Sediment flows into Spring Creek, which flows into Majors Creek.
Majors Creek residents are not satisfied with environmental regulations for a new gold mine under construction in the historic mining village east of Canberra, after heavy rain caused a sediment basin to overflow on Sunday into creeks.
Earthworks began about two weeks ago on the underground mine to prepare for buildings and an access road, but stopped late last week when heavy rain was forecast.
Separate to the overflow, the office of Greens mining spokesman Jeremy Buckingham confirmed he would be putting questions on notice about regulations on disposing of waste left from test drilling at the Dargues Reef site.
Majors Creek resident Steve Redden who raised the issue said he was not satisfied with how bags of rock dust containing high-grade sulphide were dumped, even though this complied with Department of Primary Industries regulations. He left his job with the former owner of Dargues Reef mine, Cortona Resources, and raised the issue with MPs and the Environmental Defenders Office.
Unity Mining, which merged with Cortona to develop the $90 million project, said sediment and water controls are compliant and the company is working to prevent spills.
Members of a community consultative committee were alerted on Sunday morning about a murky discharge into Spring Creek which flows into Majors Creek.
Committee member Bill Waterhouse said residents felt let down when they could not get information about the spill from what they believed to be a 24-hour hotline.
He said the mine responded as quickly as possible, but ominous signs had emerged that regulations were inadequate.
''This is not about a toxic spill, it's about dirty water, baby poo brown flowing into a clear creek,'' Mr Waterhouse said.
He said after rain flushed out creeks residents downstream opened up pumping systems to draw water, only to discover dirty sediment the following morning.
He rejected the mine's argument that an unusually high amount of rain had caused the problem because heavy rain often fell in Majors Creek.
''If they built to a standard of water management, that model is not good enough. That's been my underlying gut feeling all along.
''I felt these people were ahead of the game, they are experienced mine people. The first little test, we find that there's something misleading. The hotline is not 24 hours.''
Mr Waterhouse expects a tougher test for environmental controls when blasting begins at night. Unity Mining spokesman Ian Howarth said a catchment dam in the sediment basin had not failed and was still intact, but could not handle the volume of water.
Mr Howarth said the information line was available 24 hours a day for people to leave messages and was manned during office hours.
''We have had a month's worth of rain in one 36-hour period and the facilities and earthworks which were required were installed in accordance with all the approvals.''
He said downstream residents would be clever enough to avoid filling tanks from streams with muddy water.