Science & Environment

River Thames breaks records for water flows in January

The amount of water flowing through the Thames this January was the highest recorded for that month since records began in 1883.

Data from the Centre for Ecology & Hydrology (CEH) shows that the rate of water flow has now exceeded 275 cubic metres per second for more than 50 days.

Image copyright Nerc
Image caption The numbers in circles indicate the percentage of the average flow for these rivers recorded in January.

This is nearly twice the record duration for sustained high flow.

The CEH says that Southern Britain is likely to have the wettest winter ever recorded

Scientists from the Centre measure water flow on all the major British rivers. This winter has been a busy time for their instruments, as they have detected record-breaking rates of flow on a majority of rivers in Southern Britain.

At Kingston upon Thames, south-west London, the river has been recorded exceeding 275 cubic metres per second for 52 days.

While the river has seen higher flows, especially before 1950, the scientists say the duration of this intense flow is nearly twice the previous longest time on record.

"Not only has the river Thames been extremely high, its been extremely high for a long time, throughout January and now in February and the total volume of water coming down the Thames has been the highest since 1883," said Prof Mike Acreman from the Centre for Ecology and Hydrology.

Records under threat

The researchers say that increased flood defences and changes to the flow of the river mean that the number of houses at risk of flooding is much lower than the deadly flood of 1947.

The CEH estimate that the overall rainfall picture for southern Britain is heading towards a new high.

"Our rainfall figures suggest it's been the wettest winter since 1910, and here we have some data on river flow records, and many of these are very exceptional and many of these have exceeded the total in January over the whole period of record," said Prof Acreman.

The outlook remains grim and could remain that way for weeks if not months. Not only are the rivers at record levels, and likely to rise with the threatened downpours due over the next few days, but because the amount of water in the ground is now so high there is no room left for fresh accumulations.

"The Met Office are forecasting that we've got more heavy storms to come, at the moment, the rivers are already flowing over banks," said Prof Acreman.

"But we've got the added problem that the groundwater levels are rising, so with the combination of those two we are likely to have severe flooding for the next few months."

Follow Matt on Twitter @mattmcgratthbbc.

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