30%. Reductions in energy consumption have slashed energy bills by $30 million a year. Solar panels have been established on many CBD buildings in an effort to minimise carbon pollution by around 3,000 tonnes a year. The city also has an "urban forest growth strategy", in which it aims to regular increase the tree coverage in the city by frequently planting trees with strong leaf density and vegetation to provide cleaner air and create moisture during hot weather, thus lowering city temperatures. Sydney has also become a leader in the development of green office buildings and enforcing the requirement of all building proposals to be energy-efficient. The One Central Park development, completed in 2013, is an example of this implementation and design. Utilities Obtaining sufficient fresh water was difficult during early colonial times. A catchment called the Tank Stream sourced water from what is now the CBD but was little more than an open sewer by the end of the 1700s. The Botany Swamps Scheme was one of several ventures during the mid-1800s that saw the construction of wells, tunnels, steam pumping stations, and small dams to service Sydney's growing population. The first genuine solution to Sydney's water demands was the Upper Nepean Scheme which came into operation in 1886 and cost over £2 million. It transports water from the Nepean, Cataract, and Cordeaux rivers and continues to service about 15% of Sydney's total water needs. Dams were built on these three rivers between 1907 and 1935. In 1977 the Shoalhaven Scheme brought several more dams into service. The state-owned corporation WaterNSW now manages eleven major dams: Warragamba one of the largest domestic water supply dams in the world, Woronora, Cataract, Cordeaux, Nepean, Avon, Wingecarribee Reservoir, Fitzroy Falls Reservoir, Tallowa, the Blue Mountains Dams, and Prospect Reservoir. Water is collected from five catchment areas covering and total storage amounts to . The Sydney Desalination Plant came into operation in 2010. WaterNSW supplies bulk water to Sydney Water, a state-owned corporation that operates water distribution, sewerage and storm water management services across greater Sydney. The two distributors which maintain Sydney's electricity infrastructure are Ausgrid and Endeavour Energy. Their combined networks include over 815,000 power poles and of electricity cables. See also List of museums in Sydney List of people from Sydney List of public art in the City of Sydney List of songs about Sydney Outline of Sydney Notes References External