The court heard, on February 1 Donald went on holiday leaving a relief milker in charge of the property whom he had told the irrigator was set up and didn't need any attention.
However, a few days later the relief milker noticed an arm on the irrigator was broken and was discharging effluent onto paddocks which was ponding and flowing into nearby waterways.
Between February 7 and 11, eight milkings were undertaken where an un-permitted amount of effluent was being pumped onto paddocks with raw effluent travelling through bushes into the waterway, the court heard.
On his return, Donald arranged for the irrigator to be repaired.
Donald's defence lawyer Louise Elder told the court she would be applying for a 106 discharge, which would allow her client to avoid a conviction.
Judge Tuohy said an environment warranted judge needed to carry out sentencing and remanded Donald at large to reappear on October 17 for sentencing.