Avilla Centerra Crossing is a gated, multi-family community located in Goodyear, AZ. The 16.67-acre site consists of modern, stylish new homes that feature open floor plans, 10-foot ceilings, and high-end finishes. The community is also planned to include a resort-style pool and spa, covered seating, barbeque areas, and grassy open spaces, as well as a dog park.
Engineers at Terrascape Consulting planned to capture stormwater runoff and discharge it into a dry well. The runoff is stored in a underground detention system made from 1,000 LF of 120" diameter Aluminized Steel Type 2 before being released into the drywell. However, the City of Goodyear recently began requiring pretreatment for retained water prior to being discharged into drywells. Hydrodynamic separation (HDS) was the technology of choice for this application. HDS is a new technology to some engineers and contractors in the area, so design and installation support were very important to ensuring the proper products were chosen, specified appropriately, and installed correctly in order to meet the City of Goodyear’s intention of pretreatment.
After review, the Contech CDS system was selected. CDS is a swirl concentrator hybrid technology that uses continuous deflective separation – a combination of swirl concentration and indirect screening to screen, separate and trap debris, sediment, and hydrocarbons from stormwater runoff. The indirect screening capability of the system allows for 100% removal of floatables and neutrally buoyant material debris 2.4mm or larger, without binding. CDS retains all captured pollutants, even at high flow rates, and provides easy access for maintenance. The CDS is able to internally bypass flows from larger storm events and still achieve 100% capture of trash and debris as well as a high level of TSS removal.
Three CDS units were installed on the site. Contech Field Representative Jay Fair was on site during installation to assist White and White Contracting with the installation. The units were all 96” in diameter. The precaster delivered the units and the contractor had a crane pick the pieces to set them. The Contech Field Representative installed the internal components for the units, which is standard procedure for units of this size. The total installation time for each unit was about four hours.
“We were really impressed with Contech’s attention to detail regarding the scheduling and delivery of the CDS units on the Avilla Centerra project,” said Tyler White from White and White Contracting. “Jay Fair was an excellent resource both during the delivery and more importantly during the installation of the units.”