Toowoomba Regional Council (TRC) has closed Cressbrook and Perseverance Dams for water-based activities until further notice.
TRC Environment and Community Committee Portfolio Leader Cr Tim McMahon said Council officers had made the decision to stop water-based activities at the two dam sites as required under recreational guidelines.
"This is a precautionary closure to ensure visitors do not suffer any health concerns due to toxins present in Cressbrook Dam and Perseverance Dam," Cr McMahon said.
"While the recent rain has certainly been welcome, our officers have advised us we need to close the dams due to water quality concerns linked to recent run-off into the dam.
"We're hoping to have the dams re-opened as soon as possible and to do this, Council will conduct its regular testing regime to determine when this can happen.
"We appreciate the timing of these closures aren't ideal and while we would have preferred to have the facilities open for water-based activities however, we simply can't take any health risks at this time.
"Fortunately, Council's treatment plant is capable of treating this level of toxin and as such there will be no change to the picnic ground or camping ground sites so community members are welcome to use these facilities.
"Council monitors its dams weekly for algae and numerous microbiological parameters including E.coli. We also test chemical parameters such as iron, manganese, alkalinity, hardness, ammonia, nitrate, colour, turbidity and phosphate.
"The treatment process is also closely monitored (daily). When the water leaves the treatment plant, we conduct tests in the distribution system under our Drinking Water Quality Management Plans.
"These plans line up with the Water Supply (Safety and Reliability) Act 2008."
To view activities open or closed at the dams, please visit www.tr.qld.gov.au/damstatus
