The Hesperia Commerce Center is a 200-acre development with 3.4 million square feet of warehouse and distribution buildings along with 15 acres of smaller service commercial industrial buildings.
Stormwater retention with pretreatment was needed to meet local regulations and site budget and space constraints. Westland Group, the project civil engineer, has done many projects with Contech and have come to rely on Contech as a first-choice partner to help with their design process, along with providing materials and site construction support.
An above ground pond would have used too much valuable land space, so engineers at the Westland Group collaborated with Contech to design two underground detention systems using corrugated Metal Pipe (CMP).
The first system was constructed from 4,426 LF of 144” perforated Aluminized Steel Type 2 providing 293,940 cf of storage. The second system was constructed from 618 LF of 162” perforated Aluminized Steel Type 2 providing 88,768 cf of storage. The combined storage for the two systems is 383,708 cf. Using large diameter pipe allowed the engineers to use the maximum amount of available depth and minimize the size of the system. In addition, the pipe was made in 40’ sections to reduce the number of deliveries needed and minimize freight costs.
Three CDS hydrodynamic separators were placed at various locations to provide pretreatment to the detention system. The CDS hydrodynamic separator uses swirl concentration and continuous deflective separation to screen, separate and trap trash, debris, sediment, and hydrocarbons from stormwater runoff. Pretreatment will prolong the life of the retention system by removing debris and sediment that can collect on the invert and within the stone backfill voids. In addition, the CDS systems are easier to clean and maintain compared to the infiltration system itself.