Premium pond protection for new development

A large-scale Rocla water quality solution, capable of managing 24,000L of water per second, is providing industry-leading protection against urban generated stormwater pollutants for Australand’s Fairwater Residential 800-lot, stage one development in Blacktown, Western Sydney.

With the development set around 9.5 hectares of parks and waterways to provide attractive open areas for families, the central pond is a key aesthetic feature of the development.

The brief to engineering consultant Craig & Rhodes by the developer was to provide the highest level of pollutant capture, so that litter and sediment were captured from upstream urban catchments before stormwater entered the pond.

Henry Ha, Water Quality Specification Engineer for Rocla said the Rocla Product Application Design (PAD) team worked closely with Craig and Rhodes to overcome a number of technical challenges. “The system had to be able to treat and bypass stormwater flows from a wider catchment outside of the development, being some 78 hectares, supplied by twin 1500mm diameter pipes. At peak flow, the twin 1500mm diameter inlet pipes will supply 24,000L per second through the gross pollutant trap (GPT) unit. At this rate, you’d fill an average backyard swimming pool every two seconds,” he said.

A cast in situ diversion chamber the size of a large living room was installed to handle peak flows from the catchment along with a Rocla CDS® GPT and a Rocla Downstream Defender® 3000 separation unit.

“The CDS®  provides an industry leading, engineered solution to capture gross pollutants, such as litter, leaves, and sediments. It is efficient and robust, due to its ability to self clean its capture screens,” said Henry. “The Downstream Defender® was installed in addition to the CDS® unit, to provide further polishing of the stormwater, to filter out free oils and sediment.”

The two Rocla units combined will ensure that the pond stays clean, playing its all-important role in the ongoing desirability of this important new urban space.

Frank Carrozza, Urban Development Project Manager from Craig
& Rhodes says his consultancy tends to work with Rocla in Blacktown because the council trusts the performance and quality of Rocla product. “Rocla’s service and assistance to meet both our requirements and council requirements was really good,” he said. “They ran a number of scenarios and offered solutions to get it to work.”

Frank says the Rocla team helped minimise delays by working closely with Craig & Rhodes during the drafting phase to expedite the design development, and by providing access to a number of people throughout the process.

Rocla’s PAD team of Darren Cook, Peter Warnock, Stephen D Baker and Chris Bordignon specialises in assisting customers and consultants to ensure Rocla products are used to best effect within the requirements or constraints of a project and, more importantly, that nothing is left to chance.

In some cases, such as the system for Fairwater Residential, this means making modifications to the product to produce the desired result. “In this case, the complex detailing of the treatment train configuration (multiple treatment units) and associated levels had to fit within a tight hydraulic profile, in order to avoid upstream flooding during peak events,” said Stephen D Baker, Manager Water Quality for Rocla. “PAD produced a full set of detailed drawings to ensure no information was overlooked.”