Toowoomba - Water

Water

Combined water supply for the City (current as of 10 January 2011): 99.8% or 126,467 ML.

Toowoomba's third water storage Cressbrook Dam was completed in 1983 and supplied water to Toowoomba in 1988. It has a full capacity of about 80,000 megalitres bringing total capacity of the three dams, Cooby, Perseverance, and Cressbrook, to 126,000 megalitres.

The city also has underground supplies in fractured basalt. Toowoomba sits above the eastern edge of the Great Artesian Basin and to the west underground water is available beneath agricultural alluvium.

The average rainfall in the period 1998 to 2005 has been 30% below the long term average consistent with a prolonged drought and this trend continued through to spring of 2007. In mid 2005, the water situation for the city was becoming critical with water supply levels below 30%. Environmental flows from Cressbrook Dam into Cressbrook Creek were allowed to cease as Toowoomba approached level five water restrictions. During March 2006 the surface water storage in the dams fell below 25% of full capacity, falling even more to 12.8% as of 10 March 2008. The city's water supply was at an all time low of 7.7% in December 2009.

The previous Toowoomba Mayor Dianne Thorley proposed a controversial potable re-use project under the Toowoomba Water Futures plan which would result in water reclaimed from the Wetalla Sewage Treatment Plant being returned to Cooby Dam to provide 25% of the potable water supply for Toowoomba. Other water supply options include importing water from Oakey Creek Groundwater Management Area (average TDS = 1660 mg/L), importing water from Condamine Groundwater Management Area (Average TDS = 740 mg/L), and water from coal seam gas production (TDS = 1200–4300 mg/L).

One of the difficulties with the Water Futures proposal was that it relied on Acland Coal, a subsidiary of New Hope Corporation, taking the reverse osmosis waste stream. However, they had never agreed to this. Without their involvement, 6 square kilometres (2.3 sq mi) of evaporation ponds, costing at least an additional $70 million, would have been required. This amount was not included in Council's budget for the Water Futures project.

On 29 July 2006 Toowoomba City Council conducted a poll of Toowoomba residents on the proposal to use this multi-barrier filtration system for filtering sewage for drinking purposes. The poll question was: "Do you support the addition of purified recycled water to Toowoomba’s water supply via Cooby Dam as proposed by Water Futures – Toowoomba?” 38% of voters supported the proposal and 62% opposed. This meant that despite dams reaching critical levels, the city rejected the use of recycled water in a plebiscite. Since the public rejection in 2006 of adding recycled sewage to the drinking water supply, water conservation measures have included harvesting stormwater for use in public parks and adding filtered groundwater to the town water supply.The city was under level 5 water restrictions as of 26 September 2006. This prohibits residents from using town water on their lawns, gardens or cars, and residents are strongly urged to cut down on water consumption.

In 2007, the Toowoomba City Council commenced a bore drilling program to augment the dwindling dam supplies and constructed several subartesian bores across the city and one artesian bore at Wetalla in the city's north. Many of the subartesian bores provided potable water with a reliable yield and have been developed into production however the artesian bore's water quality was very poor, prohibiting development as a potable source. This was an expensive setback for the city as the cost was over A$2 million for drilling to over 700 metres. In January 2008, yield testing had been stalled due to the unavailability of appropriate pumping equipment. The Toowoomba Regional Council began supplementing the city's water supply with bore water from the Great Artesian Basin in September 2009. Groundwater has become a significant contributor to the city's water supply needs and now constitutes one third of the total volume of water treated for reticulated supply (160 ML per week).

The state government has built a $187 million pipeline from Wivenhoe Dam to Toowoomba. Water pumping along the 38 km pipeline to Cressbrook Dam began in January 2010.