As an alternative to installing a bioretention or large underground filter system for the expansion of the SurgiCentre in Toowoomba, consulting engineers Kehoe Myers have specified Rocla’s unique enviss™ Sentinel Pit, the only ‘at source’ engineered solution to filtering carpark water runoff available in Australia.
“With the enviss™ Sentinel Pit treating water at the surface (at source) it means you’re essentially treating lower flows than you would downstream with an underground ‘end of line’ system. This makes the enviss™ Sentinel Pit a far more economical solution,” said Nathan Swaffer, Sales Engineer for Rocla.
Nathan says the enviss™ Sentinel Pits are also easier to maintain. “You lift the grate, replace the media bags inside and drop the grate back down. There is no special cleaning equipment or confined space certificate required, which means cleaning can easily be carried out by existing maintenance staff, at a huge cost saving to the asset owner.”
“The biggest thing for this site was the tightness due to the existing levels on the site,” said Mark Borgelt from Kehoe Myers. “We had limited stormwater drainage around the site roadways so therefore all the stormwater had to be discharged either to surface or the existing kerb and channel. This meant the depth of any system that we put in was critical. From the investigation of all the different facilities available, the Rocla enviss™ Sentinel Pit was the one that allowed us the minimum depth from intake at surface level to the outlet invert.”
After calculating the required treatment surface area, a total of five units were placed in the back carpark and a further eight in the front of the site. Steve Wilkes, Hydraulic and Civil Manager from Hutchinson Builders, who were tasked with installation, is a fan. “The enviss™ Sentinel Pits are much easier to install than detention systems because they were interlocking and came packaged. All we had to do was work the height out, get the falls and then install. It’s an easy step-by-step process. For us being a large company with numerous jobs on the go at any one time, we didn’t have to rely on deliveries of sand, certification etc. This is a completely certified product that you simply buy and install.”