Technical Description:
- 20 Filterra Bioscape Vaults
Robertson Ranch is a master plan community located just three miles from the beach in Carlsbad California. The 400-acre development offers “luxury coastal living” and contains single-family homes between 1,500 and 5,000 square feet.
The development uses a unique stormwater management solution that incorporates Filterra Bioscape Vaults and pocket lawn spaces for enhanced visual curb appeal and passive recreation opportunities.
Water from roofs, driveways, and streets routes into curb inlets that contain flow controls. The low flow “first flush” is routed to the Filterra systems and the high flows and discharge from the Filterra systems are connected downstream and discharge into underground detention storage. Stormwater is then discharged into the municipal storm sewer system and, ultimately, the ocean.
In addition to other Low Impact Development (LID) features required by the San Diego Regional Water Quality Control Board and City of Carlsbad MS4 permit, O’Day Consultants designed the site with nearly 30 biofiltration basins for the purposes of treatment control, reducing TSS, nutrients, and metals. Contech worked with O’Day and Toll Brothers to change many of the biofiltration basins to Filterra systems, as they greatly reduced basin size, allowing for increased recreational green space that allowed homes located near the new green spaces to sell at a premium. In addition, the use of Filterra allowed for a reduction in the use of retaining walls around the above-ground basins resulting in significant cost savings.
Contech stormwater engineers coordinated extensively between O’Day, Toll Brothers, and the City of Carlsbad to get Filterra approved for the project and to size the Filterra Bioscape systems to make them fit into the existing layout of the site. Contech engineers designed twenty Bioscape vaults that ranged in size from 6’x12’ to 8’x16’.
Given the size of the site and how the construction was phased, the installation of the Filterra systems took place over the course of a year. Contech provided installation support and guidance, including having representatives on-site during installation.
Contech’s solution to use compact Filterra Bioscape vaults allowed additional valuable green spaces, removed many costly retaining walls, and increased the sell prices of the surrounding lots. The Filterra systems were incorporated into the green spaces, and with their open-tops and lush vegetation, providing an aesthetically pleasing feature. The owner was extremely very pleased with the support they received from Contech as well as the value the use of Filterra added to the project. The project is a great case study on how compact proprietary biofilters like Filterra can be utilized as LID solutions to help meet the challenging stormwater permit requirements.
Technical Description:
- 20 Filterra Bioscape Vaults