A Morrinsville stock feed company has been convicted of illegally discharging a combination of dairy farm effluent and dairy byproducts into a stream.

Orion Haulage Limited has been fined $32,400 after contaminating a Walton waterway in October of 2013.

Morrinsville stock feed company Orion Haulage Limited has been fined $32,400. Photo: File

The Hamilton District Court heard the company's careless approach to managing pond levels allowed for it to raise to the point of overflowing, allowing the contents of the pond to reach the stream.

Hamilton District Court Judge Melanie Harland says in her sentencing decision the defendant did not have in place an 'appropriate call-back or call-up contingency plan in place.”

'Having been told that the pond was almost full and having identified that the tractor used to irrigate the pond was unavailable to its employee, the defendant should have followed the matter up later the same day or at least the next day.”

In October of 2013 Waikato Regional Council staff inspected the stream and found it to be cloudy and smelling of effluent.

Tracking the stream back to a nearby dairy farm they found a combination of dairy farm effluent and whey permeate discharging from an effluent pond directly on to the banks of the stream.

An investigation showed the farm's effluent management was responsibility of Orion Haulage, which held resource consent to spread the dairy by-products on to the farm subject to certain conditions.

Council investigations manager Patrick Lynch says this case highlights the need for farms to regularly check their practices and systems.

'Even when a farm has good infrastructure in place there is still a great need for systems to be managed at all times to prevent these types of discharges to the environment.”