The Hydrodynamic Separator is like a trusted Ford pickup, reliable and easy to maintain. Like a dependable Ford, the Hydrodynamic Separator (HDS) might seem a bit dull next to the shiny new low impact development (LID) practices, but in reality, this equipment is essential to a well-rounded LID plan.

LID practices have dramatically expanded. They focus on landscape-based and water retention designs that reduce runoff volume and mimic predevelopment hydrology to meet goals of runoff reduction and water quality treatment close to the runoff source. Plus regulations often reward developers for infiltration and/or rainwater harvesting. Regulatory agencies also recognize the added value of HDS for upstream protection of sensitive LID practices. Too often HDS has been relegated to traditional, end-of-pipe solutions. Not so fast! Hydrodynamic separators play an important role in developing a treatment train that is essential to the long-term success of LID practices, including infiltration, harvesting, bioretention and storage.

At first a combined approach using HDS can seem counterintuitive to LID, it’s actually a comprehensive, long-term solution that can address problems before they start. Over time, this treatment train approach can reduce the long-term harmful buildup of particles, dirt and trash within LID facilities. For example, one Chattanooga, Tennessee customer embraced this idea and used an HDS to pretreat runoff for an underground rainwater harvesting structure used for surface infiltration landscaping irrigation, toilet flushing, and even a decorative fountain on top of both structures.

As you can see from this example, the best of both a traditional and progressive approach can improve aesthetics, reduce maintenance time and costs for the facility, increase the entire system lifecycle, all the while enhancing property equity to maximize land use from that of a conventional stormwater management approach. 

The first Aqua-Swirl in Bahrain was installed in the parking lot of the now iconic Four Seasons Hotel.  Bahrain Bay is the Kingdom of Bahrain’s first master planned mixed-use waterfront community, situated off the northeast coast of the capital Manama. The $2.5 billion development has a masterplan designed to create a fusion of residential, commercial, retail, tourism, and community facilities and public amenities.

The engineering wonder is built on a reclaimed island in the center of Bahrain Bay.

The project included two Aqua-Swirl AS-6s to return clean water to the bay and reduce flooding. Though rainfall is scarce, large amounts of rain tend to fall at once, creating runoff and often flooding. Having a solution that allows for high water flows was essential. The Aqua-Swirl treats flows up to 178L/s.

“Service is extremely important for this client, so ensuring that runoff doesn’t collect on the car lots was a high priority. No one wants cars flooded at this high-rise,” said Sellam Hmadouch, Aqua-Shield’s Middle-East representative.  

Check out the awesome photos of this engineering feat below. 

Check out this article about flood management in Mount Vernon that was recently published in Storm Water Solutions.

Located along the banks of the Skagit River 60 miles north of Seattle is the City of Mount Vernon, Wash. This community, which is known for its annual Tulip Festival street fair, has been plagued by immense flooding. The devastating effects of this flooding have limited the city’s ability to promote its unique tourist opportunities.

In order to alleviate the flooding issue, the city developed a multi-year plan that included the purchase of a mobile floodwall that could be installed during events. This was utilized as a stopgap measure while designers worked on developing a more permanent fix. The long-term solution decided upon was the $27.3 million Private-Public Partnership Waterfront Revitalization Plan, which was broken down into multiple phases.

Read the whole case study in Storm Water Management.