Sembawang Hot Spring

The Sembawang Hot Spring (pinyin: sanbawang wenquan), located at Gambas Avenue between Woodlands Avenue 12 and Sembawang Road, is the only natural hot spring on the main island of Singapore. It lies in a wooded area about 100 m off the main road. The spring is believed by locals to have healing properties, and its water has been bottled commercially by Fraser and Neave, under the brand name of Seletaris. Since its discovery in 1909, the spring, now on land belonging to a military air base, has gone through several changes of ownership and abortive redevelopment plans. The hot spring is less frequented nowadays but remains a popular venue for weekend visitors.

History
In 1909, a Chinese merchant named Seah Eng Keong, the son of Chinese pioneer Seah Liang Seah, discovered hot springs in his pineapple estate in Sembawang. The three springs were channelled into one, so that the water would be conveniently concentrated in one area. A well was built along the spring, which became popular with the villagers, who frequently sought the waters for their supposed healing powers. The spring's fame spread, resulting in the village becoming known as Kampong Ayer Panas, which means "Village of Hot Water" in Malay.

Soft drinks firm Fraser & Neave (F&N) acquired the site in 1922, and set up a bottling plant at nearby Semangat Ayer to tap the mineral water, which they labelled Seletaris. During the Second World War, the spring's flow was temporarily interrupted when a bomb fell near the well during a Japanese air raid over Singapore in 1942. After Singapore was taken, the Japanese forces built a number of recreational thermal baths in the area.

The hot spring began to be frequented by gamblers in 1960, who took "good luck" baths before the start of horse races. That same year, the villagers started to urge the authorities to develop the area into a spa-like tourist resort. However, F&N shelved the idea after geologists failed to find the source of the spring. In 1967, the idea of the spa surfaced again, when F&N proposed plans for the development of baths, restaurants, a miniature golf course and even a nature reserve. Once again though the plans were not implemented, so the hot spring site remained dilapidated and forgotten.

Redevelopment
In 1998, The Ministry of Defence (Mindef) acquired the land containing the spring for the expansion of the nearby Sembawang Air Base, leaving F&N with less than 4 hectares (10 acres) of land. Its water-bottling plant survived until the early 1990s however. In January 2002, crowds flocked to the hot spring, which had caught the attention of Singaporeans after the surrounding land had been cleared to begin construction work on the air base extension. Sembawang community leaders gathered signatures to petition Mindef, which was preparing to fence off the area, to preserve and develop the hot spring. Mindef agreed to the appeals and constructed a side gate for the public to gain access to the spring.

During that same year, a rash of scalding cases, including an incident in which a 57-year old diabetic man lost six toes to gangrene after bathing in the hot spring, prompted the Singapore General Hospital to warn that people with nerve disorders or diseases affecting blood circulation should stay away. Soon after, rumours that the well was haunted by the ghost of a Malay boy who had met his death by falling into the boiling spring water began to circulate; a Chinese curse, written in graffiti on the wall that now encloses the well, promised a similar fate to anyone who vandalised the premises. As a result of the negative publicity, and the redevelopment of the area around the spring, public interest began to wane and the number of visitors dwindled.

Present day
During its peak, up to 1,000 people visited the hot spring at weekends. On 1 March 2002, it was closed for two months while improvement works were carried out to the area around the spring, which had become sodden and muddy. Litter had also become a problem because of the large numbers of visitors. The former dirt track leading to the spring was paved, and lined with bougainvillea bushes and high fences to protect the security of the air base. Drainage pipes were also installed. Mindef, which owns the land, allows public access between 7 am and 7 pm daily, at no charge. When the spring reopened, on 1 May 2002, more than 100 people visited the site despite the afternoon drizzle. At the same time, new free-hold condominiums were built in the surrounding area; one of the developments, built by the property arm of F&N in 2001, is called Seletaris after the company's former mineral water.

In July 2005, a Business Times reader proposed that the relevant authorities should explore the possibility of tapping the geothermal heat that lies many miles under Sembawang&mdash;similar to the project in South Australia's Cooper Basin&mdash;in order to reduce Singapore's reliance on oil and gas. The proposal was not acted upon.

As of 2008, the well can still be seen locked inside a red-brick enclosure with a steel gate, and its heat can be felt outside the building. Numerous plastic chairs, pails and makeshift tubs left by visitors are stored at the perimeter of the compound, which has a makeshift shed in one corner. Caretakers manage the site to ensure its overall cleanliness, although toilets are still lacking on the premises. The hot spring is less frequented nowadays but remains popular at weekends and on public holidays, when regulars and families visit.

Water properties
According to local geologists, the exact source of the spring remains unknown, but it is believed that its origin may be southwest of its actual location, possibly at Bukit Timah. Hot springs are formed when underground water comes into contact with hot rock masses. The resulting high pressure causes the water to seep upwards through cracks, forcing itself out of the ground as a spring.

A series of tests conducted by the PSB Corporation and SGS Testing & Control Services found the spring water contains 420 mg of chloride per litre, an amount which is substantially higher than the 35 to 100 mg in the water from Choa Chu Kang and Bedok waterworks. It was also found that the sulphide content is three times more than tap water and the spring water is also slightly alkaline due to the presence of minerals. This led many to believe that the spring waters have health benefits and thousands flocked to the hot spring, in a search for cures for skin conditions like psoriasis and acne, as well as debilitating ailments like rheumatism and arthritis. Although local rheumatologists conceded that hydrotherapy is an accepted treatment that can be helpful for mild forms of rheumatism or muscle strain, they, along with dermatologists, remain sceptical of claims about the healing powers of the spring water.

Water bubbles continuously in the well, releasing a slightly unpleasant sulphur odour together with steam. The temperature of the spring water is around 131 °C. In an investigation carried out by the Nanyang Technological University in 1994, the hot spring was found to have an estimated yield of approximately 150 l per minute at ground level through installed steel casings.