Over a three month period in 2019, Bay of Plenty Regional Council officers found discharges of "dirty" water - laden with sediment - from the company site into the stormwater system, flowing into Tauranga Harbour.
Judge Dickey said CRS was aware there was an issue from at least August 2018 and was issued an abatement notice the following month.
It did not, however, engage a consultant to advise it on how to fix the problem until October 2019, the judge said.
"I find that the company has dragged its feet in appropriately addressing the problem, even though it was aware there was an issue from at least August 2018.
"There have been at least five occasions where discharges occurred over a three-month period. The charges are, however, representative and allege offending between July and October 2019.
"I conclude that the defendant did not respond with sufficient urgency or diligence to the ongoing sediment discharge problems at its site. It had a number of opportunities to do that, dating back to September 2018 when it first received an abatement notice.
"Accordingly, I determine that the defendant was highly careless in its approach to management of stormwater on its site."
She found the environmental and cultural effects of the offending were moderately serious, and she was concerned about the effects on the local community and matters raised by iwi.
In their victim impact statement, the Whareroa Marae community said the sediment discharges caused damage to Tangaroa and his children, which was detrimental to the community's wairua – spiritual and mental wellbeing.
Ngāi Te Rangi told the court the discharges disrupted the foundations of Ngaiterangitanga because of the way they interfered with traditional and ancestral connections to place, cultural practices and intergenerational responsibilities.
The council said increased sedimentation is an issue for Tauranga Harbour and has a range of harmful effects on ocean-floor organisms and habitats as well as the overall ecological health of the harbour.
Compliance manager Alex Miller said the penalty in the CRS case reflected the impacts of sediment discharges to Tauranga Moana.
Miller said it sends a stern reminder to businesses that they need to manage and maintain their site to avoid these sorts of discharges occurring.
