HANSARD OF THE LEGISLATIVE COUNCIL
Wednesday 18 April 2007
WEST TAMAR WATER SUPPLY
Mr FINCH (Question) - Mr President, I have a question to the honourable Leader. Is the Leader aware of problems with the quality of West Tamar's water supply from the Trevallyn Dam and can he give an assurance that such problems will not be exacerbated by any pulp mill extracting water from the dam in a dry period such as the present one?
Mr PARKINSON - I thank the honourable member for his question. Rumour has it that the quality of the water in the dam has something to do with where the honourable member takes his morning walks, but we will not go into that.
Mr PARKINSON - I am advised that the water quality problems have arisen as a direct result of algal bloom in Lake Trevallyn from which Esk Water draws water for supply to the West Tamar area. Algal blooms are not uncommon in water supply reservoirs throughout Australia and their occurrence is influenced by a combination of factors such as nutrient availability in the reservoir, low inflows of water into the reservoir and warm, still climatic conditions. This year's warm summer and low inflows due to the drought have provided suitable conditions for the Lake Trevallyn bloom. The problem has been exacerbated as the low water levels in the Great Lake have made it impractical to provide flushing flows through the lower South Esk River and Lake Trevallyn which could have controlled the algal bloom.
The pulp mill will draw water from the Trevallyn Dam under a contractual agreement with Hydro Tasmania - that is if it goes ahead. The required water supply for the pulp mill will be 26 gigalitres or 26 000 megalitres per annum based on the proposed 350-day operating year. The daily demand will be 75 megalitres. The Trevallyn Dam has a capacity of 12 000 megalitres so on an average daily basis the pulp mill extraction of 75 megalitres would be insignificant, however the question as to whether or not the water extraction for the pulp mill will exacerbate the water quality problems in Lake Trevallyn cannot be answered categorically yes or no as the development of algal blooms is a complex process.
Nonetheless, Mr President, on the information provided it is clear that the lower amount of water to be provided for the mill in proportion to the capacity of Lake Trevallyn makes it most unlikely that the extraction will exacerbate water quality problems.