The last time the M Chinnaswamy Stadium hosted a Test match - between India and South Africa in November 2015 - wet weather ruled out play on four of the five days. The rains had been fairly persistent, due to tropical storms in neighbouring areas, but not brutal to the extent of losing four full days. That only 81 overs were bowled was down to the wetness of the outfield.
The third and final T20I between India and England on Wednesday will be the first match at the ground since the IPL final in May. In the downtime, the Chinnaswamy Stadium has had a comprehensive makeover of its outfield and drainage. With each washout costing the association crores, the KSCA, in a bid to do away with the wet outfield problem, has installed a subsurface aeration system that is aimed at starting play within minutes after rain ceases.
"This system is meant for turf conditioning and is something that works 365 days a year," Anil Kumar, the managing director of Great Sports Infra, the company that installed the system, told ESPNcricinfo. "Rather than in the past, when you were treating the problem after it stopped raining, here it is treated as it rains. We started the project in June and completed it in 150-160 days. It cost us about Rs 4.5 crores, though the KSCA had to supply some material of their own, like sand, gravel and a few other things."
So how does subsurface aeration work? The system is powered by a 200-horsepower machine, developed by the American company SubAir. The machine primarily functions in two modes - a pressure mode and a suction mode. The suction mode is vacuum-powered and is used to draw water out of the outfield. The machine has a capacity of flushing out upto 10,000 litres per minute. The act of drawing out the water begins as and when it rains, which speeds up the drying process. The pressure mode is used to pump oxygen to the grass, which ensures it stays healthy. The pressure mode is the default mode given that rains are not an everyday occurrence and the grassroots need fresh air regularly.
To make sure that water is drawn out as soon as the rain begins to fall, there are remote sensors embedded in various parts of the outfield. These sensors can detect the amount of water, and once it exceeds the normal level, they send a signal to the machine, which automatically switches to suction mode.
Installation of the machine was only half the job. To ensure that the water sucked out is flushed out efficiently, a new drainage system had to be laid. That meant the outfield was dug up and a new sand base was laid, replacing the old red soil one that had been in place since 1968. "Sand is the best consolidating material, and it allows the water to go down," PR Viswanathan, BCCI's South Zone curator, said.
"If you take regular soil and water, it will swell and become a lump, which does not happen with sand. The drainage system takes the water out, but in other kinds of soil, the surface moisture is retained. Sand, on the other hand, does not hold water. It allows water to percolate, which means the outfield is less slippery and the risk of injury is minimised. Sand is expensive, and you need to be very good with maintenance, especially in cool climates like Bangalore, where fungal infection is something to look out for."
With the new system, which is called sub-soil drainage, built as per the standards of the United States Golf Association, water penetrates the sand layers and goes through a network of pipes that connect to the water separator tank, where pumps have been fit in. These pumps then throw the water into the main drains. It helps that the ground is situated on a higher plane than its surroundings, which makes for natural drainage. To quicken the process of water removal, the pipes converge at one point, which is connected to the SubAir machine. But work still remains to be done.
"We have got a water tank that has got a capacity of three lakh litres. And we are going to have another tank of about five-lakh litre capacity," K Sriram, the chief curator, said. "We will start on that work after this match.
"We are trying to recycle as much water as we can. We have around 12 or 13 recharge points in and around the ground for the excess water so that the borewell gets recharged. After those get saturated, there is a well near the pavilion where the water will go."
The relaying of the outfield had been long overdue, given the hardness of the surface and excess growth of weeds due to the formation of alkaline that infected the grass. Digging up the area was not an easy task, as they encountered hard rocks at various parts of the ground that had to be drilled and taken out. That apart, remedies were applied on the pitch, where excess soil was removed to bring in some freshness.
Originally designed for golf courses, subsurface aeration is a tried method in other sports stadiums across the world. But this is the first such application on a cricket field. "The one thing that is really unique to cricket is they use the same ball for the entire match," Kevin Crowe, the senior vice-president of SubAir, said. "In baseball, for example, which is the closest thing to cricket, if the ground is wet, they just toss that baseball out and use a new baseball, while in cricket, they need to keep the ball dry because they use the same ball for the entire match. So part of our design was that we want water to drain rapidly.
"The other thing is that, normally, on a baseball or a soccer field, you do the whole thing exactly the same. But because the pitch in the centre needed to remain clay, we had to work around those areas, which created some uniqueness in the drainage design."
The SubAir machine is digitally operated. Schedules are set for an entire month and the pressure mode is usually activated every hour to aerate the roots, but the frequency can vary depending on the weather conditions. The air is emitted with sufficient force to be discernible to the naked eye. "You keep a light object on the turf when the air is being pumped, and you will see it get thrown up in the air," Sriram said. Besides, the system can be operated via a mobile application, which means glitches can be fixed from any corner of the world.
It kicks into suction mode automatically in the event of rain, but given the force with which the water is drawn out, is there the risk of too much moisture being sucked out and the pitch changing behaviour? "We have left the pitch intact. We did not touch it," Anil said. "We treated only the outfield, so we are not going anywhere that will change the nature of how the ball will behave on the pitch. It's the outfield which usually remains uncovered and which is really the cause of the delays and cancellations. Anything except for the main square is pretty much covered, right up till beyond the boundary."
The system can also help in controlling dew, but won't eradicate it altogether. "The reason dew forms, in terms of the temperature variation, is a lack of air blowing above the grass surface," Anil said. "The difference in temperature, the grass being a bit cooler and the air that is above it being slightly warmer, leads to the moisture of the grass. With the combination of suction and aeration that we keep running alternatively, we can minimise dew, but cannot eliminate it completely."
Anil further said that cricket associations, both within and outside India, have shown interest and taken proposals, but have not signed any contract yet. "Quite a few are waiting for this first installation to happen and to actually see it in action."
The previous year saw its share of bizarre washouts, most notably the Port of Spain Test between West Indies and India in August, and the Durban Test between South Africa and New Zealand, both of which did not produce a result due to the grounds' inability to deal with rain. In an era of ever-increasing focus on result-oriented matches, and four-day Tests being mooted, if the system succeeds, it may not be too long before other associations follow the lead.