Council manager of resource management group Iain Maxwell said Eastland Group completed repairs and all three sluice gates were now closed.
The reservoir was filling and, once full, power generation would begin again.
"The closure of the sluice gates means the sediment discharge down the river has stopped, however there is still a large amount of sediment that needs to move through the river system," Mr Maxwell said.
The council would soon start discussions with the Eastland Group around the future management of the dam to ensure the situation would not happen again.
He said a thorough investigation, into how the situation occurred and its effect on the community and the environment, was continuing.
A decision on whether any party will be prosecuted would be made once the investigation was completed and all facts known.