed that when the 15-mile-long Thames Tideway Tunnel—london’s ‘super sewer’—opens in 2025 it will still allow 2.5 million tons of sewage-infected water to flow into the river. Although this number seems rather large it is a massive improvement on the current Victorian-era sewer system, which can release up to 39 million tons of sewage into the Thames every year, according to regulator OFWAT. In a speech to the House of Commons’s Environment Committee, Thames Water boss Sarah Bentley said that the new tunnel was big enough to fit three double-decker buses. ‘It would need to be twice as big to reduce it down to zero spills,’ she added.