Drought problem? - Dig a borehole!
Tom Whipple, Science Correspondent to The Times (Tuesday April 3 2012) put this forward in his 'A sprinkling of ideas' as a possible way to beat the drought restrictions.
He writes "As long as you are taking less than 20 tonnes of water a day, no licence is needed to extract your own water from underground streams. Rather than dowsing, most people now go to specialist hydrogeologists, who can find water and build a borehole."
So, if a borehole is not an option, what could you do?
In the face of this drought, where should you look to find water?
Where should you buy a house if a moist garden is desired? This is all to do with the supply of water to the soils and their ability to retain water once wet without becoming waterlogged.
- Areas of clayey soils retain water in their upper layers after rain but much of this water stays in the topsoil, never goes down to depth and of that water that does soak into the lower soil layers much becomes locked up and unavailable to plant roots. After heavy rain, clayey soils can remain wet for long periods staying cool and drowning your vegetable crops.
- Light coarse sandy soils, especially with flint gravel, rapidly soak up rain and pass it downwards deeper into the substrate where it becomes lost. The coarse nature of the soils means that there is very little water retention and the high flint content means that most of the soil cannot hold water anyway because flints are solid and impervious to water.
- Areas with high water tables such as on river floodplains and areas with many active springs and seepages can remain wet and cold all year around and lack of aeration means that roots will not thrive.
So just where do you look? I would favour areas of fine silty sandy soils with a wide catchment area to supply water.
- While fine silty sandy soils can dry out in the surface, they have a higher water holding ability in the subsoil (held between the silt and fine sand grains) and which remains available to the suction applied by root hairs and allowing the plants to keep growing when those on coarser gravelly sands and those on clays have long gone yellow and wilted.
- Chalkland soils can also be good, especially where the chalk is covered by a layer of silty clay loam. These soils are easily rootable and deep roots can tap into the very fine water saturated pores in the chalk that release water to the roots slowly over a long period of time.
- Keeping sandy soils covered by a thick layer of organic mulch and avoiding constant digging or hoeing will keep the water in the soils that would otherwise be lost.
For further information on geology, water and soil, check out our sister websites www.hydro-ecology.co.uk and www.soilandwater.co.uk
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