Rain and Drought: the groundwater story

In spite of heavy rain and floods affecting much of Britain this Spring, Southern Britain, is still officially in drought.

What to many people seems a perplexing contradiction can be explained by science and that's why geologists from the LWEC-accredited Groundwater Science Programme, led by the Natural Environment Research Council, have been helping the BBC's Inside Out programme makers.

Their key message is that the drought we are still in has its roots over a two year period rather than just two weeks and it affects  water underground, known as groundwater, more than it affects rivers.

Rob Ward, Head of Groundwater Science at BGS, says,

"Because the current drought has developed over a long period of time and groundwater levels are now so low, it will take four to five months of above average rainfall, like we’re experiencing now, to fully replenish affected aquifers."

"A groundwater drought can be likened to a bank account that is overdrawn. If we keep spending (abstracting water) the debt will increase (groundwater levels get lower). If the debt gets too bad, then when we pay in our wages (rainfall recharge) it won’t cover the debt. It’ll get even worse if our wages are cut (dry winters). If we are going to get out of debt we need reduce how much we spend (hose pipe bans and other restrictions) and keep paying in our wages – however much we get. It may take a long time until we’re back in the black just like it will take us a long time to overcome the current drought."

Inside Out Special: Drought 2012 is broadcast on Wednesday, 2 May at 19:30 BST on BBC One England and for seven days thereafter on the iPlayer. A clip from the programme is available on the BBC Inside Out website.

Source: The British Geological Survey website.