THE proposed New Acland mine expansion could cause increased flooding along a rail line upstream from Jondaryan, a court has heard.
The Queensland Land Court is hearing a legal challenge to the proposed third stage of miner New Hope's New Acland mine outside Toowoomba.
New Hope witness on surface water Greg Roads told the court on Wednesday the completed mine might cause an increased risk of flooding in areas upstream from Jondaryan.
Mine opponent Dr Tanya Plant suggested to Mr Roads the changes would cause Jondaryan itself to flood more regularly.
But Mr Roads said there was unlikely to be a change in water depth or velocity at Jondaryan itself.
"It's not Jondaryan itself (that will be affected)," he said.
"It's basically an unused paddock."
The court was shown documents predicting the depth and velocity of water in one-in-10-year floods, one-in-100-year floods and one-in-1000-year floods.
Mr Roads said a one-in-10-year flood would require about 100mm of rain in the space of a few hours. He said a one-in-1000-year flood likely had not been seen in recorded history.
Following hearings this week, the case will be adjourned to May 9. - ARM NEWSDESK