A Bay of Plenty logistics firm is awaiting sentence after it admitted illegally discharging sediment contaminated water which flowed into the Whakatane and Waimana Rivers.
Waiotahi Contractors Ltd, which earlier pleaded guilty to two charges, was due to be sentenced by Judge David Kirkpatrick in the Environment Court at Tauranga on Tuesday.
After hearing legal arguments from the company's lawyer and the prosecutor for the Bay of Plenty Regional Council, Judge Kirkpatrick reserved his decision
Waiotohi Contractors carries out roading, infrastructure and earthworks and also operates four quarries in the Bay of Plenty region.
The defendant has admitted that it discharged a contaminant on to or into land where it entered a waterway, which happened from an industrial or trade premises.
Both charges laid by the regional council each attract a maximum fine of $600,000.
The prosecution relates to the discharge of sediment contaminated water from Waiotahi's aggregate washing and crushing facility in Taneatua on September 7 last year.
The overflow from two settlement ponds was discovered by a regional council enforcement officer during a routine inspection at the site.
The contaminated water ended up in the Whakatane and Waimana Rivers, the court heard.
Both rivers are highly valued ecological sites, including significant trout habitats, and the Whakatane River is also a whitebait spawning site.
The discharge was also in breach of an abatement notice issued by the council in 2013.
The regional council's lawyer Adam Hopkinson submitted that given the scale of this offending a fine of $60,000 was appropriate before any credits for mitigating factors.
There also needed to be an uplift of 5 per cent to reflect the previous compliance issues, but that could be offset by a similar discount for Waiotahi's "exceptional cooperation".
Hopkinson described this offending as a "systemic" failure by the defendant, in light of earlier non-compliance issues at the same site.
In 2007 a council enforcement officer found one of the settlement ponds had overflowed and discharged sediment contaminated water into the Waimana River.
A similar discharge into the Whakatane River in 2013 sparked the abatement notice.
Hopkinson said these type of discharges could have been avoided if Waiotahi had undertaken risk management measures earlier.
That included staff regularly checking the bunds on the settlement ponds, he said.
Hans Cotterill, the lawyer for Waiotahi Contractors Ltd, argued the September 7 offending was "moderately serious" and not at the level of gravity pitched by the prosecution.
"In terms of culpability it is accepted this was a significant oversight, but there no evidence to suggest there have been significant or lasting impacts," he said.
Cotterill also submitted that Judge Kirkpatrick should allow significantly more credits for "extraordinary remorse" and the immediate remedial measures taken.