Bukit Batok park still safe for visitors despite mudslides

Bukit Batok Nature Park remains safe for visitors, as a section of the park affected by recent mudslides is not accessible to the public, said the National Parks Board (NParks) yesterday.

This comes as residents have raised safety concerns over frequent mudslides off the face of a cliff at the park, which they said have been ongoing for close to two months.

In response to queries from The Straits Times, NParks' group director for conservation Lim Liang Jim said the incidents of slope failure could have been caused by "the loading of saturated soil above the cliff, brought about by the heavy rains" in the past two months.

"As the section of the park affected by the slope failure incidents is not accessible to the public, the park is still safe for visitors.

"Access to the observation area at the quarry remains open, as the cliff is not linked to the observation area," he said.

A regular at the park, who wanted to be known only as Mr Tin, said he has observed mud falling down the cliff for close to two months in his twice-daily visits there.

"Mud has piled up ever since," said the 75-year-old retired engineering manager.

"I can even hear the sound at night from where I live," said Mr Tin, who lives in a condominium in Hillview Avenue located about 600m away.

"It can get a bit scary if a bigger chunk of mud comes down," he added, noting that some large boulders and trees growing on the cliff had also been dislodged.

Mr Tin added that a smaller mudslide, which has since stopped, also occurred about two to three months ago at a nearby slope, closer to one of the transmitting towers of Bukit Batok Transmitting Station.

"I'm worried that the mudslides will affect the tower," he said.

NParks' Mr Lim said that other than the slope failure incidents at the quarry, there were another two slope failure incidents between the quarry and a shelter at the park that occurred in late August.

"The footpath between the quarry and Shelter E has since been closed for stabilisation works.

"For public safety, NParks would like to remind park visitors to keep to designated trails and not to go off trail," he added.

When The Straits Times visited the park around 11.30am yesterday, there was a pile of sand-coloured mud at the foot of the cliff, which used to be part of a quarry. Large boulders and tree branches were embedded within the pile.

Chunks of mud would intermittently break off from the cliff, falling onto the pile below with a loud crack that reverberated throughout the quarry.

Mr Eric Tan, who was cycling at the park yesterday on his daily visit, also said the mudslide started around September.

"Big chunks came down initially, then smaller bits of debris more recently," said Mr Tan, who is in his 50s.

He noted that the cliff used to be pristine, with trees growing on it.

Other parkgoers, however, felt the debris posed no immediate danger.

Educator Angeline Ho, 30, said that, compared with the situation yesterday, the slope was "quite intact" on her last visit to the park in July.

She said she was elsewhere in the park when she heard a loud sound around 11.15am.

The avid birdwatcher, who lives in nearby Bukit Batok, feels intervention would be necessary only if the mudslides pose a risk to human life.

"I think this (erosion) is part of nature, so we should just let it be as it's not on the path where human beings normally walk."

Environmental consultant Tony O'Dempsey said incidents of soil slippage occur when the soil on a slope becomes saturated with water.

Mr O'Dempsey said: "The lower section of the slope can no longer support the weight of water and soil above, and it moves out; the soil above having lost support then moves down.

"The cause is often poor or non-existent drainage at the top of the slope, which allows run-off from the water catchment above to cascade over the slope, resulting in saturation."

A possible solution, he said, would be to install cut-out drains at the top of the slope, where possible.

Ms Low Yen Ling, an MP for Chua Chu Kang GRC, noted this was not the first time that the cliff has experienced slope failure.

"We have been keeping a close watch over these areas, and have been working closely with the relevant government agencies to help rectify the affected areas and implement safety measures," she told The Straits Times.

A footpath along the affected area has been closed since the end of September and NParks had put up signs warning residents about the situation, she added.

Mudslides: How to avoid them and what to do when you encounter one

Q What causes mudslides?

A Mudslides can occur following heavy rainfall, which causes large amounts of water to accumulate and inundate the soil on steep slopes, loosening the top layers.

Areas with sparse vegetation, often caused by human activities or wildfires, are particularly prone to mudslides.

The roots of plants help to hold the soil together and promote surface run-off, with water flowing down the slope instead of seeping into the soil.

A lack of sufficient greenery means that rain falls directly on the soil itself. Climate change increases the frequency and volume of rainfall, leading to more flash floods that can cause mudslides.

A Hikers and parkgoers should stay on marked trails and check the weather forecast for heavy rain.

They should also be careful when walking near slopes that are bare or where construction worksites are located as mudslides are more likely to occur there.

Look out for trickles of flowing mud, which may signal that a mudslide is developing.

A Stay away from the site and move to safety. Flooding or a larger mudslide can occur after the initial incident. If you spot any injured or trapped persons as a result of the mudslide, check on them only if you can do so without entering the site of the mudslide.

A As the section of the park affected by the slope failure incidents is not accessible to the public, the park is still safe for visitors, said the National Parks Board (NParks). Access to the observation area at the quarry remains open as the cliff is not linked to the observation area.

A Other than the slope failure incidents at the quarry, there were another two incidents between the quarry and Shelter E that had occurred in late August, said NParks. The footpath between the quarry and Shelter E has since been closed for stabilisation works.