For most of golf history, irrigation came only from the skies. That might be OK in soggy Scotland, but once the game had spread to parched Portugal, relying solely on rain was always going to be inadequate.

Early artificial irrigation involved a greenkeeper going out with a hose, and using his thumb to regulate the flow. Now, by contrast, irrigation systems are capable – as a result of computerised control – of putting a precise amount of water on a specific part of the golf course. But they are also capable – as a result of improvements in pumping and sprinkler technology – of applying vast amounts of water in an extremely short time. They are also – again, as a result of improved technology – potentially extremely expensive.

"A complex irrigation system that covers fairways as well as greens, tees and approaches might represent 25 per cent of the total cost of development for a new golf course," says architect Howard Swan. "The course we built at Boavista in Portugal a few years ago needed this kind of system, as you would expect in such a warm climate. In a cool, damp climate, where you can get away without irrigating fairways, you might only spend ten per cent of the budget on irrigation. I do believe that there is a tendency to install overly sophisticated systems. Not every bit of grass on the golf course needs to be irrigated."

"It's in the interests of the greenkeeper to minimise water consumption, because he wants merely to keep the plant alive. He doesn't want it to grow too strongly," says golf course constructor Brian Pierson. Early sprinkler-based irrigation systems, though, were not necessarily capable of this level of precision: they would be used for long enough to get the driest part of the golf course sufficiently wet - which, of course, means the rest of the course would get more water than it needed. "The irony is that the scarcer water is, the more you need a powerful irrigation system," says consultant Giles Wardle of Irriplan.

"Where there is overspend on irrigation, it usually comes about during installation, rather than overspecification," says John Shepherd of irrigation giant Hunter Industries. "In some cases – we came across one in Tenerife where the underlying rock was volcanic – it's very difficult to predict installation costs." Shepherd also points out that golf course contractors will typically engage a separate, specialist company to install the irrigation system, and that, while this may result in a better job, it does make putting together an accurate budget more difficult.

Historic North Berwick Golf Club, in East Lothian, Scotland, has recently installed a complex new irrigation system – and can testify to Shepherd's claim that the progress of a project can't be guaranteed once you have broken ground. The new system, installed by contractor Arden Lea Irrigation, covers all greens, approaches, fairways and tees, as well as some carries and walkways. It also included putting greens, the turf nursery, plus greens and tees on the nearby children's course.

Irrigation consultants Robin Hume Associates designed the upgraded system for North Berwick.

Designer Adrian Mottram says: "The existing system was ailing and the greens – some of which are unusually large – were suffering from poor coverage. The challenge was to provide a more efficient system, which would give them the flexibility to put precisely the required quantity of water anywhere on the course at a moment's notice.

"Once the project was under way, we discovered there was sandstone underground – about 300mm deep – which we needed to get through to lay the mains pipework at about 600 or 700mm. This meant they had to use a tool similar to a hammer drill to break up the stone. Only then the pipe be laid at the specified depth."

On the large greens, where achieving the correct water throw is essential, 15 Toro 690s – the largest sprinklers on the market – were used. Some 500 Toro 800 Series sprinklers were employed overall, plus 90 of the 2001S, 50 Toro 720Gs and 30 of the new 835S sprinklers for the children's course. Fifty P220 solenoid valves were fitted on tees only, for block control, and a new 3-wire, 6-zone PC-based Trident controller was installed to run the whole operation. This will be upgraded to include VIP mapping in the near future.

The equipment also includes a hand-held remote controller for instant watering anywhere on the course, and a fully automated pumping system using variable speed technology, to ensure that flow demand is delivered exactly. North Berwick superintendent Stuart Greenwood says: "It was important that we disrupted the course as little as possible. You wouldn't know any work was done at all and there was no disruption to play."

"The new system gives us complete control over when and where we water, and ensures we can cope with any climate changes," adds Greenwood. "Every year we have 50,000 rounds of golf, so course maintenance is a full-time job. The new irrigation is giving us that additional timesaving element and a good deal of flexibility."

PGA National Ireland, a new course near Dublin, will open in early 2006. Its irrigation system is controlled by Rain Bird's Stratus 11 system installed in the central pumping house, and combined with a Freedom radio-telephone system.

With such a system, water can be controlled to almost infinite degrees, right down to the amounts delivered by the sprinkler heads themselves. Each can be programmed to provide either a lot if it's required, or a little – 'syringing' – to ensure sufficient moisture for growth while delivering firm and fast greens and fairways.

"When you're growing a course in, you've basically got to get it right, every day and every week, over an 18 month to two year period," says course superintendent Damon Kirk. "If an irrigation system lets you down on one baking hot day – and we do have a few of them over here – the grass can be seriously affected, root growth can be significantly damaged, and so on. That's without adding all the implications down the line of opening dates and revenue targets."

"Last year while friends of mine in England were watching their water levels drop by the day, we always had plenty of water in our eight lakes. But whatever your water resource, you want the reassurance that the system's going to make the most of whatever you've got."

Among some traditionalists, there is a degree suspicion of these high-tech irrigation systems: it seems that some people believe that a large investment in irrigation leads almost inexorably to overwatering and a soggy golf course. That need not be the case, though some courses, such as Open Championship venue Carnoustie, have been criticised for their overly green appearance. "Just because the irrigation system is there doesn't mean you have to use it all the time. On a links course, the irrigation system should be there to help the superintendent keep the grass alive, not to make it lush and green," says John Shepherd.Victor Jamison of Rain Bird agrees: "It's both a maintenance tool and an insurance policy. It's down to the course manager to make appropriate use of the technology available to him." In fact, the precision watering enabled by expensive irrigation systems should make it possible for the superintendent to generate precisely the conditions the membership wants, because specific quantities of water can be directed to specific parts of the course, rather than just dumping water on regardless.

"I feel you often have memberships asking for different things," says Jamison. "Some like a nice hard fairway that the ball is going to run on, but others prefer to know that when they put the ball up in the air it will stop. Greenkeepers are put in an awkward position, because they can't please everyone. And if they want to keep the course lean and mean, sometimes they might have to take the odd risk. But control technology is making that kind of fine tuning much more feasible." Such high-spec systems, though, aren't necessarily the order of the day for most golf clubs. "Pretty much every project is a compromise between what is ideal, and what is possible with the budget available," says Shepherd. "Part of the decision relates to what resources are available in a particular country.Valve and head sprinklers give most control, but they do require more skilled maintenance. So, for example, on a recent project in Bulgaria, we used valve and head sprinklers on greens and approaches, but more simple technology elsewhere."

In the end, though, the technology is only as effective as the person or people operating it. If high-specification systems are installed at a course, then training for greenkeeping staff in the skills needed to operate the computer controllers is essential. Even with lower spec systems, greenkeepers need to be highly alert to the needs of their turf and the peculiarities of their site. "When I started in the business 35 years ago, if you held a hose and sprayed the golf course, that was regarded as sophisticated," says Howard Swan. "But even with computerised single head systems, you still need to look at hand watering of certain areas of the course. And only the superintendent knows exactly where."

This article first appeared in issue 3 of Golf Course Architecture, published in January 2006.