Storage Basin Harvests Runoff for Non-Potable Reuse

Located at the base of the Santa Monica Pier, the Deauville basin will be used to harvest up to 1.6 million gal of storm water runoff from the pier’s downtown drainage basin. The harvested runoff then will be diverted to the Santa Monica Urban Runoff Recycling Facility for treatment and distributed for non-potable uses. Overflows from the tank will be discharged into the sanitary sewer system.

The project was scoped in May 2017 and originally designed as a modular precast StormCapture system. After evaluation of the project’s design and specification requirements, Oldcastle proposed the use of a precast panel vault system in lieu of a conventional modular StormCapture system as an engineered solution.

The challenge was to design a system 262 ft long by 78 ft wide by 12 ft tall (inside depth) to be built on sandy soil with a water table at grade and support 15 ft of compacted backfilled soil on a surface parking lot covering the entire basin. The system needed to be watertight when filled with 1.6 million gal of storm water runoff and pass a mandatory 24-hour leak test.

To fully comply with leak test requirements, the basin was designed to withstand hydrostatic loads and hydrodynamic loads during the test, without any external support or backfill. Oldcastle recognized the need for pursuing an alternative solution that was both practical and economical.

This successful design-build project was the result of an early and ongoing collaborative effort between the engineer of record, general contractor, Oldcastle’s sales and engineering group in Southern California, and Oldcastle engineers in Auburn, Wash. Relying on the Auburn team’s experience with design and manufacturing panel vault systems was invaluable in developing the solution.

Overall, the project consisted of 191 precast wall panels and roof slabs. Production at the Oldcastle plant in Fontana, Calif., began Jan. 30, 2018, and was completed March 26, 2018. Onsite installation of the system started March 13, 2018, with the last roof panel installed April 3, 2018. In addition to the precast basin supplied by Oldcastle’s Southern California branch, the general contractor also chose to use a proprietary OneLift pump station supplied by Oldcastle’s Chandler, Ariz., branch.