Shap Long Reservoir (also known as Chi Ma Wan Reservoir or Shap Long Irrigation Reservoir), built in 1955, is a reservoir located in Chi Ma Wan Peninsula and Lantau South Country Park in Chi Ma Wan, Lantau Island, Hong Kong.[1] The Chi Ma Wan Country Trail and the Chi Ma Wan Mountain Bike Trail pass through the reservoir.[2][3] The reservoir used to be the main water source for the residents of Cheung Chau, Peng Chau and Hei Ling Chau in the Islands District before being converted into an irrigation reservoir in the 1970s.