Around 80 per cent of London’s water comes from the River Thames and the River Lee and is stored in reservoirs in south-west London and the Lee Valley
London and much of the UK remain in a state of drought despite the end of the heatwaves and the return of rain clouds to British skies. Many of us in London will be wondering how this is, despite a few deluges of rain that have drenched the capital this week.
But it’s a testament to how hot and dry the summer was, with six heatwaves and record-breaking temperatures, that the drought continues. As a result, there is still a water shortage, forcing Thames Water to issue a hosepipe ban on July 23. In fact, we will remain in a drought until the country sees ‘sustained rainfall’ nationwide, the Environment Agency has said.
Public water supply is contingent on rainfall, and London actually receives less rain than Sydney and Barcelona. Consistent rainfall is essential to maintain water levels, and winter rain refills the natural underground aquifers that feed the rivers.
Summer rain is largely taken up by plants and lost through evaporation, leaving very little available to recharge groundwater sources. Thames Water told MyLondon there isn’t a set reservoir storage percentage at which a drought is declared.
This is because reservoir storage is just one of the factors the Environment Agency considers when deciding whether to declare a drought in a given area.
September drought
Ten areas of England were in drought status at the start of September: East Anglia; Hertfordshire and North London; Thames; Devon, Cornwall and Isles of Scilly; West Midlands; Wessex; Kent and South London; Solent and South Downs; East Midlands; Lincolnshire and Northamptonshire. The remaining areas were in “prolonged dry weather status”, according to the Environment Agency.
Rainfall across August reached 78 per cent of the long-term average nationally, although south-east England received only 54 per cent. The Met Office said autumn had marked a “significant change of weather type from summer, which was dominated by dry conditions”.
It added that the first week of autumn had seen 18mm of rain fall across the UK, with more heavy rain forecast this week, especially in western areas.
Where is London’s water held?
Around 80 per cent of London’s water comes from the River Thames and the River Lee, which is stored in reservoirs in south-west London and the Lee Valley. The rest comes from groundwater, and Thames Water also has a desalination plant in London, in case of drought.
‘Recent rain has a limited impact’
A Thames Water spokesperson said: “The recent rain has been welcome but has had only a limited impact following many months of exceptionally hot and dry weather across our region. Although we want to lift the hosepipe ban as soon as we can, a few showers will not be enough.
“We need sustained, significant rainfall over months to help rivers recover and groundwater levels recharge before reservoir levels can fully recover. We continue to monitor conditions closely and are grateful to customers for continuing to use water wisely. Their support remains essential as we manage water resources following what the Met Office has declared to be the warmest summer on record.”
Looking for more from MyLondon? Subscribe to our daily newsletters here for the latest and greatest updates from across London.
