Drought? Flash floods? Wrong sort of rain? How British!

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The last Saturday of April, and we’ve certainly had April showers – hail showers…
Many of our clients have asked why, when they can see water levels in local streams and ponds rising, do we still have a hosepipe ban? Oh yes and why is it the ‘wrong sort of rain’? Isn’t rain, well, rain? And wet?

Taking the second question first: using analogy of a sponge makes it easier to explain. Take a dry, hard sponge, drip water onto it constantly, it becomes sodden. Equally, dripping water onto it until damp then pouring water onto it, the water is still soaked up by the sponge. Take a dry, hard sponge and drown it with a bucketful of water held above and the water bounces off…
Hence ‘wrong sort of rain’; it bounces off the soil rather than soaking nicely through to wet plant roots and work its way down to the water table. It flushes itself into drains and sewers; catapults off impermeable concrete and washes away nutrient rich top soil.

Taking the first question second; yes thankfully there are some streams and ponds which have rising water levels. However, we’re still in a drought situation because the reservoirs and rivers need a lot more water; they have been deprived of rain for more than a few weeks. So what is or makes a drought? A drought is a shortage of rainfall which consequently causes a shortage of water for the environment, ie habitats, flora, fauna (animals), agriculture, industry, businesses, households, domestic gardens, parks – in fact just about everything and everyone. 

There are basically two kinds of drought; a short intense drought caused by a heat wave and lack of rain; then a longer term drought that develops over time, ie where there has not been enough rain over previous months. In the UK we generally get most of our rain over the winter months, and the last two years have been well below average, in other words, dry (if snowy). Think back to spring 2011 – again, drier than normal. This means that the reservoirs and rivers have not been able to fill up as per usual.

Importantly, the groundwater levels, which are the underground water resource, are also at seriously low levels. This is the water that would fill wells; that is tapped by bore holes and that fills rivers, lakes and reservoirs from below as the rain fills them from above. Without getting too technical, and using the sponge analogy again, the ground, or rather the soil, has a capacity to hold water both near the surface and lower down at the bedrock level.

The amount of water a soil is capable of retaining varies (this bit you probably know); sandy soils are not good at holding water, so gardeners need to add lots of organic matter to increase their ability to retain water so the plants have something to drink. Clay soils in contrast are very good at holding water (put simply, it’s because the clay soil particles are tiny so there’s more room in between them for the water). That’s why clay soil is often muddy and unworkable over wet winters, it is full of water. Or rather it should be full of water; not in a drought.

Going back to the short intense drought, whilst shallow ponds will dry up and clay soil crack on the surface, below ground, lower than most gardeners are likely to dig there are still reserves of water. So the effects are mainly short term, although from a climate perspective they would still need monitoring to see if they’re part of a larger trend.

A drought that has developed over time – our two dry winters, for example –is different. Groundwater levels need to replenish over the ‘wet season’ as during the growing season trees and plants use most of the rainfall before it soaks down through the soil to the lower levels. It is actually a good system, if you think about it. The soil stores the water until it’s needed, the plants make use of the bounty from the skies first before drawing on the reserves. Nature is really quite efficient.

One of the problems with a long term drought is that humans, especially in the developed world and definitely in Great Britain, are generally profligate with water, ie not just that we use a lot of water but we waste it. Not always on purpose, often without realising we’re doing so. We have to change our mindset and our habits, and that includes new builds having grey water and water catchment systems as standard; and ways of retrofitting older houses, offices and industrial premises, parks, farms, nurseries…

At Plews we care about water conservation; our planting schemes are designed to be miserly in their watering needs once established. Plus we have plenty of ideas and solutions to make your garden – at home or at work – an oasis in the desert

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