Stepping into Upper Peirce Reservoir Park feels very much like entering a secret garden.
Even just getting to it is like a journey into the unknown.
The park is a 10-minute drive or 40-minute walk from Old Upper Thomson Road, and the rewards are great once you get there: Lush greenery, a glistening body of water and a gentle breeze. It is a treat for the mind, body and soul.
Aside from the chirping of birds and rustling of leaves, the park is serene.
At one end is the Singapore International Country Club, with its manicured golf course.
Even the nearby Lower Peirce Reservoir Park sees far more activity. Taiji and yoga groups meet there at 5.30am every day.
It is this very isolation that draws local residents and other visitors to the lesser known of the two Peirce Reservoir parks.
"It is a very serene environment, away from pollution. It is also not very crowded," said Ms Veronica Ong, 56, a real estate agent who lives nearby.
Retiree David Tan, 64, added: "The morning air is very fresh. Going there makes me feel more alive."
When The Straits Times visited on Wednesday and yesterday, there were fewer than five people there each day.
The park's isolation could be because the distinction between Upper and Lower Peirce Reservoir did not exist initially.
Originally known as the Kallang River Reservoir, it was renamed Peirce Reservoir in 1922 after Robert Peirce, the Municipal Engineer of Singapore from 1901 to 1916.
It was only in the late 1960s that increasing demand for water led the then Public Utilities Board (PUB) to examine the feasibility of increasing Peirce Reservoir's capacity.
A higher dam was built upstream of the existing dam in 1970, leading to the implementation of the Upper Peirce Scheme in 1971.
Officially opened by then Prime Minister Lee Kuan Yew on Feb 27, 1977, the Upper Peirce Reservoir has a storage capacity of up to 27.8 million cubic m of water.
It is the largest impounding reservoir in Singapore and the second-largest reservoir after Marina Reservoir in terms of storage capacity.
It also acts as a storage area for the excess water that Marina Reservoir is unable to store.
The reservoir, together with those at MacRitchie, Lower Peirce and Upper Seletar, form the Central Catchment Nature Reserve.
The huge body of water and surrounding foliage provides an optimum environment for wildlife to thrive.
Just last month, Prime Minister Lee Hsien Loong shared a picture that he took of a rare black-headed collar snake on his Facebook page after a visit to the park.
Monkeys and wild dogs are also a common sight and wild boars have also been spotted.
Prominent signs put up by the National Parks Board (NParks) caution visitors against feeding the animals or approaching them.
However, residents nearby have complained of unwelcome visitors in their houses.
One, who wished to be known only as Mrs Koh, 44, said: "We moved here in February and have had two incidents of monkeys entering our home.
"One of them took a box of noodles and opened it, and we had to clean up the mess."
Fellow resident Ms Ong said: "Although we haven't had any incidents this year, when we first moved in, we had no way to stop them from coming.
"Sometimes, we would wake up and find them sitting on the ledge."
On the whole, residents there love being surrounded by nature.
Engineer Moses Ng, 53, said: "My family moved here precisely because we want to feel close to nature. We love the fresh air that blows in.
"I like it here a lot. You don't have to go overseas to catch a beautiful sunset when there is one right on your doorstep."
For Mrs Koh, the surrounding greenery is a treat.
"These days, instead of monkeys, we often wake up to birds chirping while resting on our plants," she said.
"It is quite amazing. I have never seen so many different types of birds, and of so many different colours, before.
" I am very happy to be able to live here."
This article was first published on May 29, 2015.
Get a copy of The Straits Times or go to straitstimes.com for more stories.