Managing concrete slurry

An Auckland construction company was hit with a $35,000 fine after pleading guilty to three RMA charges for repeated sediment and concrete slurry escapes.

 

The charges involved releasing contaminants, violating regional sediment control requirements, and disregarding an abatement notice from Auckland Council.

 

“Resource consents, erosion, and sediment control rules exist to protect Auckland’s waterways and harbours,” Auckland Council’s Team Leader Investigations Paul Cowling said. “Developers must follow those requirements and respond promptly when issues are identified.”

 

Cowling said the case’s outcome should remind everyone of the critical need for proper oversight and maintenance of erosion and sediment controls on active construction sites.

 

“Developers have a responsibility to ensure sediment stays on site, not in Auckland’s stormwater system, polluting our waterways.”

 

Auckland Council recommends creating an Erosion & Sediment Control Plan before any work begins, separating clean water from disturbed areas, installing effective sediment controls like silt fences and retention ponds, and containing all concrete washwater on site.

 

Regular inspection and maintenance of these controls, stabilizing exposed soil quickly, and protecting stockpiled materials are also key steps in preventing pollution.

 

Following these guidelines not only helps developers comply with the Resource Management Act but also protects waterways from unnecessary contamination.

 

The council emphasizes staff training and accountability, making sure all workers understand sediment controls, concrete washout procedures, and emergency spill responses.

 

Clearly marked washout areas, proper bunding, and having an environmental compliance officer on site help prevent breaches before they occur.

 

Regular inspection of silt fences, sediment traps, and diversion channels, particularly after rainfall, is essential to catch issues early.

 

Keeping detailed records of inspections, maintenance, and corrective actions demonstrates compliance to regulators.

 

Developers are encouraged to adopt sustainable practices, such as reusable washout systems and recycling excess concrete, to minimize pollution and waste.

 

Low-impact earthworks techniques can also help reduce runoff and environmental risk.

 

Following these measures not only protects waterways but can lower project costs over time.