 The reservoir can now be drawn on when needed to supplement the Warragamba Pipeline and Upper Canal inflows into the Filtration Plant.It remains an essential component of Sydney's water supply system and therefore is critical Government infrastructure.Prior to construction of the Prospect Water Filtration Plant, the water supply was delivered to the Lower Canal via the scour/outlet system, which consists of a number of components (including submerged inlet pipelines, outlet tower with access walkway, lower valve house with outlet to the Lower Canal, scour pipelines, various control and guard valves, brick-lined interconnecting tunnel between outlet valve and lower valve house, with ventilation shaft and access shaft/manhole, discharge pipelines under the Sydney Water Corporation-owned picnic area and an outlet structure.