That sinking feeling
As the prospect looms large of steep rises in water bills, the opportunities look even brighter for clubs to invest in water management measures, such as boreholes, that could save them tens of thousands of pounds and more, annually.
Rainfall may have reached record levels over winter and through spring but recent climatic trends suggest unprecedented heat is also a fact of life now, and when drought descends on us, government bodies such as the Environment Agency (EA) act swiftly.
“The EA knows the locations of boreholes across the country and can impose a ban on abstracting water from them if the public water supply is under threat,” says groundwork specialist Richard Greenaway, who advises clients on the feasibility of drilling on their land.
Having sunk boreholes and installed supporting plant and equipment for golf clubs across Britain, he believes they present an even more cogent solution now, in the face of steeply rising mains water bills.
“They only make sense financially for those drawing large quantities, golf clubs for example, and payback times can be as short as two or three years. From then on, the water’s free,’ he says.
The regulatory framework surrounding them is surprisingly straightforward, at least at the lower end of consumption. “Anyone can extract up to 20m3 (20,000l) a day without requiring a licence to bore.”
“More than that and you have to contact the EA for a licence to abstract, but there is no restriction on where you can sink one, except when it will interfere with existing sources. The EA maps borehole sites so knows if there is a danger of that.”
Equivalent to three skip-fulls of water, the threshold for licence-free abstraction sounds plenty enough, but in the wider picture, it isn’t. Some 660 million gallons of water are lost from the mains network every day across the country because of leaking pipes, figures reveal.
Security of supply will be a concern for clubs wishing to avoid interrupted service. Recent contamination of regional potable water disrupted thousands of homes, and not for the first time.
“At 20m3 a day mains draw, your water bill will be around £20,000 a year,” Richard gauges. “Most golf clubs use up to that quantity but some want three times that amount, making investment in a borehole an even more attractive proposition.”
Sinking a borehole to abstract water for irrigation is likely to be looked on kindly by the EA, as it goes back on to the ground, Richard explains, but there’s not an open door everywhere in the country, he adds, “It’s not granting abstraction licences in Hampshire currently.”
England sits on a complex geological substrate. “In the south, predominantly chalk, which absorbs a lot of water. The water quality is exceptional, with lots of lime in it.”
“Most of Cornwall rests on solid rock and underground water is few and far between. Great oolite and carillon lie beneath the Cotswolds. South of Birmingham, it’s mudstone and quality can vary. The North is more permeable and water percolates layers faster.”
Below 50m under the surface is ‘a huge swimming pool’ – aquifers holding water that has filtered through layers, sometimes taking centuries to do so, resulting in purity Richard says is so high, it’s drinkable straight from the ground, without any need to add chemicals such as the fluorosilicate acid, aluminium sulphate, calcium hydroxide and sodium silicofluoride which tap water can contain.
“Groundwater is so clean mainly for three reasons,” he explains. “All life needs light, oxygen and warmth. Underground, there’s no light, little oxygen and the temperature is only around 6 degrees C. Water percolates through the ground surface then starts its long, slow journey down to the aquifer.”
First step in a golf club borehole project is to evaluate the ground formations under the course to discover how much water is available to extract. “Some areas on chalk or marl formations can provide hundreds of cubic meters of water a day. Other aquifers, on rock formations, may yield only three or four,” Richards says.
Other factors may prohibit one sometimes. “I access the British Geological Survey’s historical records service to research where they have already been sunk locally. A free report informs clubs of my findings.”
The BGS Water Situation Report reveals the water table level, which rises and falls depending on rainfall. “The average between winter and summer across the country is about 8m.”
Sinking a borehole starts with drilling through the surface into central areas, where the bore penetrates fissures or fractures in the rocky layers. Their number determines how much water floods the bore, which may be anything from 5 to 1,000m3 a day.
“Typical depth is 90m and I advise at least a 30m column of water standing in the borehole to future proof supply and allow for seasonal variations in aquifer levels. Pumping equipment with up to 10 bar pressure capacity will lie near the bottom of the bore, which is fitted with a protective stainless steel rising main. Water’s then channelled into tanks then pumps through pipes around the course.”
The cost of installing a borehole – typically a four to six week project - depends on many factors, Richard says, including depth sunk, material drilled, access, pipework runs and trenching.
“Every borehole is different, making it hard to generalise, but payback times average four years, sometimes less. My advice to clubs is always seek out a contractor who can deliver a turnkey project as the knowhow needed to construct a borehole requires the skills of a plumber, electrician, groundwater specialist and pumping engineer.”