Deep within Chi Ma Wan Peninsula, lies a hidden gem. This is the Shap Long Irrigation Reservoir. It is also known as Chi Ma Wan Reservoir.
The Shap Long Irrigation Reservoir was built in 1955. It is located in the Lantau South Country Park. The reservoir used to be the main water source. It served residents of Cheung Chau, Peng Chau, and Hei Ling Chau. These islands are in the Islands District. Later, in the 1970s, it became an irrigation reservoir.
Before the Shek Pik Reservoir existed, Cheung Chau relied on groundwater. As Cheung Chau’s population grew, water became a problem. The Hong Kong Government stepped in. It built a concrete dam on Chi Ma Wan Peninsula. This dam created a reservoir with a capacity of about 130,000 cubic meters. It measured 91.1 meters long and 15 meters high. A 6-inch submarine pipe carried water to Cheung Chau Ferry Pier. From there, it went to Tai Kwai Wan’s water storage tanks.
The government followed a familiar practice. They built a fountain at the landing site. This mirrored the first submarine water pipeline from Hong Kong Island to Kowloon. A water spray ceremony marked the opening in August 1955.
However, Cheung Chau joined Hong Kong’s water supply network in the 1970s. This made Shap Long Reservoir obsolete for its original purpose. Instead, it began supporting local farming, meeting irrigation needs.
Construction of the dam started in September 1954. The goal was to impound 30 million gallons of water. This would provide fresh water to Cheung Chau. Filters, a pump house and a service reservoir were built on the island. Water flowed through a 150mm steel submarine pipeline. This pipeline stretched 1.3 km. It connected to 3.6 km of 150mm cement asbestos pipe. A new 300mm water main arrived in 1963. It supplied water from the new Silver Mine Bay Water Treatment Works.
Today, the Shap Long Irrigation Reservoir sits in a remote location. Clear and unpolluted tributaries feed it. The area remains undisturbed by human activity. Tree-lined valleys and mature woodlands surround the reservoir. This isolation has prevented the invasion of alien species. It has also allowed freshwater fish to flourish. Oryzias curvinotus, a local fish species, thrives here.
Hikers can explore the area. The Chi Ma Wan Country Trail passes by the reservoir. The Chi Ma Wan Mountain Bike Trail also goes through here. To reach this tranquil spot, you can take a bus to Pui O. From there, a one-hour walk along Chi Ma Wan Road leads to the Shap Long Irrigation Reservoir.