3 Sep 2012

The state of our water resources after wettest summer in 100 years

Following two consecutive dry winters in the UK, water resources were twice deprived of their most important annual replenishment cycle, leading to a large swathe of England gaining official drought status earlier this year.

However, it could be argued that the weather has a sense of irony, because no sooner that the drought area was expanded and hosepipe bans put in place, the heavens opened and stayed open.

April was the wettest ever recorded in the UK with more than double the normal amount of rainfall, with some parts of England having more than 230 per cent of the average.

Whilst May provided some temporary warmth and sunshine, June took on April’s theme with the wettest June ever recorded – again with more than double the amount of rainfall normally expected.

Then last week, there was a confirmation of what most of us had expected. Summer this year has been wet – very wet. Provisional figures from the Met Office show that we’ve just had the wettest summer in 100 years and also the second wettest on record.

So what is the state of our water resources across England and Wales where just a few months ago drought was a huge concern?

Soil moisture deficit

This is a measure of how much water is present in the soil. If there deficit is high then it means the soil is lacking water and vice versa.

The latest figures from the Environment Agency show that soil moisture deficits are low, meaning that soils across England and Wales have much more moisture present that would normally be expected at this time of year.

River flows

A few months ago, the lack of water flowing through streams and rivers was a big concern – especially from an environmental point of view.

Plants and animals were suffering as the lack of water present meant that quality was falling, as was the amount of oxygen, putting stress on species dependent on the river environment.

However, the situation has vastly improved with all the rain that has fallen through the summer, with river flows at all measuring points above normal or higher for this time of year.

Reservoir stocks

Earlier this year, there were some reservoirs that were very low for this time of year and less than 30 per cent full, which resulted in hosepipe bans being put in place across some eastern parts of England.

As with river flows there has been a huge turn around in fortunes. Every reservoir in England and Wales, except one, is at the normal level or above for the end of summer.

Groundwater levels

This was the most worrying factor a few months ago because groundwater levels were very low across much of England.

The greatest concern was for eastern parts of England, where around half of public water supplies are sourced from groundwater.

Normally during summer, it is very difficult for rain to reach deep down to recharge the groundwater levels because evaporation rates are higher and growing plants take up a lot of water through their roots.

However, due to the sheer volume of rainfall and the lack of any prolonged dry, hot spells, water has managed to percolate downwards into the aquifers.

Whilst parts of the north Midlands and two sites in south east England still have groundwater levels below normal, the rest of England and Wales are back to normal or above.

Importance of this winter’s rainfall

Although there has been a remarkable turnaround in the water resources situation for England and Wales this summer, the amount of rain that falls this coming winter is still important.

Winter is the main period of recharge and whilst the wet summer we’ve just had has really helped, a winter of average rainfall would ensure that we are in good stead for summer next year.

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