A farming company has been convicted and fined $41,850 after a Reporoa stream was found to be "flowing green with effluent".

Judge Melanie Harland convicted and fined Bella Ridge Farms Ltd in the Rotorua District Court this week for discharging a large volume of dairy effluent from a farm into the Mangatete Stream.

The prosecution was brought by Waikato Regional Council after it was contacted by a member of the public who reported that the Mangatete Stream was "flowing green with effluent".

The council estimated that approximately 450cu m of dairy effluent had been lost into the environment in November 2016. This is the equivalent of 17 truck and trailer units full of effluent, it said.


The volume was such that it was able to be detected 8km downstream at Lake Ohakuri.

The subsequent investigation found that an effluent irrigation pipe had been disconnected and effluent had then siphoned from the pipe by gravity over a 14-hour period.

The effluent flowed across a short distance of land and into the stream.

Following the conviction Waikato Regional Council urged dairy farmers to seek advice about effluent management from accredited experts.

The council's investigations and incident response manager, Patrick Lynch, said the incident was completely avoidable.

"The farmer had invested heavily in attempts to manage his effluent, however, he did not source good advice.

"The system did not have the usual safeguards and this discharge was the outcome. We strongly urge farmers to work with accredited dairy effluent designers to ensure their systems are fit for purpose," Lynch said.

Bella Ridge Farms Limited did not want to comment on the conviction.