 However the filtration plant can draw water directly from the Reservoir if needed.This is one of the largest such facilities in the world and it has changed the role of the Reservoir to that of a service reservoir and large off-line settling basin for the Warragamba and Upper Canal systems in the event of a water quality problem, covering daily fluctuations of demand in the distribution system.Since its construction, parts of the area surrounding the reservoir have formerly been used for passive community recreation, and consequently the Water Board provided numerous parks and picnic facilities, primarily on its eastern side.