Cave Creek, Arizona, a picturesque suburb of Phoenix, is the location of Palomino Estates, the newest development of single-family homes built by Pulte Homes.
In the Phoenix metro area, stormwater is detained underground and infiltrated through dry wells. A settling chamber is required for each dry well to capture sediment before it enters the downstream structures.
Contech worked with engineers from Cardno Inc. to design two underground detention systems using 120" diameter corrugated metal pipe (CMP). Using large-diameter CMP maximized the system's storage capacity and reduced the system footprint, which minimized excavation costs. The first system consists of two 100' long barrels that provide 15,944 CF of storage. The second system consists of four 156' long barrels that provide 49,716 CF of storage.
The runoff from these two detention systems is discharged into nine dry wells. The City of Phoenix recently approved the CDS hydrodynamic separator as an alternative to sediment chambers that are typically used to pretreat dry wells. Rather than having a separate settling chamber for each dry well, a CDS system was placed downstream of each detention system. Runoff is treated within the CDS systems before being conveyed to the dry wells. This allowed for the replacement of 9 settling chambers with 2 CDS units, providing significant cost savings. Also, the CDS offers a higher level of treatment than settling chambers, removing high levels of sediment, trash, and debris.
Since this was the first time a CDS was installed in this area, a Contech Field Representative was onsite to assist Swengel – Robbins with the installation. The installation went smoothly, taking less than one hour.