Surface water management

Quarries have the potential to be a major contributor to sediment discharges to sensitive waters. In 2015 the EPA conducted an extensive water quality audit and investigations. Since then it has been engaging with Hanson and driving improvements at the White Rock Quarry.

In 2017 Hanson was required (through a licence condition) to develop and implement an environment improvement program (EIP) in line with the Environment Protection (Water Quality) Policy 2015. The purpose of the EIP was to identify and undertake a range of short-, medium-, and long-term actions to improve stormwater quality and reduce sediment discharge off site.

In addition, a water quality monitoring program that was stipulated in its EPA licence required Hanson to engage independent consultants to conduct continuous water quality monitoring at the site. This data is reported to the EPA on a quarterly and annual basis, and the results inform the effectiveness of existing and implemented management measures.

Significant improvements have been made through the actions implemented in the EIP, including diversion of conservation park clean flows, site drainage and sediment capture structures, and construction of a sediment basin (SB1) to treat stormwater.

Additional management actions required under the EIP include the construction of a new sediment basin (SB2A) and the refurbishment of the existing sediment basin (SB2B) to further assist in managing surface water during high rainfall events. In addition, Hanson is in the process of reviewing the site’s water quality monitoring plan, and developing a water quality trigger action and response plan (TARP).

However, discharges from the site have continued to exceed standards at times and further work is required.

A major milestone in the EIP involves implementation of an active treatment basin, where water undergoes an advanced settling process. This innovative technology is expected to make a significant improvement to Hanson’s existing sediment management strategies.

On 20 May 2022, DEM issued a compliance order under the Mining Act 1971 to address surface water management issues at the site and a number of the EPA’s regulatory requirements are incorporated into this Compliance Order.

The EPA will continue to support DEM and ensure EPA’s regulatory requirements are met through DEM’s consolidated compliance strategy (or independently where applicable).