The Reed Marshes in the Park include the reedbed filter at the freshwater marshes and a dense stretch of reeds growing along the Wildside Walk. The reedbed filter, covering about 1 hectare of area, is built to treat the water taken from storm water runoff of Tin Shui Wai before it enters the freshwater wetland system of the Park. Reed marshes in the Park provide shelters and food for many kinds of organisms, including birds, amphibians, reptiles and insects.