Why are Canberra's sports grounds closed because of rain? A tiny moisture-content sensor is helping with the answer

Luke Halpin, the ACT's senior director of sports grounds and facilities, goes deeper than that. About two or three inches deeper, to be more specific.

That's where you'll find the tiny cigar-shaped devices buried below the surface at venues around the capital Halpin hopes will help end the confusion and frustration associated with one of the city's most divisive topics: wet-weather sport cancellations.

It can be revealed the government is trialling 10 moisture-content sensors to measure the saturation levels of sports fields and to help Halpin and his team decide if weekend play can go ahead.

"We could let some games go ahead, but fields might be out of action for three weeks afterwards. No one wants that," Halpin said.

"Southwell Park went from a sports field to 'Lake Lyneham' last week. The ground is so saturated and there's nowhere for the water to go, it pools on the surface.

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"I understand it can be divisive. But we make those decisions in the best interest of everyone."

The persistent rain on Thursday led to venues being closed for training again on Friday to give them the best possible opportunity to reopen for games on the weekend.

The Melba fields were effectively under water, while water was still pooling at Lyneham.

There has been a major shift over the past 20 years. Many remember growing up on muddy fields, wearing the mess as a badge of honour after weekend play.

It sparks frustration among parents when cancellation decisions are made because they want their children to experience the same joy they had as youngsters.

Equally, Halpin says he receives just as many thank yous from parents who would prefer to stay out of the cold and wet, as well as from sports who need smoother and safer surfaces. But he wants to peel back the curtains on how the decision is made to create a greater understanding.

"One week someone will complain we close the ground, and then if we play and destroy the field they complain that it's muddy and in poor condition," Halpin said.

"Hopefully we can provide clear and up to date information so people understand what is behind the decisions.

"We're trying to prevent damage. It's the public's asset, and we want to make sure it's a quality ground whenever it's in use."

Waramanga depot manager Phil Davies has led the charge in trying to find ways to get more accurate information about the state of Canberra's playing fields.

It led him to find moisture-content sensors, send information to officials every four hours about saturation levels and drainage.

They were buried at 10 locations, including the Waramanga playing fields, four months ago and the government is collating the winter-sport season data to inform decisions for next year.

Halpin compares eyes-on-the-ground reports from venue managers with what the devices are telling him.

There are 90 government-maintained turf facilities in Canberra and there were almost 29,000 bookings made to use them in the past 12 months. Each one handles the wet differently

"Any damage that occurs really happens below the surface. The layers of sand ... the drainage. The sensors are giving us a different and new way to measure that," Halpin said.

The data gathered this year will be used as a base level for future decisions likely to be presented to winter sports before the 2023 campaign to help develop cancellation strategies.

Some sports - rugby league, rugby union and Australian football - would happily play through all conditions. Soccer prefers a more even playing surface, while cricket uses many of the same fields as league, union or Australian football sides.

"It might be OK for the rugby codes to cut up a ground, but if they did that every week we wouldn't be able to repair them in time for cricket," Halpin said.

Part of the problem this year has been the fields being so wet and soft that maintenance staff can't use the machines needed to repair damage and improve drainage.

Canberra's wet winter has led to several weekends of lost action, including a complete shutdown last weekend after a deluge of more than 60mm of rain.

Halpin points to the data from the Waramanga sensor to illustrate the saturation levels as water pooled on fields around Canberra.

The Waramanga field saturation level on August 2 was 53 per cent. That jumped to 66 per cent when the rain hit on August 4 and has only fallen back down to 65 per cent because of the dreary weather this week.

"That's pretty telling. Our drainage system can't cope," Halpin said. "Each ground is different, but if we can work with this and the sports we can maybe get more sports happening during winter if we manage grounds correctly."

Two months earlier saturation level peaked at 69.1 per cent, prompting a ground closure.

The government will analyse the data at the end of the season to determine what saturation levels are appropriate for cancellations or playing on.

Once that has been set, the government will look to implement a staged approach to wet-weather conditions.

Step one could be training cancellations to protect fields for matches. The next step could be prioritising certain divisions or fixtures if conditions worsen. And a blanket cancellation of all games would be the last option.

"If we know that a saturation level of 50 per cent is good condition, then when it gets to 60 per cent we could start talking to sporting bodies about prioritising games," Halpin said.

"If everything goes well, when we get to Wednesday we can start that negotiation."

The small devices have a sim card and can send data even when placed under the surface.

They have been used for the past four months as an extra tool and Halpin hopes the data collected this winter will give the government a base level for 2023 and beyond.

They measure saturation levels and drainage, which helps build the picture.

"When it's too wet, any damage that happens does a lot of damage underneath and that also affects drainage," Halpin said.

"We're trying to prevent that damage. It's the public's asset, and we want to make sure it's a quality ground whenever it's in use."

The call to close grounds is usually left as late as possible to allow the fields time to dry, or the weather forecast to change.

"The hope is [the moisture sensors] will help us make predictions earlier. So by Wednesday, we can start negotiating with sports about what are priority games and what might happen on the weekend," he said.

"And hopefully we can make the information from the sensors available to everyone, so they can see why decisions or made and see the data so they can predict as well."

The recent frustration stems from three years of interrupted sport. Many 2020 and 2021 seasons were cancelled because of COVID-19 lockdowns and safety concerns.

This year they're being stifled by constant rain and soggy fields.

Halpin says the government bases its decision on the expected damage to the turf, the cost and time required to repair it and the flow-on effects across seasons.

"They are public facilities and we need to keep that in mind. They need to be in good condition for all sports and seasons," Halpin said.

Most games are unable to be rescheduled, meaning players are robbed of several opportunities per season.

The government does consider exemption requests, especially in top-tier competitions and when there are finals implications.

Some sports - rugby league, rugby union and Australian football - would happily play through all conditions. Soccer prefers a more even playing surface, while cricket uses many of the same fields as league, union or Australian football sides.

"It might be OK for the rugby codes to cut up a ground, but if they did that every week we wouldn't be able to repair them in time for cricket," Halpin said.

Part of the problem this year has been the fields being so wet and soft that maintenance staff can't use the machines needed to repair damage and improve drainage.

Privately-operated venues - like the AIS, Viking Park and private schools - make their own decisions about whether to proceed with play.

"They might have money to be able to fix one or two fields, but there are 90 government operated complexes, some with multiple fields. And the damage bill goes up every time you play on," Halpin said.

More than a decade ago the government investigated the need for more synthetic fields because of the cost of watering turf facilities during a drought.

Several have been built around Canberra, including Gold Creek, Melrose and Hawker, while the AIS and ANU also operate their own fields.

The changing climate, however, is now forcing the government to think about the need for more synthetic fields to avoid wet-weather cancellations.

Soccer is the main user of synthetic facilities because it provides an even playing surface for users. The government is assessing the how often they are used and the wear-and-tear of those facilities to determine if building more is an option for the future.

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