We speak to Prof Kevin Hiscock, an environmental scientist from the University of East Anglia, about the growing issue of depleting water resources in the UK.
Is there a strict scientific definition of exactly what we mean by drought and are we heading for one?
There isn’t actually a strict definition. We can think in terms of a meteorological drought, in terms of a deficit of rainfall like we see in the last few months, agricultural drought, particularly if that dry weather is at the same time as the irrigation season in the summer. But I also think in terms of hydrological drought, which is perhaps the worst in respect of maintaining the water supply for both our drinking water, and also to support the environment.
But they develop over a longer period than several weeks of no rainfall. In the recent period, we’ve seen months of lower rainfall than usual. So, one dry spring leading into another dry autumn or winter makes the problem worse.
Next year we could see more of an issue if we don’t get some rainfall over the critical winter period. But certainly, now we’re finding that the drought is developing.
How does water move around the landscape?
The rainfall infiltrates the soil and then slowly moves down to the water table and then gradually that water will move towards the discharge area, which is the river or a wetland.
England is underlain by chalk. And that chalk is a huge reservoir of water. One-third of the drinking supply in England will be from the chalk aquifer. Essentially, we’ve got this this large water cycle, rainfall, infiltration, rainwater discharge into the river and then down to the estuary, back to sea to connect up to the water cycle. But groundwater is really important for our river flow and for our public supply.
What is the current situation with UK water resource management?
All water companies go through a five-year planning cycle, the so-called AMP period, the asset management period cycle, and they should be looking at their longer-term projections for demand that will take into account population increase as well as climate change factors. If insufficient water is available in the longer term you’ve got to plan to build storage into the system.
We do need to build headroom and that depends on the nature again of your geography -whether you have groundwater resources that you can use, whether you are entirely dependent on surface reservoirs like you may be more in the west of the country and the north of the country.
You can also move resources around in a region. So, for example, in the wetter northern parts of Britain, you could divert water southwards, which we see presently with a big pipeline being built from Humberside down through to Essex at this time to try and redistribute the resource.
The headlines always are always about hosepipe bans, but what about agriculture and food supply?
We’re seeing now that crops are just dying in the fields. The Environment Agency do have the power to stop farmers from irrigating – the so-called Section 57 of the Water Act – that is when the farmers particularly get upset. But this summer period, farmers have been able to continue irrigating towards the end of the season.
When I think back to the drought of 1989 through to 1992 in the Anglian region, there was a ban on irrigation and the farmers were very unhappy with that. And so you get this classic conflict of interest between the need to protect the water, the public supply, and the need for irrigation.
What about other land management solutions?
Planting woodland or introducing beavers into the landscape is very effective. Water engineers also have ways of cultivating the ground to create a more textured soil so the infiltration occurs more easily. You also have approaches like regenerative farming, or minimum tillage, to avoid ploughing of the soil. We can help build the soil structure and increase the organic content in that soil. It becomes more fibrous and is able to act like a sponge.
I also think that we can extend these ideas into the built environment. So when you think about the amount of concrete and tarmac in urban areas and how quickly you see flooding. We can use sustainable urban drainage systems or SUDS. These are things like ponds or wetlands within a new housing development. Greening up our urban space, and thinking in terms of these sustainable drainage systems is another a good way of holding out water in in the catchment.
Is there anything the public can do to help?
I think we can all help. At this time, not using the hosepipe or the sprinkler, putting on the dishwasher or the washing machine when it’s full. It’s great to be able to to harvest rainwater in a water butt for watering the garden during a dry spell.. Taking showers instead of baths.
These are all steps that we can take. But ultimately in the longer term, I’m amazed to see that we never have a label on, say, a washing machine telling of the high water efficiency. There’s an energy efficiency label. And also leakage on our own properties. If your water meter continues to turn and there’s an issue with some form of leakage on your side of the of the water network.
What does the future picture look like?
We think ahead into the future, periods like this will become more frequent. This is the best that we can see from the climate modelling scenarios, even though there’s uncertainty around predicting rainfall totals.
By our best estimates, the scenarios for the future climate suggest in the south and east of England there will be increasing summer drought frequency and more intense drought and indeed over wider areas.
But that’s not for the whole of the UK. As you go towards the northern part of the UK, the scenario there is for normal or wetter conditions, but not quite the severity that we might expect in terms of droughts in the future.
The other characteristic is the all important winter rainfall, when we need the recharge to occur, to top up our aquifers that support our rivers. This will occur on fewer days. So the southern areas will get drier and northern areas will get a little wetter. That’s the general pattern.
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